I recently traveled to Austin, Texas for the RESNET Annual Meeting. I was asked to speak to energy raters about SIPs and Retrofit Panels, and the timing couldn’t have been better as two weeks earlier I had attended HERS training with Energy Vanguard in Atlanta, Georgia.
You’re aware that a HERS score is like golf – the lower the score the better. If your home scores a 100, your home is performing on par to the model energy code. If you’re at the opposite end of the spectrum with a perfect score of “0”, you own a Net Zero energy home, or one that produces as much energy as it consumes. You could even score in the negative numbers. This would require energy generating components, or as we often say, “Alternative Energy”.
The key is to understand the difference between consuming and producing. Without any alternative energy components, the lowest HERS score achievable is in the high 30’s. I’ve seen a 39, I’ve built a 49, and I’ve heard of a 37. These low numbers represent a combination of good design, impeccable air sealing, high levels of insulation, proper fenestration specification, proper HVAC specifications, and energy efficient lighting and appliances. All of the above numbers were a function of reducing energy consumption. If the consumer wants a truly energy efficient home, that consumer should be asking for a home that efficiently uses energy. Creating or producing energy does not equal energy efficiency.
To take this point to an absurd level, imagine what the HERS score might be for a building that also happens to be a coal-burning power plant with the capacity to produce hundreds of megawatts of electricity. Should we reward this concrete, steel and block structure with a HERS score of -1,000,000 and then applaud its energy efficiency? Its only attribute that contributes to its artificially low number is that it produces energy. I believe the same argument can be made for buildings that claim to be energy efficient because they have wind, PV, or solar thermal panels installed.
I’m not an enemy of the solar industry or any other form of alternative energy. However, I want people to properly separate the production and consumption portions of their structure before they categorically declare their building “energy efficient”.
I am constantly frustrated by building magazines, websites, and blogs displaying the latest home draped in alternative energy-producing components. Inevitably the caption touts “energy efficiency” and the proof of that is a HERS score near or below zero.
I’ll continue to argue with raters, fellow builders, industry professionals, and future home owners that real energy efficiency can’t be bought. It can only be built.