When people shop for a home, they tend to focus on the information listings put front and centre: price, floor area, number of bedrooms and location. Rarely do listings show how a home can shape a household’s carbon footprint through energy use and commuting.That is a significant blind spot. A home purchase can influence how much energy a household uses, how far its members travel and how much they spend on utilities and maintenance.Yet buyers often make one of the biggest financial decisions of their lives without a clear picture of a home’s carbon footprint or heating, cooling and maintenance costs.Buildings account for about 18 per cent of Canada’s emissions, including electricity-related emissions, making them the third-largest emitting sector after the oil and gas and transportation sectors.To examine the extent to which sustainability factors into homebuying decisions, we studied real housing choices in Ottawa and compared the carbon footprints of the homes people selected with those of lower-emission alternatives.Testing real housing choicesWe asked 317 Ottawa residents to take part in an online home-choice experiment in fall 2024. Participants were divided into three income groups and shown 10 real Ottawa-area listings within a price range suited to their income.We did not tell participants the study was about sustainability. Instead, we simply asked which home they would be most likely to buy.The listings resembled those on a real estate website, with photographs, price, location, approximate size, bedrooms, bathrooms and the age of the home. They did not provide an energy rating, estimated carbon footprint or comparable information about energy performance.Each income group was shown one home with lower-emission features, such as a cold-climate heat pump, better attic insulation or energy-efficient windows. These homes were not labelled or promoted as “green.”After participants made their choices, we estimated the annual energy use and greenhouse gas emissions of every home.We also included commuting. A low-energy home may not be the lowest-carbon choice if living there requires long daily drives. We estimated commuting emissions using participants’ workplace locations, commuting frequency, transportation choices and vehicle types.Chosen homes emitted more carbonThe results were striking. Across the full sample, the homes participants selected had median annual carbon emissions of 6.93 tonnes, including home energy use and commuting. By comparison, the lowest-emission options available to participants had median annual emissions of only 1.6 tonnes.In other words, the homes people chose produced more than four times as much carbon as the lowest-emission choices made available to them.The greener options were generally not chosen more often than chance would predict. After making their selections, 54 per cent of participants said energy efficiency had not influenced their decision at all. When asked what attracted them to their chosen home, participants most often mentioned neighbourhood, price and space. Some also pointed to recurring expenses shown in the listings, such as property taxes and condo fees.This doesn’t mean buyers don’t care about climate change. People cannot compare information they never receive in the first place. Many are also trying to find an affordable home that suits their family. Better labelling could helpThe information and incentives surrounding home-buying decisions need to improve. A standardized label on residential listings would be a useful starting point for helping buyers compare the environmental impact and long-term costs of different homes. It could show expected annual energy use, greenhouse gas emissions and energy costs, alongside information about the age and condition of major building systems.Such labels could be equally valuable in rental listings, helping renters on tight monthly budgets compare expected utility costs. For landlords, the transparency could create an incentive to improve less energy-efficient properties.Much of the information needed to produce these labels already exists. Large datasets, such as the property assessment rolls used for municipal taxation, contain details about building size, age, type and location. This data could support models that estimate energy use, emissions and long-term costs.Other jurisdictions already require energy-performance information. Across the European Union, owners must provide an energy-performance certificate when a home is sold or rented, and energy-performance information must appear in property advertisements. Canada is improving access to consistent home labels through the National Approach to Home Labelling initiative. Building on these efforts, any wider Canadian system should be tested with buyers, renters and realtors to ensure the information is clearly understood and used.Property taxes also play a roleProperty taxation can also send signals about where people live. Ontario’s property assessments are still based on Jan. 1, 2016 values because the province postponed its 2020 reassessment update. Housing prices have changed substantially since then, and not equally across neighbourhoods.Consider central Ottawa and Kanata, a large suburban community in the city’s west end. In 2017, the two areas had roughly similar property taxes for every $100,000 of market value. By 2026, the rates were about $842 in central Ottawa and $692 in Kanata. For two homes each selling for $750,000, that gap could amount to a tax difference of about $1,126 a year.This doesn’t mean property taxes cause higher emissions, but it illustrates how tax and housing systems can create different financial incentives for different locations. Lower-density communities often require more roads, pipes and other municipal infrastructure per household and can make car dependence more likely.Resuming regular property reassessments would help bring assessments back into line with current market conditions and could reduce some of these unintended distortions.People will always care about price, space and location. We should work with that reality by giving buyers clear information about energy, emissions and long-term costs, and avoid policies that make higher-carbon choices more attractive.Brodie Hobson, a research engineer at CanmetENERGY, Natural Resources Canada, co-authored this article.The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.