Decarbonizing My House and the Magnitude of the Building Decarbonization Challenge.
Most discussions of building decarbonization start with talking about zoning code changes and other modifications for new buildings, like prohibiting gas hookups. The problem is that 90% of the buildings that will be around in 2050 are here today, and so building decarbonization is primarily a question of retrofits. There are a number of startups that are looking into sophisticated AI solutions for controlling energy use in existing public, commercial and industrial buildings by connecting the building automation systems to cloud based controllers, and these solutions are likely to yield important and substantial changes.
But the problem of residential building decarbonization through retrofits is a much more difficult challenge. Single family homes are the responsibility of the homeowner to maintain, and most homeowners don’t have the time or money for the kind of deep remodeling work needed for a through decarbonization. If they do remodeling, it is primarily for aesthetics, to increase the resale value of their homes. Multifamily residences are even more of a challenge, because of the misaligned incentives between renters and landlords. Whereas the landlords have to invest in the building decarbonization measures, the renters reap the benefits in terms of reduced energy costs and improved habitability, yet the landlords can’t recover the costs by increasing rents because rents are already too high.
When we moved into our house in 2003, we decided to make building decarbonization a top priority. Whenever we did any remodeling for aesthetics, we also tried to incorporate a decarbonization component, like improving insulation. A few of the measures we took were free, like turning the thermostat down to 64 degrees in winter. Others were low cost, like buying a retractable wash line and drying rack and drying our cloths outside in summer. Many cost varying amounts and came with the usual hassle of finding a contractor and then finding out that (s)he wasn’t really trained to install the kinds of equipment we wanted, like installing an air to water heat pump. One huge benefit was when we signed up with SVCE for 100% renewable energy in 2018, so even the energy we draw from the grid is carbon free.
Overall, we managed to reduce our building’s yearly carbon emissions from 6,632.00 kg/yr in 2003 to 666.00kg/yr in 2021, an almost 10x improvement. The only gas-fired appliance in regular use is a stove which we seldom use. Our home emits 0.333 kg/sq ft whereas the average home in California emits 2.1367 kg/sq ft. The cost was approximately $55.69/ kg removed or $2.93 /kg/year. The graph below shows the yearly electricity and gas (in kwh) use and the carbon emissions (in kg) between 2003 and November 2021.
I think the take away from my experience is that, absent an even stronger government policy for residential building decarbonization than is the Build Back Better bill, most residential buildings will be emitting the same amount of carbon in 2030 as they are today unfortunately. Unless building owners are forced to do the remodeling work, like they are told their gas service will be shut off on a certain date, or are given some kind of major incentive in excess of what it would cost them to do the work, most simply won't do it. Thankfully, the situation with cars is much easier, because cars are replaced on average around once every 10 years, while most buildings last for 50 years or more, so replacing fossil fueled cars with electric cars within 15-20 years with a modestly supportive government policy seems very doable.