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Energy Solutions

Time to Tune Up Your Heating System

When inspecting your heating system, recognize that some things you can do yourself, and others are best done by a professional.
Image Credit: Bakerview Home Inspections

Mechanical systems need to be tuned up periodically to keep them operating smoothly and efficiently. That’s true with our cars, and it’s true with our heating systems. If you haven’t done so already, now is the time to get your heating system inspected, cleaned, and tuned.

Some of this annual maintenance can be done by homeowners, but most of it should be done by a heating system technician.

Here are some things you can do yourself:

Check and adjust your thermostats. If you have programmable thermostats in your house, take advantage of their convenience and savings potential by properly setting them. Most provide multiple time-periods during weekdays, with potential for separate settings on weekends. For more on programmable thermostats, see my prior column, “Using Thermostats.”

Replace air filters. If you have a forced-air distribution system with a furnace or heat pump, replace the primary air filter at the start of the heating season and then every month or two throughout the heating season, depending on how dirty it gets. Replacement filters cost a few dollars apiece and help your system operate efficiently.

Inspect and clean air registers or baseboard radiators. Efficient heating depends on warm air rising into your rooms from hot-air registers or baseboard radiators (convectors). Make sure these aren’t blocked by carpets or furniture, and vacuum them at the start of the heating season to improve heat transfer.

Tune-up measures that should be done by a professional:

Required heating system maintenance depends on the type of fuel and system you have. In general, oil-fired equipment is a lot dirtier than gas-fired equipment. Oil boilers and furnaces should be cleaned and tuned up every year (in some cases twice a year), while some natural gas- and propane-fired equipment can go for two or even three years between servicing–though I still recommend an annual inspection for safety reasons. A few of the components of this servicing are described below:

Inspect and clean the boiler or furnace. Proper operation requires well-functioning heat exchangers in a furnace or boiler; soot deposits should be cleaned off. The burner nozzle needs to be cleaned to ensure proper firing. And the flue pipe may need cleaning, as deposits may reduce the draft, causing problems.

Measure combustion efficiency. Ask for a written report on the combustion efficiency of your heating system. Heating technicians determine combustion efficiency through a combination of measurements that can include flue temperature, percent carbon dioxide or oxygen in the flue gases, smoke (mostly an issue with oil systems), carbon monoxide, and draft (the pressure differential that exhausts flue gases). Often, the combustion efficiency is tested both before and after cleaning and tune-up; ask for written results of both.

Safety check. Combustion-based heating systems consume oxygen and produce heat along with two primary combustion products (carbon dioxide and water vapor). There are also unwanted combustion byproducts, including carbon monoxide, nitrous oxides, and smoke. The heating system should be inspected for cracks and failed seals that may be allowing flue gases to escape into the home. A heating technician will be able to identify if flue gas “spillage” or “backdrafting” is happening, especially with oil-fired systems, due to soot deposits. Backdrafting problems can arise if changes made in the house, such as general air tightening or installing a central vacuum system or a high-velocity kitchen range hood fan, affect air pressure. Backdrafting is a dangerous condition that should be corrected.

Duct testing. If you have a forced-air system, it’s a good idea to have your duct system tested for air tightness and, if necessary, sealed with duct mastic. This is particularly important if the ducts run through unconditioned space, such as an unheated attic, crawl space, or basement. Ask if your heating system technician has a “Duct Blaster” for this testing. Ducts in unheated spaces should be well insulated.

Recommendations for heating system improvements. During the annual heating system tune-up, ask if modifications would improve performance and efficiency. For example, if your heating system comes on for fairly short periods of time even in the coldest weather, it may make sense to downsize the burner nozzle, which will reduce the fuel consumption (and heat output), so the furnace or boiler will cycle on and off less. With an older oil system, ask if it makes sense to install a “draft reduction” system that will lessen the amount of heat going up the chimney. And if you don’t have them already, by all means consider programmable thermostats.

As you are thinking about improvements to the heating system, don’t forget about the house envelope–buttoning up should be your top priority for reducing energy use for heating.

I invite you to share your comments on this blog. You can also follow my musings on Twitter.


  1. GBA Editor
    Martin Holladay | | #1

    Watch out, Alex — here comes Michael Blasnik
    Every time he gives a presentation at a conference, Michael Blasnik questions the wisdom of frequent furnace filter changes and annual heating system checks. I'm sure he'll arrive soon to speak for himself. At an annual cost of $110 to $200, it's certainly true that furnace checks can't be justified by energy savings (if any). And, as Michael likes to say, dirty filters are more effective at cleaning air than clean filters.

    There's one heating system maintenance item that MUST be done annually: if you burn wood, clean your chimney.

  2. homedesign | | #2

    Not True For AC Coils
    Martin & Michael Blasnik,
    Perhaps timely changing of filters is not so critical with Heaters...
    I would not press my luck...
    It is very important for AC coils...
    Dirty filters cause slow air movement and freeze-ups .. costly service calls and sometimes condensate overflow.

  3. user-716970 | | #3

    Just Change It
    While working for an HVAC contractor, we had many calls because of low heat output. Quite a few of these calls were the result of plugged filters causing the furnace to overheat and go off on high limit...a potentially dangerous and damaging situation. Check your filter even more often if you have furry house pets...

  4. Michael Blasnik | | #4

    filters and tune-ups
    Martin has called me here I am ;)

    To be clear, I do not advocate leaving filters in forever. It's just that frequent advice about changing them every month to save energy is bogus -- there is no data to support such claims. Changing cheap filters once per season is generally fine while more fancier and more efficient filters might need to be changed a little more frequently. I would guess that systems that are going off on high limit due to dirty filters have occupants who didn't know they had a filter or hadn't changed it in multiple years.

    For cooling, air flow is more important for efficiency but it takes a very dirty filter to reduce flow substantially. For systems with low air flow due to restrictive ductwork or other problems, then filter changes may be more important. But for systems with adequate air flow, once is season is probably fine. Also, recent research in Wisconsin found that air conditioners can have too much air flow, not too little. For those systems, a dirty filter would improve efficiency (at least for a standard PSC fan motor).

    In terms of tune-ups. There are no studies that demonstrate significant energy savings from tuning up gas furnaces but there are studies that show no energy savings and some that show no measurable improvements in SSE after a tune-up. These studies are for older systems. For newer equipment, the potential value of a tune-up is even more remote. Annual tune-ups are just a waste of money and energy (the contractor drives to your home...).

    For oil systems, tune-ups can make more sense (there are more things that actually get dirty) although studies showing energy savings are few and far between and suggest that savings may only be found for systems that hadn't been services in many years.

    Heating system safety checks should be done every few years, but I wouldn't have much faith in the types of safety checks done by the average contractor in the yellow pages. I'd recommend a CO detector.

  5. Kevin A Gerrity | | #5

    Tune-ups should not be about savings, but rather about proper operation, safety and longer life of your heating/cooling system.

    Just as your car needs regular maintenance to last longer, your heating and cooling systems do to. However you do not need to have a professional do this every time. You should at least twice a year do a visual inspection and cob web cleaning of your own heating and cooling systems.

    I recommend that when you do call a Professionnal make sure you are there and watch what they do. If they do not like that find some one else to spend your money with. Ask questions? Many! Find out as much as you can about your heating and cooling systems, don't be afraid, it is your home of place of business, not to mention your money.

    At first when you buy a home you should have the system tuned-up every year. Do not assume the previous home owner took proper care of the system. Then once you have an understand of your heating and cooling system you and your Professional can come up with a plan of proper maintenance. Oil should be check every year and Natural Gas and Propane every 2 years.

    Remember it is not about what you will save today, but what you will prevent tomorrow. A Professional heating and cooling company will show you how to do a basic inspection your self and help prevent higher replacement costs in the future.

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