Customer responses to environmentally certified hotels: the moderating effect of environmental consciousness on the formation of behavioral intentions

ABSTRACT Environmental certifications are considered an extremely useful tool to promote sustainable tourism; however, little is known about customer perceptions of these schemes and how these certifications might relate to customer behavior when there are customer segments with different levels of environmental consciousness. This study develops a model that investigates the relationship between green practices, green image, environmental consciousness and the behavioral intentions of customers in a certified hotel context. The study examines the direct and moderating role of environmental consciousness in the formation of behavioral intentions based on green initiatives. To test the proposed model empirically, 502 personal surveys of hotel customers were conducted in Spain using a structured questionnaire. The findings show that customer perceptions of green practices have a directly positive effect on a hotel's green image. At the same time, this green image has directly positive effects on customer behavioral intentions toward certified hotels. The authors also found that the higher the environmental consciousness of consumers, the greater their intention to stay, to spread positive word-of-mouth and pay a premium for environmentally certified hotels. Finally, consumer environmental consciousness also exerts a moderating effect on the causal relationship between green image and behavioral intentions.


Introduction
Environmental sustainability is fundamental for tourism competitiveness, especially from a long-term perspective (Hu & Wall, 2005). Growing environmental awareness has made customers change their attitudes and increasingly demand that industries provide products and services that are environmentally friendly and ethically correct. The tourism industry in general, and the hospitality sector in particular, are no exception. Actually, the hospitality industry faces increasing pressure to operate in a more eco-friendly manner given its negative effect on the natural environment. This pressure comes not only from externally imposed government regulations, but also from stakeholder demands, which are becoming an important stimulator. The industry's impact on the natural environment includes habitat destruction, water and energy over-consumption and soil, water and air contamination (Bohdanowicz, 2005). For these reasons, a number of stakeholders, including consumers, non-governmental organizations and activist groups, have called for the hospitality industry to actively engage in addressing environmental issues.
Hospitality managers need to admit their environmental responsibility and find effective ways to respond to these demands since perceived deficiencies in environmental management can be damaging to corporate image and profitability (Holden, 2000). Since environmental responsibility is considered to be one of the most important aspects of a tourism company's responsible behavior, hospitality companies cannot afford the financial and reputational risk associated with the lack of environmental commitment (Mensah & Blackson, 2014). In order to promote environmental management and engage environmentally conscious consumers, more and more hotels are implementing environmental certification programs. Environmental certifications act as a means to promote the voluntary implementation of sustainability practices in hotels while distinguishing real eco-friendly companies from "green-washed" products and services (Karlsson & Dolnicar, 2016). The benefits of environmental certifications for the tourism and hospitality industry can be numerous, from eliminating environmentally harmful practices, attracting eco-friendly customers to certified hotels and providing hotel guests with accurate information about environmental performance, to increasing cost savings and developing a better knowledge of job and production systems (Geerts, 2014).
Environmental certifications have been the subject of many studies. Claims about the positive effect of certifications on financial performance, differentiation advantage achievement in green niche markets, and the improvement of green image and reputation are well documented (Heikkurinen, 2010). Other academics have also explored the motivations for putting these programs into practice (Gonz alez-Benito & Gonz alez-Benito, 2005) or even the cost of implementation (Darnall & Edwards, 2006). For instance, one reason to implement these certifications is to improve relationships with the local community and have wider public relations benefits (Rowe & Higham, 2007). Studies have also explored manager and operator perceptions of these systems (Bonilla-Priego, Najera, & Font, 2011;Chan, 2013;Geerts, 2014).
Despite all this research, there is insufficient evidence about customer perceptions regarding these schemes and how these certifications might relate to customer behavior when there are consumer segments with different levels of environmental consciousness. For example, although many studies report an increased understanding of environmental issues, which has been confirmed by an increase in consumer engagement in pro-environmental purchasing decisions (Chan, 2013;Di Pietro, Cao, & Partlow, 2013;Han, Hsu, Lee, & Sheu, 2011;Kang, Stein, Heo, & Lee, 2012;Millar, Mayer, & Baloglu, 2012), others maintain that the demand for environmentally certified hotels is limited, and emphasize that little progress has been made in modifying consumer behavior (Baker, Davis, & Weaver, 2014;Levi & Park, 2011;Line & Hanks, 2016). Such inconsistencies indicate only a partial understanding of the factors affecting green consumer behavior and emphasize the need for further research in this area. The authors suggest that these mixed findings may be partially ascribable to the mediating and moderating factors that significantly affect customer decision-making processes regarding green products and services.
Following the conceptual framework provided by Gao, Mattila, and Lee (2016), the authors of this study suggest a comprehensive model including two broad categories leading to pro-environmental behavior: internalized perceptions (e.g. environmental consciousness) and the external perceptions of the firm (e.g. perceptions of green practices and green image). As such, the present paper attempts to explore the conditions under which customer perceptions about green practices lead to favorable behavioral intentions toward certified hotels by considering the mediating effect of green image and the direct and moderating effects of environmental consciousness. Existing studies in environmental psychology and consumer behavior have shown that green image and environmental consciousness are fundamental concepts in explaining green consumer behavior (Huang, Lin, Lai, & Lin, 2014;Jeong, Jang, Day, & Ha, 2014;Kim, 2015;Lee, Hsu, Han, & Kim, 2010;Mart ınez, 2015;Namkung & Jang, 2013); however, previous research has had an inclination to investigate these variables separately. It is, therefore, clear that hospitality theory and practice must include these essential factors as central constructs in order to explain the behavioral intentions of customers regarding green accommodation products and services to promote sustainable tourism and develop effective green marketing strategies in a hotel context. The next section provides an overview of the effect of green practices, green image, environmental consciousness and customer behavioral intentions. The authors will then describe the methodology, including measures of variables, data collection procedures and sample characteristics. The results are then presented, followed by a discussion of theoretical and managerial implications. Finally, research limitations and future lines of research are outlined.

Conceptual framework
Green practices and green image in certified hotels Companies show their environmental responsibility by making a green commitment in order to voluntarily adopt ecological initiatives (Castro, Amores-Salvado, & Navas-L opez, 2016). One of the main expressions of this green commitment is environmental certification programs. Within the context of accommodation, the implementation of environmental certifications by hotel companies is considered an essential prerequisite to attract and retain an increasing market segment of pro-environmental customers who have a preference for, and are willing to purchase, sustainable and green accommodation products (Chen & Tung, 2010). Compared to a non-certified hotel, an environmentally certified hotel makes efforts in the areas of reducing, reusing and recycling (the three Rs), and in the key aspects of efficiency and energy (the two Es) (Gilg, Barr, & Ford, 2005).
Environmental certifications are considered to improve environmental performance by helping firms to focus on environmental management and also enhance internal supervision of environmental performance (Darnall & Sides, 2008). A number of certified hotels are devoting efforts to identifying and putting into practice the best initiatives to show their commitment to environmental preservation (Bruns-Smith, Choy, Chong, & Verma, 2015), such as installing solar panels, using polyester layers to coat windows, updating the heating systems in swimming pools, replacing electricity with gas as a source of energy for the laundry and catering services, replacing current appliances with water-efficient ones, installing graywater recycling systems that reuse wash water, or composting organic waste to produce fertilizers (Chan et al., 2008).
Environmental certifications also benefit consumers by providing a guarantee of quality and reliability (Esparon, Gyuris, & Stoeckl, 2014). When adopting an official third-party environmental certification, hotel companies obtain access to the knowledge of the certification institution that provides them with personalized information about the implementation of environmental practices. Hoteliers reduce claims of "green-washing" in this way. Companies attempting to "green-wash" their corporate image selectively disclose favorable information about their environmental performance while neglecting to make negative facts public (Lyon & Maxwell, 2011). Certification bodies establish predefined rules and goals and assess whether the audited hotels comply with them (Font, 2002). Thirdparty environmental certifications, therefore, give credibility to claims about corporate environmental performance and sustainable practices adopted by hotel companies.
Before explaining the notion of companies' green image and its connection with environmental initiatives in a certified hotel context, it is necessary to briefly explain the concept of overall image. To date, a precise definition of this concept has been elusive, and scholars have defined it in several ways. For instance, Bloemer and Ruyter (1998) conceptualized it as consumers' total perceptions of the salient attributes of a firm. These authors consider overall image to be an evaluative concept about the functions of attributes of a specific object (e.g. product/service, company, etc.). Assael (1984) provides one of the most concrete definitions of overall image, presenting it as a consumer's total perceptions of a product (or a firm) shaped by processing information from diverse sources. Previous research argues that customers can benefit from the overall image of companies as it provides them with functional, experiential and symbolic benefits (Park, Jaworski, & MacInnis, 1986). According to these authors, functional and experiential benefits correspond to product-related attributes while symbolic benefits are related to underlying psychological needs of customers, such as personal expression, and correspond to attributes that are not related to the product or service. The early works on image theory suggest that an individual's behavior is based on a psychological or distorted representation of objective reality that exists in an individual's mind (Martineau, 1958). Therefore, consumers' behaviors are more likely to be determined by an image than by objective reality. In service markets, such as the hospitality industry, overall image is expected to play an important role, especially as it is difficult to differentiate products or services based on tangible quality features (Han, Hsu, & Lee, 2009).
By focusing our analysis on the environmental or green image of companies, this concept has become increasingly relevant since the 1980s, when consumers become aware of environmental issues (e.g. increased drought, habitat destruction, rising sea levels, etc.) and their consequences for the planet. Accordingly, tourism companies are developing new corporate approaches, such as green marketing strategies, to satisfy environmental requirements for customers (Polonsky, 1994). The concept of green marketing comprises "all activities designed to generate and facilitate any exchanges intended to satisfy human needs or wants, such that the satisfaction of these needs and wants occur, with minimal detrimental impact on the natural environment" (Polonsky, 1994, p. 2). Accordingly, the green marketing literature examines environmental concerns within the discipline of marketing. Prior literature suggests that companies should undertake green marketing strategies to find out customers' green needs, to launch green products, to divide the market into different segments, to formulate green positioning strategies and to implement a green marketing mix program (Chen & Chang, 2013). Similarly, green image is more important for companies in the current environment of rising of environmental consciousness and international regulations of environmental protection, such as those operating in the tourism industry (Bohdanowicz, 2006).
Consistent with previous research, the term of green (overall) image is defined in this study as a set of perceptions of a firm in a consumer's mind that is connected to environmental commitment and concerns (Mart ınez, 2015). A company's green image thus involves the environmental or greenrelated attributes of the firm that its stakeholders come to perceive (Castro et al., 2016). Specifically, a hotel's green image can be described as consumers' mental perceptions of a particular hotel company that are linked to environmental concerns and can be expressed as a function of the most important green attributes of a particular hotel company (Jeong, Jang, Day, & Ha, 2014). Similarly, customers' perceptions of the green image of a hotel can be measured by the function of green practices that are important for the evaluation of the greenness of the hotel.
A good green image acts as a clear signal of a firm's environmental commitment toward its key stakeholders and represents an effective means to improve not only environmental differentiation but also profitability (Heikkurinen, 2010). Hospitality companies promote their green image to show their actual commitment toward sustainable issues, demonstrating to stakeholders their achievements in natural environmental protection (Wong, Lai, Shang, & Lu, 2013).
Research indicates that not only green practices but also environmental certifications can be components with which to develop the green image of a company (Boiral, 2011;Heikkurinen, 2010;Jeong et al., 2014;Namkung & Jang, 2013;Ritchie & Crouch, 2003;Wong et al., 2013). These studies propose that the green practices of environmentally certified hotels offer various opportunities, such as improved stakeholder relationships and better corporate image and reputation. In this regard, environmental initiatives make a company's products and services unique, enhancing the firm's green image and thus increasing demand among environmentally conscious consumers. For instance, Ritchie and Crouch (2003) demonstrate how a positive green image can be created through the adoption and implementation of environmental systems. These authors suggest that the creation and development of this image is a relevant factor in the formulation of successful marketing strategies and in company competitiveness. Similarly, Boiral (2011) reports that the adoption of environmental certification helps firms with their environmentally friendly image-building efforts. It, therefore, seems obvious that these ideas should be extrapolated, and to think that green attributes in the hotel industry (e.g. recycling, energy and water conservation, environmental friendly packaging, etc.) can affect a customer's green image of a particular certified hotel. It is thus reasonable to propose the following hypothesis: H 1 : Customer perceptions of green practices positively affect the green image of environmentally certified hotels.

Green image and customer behavioral intentions
Many scholars and practitioners in the tourism industry have shown great interest in the concept of a company's image due to its effects on customer behavioral decisions (Durna, Dedeoglu, & Balikcioglu, 2015;Han et al., 2009;Jeong et al., 2014;Lee et al., 2010;Lin, Morais, & Kerstetter, 2007;Mart ınez, 2015;Ryu, Lee, & Kim, 2012). Building positive intentions in customers is an important goal for hospitality businesses, since these intentions will ultimately increase customer retention rates and profits (Han et al., 2009). Consumer behavioral intentions represent the likelihood of consumer engagement in a specific behavior (Azjen & Fishbein, 1980). According to Fishbein and Ajzen (1975), behavioral intentions are the closest antecedents of actual behavior when examining individual decision-making processes. This implies that scholars are able to predict specific behaviors with considerable accuracy from intentions to engage in the behavior under consideration. Behavioral intentions have been studied by examining three key dimensions: willingness to repurchase products or services from a company, to pay a premium price for these products and to recommend the company or to make positive comments about the company's services (Gao et al., 2016;Zeithaml, Berry, & Parasuraman, 1996). Consistent with these previous studies, in this study in the green hospitality context, such intentions reflect consumer intentions to stay, spread word-of-mouth or be willing to pay a premium price to stay at an environmentally certified hotel.
Previous studies support the effect of the green image of companies on customer behavior. In the hospitality setting, Lee et al. (2010) support the relationship between a green cognitive and affective image and customer behavioral intentions (in terms of intention to revisit, intention to offer positive recommendations and willingness to pay a premium). Liu, Wong, Shi, Chu, and Brock (2014) found that perceived green image can enhance perceived brand quality and brand preference. In the same vein, Mart ınez (2015) shows that green image has a positive direct effect on customer trust, satisfaction and loyalty. Kim (2015) demonstrated that environmental programs recognized (perceived) by restaurant consumers generate favorable attitudes and intention to purchase from these companies. This study, therefore, proposes the following research hypotheses:

The effect of environmental consciousness on the relationship between green image and customer behavioral intentions
The concept of environmental consciousness involves specific psychological factors related to an individual's propensity to engage in pro-environmental behaviors (Zelezny & Schultz, 2000). Environmental concern is an evaluation of, or an attitude toward, facts, one's own behavior or other's behavior with consequences for the environment (Schlegelmilch, Bohlen, & Diamantopoulos, 1996). In the context of this study, environmental consciousness refers to the degree to which hotel guests are concerned about environmental problems and are willing to make an effort to solve them (e.g. stay in an environmentally certified hotel) (Dunlap & Jones, 2002).
The means-end theory (Gutman, 1982) and the Schwartz's values theory (Schwartz, 1977) provide a theoretical foundation on which to explore the direct effect of environmental consciousness on consumer behavior and the effect of this variable on the relationship between a hotel's green image and customer behavioral intentions toward environmentally certified hotels. According to the means-end theory, in a green context, customers choose to stay in a hotel that supports environmental initiatives (i.e. means) to achieve their desired values (i.e. the end) (Huber, Herrmann, & Morgan, 2001). In this sense, customer values such as feelings of self-esteem are essential for explaining proenvironmental behaviors (Karp, 1996). Past research has suggested that values play a role in specific situations when they are activated by a set of altruistic concerns (e.g. environmental degradation, global warming, resources depletion, etc.). Allen and Ferrand (1999) hypothesized that in order to act pro-environmentally, individuals must focus beyond themselves and be concerned about the community at large. They suggested that this state of "actively caring" can only occur if the need for selfesteem (together with the need for belonging, personal control, self-efficacy and optimism) has been satisfied. In addition, Schwartz (1977) argued that altruistic behavior would occur when individuals hold personal norms with regard to a specific behavior (e.g. pro-environmental behavior). This author further argued that these norms are the results of both the awareness of the consequences of engaging (or not engaging) in the behavior and the ascription of personal responsibility for carrying out the altruistic behavior. In recent years, due to serious environmental problems, more consumers have developed environmental consciousness. As staying in an environmentally certified hotel may be considered as a way of showing deeper pro-environmental values, the more consumers perceive themselves as environmentally conscious the more positive their behavioral intentions will be toward certified hotels.
Previous studies in the hospitality context support the direct effect of environmental consciousness on consumer behavioral intentions. For instance,  found that guests with higher degrees of environmental concerns develop a greater willingness to pay more to stay in green hotels. On the other hand, Huang et al. (2014) suggest that customers with a high degree of environmental consciousness use products and services that are environmentally beneficial or protect the environment to a greater extent. Based on this discussion, this study proposes the following hypotheses: H 3 : Customer environmental consciousness positively affects their behavioral intentions: H 3a : Customer environmental consciousness positively affects their intentions to stay at environmentally certified hotels. H 3b : Customer environmental consciousness positively affects their intentions to spread positive word-of-mouth about environmentally certified hotels. H 3c : Customer environmental consciousness positively affects their willingness to pay a premium price for staying at environmentally certified hotels.
Research also supports the moderating effect of environmental consciousness on the perception of a hotel's green image and consumer behavior. Green practices allow certified hotels to differentiate themselves from competitors (Manaktola & Jauhari, 2007). In addition, as previously mentioned, image is expressed as a function of the salient attributes of a particular firm that are evaluated and compared to one another (Bloemer & Ruyter, 1998) and customer environmental concerns are associated with their personal values (Schwartz, 1977). Therefore, customers who are more concerned about ecological problems may be more likely to consider environmental issues (e.g. environmental certifications) when they make a lodging decision than those who do not perceive themselves as environmentally conscious. As staying at an environmentally certified hotel could be considered as reflecting deep environment-related self-perceptions, the more consumers perceive themselves as environmentally conscious, the more green attributes will influence customers' (perceived) green image of a particular hotel. In turn, consumers will be more likely to develop positive behavioral intentions (e.g. visit intention, intention to spread word-of-mouth and willingness to pay) toward environmentally certified hotels in order to satisfy their personal values and thereby increasing their levels of self-esteem. In this sense, the authors believe that it is not enough for hotel guests to perceive a company as green or environmentally friendly (e.g. green image), as this may not sufficiently motivate them to develop a favorable behavioral response toward the company. In this study, the authors therefore propose and test not only the direct effect of customer environmental consciousness on their behavior but also its moderating effect, so that if customers are more sensitive to environmental problems (e.g. higher levels of environmental consciousness) the effect of a green image will be stronger on consumer behavioral intentions.
Prior studies confirm the relevant role of environmental consciousness as a moderator in the relationship between a company's green image and consumer behavior. In their study of restaurants, Namkung and Jang (2013) indicated that consumer self-perception of environmental consciousness moderated their evaluation of green practices, a firm's green brand image and customer willingness to revisit the restaurant. These authors propose that consumers have different degrees of environmental consciousness so that their green behavior will be different. They also confirm that consumers with stronger environmental consciousness have higher opinions of a restaurant's green image and show more positive future behavioral intentions given the stronger effect of green image on consumer intentions to revisit. Thus, this study proposes the following hypotheses: H 4 : For those customers with a high degree of environmental consciousness the relationship between the perception of a hotel's green image and their behavioral intentions will be stronger than for those customers with a low degree of environmental consciousness.
H 4a : For those customers with a high degree of environmental consciousness, the relationship between the perception of a hotel's green image and their intentions to visit an environmentally certified hotel will be stronger than for those customers with a low degree of environmental consciousness. H 4b : For those customers with a high degree of environmental consciousness, the relationship between the perception of a hotel's green image and their intentions to spread positive word-of-mouth about an environmentally certified hotel will be stronger than for those customers with a low degree of environmental consciousness. H 4c : For those customers with a high degree of environmental consciousness, the relationship among the perception of a hotel's green image and their willingness to pay more to stay at an environmentally certified hotel will be stronger than for those customers with a low degree of environmental consciousness.

Measures
Since environmental certifications are highly product-specific, they are able to provide certifications for different types of tourism businesses (e.g. accommodation, restoration, transportation, etc.). As such, to fulfill our research objectives a questionnaire was developed and aimed at guests staying at Spanish hotels. The authors decided to study hotel guests to guarantee that the individuals who were interviewed had sufficient knowledge of hospitality services and were used to making decisions about hotel booking, so they could take into consideration the fact that a hotel is environmentally certified. For each item, respondents were asked to rate their level of agreement (or disagreement) using a seven-point Likert scale. Participants were given general information about environmental certifications and their goals in order to ensure that respondents were able to manifest their judgments about these schemes. The survey solicited information regarding demographics and traveling characteristics of respondents, including gender, age, level of education, occupation, purpose of travel and previous experience with a certified hotel.
We adopted the measurement scales from previous studies for all the constructs of our model. These items are presented in Appendix.

Data collection and sample profile
A sample of hotel customers in Spain was surveyed using a structured questionnaire to validate the research hypotheses. Given that Spain has a substantial population of certified hotels, this country can serve as an interesting context in which to test our research model. Personal surveys were carried out in respondents' homes to ensure their comfort and to make sure that they took time to answer the questions calmly and thoughtfully. The length of each interview averaged 10-15 minutes to avoid fatigue in the respondents. University students collaborated in collecting and gathering data. A convenience sample was used (non-probabilistic sampling procedure). With the aim of ensuring greater representativeness of the data, the authors employed multistage sampling, using quotas based on guests' gender and age to replicate the profile of the Spanish population. Table 1 displays the profile of respondents.
Following an orthodox approach in quantitative research, the authors conducted a thorough inspection of the database, checking for missing values and outliers. The invalid questionnaires were eliminated so that they did not affect the results in further analyses; however, this fact did not significantly affect the distribution of the sample with regard to the quotas established in the sampling procedure. After eliminating invalid questionnaires, we obtained 502 surveys.
To explore the issue of non-response bias, the authors tested for differences between early and late respondents (Armstrong & Overton, 1977). Early responses were defined as the first 75% of returned questionnaires. The last 25% were considered late respondents and representative of individuals who did not respond to the survey. Early and late respondents were compared for gender, age, education and occupation using a t-test and no significant differences were found, suggesting that non-response bias was not an issue. Bias anonymity and confidentiality were verbally emphasized in order to control for social desirability (Chung & Monroe, 2003). The authors emphasized anonymity and confidentiality, and that there were no right or wrong answers, so as to further decrease social desirability bias. Finally, this study collected data through a single instrument, common method variance (CMV) may exist, which may result in invalid conclusions being made about the relationships between the proposed variables. Harman's one-factor approach was used to overcome this limitation (Podsakoff, MacKenzie, Lee, & Podsakoff, 2003). An exploratory factor analysis (fixed on one-factor extraction without any rotations) was conducted for the 25 items that were manifested in six factors, in order to determine the total variance of the single extracted factor and estimate whether the total variance of the single factor was below the cut-off value of 50%. Our results revealed that the single general factor accounted for 43.48% of the total variance explained for the 25 items, suggesting no indication of CMV.

Results
In order to test the research hypotheses proposed, the authors followed a partial least squaresstructural equation modelling (PLS-SEM) approach which is especially suited for the estimation of moderating effects. This study followed a two-step approach in order to analyze and interpret PLS results (Chin, 2010): (1) assessment of the outer (measurement) model and (2) testing the inner (structural) model. Moderating effects were tested following the "product indicator approach" (Chin, Marcolin, & Newsted, 2003), which is provided by default in SmartPLS and is applicable when the moderator and the independent constructs are reflective, as is the case in our study.

Evaluation of the measurement model
The results obtained in the estimation of the measurement model confirm the appropriate psychometric properties of the measurement scales (e.g. reliability and validity). The reliability of measurement scales is confirmed (Table 2), as the Cronbach's alpha and compound reliability coefficients (Bagozzi & Yi, 1988) are, in every case, clearly above the required minimum values of 0.7 (Hair, Anderson, Tatham, & Black, 2010). The convergent validity of the measurement instruments is supported  (Table 2) as the values of the AVE coefficient are, in all cases, greater than 0.50 at the construct level and all item loadings are above or very close to 0.7 and are significant at the 0.01 level. Only in the case of item ENC1 (for environmental consciousness) did the item loading take a value of 0.64, but following the recommendations by Hair, Ringle, and Sarstedt (2013), we decided to keep the item in the scale as the reliability of the instrument is over the recommended limits. Third, this study follows three approaches to measure the discriminant validity of the measurement scales (Tables 3 and 4). The cross loadings of an item's outer loading on the associated construct are greater than all of its loadings on other constructs (e.g. cross loadings). All the factors fulfill the criterion proposed by Fornell and Larcker (1981), as the square root of each AVE coefficient is greater than the correlations between the constructs. Finally, in all cases, the heterotrait-monotrait (HT-MT) values are below the threshold of 0.85 of 0.90 (Table 4) (Henseler, Ringle, & Sarstedt, 2015). These results confirm the discriminant validity of the measurement scales used in the empirical research.

Evaluation of the structural model
This research follows the three-step approach proposed by Ald as (2016) to analyze the structural model: (1) coefficient of determination (R 2 value) for the latent variables, (2) predictive relevance Q 2 (blindfolding), and (3) significance of the structural model path coefficients and effect size (bootstrapping).
This study uses a resampling bootstrap method with 5000, along with each bootstrap sample containing the same number of observations as the original sample (e.g. 502 bootstrap cases), to generate standard errors and t-values (Chin, 1998;Hair et al., 2013). The study assesses estimated path relationships between the latent variables in the model through the sign and magnitude of path coefficients. The results of the estimation of the structural model are summarized in Figure 1.
R 2 statistics take values above 0.40 in all cases, which shows that the theoretical model proposed provides a moderate explanation of the variance of the dependent variables, according to the reference levels proposed by Chin (1998). Additionally, using the blindfolding procedure, all Q 2 values are considerably above zero, thus supporting the predicting relevance of the model regarding the dependent variables. Finally, the significance of the structural model path coefficients and effect size was tested using the bootstrapping procedure (two-tailed test). Table 5 summarizes the results obtained for the direct and moderating effects, including the path coefficients, effect size (f 2 ), t-values and level of significance. The empirical evidence obtained in this study, therefore, supports all the research hypotheses proposed in our theoretical model, except the direct effect of green image on intention to spread positive word-of-mouth about environmentally certified hotels (Hypothesis H 2b ). In addition, the Cohen's f 2 for the significant paths in the inner model were all above 0.02, with the only exception being the moderating effect of environmental consciousness on the relationship between green image and intention to pay. These results suggest satisfactory effects for the endogenous latent constructs (Henseler, Ringle, & Sinkovics, 2009).
The empirical evidence obtained in this study confirms the direct and positive effect of consumer perceptions of a hotel's green practices on their green image (hypothesis H 1 ). Our results also support the hypothesis that perceived green image of hotels positively affects consumer intention to stay at environmentally certified hotels (Hypothesis H 2a ) and to pay a premium price for it (Hypothesis H 2c ); however, no significant effect of green image on intention to spread positive word-of-mouth about environmentally certified hotels was found (Hypothesis H 2b ). According to this evidence, having a positive green image is a clear incentive for consumers to choose a hotel and pay a higher price, but it does not necessarily lead to positive word-of-mouth. These results also show that perceptions about a hotel's green practices have an indirect and positive effect on consumer intentions to stay at environmentally certified hotels and to pay a premium price (through its effect on green image). Moreover, the non-significance of the influence of green image on intention to spread positive wordof-mouth about environmentally certified hotels seems to imply that perceived green image  determines consumers' purchase decisions in terms of intention to stay and to pay more for environmentally certified hotels, but it is not a sufficient motivation to communicate the value of environmentally certified hotels to other consumers. In other words, green image seems to speak to consumers' responsibility with regard to their own decisions, but it is not considered a relevant attribute to spread word-of-mouth that may influence other individuals. This study also supports the strong effect of consumer environmental consciousness on behavioral intentions with regard to environmentally certified hotels. The higher the environmental consciousness of consumers, the higher their intention to stay at environmentally certified hotels (Hypothesis H 3a ), to spread positive word-of-mouth about them (Hypothesis H 3b ) and to pay a premium price for them (Hypothesis H 3c ). Finally, consumer environmental consciousness also exerts a moderating effect on the causal relationship of green image on behavioral intentions. In particular, the higher the environmental consciousness, the stronger the effect of the green image on consumer intentions to stay at environmentally certified hotels (Hypothesis H 4a ), to spread positive word-of-mouth (Hypothesis H 4b ) and to pay a premium price (Hypothesis H 4c ).

Theoretical implications
This research contributes to our understanding of the disconnect between environmental perceptions and behavioral intentions when it comes to the consumption of green hotel services, by examining the alignment of customer perceptions and the perceived behavior of environmentally certified hotels across several levels of customer environmental consciousness.
This research makes theoretical contributions to the sustainable tourism literature in general and the hospitality literature in particular, through the convergence of different research streams, specifically environmental psychology and consumer behavior. This study integrates internalized perceptions and perceptions of the firm (Gao et al., 2016) into a model to explain pro-environmental responses toward certified hotels that follow a holistic approach. By considering the degree of a customer's environmental consciousness and their perceptions of green initiatives alongside the idea that a hotel's green image is an important construct for understanding green consumer behavior, this study suggests a research framework for examining customer behavioral intentions toward environmentally certified hotels. The results presented here agree with past studies that have used both categorizations to explore consumer responses toward environmentally friendly products and services (Han et al., 2009;Jeong et al., 2014). Nevertheless, this study expands the previous research, and other studies such as those by Baker et al. (2014), Chen and Tung (2010), Di Pietro et al. (2013) or  by including different constructs, such as mediating and moderating factors.
This study presents additional theoretical contributions to the academic literature. No prior research has investigated the relationship among green practices, customer degree of environmental consciousness and their behavioral intentions in relation to a company's green image in the hotel sector. In this sense, previous studies in the hospitality literature have had an inclination to explore separate relationships between environmental consciousness, green image and green consumer behavior (Han et al., 2009;Huang et al., 2014;Jeong et al., 2014;Lee et al., 2010;Namkung & Jang, 2013). Our research distinguishes itself from previous empirical studies in considering the interactive effect of green image and environmental consciousness in promoting customer behavioral intentions in light of environmental psychology and consumer behavior issues.
This study demonstrates that customer perceptions of green practices positively affect the green images of companies, which also positively affects customer behavioral intentions in terms of staying and paying a premium for staying at an environmentally certified hotel. The effect of green image on consumer willingness to spread positive word-of-mouth is not confirmed. By implementing green practices, environmentally certified hotels can motivate customers to shape a mental image of a particular hotel's level of commitment toward environmental issues and the way in which the company presents itself with respect to its socially responsible activities, which is consistent with previous research (Durna et al., 2015). In this sense, this study demonstrates that customer perceptions of green practices act as a major driver when choosing a certified hotel. It is proved that green practices are a meaningful element, as are other key hotel service factors, such as quality service, infrastructure or the professionalism of employees in influencing customer accommodation decisions (as previous studies have demonstrated, such as the research by Alexander (2002), Briggs, Sutherland, and Drummond (2007) or Bruns-Smith et al. (2015), among others), which means that customers recognize the direct benefits of an environmentally certified hotel's attributes.
The third theoretical contribution is the extension of environmental psychology literature through the introduction of customer environmental consciousness in our model, in order to explore its role as a direct and moderating mechanism on the effect of green image on customer behavioral intentions. This study provides empirical evidence that customer environmental consciousness is a direct predictor of behavioral intentions with regard to environmentally certified hotels, suggesting that becoming environmentally concerned results in the adoption of automatic environmental purchase preferences. In this sense, this study proves that the higher environmental consciousness of consumers, the higher their intention is to stay at environmentally certified hotels, to spread positive wordof-mouth about them and to pay a premium price for them. Therefore, this research proves that when consumers have different degrees of environmental consciousness, their green behavior will also be different, which is consistent with the views of past scholars (Huang et al., 2014;. We have also demonstrated the moderating effect of this variable in the connection between a hotel's green image and customer behavior. The higher the environmental consciousness, the stronger the effect of green image on consumer intention to stay at an environmentally certified hotel, to spread positive word-of-mouth and to pay a premium price. These significant relationships can be explained by the fact that those customers with high levels of environmental consciousness are more likely to have adequate information about a hotel's green initiatives and environmental certifications, which in turn has a significant impact on certified hotels (Chen & Peng, 2012). These results, therefore, provide a valuable reminder of the importance of integrating environmental consciousness into models explaining the green consumption of hotel services.

Managerial implications
These findings have important managerial implications for tourism and hospitality companies. First at all, this study demonstrates that green image is a powerful tool with which to develop favorable customer responses in a certified hotel context. Hospitality managers should design strategies to raise perception of green-related features of environmentally certified companies and develop effective strategies to promote their green image. In this sense, environmental certification programs can become part of a hotel's green image, together with traditional factors such as service quality, price, infrastructure or location. For instance, hoteliers could obtain ecological certifications. Several international organizations offer third-party environmental certifications, such as the U.S. Green Building Council, which offers an initiative called Leadership in Energy and Environmental Design (LEED), which certifies resource-efficient constructions. Other initiatives such as the ISO 14001 or the ECO-Management and Audit Scheme help hotel companies to evaluate, manage and improve their environmental performance. By building a green image based on these aspects, environmentally certified hotel companies can enjoy the competitive advantage provided by the set of expectations around offering a certain level of environmental value (Kang & Hur, 2012). Hotels' green image that is based on environmental certifications (certified by independent and renowned agencies) will build strong relationships with environmentally conscious consumers and create differential competitive advantages, thereby introducing a new type of competitive standardenvironmental certificationsassuming that hotels consistently provide this environmental value.
Second, and given the relevance of customer perceptions of environmental certifications, managers should also emphasize the relevance of these schemes by communicating to consumers the benefits of implementing these certifications and the achievements obtained after their implementation, highlighting their impact on society. For instance, Meli a Hotels International has 141 certifications in sustainable tourism with different seals (e.g. Earthcheck, Biosphere, Travelife, LEED, ISO, Green Leaders, etc.). After obtaining these certifications, they have achieved some remarkable environmental improvements in recent years, including the reduction of the company's carbon footprint (¡3.81%) along with its water (¡7.66%) and energy consumption (¡9.40%). In this way, Meli a has minimized its environmental impact by 9.5%. This case can show consumers how environmental initiatives can generate a real impact on society and that these practices are not just marketing ploys, thereby demonstrating that environmentally certified hotels contribute meaningfully to sustainable tourism practices.
Hoteliers may promote these aspects by using multiple information sources such as advertising, public relations campaigns, sponsorships and social networks, since customer perceptions of green image may be influenced by corporate communications (Mart ınez, 2015). Nevertheless, these communicative techniques need to convince consumers to believe that environmentally certified hotels make a difference in protecting the environment (Lee et al., 2010) in order to avoid making consumers become skeptical. Through effective communication strategies promoting the achievement of official third-party environmental certifications, hoteliers can show how they make a genuine commitment to the environment and reduce ambiguity. Consequently, hotel guests would not underperceive the green overall image of certified hotels and therefore would develop positive behavioral intentions.
To conclude, hospitality companies should promote environmental consciousness since less environmentally conscious customers are often uninformed about the negative impacts that nonenvironmentally certified hotel companies have on the environment (Chen & Peng, 2012). In this sense, companies may use green marketing strategies (Polonsky, 1994) and develop specific programs to inform and educate these guests. For instance, hotel firms may organize conferences, seminars, visits to places of interest for their environmental biodiversity or contests and competitions to encourage guests to become involved in the environmental programs of companies. Similarly, hospitality managers may help customers to understand how they can minimize negative impacts, for instance, by providing information about ecological topics in public areas of hotels (e.g. rooms, information desks, etc.) or using several communication channels. To enhance their green image and develop positive customer behavioral intentions, environmentally certified hotels should actively make positioning efforts in the less environmentally conscious market. In order to encourage less conscious customers to stay more frequently at environmentally certified hotels, it is crucial to emphasize the importance of individuals' environmental decisions by providing feedback indicating that they have made a positive difference by choosing an environmentally certified company. It is also important for professionals to inform this group of consumers that environmentally certified hotels exert a positive influence on the environment. These efforts would motivate their everyday habits, which would eventually enhance their environmental purchasing decision-making.

Limitations and future lines of research
Finally, there are several limitations to this study. The empirical results were obtained from the hotel industry and therefore cannot be broadly applied to other contexts. It would be interesting to explore other accommodation (e.g. hostels, apartment rental services, etc.) and tourism industries (e.g. transportation, leisure activities, etc.) to generalize the findings presented here. In addition, this study makes use of behavioral intentions as a means of exploring to what extent the perception of green practices and hotels' green image affect consumer behavior. This fact should also be considered as a limitation since behavioral intentions have been widely used as an attitudinal loyalty indicator but they do not correspond to behavioral loyalty. Thus, future studies should focus on actual behavioral measures to thoroughly analyze the influence of green practices in a certified hotel context. This study may also not fully represent the experience across different hotel segments such as the luxury market segment. Future studies could also include internal (e.g. customer motives, values, attitudes, emotions or sense of responsibility) and external (e.g. institutional, economic, social or cultural aspects) factors to increase the explanatory power of the proposed model.

Disclosure statement
No potential conflict of interest was reported by the authors.

Notes on contributors
Dr. Patricia Mart ınez Garc ıa de Leaniz is a researcher staff at the University of Cantabria (Spain). Her current research interests include corporate social responsibility, consumer behavior and corporate marketing in the tourism sector. Her works have been published in journals of international impact such as International Journal of Contemporary Hospitality Management, Journal of Business Ethics, Service Business, International Journal of Hospitality Management, Journal of Travel and Tourism Marketing, and Journal of Hospitality Marketing & Management. She has held research stays at several international research centers such as the Center for Business Ethics (Bentley University, USA) and the Center for Advanced Tourism Studies (Hokkaido University, Japan).

Dr.
Angel Herrero Crespo is an associate professor at the University of Cantabria. His main lines of work are consumer behavior, the application of new technologies to marketing and brand management in organizations and territories. He is currently director of the Altamira University School of Tourism, head researcher in the Marketing Intelligence R & D Group, and director of chair on Place Branding at the University of Cantabria. In addition, he is a member of the Board of Directors in the Spanish Association of Academic and Professional Marketing (AEMARK). His research activity has led to the publication of 30 scientific articles published in international and national journals of recognized prestige and 9 book chapters. He has directed four doctoral theses and is currently directing three others. Finally, he has participated in more than 30 research projects with public and private funding.
Dr. Raquel G omez L opez is a lecturer in Business Management at the University of Cantabria (Spain). Her current research interests include quality management, excellence models, responsible management, family firms, innovation and tourism. Raquel's works have been published in journals of international impact such as Cornell Hospitality Quarterly, Total Quality Management & Business Excellence, and Journal of Small Business and Enterprise Development, among others. She is also author of several chapters in various collective works and one book. She regularly participates in prestigious international and national conferences, such as those organized by FERC, IFERA and ACEDE.