Welcome to my 4th blog. Today, I’m going to talk about something that I’ve seen in the field. An energy audit that I conducted several years ago.
The home was a single level ranch with a walk out basement built in the 1970’s. The basement had two bedrooms and appeared to be finished in the 1990’s. The main level had one bedroom and a masonry fireplace with a metal insert. The insert did not have sealed combustion, meaning it used inside air for the fire combustion. The house was heated by electric baseboard, other than the fireplace, there was no other heat source and no existing duct work. Walls were 2 x 4 with R-11 kraft faced insulation, the ceiling was insulated to R-19 using fiberglass batts, both well below recommended insulation values in northern climates. There was also no vapor or air sealing other than the craft facing on the insulation. The walls and ceiling were finished with wood paneling. Windows were older wood 2 pane and the doors were wood. An electric water heater was also present. Two adults lived in the home. They had an electric bill that would run as high as $1000 per month during the winter. The home was in a rural location on a lake with a very nice view. There was no access to natural gas. The well and sewer were both on site.
The objective: to lower heating and electric costs and make the home more comfortable.
The process: after asking my questions and visually inspecting the home,(read The Energy Audit-A Discription), I suggested a blower door test. This energy audit was early in my energy auditing career. I was, and still am gaining knowledge and experience. I did learn a valuable lesson at this home-be sure to cover ashes in a fireplace before conducting a blower door te
st. For those who have never seen a blower door test, I set a fan in a doorway and basically suck (or blow) air out of the house. In doing this with calibrated equipment and software, I can determine how “leaky” a house is, and with some experience, find the leak locations. I inspected the glass doors of the fireplace, which did not seal and had gaps on all sides of the glass. I figured that with the fireplace doors closed, the ashes in the fireplace would stay in place. Wrong! I dusted the living room. Spent the next 30 minutes cleaning a mess. Lesson learned!
Anyway, the house tested leaky, around 8 ACH@50 PA, more than twice what would be allowed for new construction. For those who don’t know blower door talk, I will be discussing the process and numbers in future blogs. Just know that this is a leaky house for a northern climate. The location of the leaks were all over the home, the attic, rim joist (the space between the basement and main level), of course the fireplace, windows, doors, every where I went, there was air leakage. In a previous blog, I stated that air leakage accounts for 10%-40% of heating costs, this home was 40%+.
What to do? The source for most of the high electric costs was the electric baseboard heaters. The electric provider for this customer has reduced rate programs available for heating, which will reduce costs by at least 50%. The programs are called off-peak or dual fuel space heating. The customer receives a reduced electric rate for allowing the power company to turn the heat source off and on depending on the electricity demand of the area at a given time.
For the off-peak program, heat is typically stored, either in a special electric furnace with bricks, or in a sand heat sink under the foundation of the building. Both are heated in the middle of the night, the heat that is stored, is released during the day.
The dual fuel he
ating program requires a second source of heat, (not electric) that is automatically controlled by a thermostat. Wood fireplaces usually do not qualify. Even though electric baseboard heaters are efficient at turning electricity to heat, the electric rates are typically much higher on the general service rate, which is the rate that you pay for normal electrical loads, such as lights, refrigeration, cooking, etc…
The reduced rate programs are really the only way to make an electric heat source competitive with other fuel sources. The issue with this house, electric thermal storage would require a major renovation. Remember, there is no existing duct work. That leaves duel fuel, how do you install a second source of heat to reduce the electricity rate for the baseboard heaters with no duct work? Either an LP gas wall furnace or a thermostatically controlled LP gas fireplace will work. One unit would be required on each floor, and even then, there will be cool areas when the electric baseboards are being controlled. Not a great option.
Another solution, improve the insulation and air sealing. Air sealing alone would hopefully reduce heating costs by 25% or more. Sealing all penetrations in the attic with expanding foam or caulking, such as wiring and plumbing chases, light boxes, etc… would be a good start. Sealing around the frames of windows and doors will also help. The rim joist is a big one, but remember, the basement is finished. There’s no access to the rim. Adding additional insulation in the attic would also help. There’s no good way to increase the level of insulation in the walls without remodeling.
Other suggested improvements. The electric water heater also has a program to reduce its operating cost. Similar to the off-peak heating, electric water heaters can be controlled during peak electrical use times. This will typically reduce costs by 50%. Electric water heating with this program will typically cost $15 to $20 per month for two people. There are many other smaller options for reducing electricity bills, but I’m going to save those for future blogs.
So, what was done? The answer is, I don’t know. After discussing some of the options with the homeowners, they were considering a tear down and rebuild. By the time the improvements would have been completed, along with a major renovation to bring the structure up to date, there wouldn’t have been much additional cost to start over. I completed my work, filed the report, and just like most of the audits and assessments I do, I don’t know the outcome….AGH.