Summer Fixes to a Winter Problem
The house in question is a “pretty tight” house. Last winter it had condensation and mold in the kitchen. Could it be that it is too tight? What could the owner do?”
Needless to say, there is no trace of the problem now. It’s summer. The windows are open, the place is well ventilated. One source of excess winter moisture is likely to be the overly humid, moist basement. With the heating system on, much of this moisture would be driven up into the house. Cooking, long showers, watering plants, drying clothes on an indoor line are other likely moisture sources. In winter all the warm, moist air is trapped in a tight house. Excess moisture may then condense on cool surfaces, for instance when, in order to cut heating costs, the occupants turn the thermostat way down at night and while away at work.
Problems like this are opportunities. The following five recommendations will minimize indoor moisture, while also improving the house, saving money, and solving several other problems.
- Install heat recovery ventilation to remove excess winter moisture without wasting heat. There are highly efficient ductless devices available, ideal for retrofit application in older houses.
- Replace the old “boilermate” in the basement with a heat pump water heater. This will conserve oil since the boiler will not be running outside the heating season. The savings will help the heat pump water heater pay for itself. In addition to heating water more efficiently, this appliance will help dehumidify the basement year round, keeping it dry. (Of course, the condensate from the heat pump must be removed, e.g.: by a sump pump). A heat pump water heater is efficient, because it draws its heat-energy from the basement air. It will, therefore, cool the basement somewhat, making for good root cellar conditions year-round.
- Seal the basement ceiling to prevent moist air rising into the living space and insulate it to conserve heating fuel by preventing the basement from cooling the living space above.
- Consider installing a ductless heat pump to heat the house with — instead of oil — cutting heating costs in half, with summer cooling as a bonus.
- Install solar panels to reduce occupancy costs even further.
Of course, there is up-front investment involved. However, the moisture problem will go away and heating osts will be halved, helping pay for it all. In addition, net metering at the retail rate will benefit everyone on the grid, including the electric utility, because most free solar electricity is fed into the grid precisely when peak power prices are highest. In fact, each installed solar kilowatt generates 1,200 kWh of electricity per year and saves all ratepayers 10.9¢/kWh, or $3,000 over 25 years. It also reduces carbon pollution by about 1,276 pounds and locks in an electric rate for 40+ years. That’s according to the PUC’s Value of Solar report.
Rooftop solar also increases a home's resale value. So, it appears that to do nothing is the costliest option.