•Add programmable thermostats so the furnace doesn’t work as hard while you’re away but kicks back in before you get home. In most homes, you can reduce your heating bill about two percent for each degree that you lower the thermostat for at least eight hours each day.

•Insulate your boiler with a jacket.

•Clean or replace air filters regularly.

•Clean registers and make sure they’re not blocked by furniture.

•Bleed radiators properly.

•Tune up your burner every one to three years, depending on what kind of system you have. That will keep your system running well, cut heating costs, and reduce the pollutants that seep into your home.

•Seal furnace ducts to keep them from leaking hot air or circulating dust.

•Line your chimney. High-efficiency units produce an acidic exhaust gas that should be vented only through a properly lined chimney (or through a separate duct). Reline your chimney whenever you replace an old furnace or boiler with a more efficient one, as the new unit may create more corrosive exhaust.

•Keep it up. High-efficiency units produce an acidic exhaust gas that should be vented only through a properly lined chimney (or through a separate duct).

Remember, any improvements you do around the house—from installing efficient windows to adding insulation—can help your furnace to work more efficiently. Even a tree maturing outside a window can have a positive effect. Assess the situation from time to time, and you may realize that you could use an even smaller furnace.