If your present heating system is unsatisfactory—or if it won’t serve a planned addition—you can either upgrade it or replace it. To decide which choice is best, ask yourself the following questions.
Is Your Heating Equipment Working Correctly?
Any heating device needs occasional maintenance, but some cases are especially urgent. Furnaces and boilers that burn gas, propane, or oil need reliable combustion air and unimpeded exhaust of combustion products. Burners need occasional cleaning to avoid producing deadly CO. In the worst case, a cracked furnace heat exchanger can introduce CO into your home. If you can smell natural gas, propane, or heating oil in your furnace room, call your utility or fuel supplier immediately.
Consider scheduling annual system tune-ups until you are confident your equipment is working correctly and safely. Your utility company or a BPI-certified heating inspector can provide good advice.
Are Your Heating Bills Too High?
If you have high heating bills, you may be thinking about switching fuels—say, from electricity to gas. Resist that switching itch until you have completely investigated your home’s insulation and airtightness. A new furnace or heat pump will continue to waste energy if your home is poorly insulated and/or drafty from a poorly sealed exterior.
Does Your System Keep the House Warm Enough?
If not, start by asking yourself these questions:
Next, closely inspect the air ducts. They should be sealed and insulated, unless they are enclosed within your house’s conditioned space. Sometimes—usually near the furnace—air ducts have internal dampers installed. Make sure these are fully open.
Are There Cold Spots in Your House?
Get a home performance assessment and upgrade your insulation and air sealing as needed. If you still have cold spots, ask your home energy or HVAC pro if your existing heating system can be extended to warm up those cold spots. If that isn’t an option, you may be able to install a separate system to serve a small area.
Do You Really Need a Whole New System?
If you have extensive ductwork or hydronic tubing, and it’s in good shape, you might just replace the central unit with a more efficient model. But if the ducts or tubes are in bad shape, or if insulating and repairing them is difficult because they’re in a cramped crawl space or attic, you may want a different type of system altogether. If you have one of the following systems, you should seriously consider replacing it.
Electric radiant-ceiling heat. This system yields cold feet, stagnant air, and high humidity. Hot air stays at the ceiling, and cold air lingers at the floor, providing little warmth. The one advantage is that each room usually has its own thermostat, which encourages zoning, allowing you to set the temperature of each room individually. If you aren’t ready to replace an electric radiant ceiling, emphasize air sealing, insulation, passive-solar heating, and room-by-room heating, so you won’t need this inefficient heat source often.
Electric baseboard heaters. If you’re doing a deep energy retrofit, you’ll have little need for heating; electric baseboards may be appropriate because they cost little to purchase. Otherwise, you can do better. The high energy use, the smell of frying dust, the ticking sound of a warming heater, the fire danger if a toy or blanket contacts the heating coils—all these can be avoided.
Open fireplace. Unless you’ve installed a special duct to carry outdoor air directly to your fireplace, you’re sending a lot of heated indoor air up the chimney along with the wood smoke. Even with a special duct, an open fireplace is not for serious heating. Fireplaces are wonderfully sensuous, but they waste energy and pollute your neighborhood. If you want to keep the chimney and hearth, install a highly efficient woodstove, pellet stove, or direct-vent (outside intake and exhaust air) gas insert.
Oil furnace. Replace an oil furnace with a higher-efficiency condensing gas furnace or heat pump. Have your HVAC contractor determine whether any part of your duct system is salvageable. Be sure to include ductwork to bring outdoor combustion air directly to your new furnace. You’ll get better fuel efficiency and cleaner furnace exhaust, and you’ll help reduce our dependence on imported oil.
Electric furnace. Replace this with a heat pump to significantly reduce your winter electric bill and provide summer air conditioning.