Green building assessments versus energy audits

first_imgEnergy audits can be a single slice evaluation of home performance, just looking at energy, albeit in a comprehensive analysis of energy performance. Whole-house assessments are green because they take a systems integration approach to evaluating home performance, looking at the individual and combined effects of energy, water, indoor air quality, and durability performance.What can be troubling are the unintended consequences of straight energy improvements, erosion of home performance that can inherently and inadvertently accompany reducing heat loss/gain and air sealing. Here are the most common unintended consequences of energy improvements:• Combustion safety – Every combustion appliance, be it a gas water heater, propane cooktop, gas clothes dryer, or oil-fired boiler needs make-up air. Any one of these appliances may have exhibited adequate performance when the home was leaky, but air tightening can result in backdrafting problems and increased carbon monoxide (CO) levels inside the home.Pressure measurements using a manometer and CAZ (combustion appliance zone) worst case depressurization testing address this issue.• Radon – Air tightening can increase radon levels in a home. When I insulated and air sealed our basement about 8 years ago, the radon levels doubled, from about 6 picocuries per liter (pc/l) to over 12 pc/l. Since radon is an odorless, colorless, tasteless gas, as well as a known carcinogen, keeping track of radon levels should start at the assessment and carry through as home improvements are made.Short-term electronic testing (2 – 3 days) for radon can give an adequate indication of radon problems (in a closed-up home) as part of the initial building assessment.• Moisture – Energy flows through building assemblies dries them out. A level of wetting that was never a problem can easily become one as we increase the energy efficiency (decrease the energy flows through) of a home. We have to worry about 4 ways moisture moves about: bulk water (ground water, rain, snow), capillary water (wicking through porous building materials), air-transported moisture (moisture condensing as air leaks into a home during the cooling season or out of a home during the heating season), and vapor diffusion. Any one of these or a combination can create a mold or even rot problem for a home whose moisture performance has not really changed while its energy performance has.Gross level inspection of bulk water drainage (over the structure and then ground drainage patterns), moisture meter testing, blower door testing, and vapor profiling (relative vapor permeabilities of building assembly components) can all be done as part of the building assessment (we will be addressing the vapor profile concept in a subsequent blog).• Structural – It’s not uncommon for previous electrical, plumbing, or HVAC work to have compromised the home’s structure. And this is something that can be a problem with new work as well. On the other hand, solving existing structural problems or plans to avoid new ones can be an important part of or follow-up to the initial building assessment.Visual inspection of the home’s framing can largely be done without invasive inspection.• Electro-magnetic fields (EMF) – Although the science and human health impacts of EMF in homes are far from adequately researched or understood, low- or no-cost prudent avoidance is a good policy. Common problems include the way the electric panel is grounded to plumbing, knob-and-tube wiring, and devices such as microwaves.A gauss meter is easily used to assess likely EMF problem locations.Each and all of these issues can be readily assessed and then addressed in a whole building assessment and subsequent home improvement plan. We will take a closer look at each of these issues in subsequent blogs.last_img

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