My Tiny Duplex is officially Department of Energy Zero Energy Homes certified. What does that mean? It means that I followed a bunch of building guidelines that were put in place by the best building scientists and builders in America. My HERS score was 43. What is a HERS score? I am going to attach a link here that explains the HERS score in detail, but basically it is a measure of how efficiently the home uses energy. The score is based on 0-150 and the closer to zero the more efficient your home is. The average new construction HERS score is 100.
So Tiny Duplex is more then twice as efficient as the average new construction home. What does that mean? Nothing really to most people. But to me it feels good because when I set out to build Tiny Duplex my goal was to qualify for that certification. It also means that the house should function well for years to come. You never know, but at least we did a good job air sealing. It does have a nice air exchange system so the home does get fresh air regularly through out the day, even if the windows are shut all day. So far this winter it costs $50 a month per unit for electricity which provides all the heating and cooling needs. There is no gas so electricity is the only utility bill besides the water.
I would do the program again. I would try a few different products out, but overall I liked the program and would recommend it for any first time builder or experienced builder.
Link to HERS Score Information