Keep your furnace working on the coldest days with some preparation
The vast majority of home heating systems use natural gas furnaces. Gas is efficient, clean, and
readily available. Before the dominance of natural gas, coal and later home-delivered oil were the
main energy sources for home heat. Who wants to go back to having oil delivered or shoveling coal?
Newer gas furnaces are far more efficient than older models, but they still require attention such as regularly changing the filters.
Some filters are washable and can be reused, but they eventually tear and need replacement with new reusable filters or disposable
Besides general dust, shedding pets are another reason to change filters.
Reusable filters range from basic fiberglass to costlier allergy, electrostatic, and HEPA-type filters.
Gas furnaces are sold in two major categories: mid-efficiency (approximately 80 percent efficient)
and high-efficiency (90–97 percent efficient). High-efficiency furnaces are more expensive than mid-
efficiency models by approximately a thousand dollars or so and are apt to be a better investment in a
cold climate than a moderate one. A high-efficiency furnace does require separate venting through a
PVC pipe installed through the side of your house instead of using the chimney.
Oiling the Furnace Motor
Some older furnaces require their motors be lubricated with oil periodically—check your owner’s manual.
Do not attempt to lubricate a motor that doesn’t require it.
Look for a lubricating port accessible on the outside of the motor and add only the required amount of oil—usually just a few drops.
Never use a spray lubricant such as WD-40 to lubricate a furnace motor; use only lubricating oil.
Is it worth going for the highest efficiency furnace? Some installers claim a high-efficiency furnace
is more prone to repairs because it’s more complicated than a mid-efficiency furnace.
Any furnace will work better with regular maintenance, including attending to the alters, having
annua, inspections by a heating technician, and, if needed, having professional duct cleaning.
Inspecting the Exhaust Ducting
Both the exhaust ducting and the heat ducts should be intact, completely connected, and without any corrosion.
Replace any corroded ducting—most likely it will be exhaust ducting.
If there is any loose or broken cement sealer around the exhaust pipe/chimney connection, repair it before running the furnace.
Check that the manual dampers in a forced-air system’s ductwork are open and work—they balance the system’s hot air flow.
New homes have programmable thermostats, but older homes often have mechanical, mercury-
switch thermostats that function by reacting to the ambient temperature. A programmable
thermostat controls heating and cooling by multiple time settings as well as temperature. A
new thermostat must match the voltage rating (low-voltage, mini-voltage, or line voltage) of
the old thermostat.