# RECORD 2bbd25e60ca8ea2625da98d69a5096e00200229f # TITLE: Does energy efficiency matter for prices of tenant-owned apartments? # YEAR: 2022.0 VENUE: Environmental science and pollution research international DOI: 10.1007/s11356-022-20482-w # AUTHORS: David Stenvall; P. Cerin; Bo Sjö; Gazi Salah Uddin # PAGES: 15 CANDIDATE TABLE PAGES (1-based): [8, 9, 10, 11, 12] # ABSTRACT: In this study, we use Energy Performance Certificate (EPC) information to investigate the effect of energy efficiency on the selling price of Swedish tenant-owned apartments. While there is a large body of literature on how energy efficiency affects the sales price of single-family houses, none has exclusively focused on tenant-owned apartments. For owners of tenant-owned apartments in Sweden, heating is for a large share included in the monthly fee paid to the tenant association, which usually does not change on a short-term basis. This raises the question whether homebuyers’ incentives for acquiring energy-efficient tenant-owned apartments are large enough to be capitalized into the prices. By hedonic models and matching methods, we found mixed results. In our most optimistic scenarios, tenant-owned apartments enclosed in energy-efficient buildings are sold with a premium of approximately 0.8 to 1.2% compared to apartments in non-efficient buildings. The results in this study are not robust to all model specifications and vary across regions. In comparison with recent studies using data for single-family houses in Sweden, our detected capitalization is smaller. Our results highlight a need for targeted measures if EPCs are to be fully capitalized in prices for all dwelling types in which buyers have different economic incentives for reducing their energy consumption. ===== PAGE 1 (score 9, numeric-paren 0, table-words 0, var-words 9) ===== Vol.:(0123456789) 1 3 https://doi.org/10.1007/s11356-022-20482-w RESEARCH ARTICLE Does energy efficiency matter for prices of tenant‑owned apartments? David Stenvall1 · Pontus Cerin1 · Bo Sjö1 · Gazi Salah Uddin1 Received: 15 July 2021 / Accepted: 23 April 2022 © The Author(s) 2022 Abstract In this study, we use Energy Performance Certificate (EPC) information to investigate the effect of energy efficiency on the selling price of Swedish tenant-owned apartments. While there is a large body of literature on how energy efficiency affects the sales price of single-family houses, none has exclusively focused on tenant-owned apartments. For owners of tenant-owned apartments in Sweden, heating is for a large share included in the monthly fee paid to the tenant association, which usually does not change on a short-term basis. This raises the question whether homebuyers’ incentives for acquiring energy-efficient tenant-owned apartments are large enough to be capitalized into the prices. By hedonic models and matching methods, we found mixed results. In our most optimistic scenarios, tenant-owned apartments enclosed in energy-efficient buildings are sold with a premium of approximately 0.8 to 1.2% compared to apartments in non-efficient buildings. The results in this study are not robust to all model specifications and vary across regions. In comparison with recent studies using data for single-family houses in Sweden, our detected capitalization is smaller. Our results highlight a need for targeted measures if EPCs are to be fully capitalized in prices for all dwelling types in which buyers have different economic incen- tives for reducing their energy consumption. Keywords  Energy performance certificates · Housing markets · Tenant-owned apartments · Energy efficiency · Green premium JEL Classification  D10 · Q51 · R20 Introduction Reducing the speed of climate change has in the recent dec- ade become as a top priority for numerous governments, scientists, and institutions. The EU has set up ambitious GHG emission targets in a vision for 2050, which could pose one important step-stone for the world to reach below the Paris 2-degree target and, as the union puts it, keep it down to 1.5 °C. This will, consequently, put a lot of pressure on the housing sector to abate its considerable large share of ­CO2 emissions compared to other sectors. In this context, a common European approach to reduce the energy usage by dwellings was introduced through the Energy Performance of Buildings Directive (EPBD 2002/91/EC). The directive includes a certification scheme aimed towards dwellings, namely, the Energy Performance Certificates (EPCs).1 One of the main purposes of the introduction of EPCs was to decrease potential information asymmetries between owners and prospective buyers with regard to the energy performance of dwellings. Hence, these certifications are supposed to make potential buyers aware of the energy per- formance of their future homes or buildings (e.g., Brounen and Kok 2011; Bio Intelligence Service 2013; Cerin et al. 2014; Fuerst et al. 2015; Fuerst et al. 2016a, b; EC 2020). Responsible Editor: Philippe Garrigues * Gazi Salah Uddin gazi.salah.uddin@liu.se David Stenvall david.stenvall@liu.se Pontus Cerin pontus.cerin@liu.se Bo Sjö bo.sjo@liu.se 1 Department of Management and Engineering, Linköping University, Linkoping, Sweden 1  For more information regarding the EPC in EU, see e.g., EC (2020). In the Swedish case, more information can be found on the website of the National Board of Housing, Building and Planning (Boverket 2019). / Published online: 4 May 2022 Environmental Science and Pollution Research (2022) 29:66793–66807 ===== PAGE 8 (score 103, numeric-paren 73, table-words 5, var-words 11) ===== 1 3 the number of rooms according to the VIF values (variance inflation factors). As both are control variables, they are kept in the estimations. The VIF value for our treatment vari- able for energy-efficient tenant-owned apartments, HIGH, is very low and does not suggest any problems with multi- collinearity. Our R2 over 81% is notably high, but common for hedonic price studies on the housing market, especially given that our sample consists of apartments which are more homogeneous compared to houses. As HIGH is insignifi- cant, we do not find any effect of energy efficiency on the sales price of the tenant-owned apartments. In column (2), we instead use the 4-digit postcode to control for more detailed locational effects. Our R2 now increases to 93%, which indicates that a more detailed con- trol for location is important in explaining the sales price. Our treatment, HIGH, is now significant and indicates a price premium of approximately 1.1% for energy-efficient tenant-owned apartments. This can be interpreted as approx- imately 11,000 SEK more for every 1 million in sales price for the energy-efficient homes, ceteris paribus, compared to the reference category (homes enclosed in buildings with higher energy performance than 75 kWh/m2). The size of the premium is smaller compared with the findings of Cerin et al. (2014) and Wilhelmsson (2019) that found larger pre- miums when using data for houses rather than apartments. As emphasized in “Introduction,” a large share of the home- owners of tenant-owned apartments has heating included in the monthly fee paid to the association each month, which usually does not change on a short-term basis. The fee is not based on the usages per apartment but rather the joint costs for the association. That the premium is quite low might simply reflect low economic incentives for many buyers of tenant-owned apartments. In column (3), we include our dummy, LOW, for tenant-owned apartments enclosed in tenant-owned buildings with low energy efficiency (hereafter denoted as low-efficient apartments). By including dummies for apartments with both high and low energy efficiency, the reference category is now apartments in between these two categories (medium energy efficient). The insignificance of LOW indicates that low-efficiency apartments are not sold Table 2   Full sample — hedonic price estimations The dependent variable is the logarithmic sales price. Standard errors in parenthesis. Columns (1), (2), and (3) are estimated with robust stand- ard errors. Postcode fixed effects is based on 4 digits if nothing else is stated. HIGH is a dummy variable for tenant-owned apartments enclosed in tenant-owned buildings with high energy efficiency; LOW is a dummy for tenant-owned apartments enclosed in tenant-owned buildings with low energy efficiency; Area is the size of the dwelling in square meters (log); Room is the number of rooms; Building year (age) is a dummy equal to 1 if the apartment was constructed during the given range of years (omitted category is pre-1901). Rent is the fee paid to the tenant asso- ciation each month in SEK (log). We also include a dummy variable equal to 1 for apartments with double construction years (see the explana- tion in the data section), for which the result is not shown Statistical significance is denoted by ***p < 0.01, **p < 0.05, *p < 0.1 (1) (2) (3) (4) (5) Energy efficiency (EPC)   HIGH 0.001 (0.007) 0.011** (0.005) 0.011** (0.005) 0.007* (0.004) 0.007* (0.004)   LOW  − 0.001 (0.002)  − 0.001 (0.002) Dwelling-specific controls   Area 0.862*** (0.019) 0.746*** (0.012) 0.746*** (0.012) 0.751*** (0.006) 0.751*** (0.006)   Rent  − 0.277*** (0.023)  − 0.144*** (0.014)  − 0.143*** (0.014)  − 0.156*** (0.004)  − 0.156*** (0.004)   Room 0.049*** (0.004) 0.060*** (0.002) 0.060*** (0.002) 0.058*** (0.002) 0.058*** (0.002)   Building year     1901–1921  − 0.041***  − 0.002  − 0.002  − 0.006  − 0.006     1922–1941  − 0.143***  − 0.066***  − 0.066***  − 0.070***  − 0.070***     1942–1961  − 0.280***  − 0.116***  − 0.116***  − 0.120***  − 0.120***     1962–1976  − 0.467***  − 0.165***  − 0.165***  − 0.163***  − 0.163***     1977–1991  − 0.304***  − 0.143***  − 0.144***  − 0.139***  − 0.139***     1992–2005  − 0.218***  − 0.074***  − 0.074***  − 0.063***  − 0.063***     2006–2019  − 0.123***  − 0.001  − 0.002  − 0.004  − 0.004 Constant 13.48*** 13.48*** 13.48*** 13.54*** 13.54*** Time fixed effects Yes Yes Yes Yes Yes Robust regression No No No Yes Yes Postal code fixed effects (2 digits) Yes Yes Yes Yes R2 0.812 0.933 0.933 0.943 0.943 Obs 21,696 21,696 21,696 21,695 21,696 66800 Environmental Science and Pollution Research (2022) 29:66793–66807 ===== PAGE 9 (score 51, numeric-paren 3, table-words 18, var-words 11) ===== 1 3 with a discount compared to medium-efficiency homes all else equal. In columns (4) and (5), we try to mitigate issues related to potential outliers by performing the estimations using the robust regression. The effect of high energy effi- ciency on the sales price is now reduced to a premium of approximately 0.7% that now is weakly significant. The effect of low efficiency on prices is still insignificant. In Table 3, we present the result from regional subsam- ples. The category South consists of the observations from the municipality of Malmö while the Mid category is based on the sales from Gothenburg and Linköping. As only a few observations of the sample from the northern cities Luleå and Umeå do qualify as energy efficient according to our boundaries, we do not run estimation solely based on these observations. As observed, the coefficient for HIGH is larg- est in the southern sample followed by the Stockholm. The effect is, however, not statistically significant for any region. Table 4 shows the hedonic price estimations using the sample of tenant-owned apartments enclosed in a tenant- owned building with an EPC grade. In (1), we classify energy-efficient apartments as those enclosed in a build- ing with the grades A or B and the other labels (C–G) as the reference category. Our results indicate that the effect of energy efficiency is positively related to the sales price but only weakly significant. The estimated premium is approximately 1.5%, all else equal, which is higher com- pared with the effect of energy efficiency in the full sample in Table 2. This 1.5% premium can be compared with the ten-basis point reduction in mortgage rate that buyers can get by certain banks if they acquire a home with an energy grade of A or B. Assuming an annual mortgage rate of 2% on a 4 million SEK loan, a 0.10-percentage point reduction is approximately 4000 SEK less per year. If not considering the time value of money or any other potential cost savings from owning an energy-efficient home, a 1.5% premium is paid off in 15 years based solely on the mortgage rate reduc- tion. Therefore, a 1.5% premium is not unreasonable based on these economic incentives. In Table 4, column (2), we instead define the energy-efficient labels as A–C and com- pare it with the less efficient grades (D–G). Even though the coefficient for the energy efficient grades is positive, the effect is not significant. Hence, our results from (1) and (2) suggest that the price premium is only present in the most energy-efficient labels, A and B. That these two labels also provide the largest interest rate reduction for homebuyers with green loans might perhaps be a part of the explana- tion. In column (3), we add dummies for the least energy efficient labels (E–G). Our result from this estimation shows no significant discount compared with the reference category (label D). In (4) and (5), we run the estimations using robust regression. Our effect found in column (4) indicates a 1% premium for labels A and B. However, this is not enough to reach statistical significance. While the robust regression barely drops any observations, it still weights the observa- tions that are not dropped. Hence, the reduced effect from 1.5% premium in column (1) to 1% in column (4) is likely due to the weighting of potential outliers rather than the actual dropping of observations. Robustness check: neighborhood controls and matching As one of the few Swedish studies, we also control for some neighborhood characteristics in our hedonic price models. In this section, we use the full sample from Table 2. Because the neighborhood data is based on DeSO regions, observa- tions belonging to the same region will get the same neigh- borhood values. In Table 5, columns (1) and (2) we start the investigation by dividing the data into income categories based on the income data. We calculate the income quar- tiles in the sample based on the incomes attached to each observation. Apartments with incomes below quartile 1 is denoted by IC1, apartments with incomes equal to or larger than quartile 1 but smaller than quartile 2 is denoted by IC2, and, lastly, apartments with incomes equal to or larger than quartile 2 but smaller than quartile 3 is denoted by IC3. As observed in Table 5, column (1), the income dum- mies (IC 1–3) are all significant with negative coefficients. This means that there is a significant difference in price, all else equal, between observations within our included income categories and our omitted reference group (high incomes above the third quartile). Our energy efficiency variable, Table 3   Regression with regional subsamples from the full sample The dependent variable is the logarithmic sales price. Standard errors are in parenthesis. Postcode fixed effects are based on 4 digits. Robust standard errors are used in the estimations. The mid region contains dwellings from the municipalities Linköping and Gothenburg, and the southern region consists of apartments from the Malmö municipal- ity. HIGH is a dummy for tenant-owned apartments enclosed in ten- ant-owned buildings with high energy efficiency. Dwelling-specific variables include the following: area (log), number of rooms in each apartment, rent or fee paid to the tenant association each month (log), and dummy for construction year (same as Tables 2 and 3). We also include a dummy variable equal to 1 for apartments with double con- struction years (see the explanation in the data section) Statistical significance is denoted by ***p < 0.01, ** p < 0.05, * p < 0.1 Stockholm South Mid HIGH 0.004 (0.006) 0.015 (0.017) 0.002 (0.008) Dwelling-specific controls Yes Yes Yes Time fixed effects Yes Yes Yes Postal code fixed effects Yes Yes Yes R2 0.913 0.885 0.912 Obs 11 468 4142 5285 66801 Environmental Science and Pollution Research (2022) 29:66793–66807 ===== PAGE 10 (score 100, numeric-paren 68, table-words 7, var-words 9) ===== 1 3 HIGH, indicates a price premium of approximately 0.8%, but it is only of a weakly statistically significant size. How- ever, when using 3-digit postcodes (a wider geographical area) in column (3), controlling for outliers using robust regression in (2) and (5), including a full set of neighbor- hood controls (3)–(5), our energy efficiency variable HIGH is no longer significant. In Table 6, we test if our estimations vary depending on the boundaries for which we classify the apartments as energy efficient. As observed, the coefficient when narrow- ing the boundaries, columns in (1) estimate of HIGH, is larger compared to the results in Table 5, but still not sig- nificant. This might be a sample size problem with relatively few observations reaching energy efficiency status. If instead increasing the boundaries in (2), we observe a non-signifi- cant premium for energy-efficient tenant-owned apartments of approximately 0.5%. In (3), we include an interaction between our energy efficiency measure and the net income in the DeSO in which each observation belongs to. By this, we want to analyze if the effect of energy efficiency on prices is different if the energy-efficient apartments are sold in a low- versus high-income area. As a comparison, an energy- efficient apartment in a neighborhood with a net income of 250,000 SEK (which is slightly below median in the sample) will according to our estimates be sold with a premium of 1.77% compared to a non-efficient apartment. However, in a neighborhood with a net income of 320,000 SEK (above median), an energy-efficient apartment is sold with a dis- count of − 0.2%. The interaction between net income and HIGH is significant even if we run the estimation with our standard boundary of 75 kWh/sqm. One possible explana- tion is that there might be a larger share of apartments in which heating is not included in the monthly fee in low- versus high-income areas. In such case, the economic incen- tives might be lower for high-income individuals. It could also be that high-income individuals simply do afford to not Table 4   Grade sample — hedonic price estimations The dependent variable is the logarithmic tenant-owned apartment sales price. Standard errors in parenthesis. Columns (1), (2), and (3) are estimated with robust standard errors. Postcode fixed effects is based on 4 digits if nothing else is stated. Area is the of the size of the dwelling in sqm (log); Room is the number of rooms; Building year (age) is a dummy equal 1 if the apartment was constructed during the given range of years (omitted category is pre 1901). Rent is the fee paid to the tenant association each month in SEK (log); Energy grades are dummy variables equal to 1 if the tenant-owned apartment belongs to a tenant-owned building with the specified EPC-grade/grades. In columns (3) and (5), the energy grade D is the omitted category, while grades C–G is omitted in columns (1) and (4) and D–G in (2). We also include a dummy variable equal to 1 for apartments with double construction years (see explanation in the data section), for which the result is not shown. Columns (1), (2), and (3) are ordinary hedonic price estimations while (4) and (5) are hedonic price model estimated by robust regressions We denote statistical significance by ***p < 0.01, **p < 0.05, *p < 0.1 (1) (2) (3) (4) (5) Energy grade (EPC)   AB 0.015* (0.009) 0.010 (0.008)   ABC 0.001 (0.005) 0.002 (0.006)  − 0.001 (0.006)   EFG 0.002 (0.005)  − 0.002 (0.005) Dwelling-specific controls   Area 0.749*** (0.023) 0.750*** (0.023) 0.750*** (0.023) 0.750*** (0.012) 0.750*** (0.012)   Rent  − 0.164*** (0.025)  − 0.165*** (0.025)  − 0.165*** (0.025)  − 0.170*** (0.009)  − 0.170*** (0.009)   Room 0.065*** (0.004) 0.065*** (0.004) 0.065*** (0.004) 0.059*** (0.003) 0.059*** (0.003)   Building year     1901–1921 0.000 0.000 0.000 0.000  − 0.001     1922–1941  − 0.059***  − 0.059***  − 0.060***  − 0.068***  − 0.068***     1942–1961  − 0.129***  − 0.129***  − 0.129***  − 0.136***  − 0.136***     1962–1976  − 0.172***  − 0.172***  − 0.172***  − 0.165***  − 0.165***     1977–1991  − 0.166***  − 0.166***  − 0.166***  − 0.158***  − 0.158***     1992–2005  − 0.091***  − 0.091***  − 0.091***  − 0.079***  − 0.079***     2006–2019 0.016 0.019 0.019 0.013 0.014 Constant 13.80*** 13.80*** 13.80*** 13.97*** 13.97*** Time fixed effects Yes Yes Yes Yes Yes Robust regression No No No Yes Yes Postal code fixed effects Yes Yes Yes Yes Yes R2 0.936 0.936 0.936 0.945 0.945 Obs 6555 6555 6555 6555 6553 66802 Environmental Science and Pollution Research (2022) 29:66793–66807 ===== PAGE 11 (score 49, numeric-paren 18, table-words 9, var-words 10) ===== 1 3 care about energy savings. As we do not have information on heating included for the full sample, we are not able to control for this. As described in the data section, ordinary hedonic price estimations might, however, suffer from methodical prob- lems. Using a propensity score method, we can address the issue of differences between the group with high energy efficiency (treatment) versus the non-energy efficient group (control). In Table 8, we use two different methods of pro- pensity score. First, we estimate the propensity score using a probit model and include the score in the hedonic model as a covariate. The propensity score in the first step is esti- mated using the treatment variables (HIGH and AB) as the dependent variable and the dwelling- and location-specific Table 5   Full sample — hedonic prices with neighborhood controls The dependent variable is the logarithmic tenant-owned apartment sales price. Standard errors in paren- thesis. HIGH is a dummy variable for tenant-owned apartments enclosed in tenant-owned buildings with high energy efficiency. IC1 is a dummy for observations that belong to a postcode with low incomes. IC2 is a dummy for low to median income postcodes while IC3 is a dummy for median to upper incomes. Neighborhood controls consists of median net income (log), share of persons with foreign origin, share of persons in rental apartments, and share of persons receiving financial aid and number of households (log). Dwelling-specific variables are area (log), number of rooms in each apartment, rent or fee paid to the tenant-association each month (log), and dummy for construction year (same as Tables 2 and 4). We also include a dummy variable equal to 1 for apartments with double construction years (see explanation in the data section) We denote statistical significance by ***p < 0.01, **p < 0.05, *p < 0.1 (1) (2) (3) (4) (5) HIGH 0.008* (0.005) 0.006 (0.004)  − 0.003(0.005) 0.003 (0.005) 0.000 (0.004) IC1  − 0.113***  − 0.092*** IC2  − 0.053***  − 0.038*** IC3  − 0.022***  − 0.015*** Dwelling-specific controls Yes Yes Yes Yes Yes Time fixed effects Yes Yes Yes Yes Yes Robust regression No Yes No No Yes Postal code fixed effects (4 digits) (4 digits) (3 digits) (4 digits) (4 digits) Neighborhood controls No No Yes Yes Yes R2 0.935 0.944 0.924 0.938 0.946 Obs 21,696 21,691 21,696 21,696 21,696 Table 6   Robustness and alternative boundaries for energy efficiency The dependent variable is the logarithmic tenant-owned apartment sales price. Standard errors are in parenthesis. HIGH is a dummy for tenant-owned apartments enclosed in tenant-owned buildings with high energy efficiency. Dwelling-specific variables consist of the following: area (log), number of rooms in each apartment, rent or fee paid to the tenant-association each month (log), and dummy for construction year (same as Tables 2 and 4). Neighborhood controls include median net income (log), share of persons with foreign origin, share of persons in rental apartments, share of persons receiving financial aid, and number of households (log). We also include a dummy variable equal to 1 for apartments with double construction years (see explanation in the data section) Statistical significance is denoted by ***p < 0.01, **p < 0.05, *p < 0.1 (1) (2) (3) HIGH (≤ 50 kWh/m2) 0.010 (0.012) HIGH (≤ 100 kWh/m2) 0.005 (0.003) 0.468*** (0.098) HIGH (≤ 100 kWh/m2) × net income  − 0.082*** (0.017) Neighborhood controls Yes Yes Yes Dwelling-specific controls Yes Yes Yes Robust regression No No No Time fixed effects Yes Yes Yes Postal code fixed effects (4 digits) (4 digits) (4 digits) R2 0.938 0.938 0.938 Obs 21,696 21,696 21,696 66803 Environmental Science and Pollution Research (2022) 29:66793–66807 ===== PAGE 12 (score 36, numeric-paren 6, table-words 11, var-words 7) ===== 1 3 variables from the hedonic estimations as independent vari- ables. Here, we chose to only include dummies with high energy efficiency and not for low efficiency. In the second method, we match the treatment and control groups based on the estimated propensity score using a nearest neighbor approach. We thereafter run the hedonic regression on this matched sample using weights from the matching process. For a discussion of these methods, see, e.g., Stuart (2010). Table 7 shows the means in the sales price and covari- ates before and after propensity score matching. As sus- pected, we can observe that the treatment group in the unmatched samples largely differs regarding the age of the tenant-owned apartments. The control groups include older apartments that are both smaller and cheaper on average. However, after the matching procedure these dif- ferences have been largely reduced. The balance in the matched samples is tested by t-tests and mean standardized differences, which can be found in appendix Table A3. These tests show that there is no significant difference between the control and treatment groups after match- ing. Table 8 shows the results from the propensity score estimations. Table 7   Mean in covariates before and after propensity score matching This table shows the treatment and control groups before and after propensity score matching. The treat- ment in the full sample is the variable HIGH, which is a dummy for tenant-owned apartments enclosed in tenant-owned buildings with high energy efficiency. The treatment for the graded sample is dummy vari- ables equal to 1 if the tenant-owned apartment belongs to a tenant-owned building with the energy grade A or B. The matched full sample is equivalent to the sample used in estimations of column (2) in Table 8. For the graded matched sample, this is equivalent to the data used in estimations of column (4) in Table 8 Full sample Graded sample Unmatched Matched Unmatched Matched Treatment Control Treatment Control Treatment Control Treatment Control Price 3,742,086 3,338,207 3,761,089 3,754,787 3,605,326 3,129,489 3,697,648 3,624,645 Area 70.9 63.6 71.1 72.5 70.2 65.9 70.1 69.0 Age 26.5 66.6 26.8 28.8 19.27 53.6 20.0 23.0 Rent 3800.4 3495.4 3805.1 3975.4 3841.6 3637.1 3839.4 3814.1 Room 2.7 2.4 2.7 2.8 2.7 2.5 2.7 2.6 Obs 1397 20,299 1377 1377 424 6131 394 394 Table 8   Result after propensity score estimations This table shows the hedonic price model with estimated propensity score as a covariate columns (1) and (3) as well as on propensity score matched samples (columns (2) and (4)). The dependent variable is the logarithmic tenant-owned apartment sales price. Standard errors are in parenthesis. HIGH is a dummy for tenant-owned apartments enclosed in tenant-owned buildings with high energy efficiency. Postcode fixed effects are 4 digits if nothing else is stated. The treatment for the graded sample is dummy variables equal to 1 if the tenant-owned apartment belongs to a tenant-owned building with the energy grade A or B. Dwelling-specific variables include area (log), number of rooms in each apartment, rent or fee paid to the tenant-association each month (log), and dummy for construction year (same as Tables 2 and 3). We also include a dummy variable equal to 1 for apartments with double construction years (see explanation in the data section) Statistical significance is denoted by ***p < 0.01, **p < 0.05, *p < 0.1 Full sample Graded sample (1) (2) (3) (4) HIGH 0.009* (0.005) 0.012** (0.005) AB 0.011 (0.009) 0.014 (0.009) Dwelling-specific controls Yes Yes Yes Yes Time fixed effects Yes Yes Yes Yes Postal code fixed effects Yes Yes Yes Yes Regression on matched sample No Yes No Yes Propensity score as control Yes No Yes No R2 0.927 0.911 0.929 0.939 Obs 16,511 2754 3638 788 66804 Environmental Science and Pollution Research (2022) 29:66793–66807 ===== PAGE 13 (score 42, numeric-paren 2, table-words 16, var-words 7) ===== 1 3 As we can see from columns (1) and (3), including the propensity score as a covariate largely reduces the effect of high energy efficiency on the sales price of tenant-owned apartments. The coefficient is positive and ranges from a 0.9 to 1.1% premium, ceteris paribus, for tenant-owned apart- ments enclosed in energy-efficient tenant-owned buildings compared to non-efficient. While the effect in the full sample is weakly significant, the estimated premium in the graded sample is insignificant. Looking at the matched samples (columns (2) and (4)), the effect is similar with the coef- ficient ranging from 1.2 to 1.4% price premium. As before, the estimations based on the full sample is weakly significant but the effect in the graded sample is insignificant. Regard- ing the insignificance in column (4), it is possible that the lack of significance could be a power issue considering the few observations. The coefficient for the treatment variable (AB) does not change much compared to the hedonic price model estimates in Table 4, column (1). We also observe that the coefficient for energy efficiency in Table 8, column (2), i.e., the non-graded sample, decreases compared to its corresponding hedonic estimates in Table 2. In this sample, we do not have the same issue with power, which indicates that other problems (such as non-randomness or sample selection) potentially may explain the differences between Tables 2 and 8. Lastly, we use an alternative matching method, the coarsened exact matching (CEM) by Iacus et al. (2012). The results of the CEM are dependent on the variables cho- sen for the matching procedure and the cut points through which these variables are coarsened. We chose to match on the most important control variables age, log rent, log area, and the number of rooms in each tenant-owned apartment. While running the CEM in Stata, it provides an algorithm to automatically choose the cut points. However, we chose the cut points by our own to ensure that this is done based on theoretical knowledge.9 We test different specifications before we end up with the final cut points. To quantify how much our cut points reduce the imbalances between the control and treatment observations, we use the multivariate L1 distance. The goal is to produce a model with as low a distance as possible. The distance in our chosen models can be found in Table A4, which are lower compared with the multivariate L1 distance produced by the Stata algorithm. In accordance with the procedure of Blackwell et al. (2009), we add the matched control variables to the hedonic regres- sion to control for the remaining imbalances. We also add the control variables that were not used in the matching. Our results are shown in Table 9. As observed, the results from the CEM are lower com- pared to the estimates produced from the propensity score or hedonic estimation in Tables 2 and 4. The estimated effect for the graded or full sample is not statistically significant. The overall result from the matching procedures gives some conflicting evidence. Although the propensity score approach in Table 7 indicates price premiums of energy effi- ciency close to the hedonic price model in Tables 2 and 4, the premiums indicated by the CEM are much lower. While results from the CEM are sensitive to the chosen cut points, the propensity score estimates are sensitive to which control observations the treatments are matched to. It is therefore very difficult to conclude which of these results are the most credible. In the previous literature, Wilhelmsson (2019) found that the price premium for single-family houses was substantially reduced when controlling for selection bias using propensity score matching. Against this background, we are not able to rule out that the results from the hedonic price models in Tables 2 and 4, at least to some extent, could be affected by sample selection bias. If such bias exists, our results from this section show that the price premium for energy-efficient tenant-owned apartments is lower compared with the results presented in Tables 2 and 4. Table 9   Hedonic estimations after coarsened exact matching (CEM) This table shows the results of hedonic price estimations weighted on the matched dataset after CEM. Standard errors are in parenthesis. The dependent variable is the logarithmic tenant-owned apartment sales price. HIGH is a dummy for tenant-owned apartments enclosed in tenant-owned buildings with high energy efficiency. Postcode fixed effects are based on 4 digits if nothing else is stated. The treatment for the graded sample is dummy variables equal to 1 if the tenant- owned apartment belongs to a tenant-owned building with the energy grade A or B. Dwelling-specific variables include area (log), number of rooms in each apartment, rent or fee paid to the tenant-association each month (log), and dummy for construction year (same as Tables 2 and 3). We also include a dummy variable equal to 1 for apartments with double construction years (see explanation in the data section) Full sample Graded sample HIGH 0.005 (0.005) AB 0.007 (0.009) Dwelling-specific controls Yes Yes Time fixed effects Yes Yes Postal code fixed effects Yes Yes R2 0.931 0.933 Obs 17,702 4373 9  Our cut points are as follows: age (0 14.5 29.5 44.5 59.5 79.5 99.5 120.5), lrent (0 7.7 8 8.3 8.45 8.52 8.7 10), larea (0 3.1 3.45 3.8 4 4.2 4.5 4.75 5 6), and rooms (0 2.25 3.75 5.25 10). For the cut points of the variables with a logarithmic transformation (larea and lrent), these are chosen with respect to corresponding values for the non- logged variables (rent and area). For instance, the range 0–3.1 for larea corresponds to the range 0–22 ­m2 without any logarithmic transformation. 66805 Environmental Science and Pollution Research (2022) 29:66793–66807