Q: My husband and I live in a house on a crawl space that is almost 20 years old. We recently replaced the heating and air conditioning. We had an energy audit that did not turn up any suggestions for changes. But our feet get cold in the winter, despite wearing heavy socks and slippers. We wonder about making two different upgrades, whether either would help the problem and which one would help more. We can afford to do one but not both. The first is to have the crawl space sealed and conditioned so that it is heated and air-conditioned. If we do this would it make the floors warmer in the winter? Also, if it is air-conditioned, would it make the floors feel cold in the summer? Would the added cost to the heating in the winter be significant? We were also warned by a contractor that we could get fumes in the house from the material used to seal the area. Is this correct?
The other option is to replace the carpeting in our family room where we spend our winter evenings and put in floor heating. Since we heat with natural gas, what would be the cost in added electric bills? One flooring dealer has told us that he can put floor heating under carpet. Is this safe and reliable? What other questions should we be asking?
A: Many utility companies offer free energy assessments for their customers that are valuable for basic energy savings, but typically don’t provide an in-depth evaluation of the home. If you’re still having issues after a free energy audit, we strongly recommend hiring a certified energy rater to pinpoint deficiencies in the home. A 20-year-old home usually needs significant upgrades to air seal the home to improve the home’s comfort levels. What you did not say is whether or not you had a problem before the heating upgrade. If the new furnace was installed using the existing 20-year-old ductwork, there may be a problem with the size of the ducts verses the output of the new furnace fan. This is something the heating, venting and air conditioning (HVAC) contractor should be able to answer. The ducts need to be sized for maximized airflow to each register in the home. Each room, except the kitchen and bathrooms, should also have a cold air return to maximize airflow.
When inspecting a crawl space on an older home, I often advise the client to close and seal the crawl space vents and to add an opening to the ductwork in the crawl. This needs to be inspected and installed by a qualified HVAC expert. There is always the problem of the ducts being oversized or undersized for the home. When conditioning the crawl space, it is important that all the foundation perimeter walls are insulated from the rim joists down to the top of the footings. It is also important that all the soils under the home are completely covered with a 6-mil or thicker vapor barrier. If your contractor uses closed cell spray-on foam to insulate the crawl, there may be an odor from the foam for a short period of time. The conditioning of the crawl will help to warm the floors and reduce energy costs and will keep the air in the crawl dry. Cold floors have not been a problem with this arrangement. In your family room the floors can be heated under the carpet using hot water pipes connected to a water heater. Plastic panels and flexible tubing are installed on the concrete floor before adding the floor covering. Warm floors are safe and will be an asset on cold winter days.
C. Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. d.Barnett@insightbb.com.