DOE’s Zero Energy Ready Home Program
By George Harvey, staff
The Department of Energy (DOE) recently renamed the Challenge Home program as Zero Energy Ready Home. This program is worth taking note of. The questions of what a zero energy-ready home is, what it implies for comfort and life, and how to achieve it should be understood.
A zero energy ready home, whether of new construction or a retrofit, is a building that will consume very little energy and can be rendered into a net-zero energy building with the addition of a small amount of renewable power. A net-zero building is a building with zero net energy consumption, meaning the total amount of energy used by the building on an annual basis is roughly equal to the amount of renewable energy created on the site. Guidelines for the Zero Energy Ready Home are published by the DOE, and can be seen at This Link. A builder of a zero net energy-ready home does not need to be a partner of the DOE program. Any builder who knows how to do it can build such houses; it is just that they will not be certified by the DOE as having been built as part of the program. They will perform the same.
Bob Irving of R. H. Irving Construction, who is a member of the DOE Zero Energy Ready Home program, shared information on both building and living in such houses. He pointed out, “Living in a home built to the standards of the Zero Energy Ready Home program, and with true net-zero energy use, should require no sacrifices other than common care about waste. If you are not wasteful, you can be as comfortable as you like while using no net energy”.
“Building to the standard is not all that hard,” Irving says. Having started work in construction based in sound environmental principles, he learned the techniques commonly used to build energy-efficient housing. When he learned of passive house systems being introduced, he studied them and realized the basic principles could be applied with good effect in somewhat less costly construction, with the same tiny environmental footprint. All you have to do is come close to the standard and apply a renewable power system.
“Start with the passive house principle,” Irving says. “This means insulating the whole envelope that you use. If you store a suitcase in the attic, that counts.” He says that under most circumstances, insulating the basement is also very important. He uses windows of R-5, and ratings of R-20 for the basement, R-40 for outside walls, and R-60 for the roof.
Air-tightness is an important issue. He uses gaskets for structural insulated panels (SIPs), and sees that all penetrations are sealed. Everything has to be checked, and any leaks need to be given attention; this is commonly done with foam sealing. The goal for most of his construction is to get a blower door test showing an air exchange rate of 1 per hour or less. He says that if the customer wishes, he can easily get to the passive house standard of 0.6 air exchanges per hour, which is for houses requiring nearly no heat input at all.
Irving likes air-source heat pumps, or mini-splits, for heating. He says he believes ground-source heat pumps (GSHP) have an initial cost that is too high in most situations, and the efficiency of mini-splits has improved to the point that the payoff for the extra investment of GSHPs may not be great enough to justify it.
What this boils down to is that to achieve the standard of the zero energy-ready home, it is simply necessary to learn to apply higher standards and more care to already existing building techniques. With thought and attention, zero net energy is perfectly achievable.
RH Irving’s web site is rhirvinghomebuilders.com .