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News & Insights

This Old House: In Defense of Older Homes as Carbon Savers

Much of the push to solve the carbon emissions problem in the building industry has focused on innovation: new building materials, new construction methods, and new carbon capture technologies. Even tenants and prospective homeowners are under the impression that new is better. 

That’s often true for other products — a new car is probably more fuel efficient than an old lemon — but it’s not always the case in real estate. Living in an older house actually can be more environmentally friendly than moving into a new build. In fact, with the right retrofits, remodeling an old building is almost always greener than building a new one.

Background: What goes into a building’s carbon footprint? 

Schools, hospitals, and homes all have different carbon emissions that are influenced by a few key factors. Measuring a structure’s carbon footprint starts with base emissions: the embodied and operational carbon of a building. 

Embodied carbon is carbon emitted during the construction, renovation, and demolition of a building. Operational carbon is emitted from operating the building’s electricity, heating and cooling, water, and so forth. 

Embodied and operational carbon are most influenced by the building materials (wood, concrete, and stone, for instance), the location of the home, the size—and the age. 

Out with the old? Not so fast.

When it comes to shrinking the carbon footprints of our homes, there’s good news and there’s bad news. The good news is that operational carbon emissions can drop fast if we make smart changes, such as using renewable energy, installing heat pumps, and using energy-efficient appliances

The challenge is that operational carbon emissions are only part of the picture. Ten percent of global greenhouse gas emissions come from the construction of new buildings and demolition of old buildings. 

A study by sustainability think tank Preservation Green Lab found that when it comes to embodied carbon, new buildings can take 10 to 80 years to catch up to old buildings that have had energy-saving retrofits. 

The Brookings Institute estimates that roughly a quarter of existing buildings in the U.S. will be demolished between 2005 and 2030 to be replaced by new structures. Even if all that new construction is more operationally efficient than older buildings, it will take decades to recover from the environmental cost of demolishing and constructing those new structures. We don’t have decades. 

But, reusing old homes is a viable solution. Using Portland, Oregon as a case study, Preservation Green Lab estimated that retrofitting single-family homes and office buildings that were on the docket for demolition would save roughly 231,000 metric tons of CO2. To put that in perspective: That’s about 15% of the county’s CO2 reduction target for the next decade.

Age is just a number. 

Of course, age is just one element that plays a role in a building’s carbon footprint. Many old homes need retrofits to reduce the operational carbon emitted. In fact, one study found carbon emissions of old homes can be cut by 84% with the right changes

Old homes generally come with a few opportunities ripe for renovation. Some homes need new insulation to reduce heating and cooling costs, as well as to get rid of less environmentally-friendly materials (like asbestos). Other homes are in better shape and can be improved with energy-efficient appliances and windows, as well as solar panels. 

Harvard’s headquarters of the Center for Green Buildings and Cities, known as HouseZero, is a good example of how retrofits can be applied to older buildings. The house was originally constructed in 1924 and gut-renovated by the school as a prototype for other, similar structures. Today, HouseZero produces zero carbon emissions and requires almost zero grid electricity for heating and cooling.

If you’re interested in making changes to your home to improve its carbon footprint, start by exploring the incentives offered in the Inflation Reduction Act. There are more than $10,000 in tax credits and rebates available to homeowners (if you were to qualify for all of them).

And, to learn more about your home’s carbon emissions and track your progress towards reducing them, claim your home for free on Carbon Title Explorer.

Claim your building and start managing its carbon emissions. It's free!
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