Keeping the Heat On: Keys to Maintaining a Furnace

HVAC fan cover at Safety Harbor Public Library

By Bob Vila

It's tempting to skip the annual furnace or boiler tune-up. Service contracts are expensive and you can often get away with skipping a year or two, especially if your fuel is gas. Gas burns cleaner than oil, so repairs are less likely and it's less critical to clean components. For a number of reasons, however, it can be risky to defer maintenance of HVAC equipment.

Safety: Cracks in heat exchangers are not uncommon and may go undetected for long periods if the system is not inspected regularly. When such cracks occur, combustion gases mix with the household air that's being heated and delivered throughout the home. These gases can include carbon monoxide, a colorless, odorless and poisonous gas that, if released into a home without a CO detector, can have tragic consequences. The HVAC technician will also check for other dangerous leaks, such as cracks at the joint where the exhaust stack meets the chimney.

Equipment life: Heating equipment that is well maintained will last 15 to 30 years; poorly maintained equipment can fail within five. No one wants the expense of replacing a furnace to come around any faster than necessary.

Efficiency: Heating equipment gradually loses efficiency the longer it goes without being serviced. A well-maintained furnace, boiler or air conditioner can save 10 percent or more on fuel costs -- typically more than enough to pay for the tune-up. A good service technician will also check your ductwork for leakage. According to, such leaks can account for losses of 20 percent or more.

Comfort & health: A tuned-up furnace will improve your comfort. Water and air temperatures are optimized, and your thermostat will be checked and recalibrated if necessary. And if you haven't already taken care of it yourself, most tune-ups will include a filter replacement to protect your equipment and remove some of the potentially unhealthy particles that float around in your home.

A quality furnace tune-up: Annual furnace or boiler maintenance is not a job that can be done in 20 minutes. It will take a professional at least 45 minutes to check things like pilot ignition, thermostat operation, draft and switches (several of which ensure safety). The technician will check mechanical components, such as bearings, pulleys and belts, to make sure they are lubricated and in good working order. To maintain peak efficiencies, the technician will also check blower wheels and heat exchangers for cleanliness and carefully clean them. Wiring must be examined for loose connections and frayed insulation. If the stack pipe to the chimney joint is loose, it must be reset with refractory cement. System performance should be measured and recorded before and after the tune-up.

Oil produces far more soot than gas does, and because all that soot can foul components, oil-fired furnaces and boilers may require more time to service. Oil-fired systems also have more moving parts, including burners, circulators, fuel tanks, and fuel tank filters. Homeowners who burn oil should have their chimneys checked annually as well for soot accumulation. This is typically not included in a furnace or boiler tune-up. Hire a certified chimney sweep to clean the chimney of an oil-fired furnace or boiler.

Be sure to hire only a certified, licensed and insured HVAC contractor to tune-up your HVAC equipment. Ask exactly what the service includes -- and hang around to watch as the work proceeds. Your furnace or boiler is probably the most expensive and important appliance in your home, so you should show it the care and respect it deserves.

Bob Vila is the home improvement expert widely known as host of TV's This Old House, Bob Vila's Home Again, and Bob Vila. Today, Bob continues his mission to help people upgrade their homes and improve their lives with advice online at His video-rich site offers a full range of fresh, authoritative content -- practical tips, inspirational ideas, and more than 1,000 videos from Bob Vila television.

Note: The views and opinions expressed in this article are those of the author and do not necessarily reflect the opinion or position of Zillow or AOL.

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Keeping the Heat On: Keys to Maintaining a Furnace

For about $75 to $200, a technician will tune up your cooling system to manufacturer-rated efficiency -- and you won't sweat the first hot weekend with an out-of-commission air conditioner.

Look for a heating and air conditioning contractor that belongs to the Air Conditioning Contractors of America, employs technicians certified by the North American Technician Excellence (NATE) program and follows the protocol for the ACCA's national standard for residential maintenance. Call your electric utility to see whether it offers incentives.

Note: Dirty filters make your air conditioner work harder, increasing energy costs and possibly damaging your equipment. Check them monthly and replace as needed, or at least every three months.

Air conditioners draw moisture from interior air, called condensate, which must run off outside. If sediment and algae clog the drains, water may back up, making your home more humid or creating water damage. Technicians will check the drains during a tune-up; if they clean them out, it could cost up to $100.

If you live in a humid climate, you may want to check and clean the drains yourself periodically. For an oddly riveting demonstration, watch this YouTube clip as the video's star suctions gobs of algae from a drain with a wet vac.

Energy Star says that for an initial investment of $50 to $150 for a programmable thermostat, you can save about $180 annually on cooling and heating bills -- if you can live with higher indoor temperatures in summer (and cooler temperatures in winter). Set the "hold" or "vacation" feature for a constant, efficient temperature when you're away for the weekend or on vacation.

In summer, you can make those settings more tolerable if you install ceiling fans. Just remember that a ceiling fan cools people, not a room, so turn it off when you leave the room.

Before you heft units to the window sills, check out this YouTube video for practical tips that will help you maximize energy efficiency -- and keep out burglars and bugs, too.

Also, take a moment to clean them. Remove a unit's front grill, then its air filter, and clean dust and dirt from the filter. Check the filter periodically throughout the cooling season.

If you live in a hot, dry climate and cool your home with an evaporative, or "swamp," cooler, you must drain and clean the cooler seasonally to remove built-up sediment and minerals. says that the more a cooler runs, the more maintenance it will need, requiring that you look at the pads, filters, reservoir and pump at least monthly. For more information on evaporative coolers, visit

Photo by Nooccar,

If the gap around a door or window is wider than a nickel, you need to reapply exterior caulk, says Bill Richardson, past president of the American Society of Home Inspectors. Check window-glazing putty, too, which seals glass into the window frame.

Add weatherstripping around doors, making sure that you can't see any daylight from inside your home. You'll save money on air conditioning and you won't have to repeat this task in the fall.

Nature's detritus -- decomposed leaves, twigs, and spring petals and seeds (think maple-tree "helicopters") -- may be worse in spring than in fall. Gutter cleaning generally costs $90 to $225 for a 2,000-square-foot home (with about 180 linear feet of gutter).

Add extensions to downspouts to carry water at least 3 to 4 feet away from your home's foundation. You can use 4-inch corrugated plastic pipe (about $7 for 10 feet).

An easy way to inspect the roof to find damaged, loose or missing shingles without risking life and limb is to use a pair of binoculars. If need be, hire a handyman to repair a few shingles ($95 to $125 for asphalt shingles, according to If the damaged section is more extensive, you'll need a roofer (who will charge $100 to $350 to replace a 10-by-10-square-foot area). Check and repair breaks in the flashing seals around vent stacks and chimneys, too.

If your home has a flat roof with a parapet (a short wall around the perimeter), look for wear and tear in the roof surface. Check the flashing that seals the joint between the parapet and roof. Heavy snow can split the flashing, resulting in leaks. If you need repairs, look for a roofer at the Web site of the National Roofing Contractors Association.

Clean out any roof drains or scuppers (openings in the parapet that allow water to drain) to avoid ponding, which could damage your roof and cause leaks below. A "roof repair" or "sewer and pipe cleaning" company can help.


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