Midcoast Green
Collaborative

Home Energy Audit Example

Our team visited the house of Peter and Becky Drum and performed an energy audit, here is an overview of the process of auditing their mid 1970's vintage home. Click images for larger versions
We first met with Peter and Becky and asked them if they had any questions, and discussed the process of the audit and what kinds of expectations they had and improvements they may need to make and what they could expect in energy reduction. We looked at their energy bills and recorded their electrical energy usage by month for the last 12 months (available on all electric utility bills).  We would have liked to record the monthly energy bills as well, but they weren't available. We got a guess on oil and wood usage.
We took measurements of the dimensions of the house. We use these not only for volume which is less important in the air leakage calculations, but also for the surface areas of various building constructions.  This is very important for estimating heat loss through all those surfaces, and is where the majority of the heat loss occurs.
Paul used a sling psychrometer to measure the internal humidity of the home.  There are 2 thermometers on a stick that are swung around in the air for a minute. One is wetted to read the "wet bulb" temperature.  Then the different temperatures are read and converted to relative humidity using a scale on the instrument.  This home read at over 72% which is quite high for the winter.  (50% is considered comfortable)
Using an infrared thermometer, Paul reads the inside surface of the front door, and the exterior ground temperature. The inside surface of the door read at 65°F while the outside temperature was 36°F on this day.  It is useful to have an outside temperature reading at the time of the blower door test.
Next we set up the blower door.  This rig replaces the least leaky exterior door in the home and by blowing air out and measuring the difference between the inside and outside pressures and taking readings this tool allows us to calculate the amount of air leakage in the home.  We don't put the blower door in the leakiest door because we want to account for all the leaks we can. We prefer the least leaky door because it will not be included in the total.  In this case the leakiest door opened into the garage and the front door was both the best weather-stripped and the preference of Peter and Becky.  The calculated total equivalent leakage area was 145 sq. in. (just over 1 sq. ft.) represents the "Equivalent Leakage Area" (EqLA) of the house. This means the combined total area of all the leaks in the house.
While the blower remains running we wak around the house feeling for cold drafts around windows and doors.  Peter found a leaky attic door in the kids bedroom.  We advised him to seal it with weather stripping and add some rigid foam to the thin 1/2" plywood door to improve the insulation.
Using a thermal imaging camera we were able to clearly identify an air leak around the edge of the front door.  The IR camera provides a color coded temperature picture, showing the actual temperatures of the area we are looking at.  It shows both surface temperatures and the temperature of the air, so we can see effect of air leakage (as long as the leaking air is of a different T from the ambient).
In the second floor bedrooms we found bad insulation in the ceilings and corners.  This could be due to poor installation or settling, or possibly moisture damage.
We also surveyed the unheated basement and recorded the performance characteristics of the boiler.  The Drum home uses baseboard radiators and the boiler also heats the domestic hot water though a boiler mate.  We discussed reducing the temperature of the water heater as an energy saving measure.  Theirs was set at 140F which is higher than necessary. We also looked at insulation levels. Found no insulation, nor vapor barrier between the heated space and the unheated basement. Also all the pipes were un-insulated. We also looked at the condition of the chimney and the general conditions.
A detailed report will go to the Drums after all the calculations are made, complete with recommendations for cost effective measures to upgrade the home's energy performance.