US Homes Keep Getting Bigger: What Does This Mean for Our CO2 Emissions?

Key takeaways

  • The top states by total CO2 emissions for the housing sector are Texas, New York, and Florida; California, the largest state in the US, ranks 6th
  • New England states have the largest CO2 emissions per home; Hawaii, DC, and the West Coast states have the lowest emissions
  • If US homes were an average of 1,200 square feet, CO2 emissions would be down 38%

Bigger and bigger homes – can we afford them? We’re not talking about prices, but about our CO2 budget

Climate change, global warming, the point of no return, sea level rising, Arctic ice melting, extinction of a high number of species, food insecurity. These are all difficult topics that make us cringe whenever we hear of them but rather easy to avoid since they all seem distant, larger than us and difficult to influence or change by one individual.

Before the Flood, the 2016 documentary produced by Leonardo DiCaprio has been praised precisely for taking these complex and abstract climate change issues and translating them in a way that they can touch all of us on a personal level. With scientific consensus that climate change is happening and it is primarily man-made through massive greenhouse gas emissions, there’s one crucial, personal, and often inconvenient conversation we need to have together.  And there’s one moment in the Before the Flood documentary that spells it out clearly. It’s about lifestyle and consumption, according to Indian environmental activist Sunita Narain.

And since one of the most impactful lifestyle decisions that we make has to do with the size of the home we live in and  since we’re in the world of real estate, we decided to see how this choice influences our energy consumption and environmental footprint. In this sense, Sunita Narain bluntly tells Leonardo Di Caprio that US consumption will put a hole in our planet, specifically due to increased consumption: “You’re building bigger, you’re building more, and using much more than before.”

The fact that we’re building bigger homes has been confirmed by a recent PropertyShark study of home sizes in the largest US citiesOver the past century, new American homes have become 74% larger on average. Even more, as the average home size increased and the average household size decreased, personal living space went up 211%. This means that the average US individual living in a new home enjoys 957 square feet of personal space and this is only exerting even more pressure on the environment.

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Given that the U.S. ranks 2nd in the world by CO2 emissions and accounts for 18% of the world’s total energy consumption, to which the residential sector contributes massively, it becomes clear that the size of our homes puts tremendous strain on the environment. Read on to find out just how much CO2 homes in different states dump into the atmosphere each year.

We’ve looked at all HVAC energy consumed by source with its corresponding CO2 emissions and correlated this with the average home size in each state with the help of data from the U.S. Energy Information Administration. We’ve also come up with some scenarios to show how things could have been different if we had built smaller and if we can still make changes quickly enough.

The states with highest overall CO2 emissions bring no surprises

When looking at total CO2 emissions that result from home energy consumption, the states that have overall higher emissions are the ones you’d expect, the most populous states, with a corresponding high number of housing units. Of the top states, New York and Florida also stand out by the total amount spent on energy – each shell out over $7 billion per year, far more than the rest of the states that made it into the top 10.

However, there’s one thing that caught our attention when looking at the top 10 states and their energy consumption. California, the most populous state and with the highest number of housing units by far, ranked 6 in CO2 emissions, far from the top 3. Texas emits over 32 million tons of CO2 yearly while New York emits over 28 million.

California, however, is close to 18 million tons of CO2 only and that’s quite low given that the state is the world’s sixth largest economy. This is due in part to the mild climate which helps California homes use less on heating and cooling and thanks to their adoption of renewable energy. There’s an extra factor that comes into play here though: the average home size in California is the second lowest in the US. Only DC homes are smaller than California’s, so even though the Golden State has the largest number of homes, the energy needed for them function is significantly lower. Which brings us again to our starting point for this study, how our home sizes influence energy consumption. And while total CO2 emissions by state can be a revealing stat, to paint a more complete picture, we also calculated the average CO2 emissions per home .

CO2 emissions per home: New England states are the heaviest polluters

When looking at CO2 emissions by home, the story starts to change and the states that occupy the top positions are all from New England with the top 3 states emitting over 5 tons of CO2 per home each year. Besides having some of the highest average sized homes of all US states, exceeding 2,000 square feet, the six New England states also rely heavily on fuel oil for heating. This, combined with cold winters, make Maine, Vermont, and New Hampshire homes the most taxing for the environment. According to the EIA, fuel oil use for heating in Maine is so widespread that the state is one of the most petroleum-dependent states in the nation. Two-thirds of homes in Maine use fuel oil as their main energy source and burning fossil fuels is the primary source of CO2 released in the atmosphere.

States with lowest CO2 emissions per home: Hawaii, DC, and the West Coast

At the other end of the spectrum, the states with lowest emissions per home are characterized by milder climate and smaller average home size which lead to less energy consumption and corresponding CO2 emissions. Besides these factors, these states don’t rely as much on fuel oil as those from New England. The least taxing for the environment are Hawaii homes with CO2 emissions of only 0.57 tons per home each year. California comes next, followed by DC where the average home size is the smallest of all states.

The other West Coast states are also adopters of renewable and alternative energy sources, so Oregon and Washington complete the top 5 least polluting US states. In Oregon, for example, hydroelectric power plants provide 68% of electricity, while Washington was the leading producer of electricity from hydroelectric sources in 2015, according to the EIA.

What if we lived like the Germans? Housing CO2 emissions would be down 45%

Of all states analyzed, DC has the smallest home size at 1,201 square feet and given that the US household now has on average 2.58 people, if the average US home size would be of this size, each person would still enjoy a comfortable 465 square feet of personal space.

In this scenario, the overall CO2 emissions caused by US homes could be down 38% translating into almost 250 million tons less CO2 polluting our planet every year. The US would also save a little over $30 billion each year in energy costs. By state, the reduction in CO2 emissions would vary, with the states that have larger homes dropping their footprint the most, led by Wisconsin which would slash its CO2 emissions in half, as the average home size in the state is 2,466 square feet now. This is more of an estimate of course since we could not account for all other factors that influence energy consumption and efficiency but it still shows that smaller sized homes would have a significant impact on CO2 emissions.

And if you think we’re being too drastic in this scenario, allowing only for an average of 1,200 square feet per home, keep in mind that the average home size in Germany, the world’s 4th economy by GDP, is 1,035 square feet according to Eurostat. If US homes were the size of German homes, CO2 emissions would be reduced by 45% which would mean close to $38 billion saved in energy spending.

In 10 years, CO2 emissions would be down 2% if we started building 1,200 square feet homes now

Since the previous scenario is not actually a valid real-life solution, we’ve also looked at what would happen if going forward new homes in the US did not exceed 1,200 square feet on average. Due to the small proportion new homes would have in the total housing stock, even if over the next 10 years homes would be built at this size, CO2 emissions would only decrease 2%.

While that doesn’t sound like much, it could still have positive impact in the long term, especially if coupled with investing more into energy efficiency and renewable energy sources. Even if the new budget proposes cuts to the EPA and the US has just left the Paris Agreement, there are a number of encouraging signs coming from both the energy sector and the housing industry. For example, renewable energy is getting cheaper, with solar leading the way and LEED-certified apartment construction in the US has quadrupled in the past 5 years according to a recent study by RENTCafé, showing that there are options we can work with in the fight against climate change.


HVAC energy consumption data used in this article comes from the latest reports by the US Energy Information Administration. The stats included the following property types: houses, condos, apartments, and mobile homes. Energy costs and CO2 emissions were calculated separately for each property type. The analysis includes energy used for heating and cooling since these are directly affected by home sizes. Energy consumption and corresponding CO2 emissions were calculated by energy source type: electricity, natural gas, LPG/propane, fuel oil, kerosene, wood. We took into account the energy type used in each state, correlated with average home sizes in order to calculate CO2 emissions.

When calculating the possible reductions in CO2 emissions, we only took into account house size and did not account for other factors that could influence energy consumption.


Andra Rus

Andra Rus

With 10+ years of experience at PropertyShark, Andra covers the latest product updates and market reports for our blog. Her work has been featured in The Real Deal, Curbed, TimeOut, The Daily Mail, Business Insider, Crain’s New York.

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