Adding a High-Wall Return
In the heating mode, it makes sense to locate both supply and return registers at or near floor level. Heated air rises from the suppliers, while heavier, cool air settles back to the returns. However, in the cooling mode it is more efficient to have the return near the top, where it can suck the rising warm air. You don’t need to rip open an entire wall to install a return register near the ceiling. The space between two studs in an interior wall can function as a return duct. You may be able to use the space between floor joists in the same way.
Avoid a spot that has other heating or plumbing runs. Wiring will not impede airflow. If the wall you’re working on includes fire blocking, you’ll need to make a third opening in the wall to remove it. A high-wall return will make a big improvement in a room’s comfort level. Your cooling system will run more efficiently, too.
1. Cut grille openings. For the greatest benefit, locate the return on an interior wall opposite a supply register, about 6 inches from the ceiling. Locate studs, drill pilot holes, then cut out the grille opening. Make another opening directly below at the floor level. Saw out the sole plate and cut a hole in the subflooring.
2. Run ductwork. If a joist cavity below runs in the right direction, turn it into a duct by adding blocking as needed and covering the bottom with sheet metal. If that is not feasible. Connect the new duct to the existing return system.
Replacing Radiators with Convectors
Radiation is a hot surface’s I i tendency to “throw” heat into the air around it. Radiation accounts for only part of the way a radiator works. Hold your hand above one and you can feel heated air rising from the top. This process, called convection, helps distribute the heat. Whether a charming antique radiator or a more modern baseboard type, the shape of the unit may be more important than physical size. Longer, lower types don’t put out any more heat than upright units, but they spread it over a broader area.
A large unit may or may not radiate more heat than a smaller one. The square-inch area of the heating surface exposed to air passing through, as well as around it, is the critical factor. So radiation units are sized according to the square inches of radiation that a unit offers. With help from your heating contractor, you can calculate the number of square inches you’ll need to warm a given area of your home.
In selecting a replacement or new unit, also consider the type of metal from which it is made. Cast-iron gains heat and dissipates heat slowly, stretching the cooling-off period between heating cycles. Units made of steel, copper, aluminum, or combinations of these metals heat up rapidly and cool quickly. This means that a single fin-type convector in an otherwise iron system could result in a room that is alternately too hot and too cool. All radiation units need room around them in order to function efficiently. A modern fin-type convector has a cover that is precisely sized to effectively move cool air up and out.
Choosing a baseboard unit. Fin-tube units (top) rely on convection, and heat and cool rapidly. Use them for hot-water— not steam—systems. Cast-iron baseboard units (bottom) also save space but maintain a more even heat. They are a good choice if used in conjunction with existing cast-iron radiators.
Remove the old radiator. Preparing to replace a radiator with a newer unit is a job best left to the pros. The boiler should be turned off and the system allowed to cool. If it’s a hot-water system, the pipes must be drained. Then the old radiator can be disconnected and, with the help of a two-wheeled cart, removed.
Installing convectors. A new convector (for hot water heat only) is easy to install. First the plate gets attached to studs in the wall. Then fin-covered copper pipes are hooked to the system using the same techniques as for standard copper pipe. In some cases valves are installed.
Make the pipe connection. Connecting a new convector to existing piping is often a challenge even for a professional plumber. In some cases the pipe can be joined directly to the old valve using a reducer fitting, as shown above. Often, however, the pipes need to be snaked around and perhaps connected beneath the floor.
Choosing Space Heaters
Many furnaces and boilers are bigger than they need to be, which means you easily can add more registers or radiation units, as shown on the preceding pages. If, however, you want to warm a sizable space, and especially if you need only part-time heat, an independent space heater might be a better alternative.
To narrow the field, ask yourself exactly what job the heater needs to do. Will it be used only occasionally or briefly for backup or auxiliary heating? If so, an electric wall, ceiling, or baseboard unit might be the answer. These are inexpensive, easy to install, and use little or no floor space. Running one for extended periods, however, will add significantly to your electricity bill. The “oil-filled” electrical units (which are actually filled with a sort of antifreeze) are comparatively efficient energy users.
Advances in wood-burning technology have turned the wood-burning stove into an efficient modern heater. Unless you cut your own wood, however, check on wood prices before you buy one. Remember that cutting wood, stacking and carrying it into the house, and removing ashes demand large expenditures of human energy. Storing wood near your home may also attract termites and other insects. Fireplaces are not included here because most do not do a good job of space-heating. Many actually rob heated air from your home through the chimney.
Wall furnace. For providing ample heat while taking up only a small amount of horizontal space, it’s hard to beat a wall furnace. Because it’s natural gas, it’s economical. Installation requires a power line, a gas line, and a vent that runs outdoors.
Wood stove. Modern wood stoves are virtually airtight; they use catalytic converters and special drafting systems to extract maximum heat from each load of logs. Some wood-burning heaters have thermostatic controls. One of these can warm a small house.
Electric wall unit. Electric heaters install anywhere and come in many different models. They are often a good choice for a small area or as a supplemental heat source to boost heat in a room that’s a little cold.
Multifuel furnace. Multifuel furnaces burn wood, coal, gas, or oil, producing heat even when you’re gone for long periods. These tend to be efficient when burning wood, and less so when burning oil or gas.