Main floor’s comfy, basement’s a freezer
QUESTION: We have a seven-yearold, 1800-square-feet bungalow that has a concrete basement. There is a walkout feature, which incorporates an enclosed three-season sunroom. One large window is in place for the view and then three standard windows are in the bedroom and workout area.
About three years ago, we had it finished, included adding a couple of cold-air returns to the basement. We hoped the basement would have more circulation and there would be an increase draw of warm air into the space. This has not happened and the basement remains cool in winter and summer. The temperature is usually around 14 C (57 F), and a bit lower in summer when the air conditioning is on.
We had a spray foam contractor insulate the spaces where the joists connect with the outside wall prior to the basement work. There is four inches of insulation in the walls. We installed a T-bar ceiling, drywall and Dri-core with laminate on the floor. There is the standard configuration of ceiling heat vents. All dampers are fully open. The windows are tri-pane with three large fixed units as part of the walkout and three basement dualpane sliders.
Is the low temperature just because cool air settles and our open design allows cool air to easily flow down the stairway into the basement? Do you have suggestions to remedy this issue?
Jim Duthie. Answer: Your situation is common and you appear to have a handle on the cause of the cold lower level, which may not be unavoidable. I will give you a few ideas to help make the space more comfortable.
I recently completed a similar job in my own home. It sounds similar to the design of my own lower level, except for the age and large windows in the walkout. The drop ceiling is an ideal product to allow access to the joist space above, while the dimple membrane subfloor and laminate will warm the feet much more than walking on concrete. While you have insulated the inside of the foundation to moderate levels, this should make little difference to the comfort if it is properly sealed with a good air/vapour barrier. While the large windows and walkout door may allow some cooler air to infiltrate from the outside, none of these should be the major contributing factor to the cold indoor air.
After eliminating most of these factors, the last item is the heating system. You are correct that the basements of most homes are typically colder that the upper floors due to normal warm air/cold air movement, but that should not account for such as dramatic difference. A few degrees differential is typical, but not to the level you have measured.
While the return-air ducting and registers in your basement may have improved airflow in the basement, it is obviously not enough. The basement is almost always colder due to the soil and concrete foundation, while cooler air settling from the main floor should be a secondary concern if the heating system is operating properly.
Try using the dampers on the main-floor heating ducts, or inside the main-floor registers, to adjust the warm airflow to all the rooms on the main floor. By restricting the warm air in these areas, you may allow more air pressure to the basement registers, warming the lower level. Rooms with south and west exposures, will have more significant solar gain during the day, and may seem much warmer than others.
On cloudy days, or at night, these registers may have to be opened a bit more, if you have partially closed them to compensate. Also, if you have large windows in the living room or family room, or a vaulted ceiling, that area may be much warmer or cooler depending on the same factors.
Another thing that may help even out the temperature between upstairs and downstairs is running the furnace fan continuously.
This will minimize the normal temperature swings that can be seen between the time the furnace is firing and is still. It may help lessen the time it takes to warm the basement, while moderating the main-floor air temperature and cycling the furnace more frequently.
Also, the location of the thermostat should be checked. Too often, in open-concept homes, thermostats are located on the main floor in a poor location due to the lack of partition walls. This can be either too close to an entry door, window, floor heat register, or other source of heat or cold. In that situation, the thermostat will not call for heat at the appropriate time, further reducing the heating capacity in the basement.
While all of these suggestions may help minimize the temperature drop as you go downstairs, it may be difficult to warm the basement enough to satisfy your comfort levels. In that situation you could turn up the thermostat when you are using the lower level, or add some supplementary heat to those areas most affected. I have purchased, but not yet installed, a wall-mounted electric fireplace to help with this issue and I anticipate using it to take the chill off my new rec room, if needed. Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the president of the Canadian Association of Home & Property Inspectors - Manitoba (www. cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website