It’s crazy, but we know more about the efficiency of our cars than we do our houses. Think about it, you probably know what kind of mileage your car gets, but unless you’re especially geeky, there’s a good chance you don’t know how your home’s energy use compares to other homes in your community. You may be wondering why should I care?
Out of my head, here they are three reasons matter:
1. A more energy efficient home costs you less.
2. It’s good for the planet, really.
3. Energy efficient houses are more comfortable.
According to the most recent statistics from the Residential Energy Consumption Survey (RECS), the average annual energy cost for all types of residential structures in the US is $1.03 per square foot. In a 2,000-square-foot home, that’s an average cost of $2,060. annually or $171 per month. That is much higher than it needs to be and it is possible to reduce the amount of energy used by 50% and more. Just a 50% reduction results in a potential energy savings of $1,030 per year. Instead of paying the utility company, it’s money you can put away in savings or use for other things. In any case, the interesting thing is that there is a lot of money that can be saved simply by improving the energy efficiency of your home.
According to Architecture 2030, buildings were responsible for 47.6% of CO2 emissions in the US in 2010. The other two chunks were transportation at 33.4% and industry at 19.9%. Buildings are the main culprits and while we need to address all three sectors, reducing CO2 emissions from buildings will have an immediate and significant impact. That is a sobering fact. It’s also a cool fact because we CAN build better buildings right now, and we clearly need to!
When buildings are built to improve energy efficiency, an often overlooked benefit is comfort. Not comfort like in the luxury spa type of experience, but comfort like in thermal comfort, no long johns experience required. The factors that improve energy efficiency and comfort are better insulation, fewer leaks and fewer thermal bridges. Building this way requires extra attention to both design and construction, but it’s certainly not rocket science, more than anything else it’s common sense and attention to detail.
If there were an MPG rating for homes, it would be The Home Energy Rating System, or HERS, the most widely recognized rating system for home energy use in the US. HERS is overseen by RESNET, the Home Energy Network. of Residential Energy. A building with a score of 100 is considered the average standard new home; the lower the HERS score, the better the performance. The ultimate energy efficiency goal is a score of ZERO, which is a zero energy home, one that produces as much energy as it uses over the course of a year.
There are two ways to get to zero. Both are legitimate and have their place. For existing buildings, often the most practical method of getting to zero is to match energy use over the course of a year with an equivalent amount from renewable energy sources, such as photovoltaics or wind power.
The other way to zero is to cap a building’s energy use before adding the renewable energy source. This is most easily accomplished with new construction, and buildings with a HERS score of 50 or less are ideal for conversion to zero energy buildings.
Low-energy buildings help limit the amount of CO2 in the atmosphere, are comfortable to live in, and save you money. We can build this way today, it takes a bit of extra effort, but once you know how to build right, there’s no going back!