It seems to be a good time to talk about some things that are confusing about home heating.
Most homes in Maine have central heating systems that use oil and are hot-water baseboard systems. Many folks call hot-water baseboards radiators. In fact, they are actually convectors. The baseboard has a copper tube inside of it with aluminum fins pressed onto the tubing. Hot water is circulated through the tubing, which heats the fins.
The air in between the fins gets heated and rises. The baseboard housing (the part we can see in the room) acts like a chimney to convect, or channel, the warmed air up through the housing.
It is important to keep the opening at the top and bottom of the baseboard open and clear in order for the heating effect to take place. That means no old magazines or newspapers up against them, no furniture right up against them, and every year or so, the covers should come off and the fins should be vacuumed.
It is also critical to keep the covers hooked onto the clips that hold them in place. If the covers are falling off, the baseboard cannot convect very well and the heat output falls off drastically. The covers come off easily if you push up or down on the front cover.
If you are installing new carpeting, make sure that the bottom opening is not choked off. The air gap should be at least three-quarters of an inch.
Hot water baseboards are also susceptible to lower water temperature. The lower you set the water temps, the less heat output.
And one more tidbit: The higher the housing, the higher the heat output, since the baseboard housing works like a chimney!
Most “regular” baseboards deliver 450 to 850 Btu per hour per foot of length at the design temperature of 180 degrees Fahrenheit. It is possible to control the heat output of a baseboard by opening or closing the movable vent in the top opening of the baseboard. If a room is too warm, simply tilt that vent to choke off the open-ing.
The predecessor to the baseboard heater was the cast-iron radiator. For years we used to pull these out of older homes and replace them with baseboards. Now they are rightly considered architectural antiques that are very effective heating devices.
Originally radiators were hooked up to solid fuel boilers. Those were mostly coal- or wood-fired. These boilers put heat out 24 hours a day during the heating season and would have delivered steady heat most of the time.
If they were continuously fired (most were), they would deliver the even heat that radiators were known for. When oil burners were introduced, they were capable of delivering a lot of heat in short bursts. This meant that the heat would cycle on and off. As this happened, the radiators would tend to go hot and cold. (Or at least hot and warm.)
This effect was one of the reasons that radiators were being pulled out and replaced by other heat distribution schemes. Another problem with hot-water radiators was that the valves would tend not to work very well and the output of heat into a room could not be controlled very well.
New radiator valves became available about 15 years ago. They were developed in Europe and are available as direct replacements for the originals, which might be 100 years old. The beauty of these new valves, other than their ease of use, is the fact that they are available with thermostatic controls.
Thermostatic control heads are passive knobs that mount on the replacement valves and control the temperature of the radiator. So with these valves we now create a heating zone wherever there is a radiator.
Another technological innovation that works well with radiators is the outdoor reset control. This is an electronic control that modulates the boiler temperature based on the outside temperature. As it gets colder outside, the boiler water is heated hotter.
This type of control, when set up properly, allows radiators to perform the way they did when originally installed.
There is a lot more to heating technology than these two concepts and we will try to hit on more of them in the next few weeks as we hover by the radiator.
Questions for Tom Gocze should be mailed to The Home Page, Bangor Daily News, P.O. Box 1329, Bangor 04402-1329. A library of his practical home-improvement videos, reference material and a home-project blog are at bangordaily