The Benefits of Deep Energy Retrofits
Weatherization and simple energy remodeling projects catch the low-hanging and cost-effective fruit. Deep energy retrofits focus on developing comprehensive, whole-house strategies to achieve a specific level of energy performance or to improve the existing home as much as possible. The difference between simply remodeling for energy efficiency and a deep energy retrofit is the extent of the work performed — and to what end. It's also safe to say that deep energy retrofits aren't for the faint of heart and cost a whole lot more than your average energy efficient remodel.
Deep energy retrofit projects often target the same areas as a simple energy efficient remodel but go a step (or many steps) further to increase energy conservation to optimal levels. Sometimes, renewable energy generation is included in the retrofit. A deep energy retrofit project may include:
- Significant building-envelope upgrades, including removal and replacement of all air-sealing and insulation systems, windows, doors and skylights.
- Upgrade of entire heating and cooling systems, including duct-system redesign, zoning, thermostat replacement and installation of on-demand water heaters and heat pumps.
- Renewable energy use and on-site power generation through installation of photovoltaic solar panels, windmills and solar water heaters.
Many deep energy retrofits cut home energy use upwards of 70 percent, as compared with about 30 percent for weatherization. Some deep energy retrofits achieve net-zero energy use, with homes producing as much energy as they use from on-site renewable resources, such as solar power. The costs of deep energy retrofit projects depend significantly on the objectives of the project.
On one end of the deep energy retrofit spectrum, a project may reduce energy use by 50 percent to 60 percent. Technical strategies may include items such as significant air sealing, attic insulation, crawlspace insulation and sealing, and a whole-house ventilation system. For example, this project in Pasadena, Calif., reduced energy use by 50 percent.
On the other end of the spectrum, a project may achieve net-zero energy use and incorporate renewable energy production. In addition to significant envelope improvements (air sealing, insulation, windows and doors), such a project would replace mechanical systems and install a renewable-energy generation system. A deep energy retrofit recently performed on a home in Las Vegas as part the ReVision Home demonstration project targeted net-zero energy performance. The project replaced every mechanical system in the home, completely renovated the building envelope using state-of-the art insulation and air-sealing materials, and installed a solar photovoltaic system to general renewable energy for the home.
These sorts of projects show us what's possible and encourage professionals, consumers and manufacturers to develop innovative solutions that will be affordable in the coming decades. The place to start on the path to a deep-energy retrofit, as with any energy-improvement effort, is with a thorough home energy audit. In this case, skip the utility-company audit suggested in our other home-energy sections. The bottom line is that you'll need a skilled, experienced contractor to perform a professional audit (not a survey) and to help you make decisions about how to move forward. Same goes for do-it-yourself surveys and tools offered online. They're useful when you’re performing weatherization and moderate energy-improvement projects, but not when undertaking a deep-energy retrofit. If you had the sniffles, you might ask your neighbor for an over-the-counter remedy recommendation. If you had pneumonia, you'd be wise to see a doctor.
Once your audit is complete, you have a road map to use to determine what measures you'll undertake. A qualified energy contractor can provide you with bids for achieving specific energy-performance goals. There are great resources available to help you understand available tax credits, rebates, and loans to finance a deep energy retrofit project. You also might want to contact the U.S. Department of Energy's Building America Program to find out if it has an interest in new retrofit research projects. You might just get some free design-engineering services, but don't tell them we said so.