October 24, 2011
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Today our groups performed our walkthrough audits for the Energy Efficiency and the Built Environment project. Our house that we audited was only a couple years old and was quite energy efficient already. We were armed with some pretty sophisticated tools and a great set of checklists that we prepared.
Dan Boyd from the Nova Scotia Homebuilders Association was on hand to perform the blower door test for us. The home we audited previously tested at 1.4 air changes per hour (ACH) but we won’t know how it faired out today until we get the data entered into HOT2000.
We tested the envelope of the building with the thermal imaging gun to look for thermal bridges. We found lots at the studs in the walls and the ceiling, as well as all along the headers and rim joists. Thermal bridges are pathways where heat escapes and are common in standard construction. Modern construction methods are working to eliminate them all together but not all builders are using them right now. We didn’t find any missing insulation or sagging around the windows.
We used an air quality meter to measure temperature, humidity, and CO2 levels on each floor. This will help us determine how effective the ventilation system is. The home has a heat recovery ventilator to reclaim the heat during the ventilation process.
The lighting was quite different throughout the house. We found compact fluorescent (CFL), halogen, as well as incandescent bulbs depending on what fixture we were looking at. We will recommend that the incandescent bulbs be replaced with CFLs.
South is located to the rear of the home and there is an excellent solar resource there. We will be creating a model for a solar system to determine the payback before we make that recommendation. I expect it will be feasible because of the location and the number of occupants (the more people the more hot water used). We will also look into using a drain water heat recovery system to reclaim heat from the drain water.
Water efficiency on the inside of the house was given attention when the home was designed, but the exterior could have some improvements. There are a lot of plants outside so a rain barrel to capture rainwater for watering would reduce potable water usage. Mulch should also be added around the shrubs to reduce evaporation from the soil and hopefully reduce the need for additional watering.
The heating system is about as good as it can get. The owner has an air source heat pump with an electric furnace for a backup. Since the subdivision was blasted out of the side of a rock mountain a ground source heat pump would be too much of an expense to be worth it.
Tomorrow we will start to sift through all the data we collected and come up with some more ideas for low cost or no cost recommendations for the home owner.