How to heat a home efficiently
Q: Should I use an electric resistance system to heat my house?
A: In general, electric resistance systems are expensive to use for heating a house. This is why most homes with all-electric heating use heat pumps that are more energy efficient. Geothermal heat pumps can be several times more efficient than resistance heating and also provides inexpensive central air-conditioning.
An electric resistance furnace is basically just several large toaster elements with a blower and ducts attached to it. Electric infloor heating, which can be used under tile, carpeting and hardwood, is technically no more efficient than an electric resistance furnace. It can be less expensive to operate, though, because it improves your comfort.
A house loses less heat through the walls, ceiling, windows, etc., when the indoor temperature is lower. The amount of electricity used is typically several percent less for each degree the thermostat is set lower. With improved comfort from infloor heating, you should be able to lower the thermostat setting considerably and not feel chilly.
Another energy saving advantage of infloor heating, as is also true with baseboard heating, is each room can have a separate computerized thermostat. This allows you to set different temperatures in various rooms and heat a room only when it is needed. For example, there is no need to keep the bedrooms toasty warm during the daytime.
Instead of heating the room air, a warm floor radiates heat upward to your body, making you feel warmer. When one's feet are warm, your entire body feels warm. Infloor heating reduces the extent of heat stratification where the hot air from a forced-air furnace naturally collects up near the ceiling.
Infloor heating is most commonly used in a concrete slab or in a tile floor with high thermal mass, but some types are specifically designed to be used under carpeting, hardwood or laminate flooring. It can actually provide better comfort under carpet and hardwood because their low thermal mass allows the floor temperature to respond faster to the wall thermostat.
In a concrete slab or under a tile floor, electric heating cable is usually laid in a serpentine pattern. In one design, long cable guides are nailed along the outer edges of the floor. Selecting how many slots to skip between cables determines the total cable length and Btu heat output. It also simplifies even spacing. Once the cable is in place, it is covered with concrete or thinset for tiles.
For use with carpeting, thin mats or sheets with electric cable embedded in them are placed on the floor before the carpeting is laid. The manufacturer can calculate the amount your rooms need and it is available for 120 or 240 voltages. Some of the systems, for smaller areas, are designed for do-it-yourself installation.
WarmlyYours has a unique design with thin electric heating cables embedded in a strong fiberglass mesh. This is particularly effective for under hardwood flooring and laminate. First, check with the hardwood flooring manufacturer about the maximum allowable temperature to avoid excessive drying of the wood. Consider installing a special programmable thermostat with a laminate and engineered wood setting to protect the materials.
Another design by Heatizon uses a low-voltage heating mesh. This mesh is only about one-eighth inch thick and is stapled directly to the subflooring. Being a safe low-voltage, installation is relatively easy. WarmlyYours also offers a wafer-thin heating kit that is placed between the pad and the carpet.
With infloor heating, you do not have to do your entire house or even an entire room, so you can add to the system as your budget allows. People sometimes just add small custom mats or sheets in front of a mirror in a dressing area or in a work area. At a home center store, a 10-foot by 30-inch heating mat costs about $200 and a matching programmable thermostat is about $140.
If you are away from home for extended periods over winter and set the thermostats very low to save electricity, there is a chance a pipe may freeze during a severe cold snap. Self-regulating electric heating cables that are attached along water pipes are available from the infloor heating cable manufacturers. They automatically self-adjust the heat output depending upon the temperature of the pipe.
The following companies offer electric infloor heating systems: Calorique, (800) 922-9276, www.calorique.com; Heatizon, (888) 239-1232, www.heatizon.com; Orbit Radiant Heating, (888) 895-0958, www.orbitradiantheating.com; Suntouch, (888) 432-8932, www.suntouch.com; and WarmlyYours, (800) 875-5285, www.warmlyyours.com.
Q: My house is only about six months old. The interior side of the band joist feels damp, but I cannot find any leaks from the exterior. Where should I check to find the source of the dampness?
A: You probably do not have a leak in the exterior envelope of your house. If you did, the band joist would be more than just damp and you would likely see a puddle somewhere.
Because your house is new, the moisture you feel on the interior surface is just from excessive humidity inside your house. New building materials often contain a lot of moisture, and it can take a year or more to air out. Because the band joist gets cold, you notice the dampness there.
• Write to James Dulley at 6906 Royalgreen Drive, Cincinnati, OH 45244 or visit dulley.com.