Forced Air Heating System Maintenance

To maintain the energy efficiency, safety, and useful life of your forced air heating system, it is important that your home maintenance program include the proper maintenance for your heating system.

 Maintenance Task #1:  Replace air filter

This task involves removing the old air filter and replacing it with a new one (or washing the old filter depending upon manufacturer's directions).  The filter is typically rectangular in shape, about 20 inches by 16 inches, and about 1 inch thick.  It slides into the main ductwork (near the inside fan unit) to help take dust, pollen, etc. out of the air that circulates in your home or building.

Something you might want to consider is getting a 'permanent' air filter for your furnace.  This is a filter that you can wash and re-use, instead of the paper kind that you have to replace and throw away.

There are two reasons for replacing this air filter:

• As a filter gets dirty over time, it begins to clog with dust, pollen, etc.  A dirty filter means the fan motor of the air conditioner has to work harder to move air through it, which means it has to consume more energy, and is therefore more expensive to operate.

• The filter helps to clean the circulating air, which makes room cleaning easier and less frequent, improves indoor air quality, and helps to provide relief to allergy sufferers.

 Maintenance Task #2:  Air duct cleaning

The condition of moisture, dust, pollen, etc. in your ductwork can create a breeding ground for molds and spores.  Cleaning the ductwork removes these contaminants and also increases the air flow efficiency of your ductwork which can save energy.

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QUESTIONS & ANSWERS from "Ask-the-Wizard":

QUESTION from rneilan on 3/3/2008:

I have a unico high velocity air and heat system.
The heat system is fired by oil.
I have three return filter vents. I am aware these filters should be changed regularly for the system to operat efficiently. However, should these filters get real dirty over a period of six months or so due to neglect etc..would it follow that the heating sytem would run overtime trying to bring the building up to the set temprature resulting in not only a higher use of electricity but also oil. If this were to occur over the winter months in New England can you estimate a a percentage the loss of efficiency. For example, as a pwercentage,how much more oil would I be burning due to the lack of efficiency. Can this be estimated? Thank You

ANSWER FROM HOME-WIZARD.COM ON 3/3/2008:

Dear rneilan:

A good rule of thumb is that dirty air filters can cost you up to an additional 10% in energy costs. Its not as much the fuel (oil) to run your furnace, but rather, its the additional electricity to push the air across filters that have higher resistance because they are dirty.

If you want to calculate more specifically what it could be costing you for your particular equipment, here is a website that describes the calculations to do this:

http://findarticles.com/p/articles/mi_pwwi/is_200510/ai_n15704065

Hope this is helpful. 
Home-Wizard.com
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QUESTION from Ken on 1/31/2008:

Hi I have to replace my steam radiator air valve. The air valve I have is shape like a long cylinder but the one I have to replace it with is shape like a bullet. My question does the shape make a different in the way steam will run through my house or is it that different brand make the air valve in different shapes?

ANSWER FROM HOME-WIZARD.COM ON 1/31/2008:

Dear Ken:

Are you refering to your steam radiator "air" valve which is located near the top of the radiator, or do you mean your steam radiator "pressure reducing" valve which is typically located near your boiler?

Home-Wizard.com
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FOLLOW-UP QUESTION from Ken on 1/31/2008:

Here's more information to my question . . . The steam radiator "pressure reducing" valve which is located near my boiler in the basement I think this is what I was referring to it is located on the top of a pipe near the boiler and you can hear it let air out from time to time . I hope I was able to explain it better to you the part seems to go by few different name Air Valve,steam radiator valve etc..

ANSWER FROM HOME-WIZARD ON 1/31/2008:

Dear Ken:

Yes, you are correct, the pressure-reducing valve is also called the “automatic make-up valve” or the “feed-water pressure regulator”. The pressure-reducing valve connects the house plumbing supply system to the boiler water. It is designed to automatically maintain an adequate amount of water in the boiler at the desired pressure (12 to 15 psi).

The pressure-reducing valve can also be part of an assembly that includes a pressure-relief valve. Some types of pressure-reducing valves have a check-valve inside of them that prevents water flowing back from the heating system into the plumbing system, and as such, it acts as a backflow preventer. Note however that some towns require the backflow preventer to be separate.

Since it sounds like your new pressure-reducing valve is significantly smaller than your previous one, I’m wondering if the one that you replaced was also a pressure-relief valve or had a check-valve inside of it. If this is the case, then your system could now be potentially operating without either a pressure-relief valve or a backflow preventer. This is not good, and it NEEDS TO BE VERIFIED AS SOON AS POSSIBLE. If you no longer have a pressure-relief valve or backflow preventer in your system, then you could potentially over-pressure your system or have heating system water flowing into your household drinking water.

Hope this is helpful.
Home-Wizard.com
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FOLLOW-UP COMMENT from KEN on 2/4/2008:

THANK YOU FOR YOUR REPLY ON THE AIR VENT I FOUND OUT THAT THE VENT I HAD WAS THE SAME KIND BUT IT WAS AN ADJUSTABLE AIR VENT. BUT TO BE ON THE SAFE SIDE I REPLACE MY AIR VENT WITH THE EXACT SAME ONE THANK YOU VERY MUCH FOR YOUR HELP

ANSWER FROM HOME-WIZARD.COM ON 2/4/2008:

Ken:

. . . you are very welcome.

Thanks for the feedback! And we're glad we could help you.

Regards,
Home-Wizard.com
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QUESTION from Bob on 5/21/2008
I always forget which way cold air returns should be set!  Is the lower one open in winter and the top close or is it the reverse?

ANSWER FROM HOME-WIZARD.COM on 5/21/2008
Bob:

Its a good question.

The way to help keep it straight is to remember that warm air rises. And then depending on the season asking "where do I want the 'unconditioned' air to come from"?

For example, in the winter, since the air near the floor will be cooler near the floor than it will be near the ceiling, and your goal in the winter is to heat the air in the room up, you will want to draw the cool air from near the floor into your heating system so that it will be heated up.

And then alternatively, in the summer, since the air near the ceiling will be warmer than near the floor, and your goal in the summer is to cool the air in the room down, then you will want to draw the warm air from near the ceiling into your air conditioning system so that it will be cooled down.

So "summer ceiling" and "winter floor".

Hope this is helpful.
Home-Wizard.com
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QUESTION from Bekkie on 8/19/2009
yes that is correct the air flow is very light coming out of the vents, we did install an in line fan hoping that would force more air out seems to be helping some. We change the air filters about every 30 to 45 days, and the airconditioner outside is ok. I would like to be able to just not have it so cold in the lower level and so warm upstairs.

Can you think of any thing else we can do?

Bekkie

ANSWER FROM HOME-WIZARD.COM on 8/19/2009
Bekkie:

Have you tried dong something like the following:

o open the supply vents on the lower level.

o have someone go upstairs and feel the upstairs supply vent.

o then fully close all of the vents on the lower level.

o then ask the person upstairs if when you closed the lower level if they could feel an increase in the air flow from the upstairs' supply vent.


If there is no (or very, very small) change in air flow when you do this, then I'm wondering if:

1) there is a damper in your ductwork that is stuck in the closed position (You said that you have only lived there for 2 year, so maybe the previous owners didn't want to spend the energy/money to cool the upstairs, so they put in a damper to keep the cooling all down on the lower level?). 

2) or there is an obstruction in the ductwork going up to your second floor.

Just let us know what you find out. If this doesn't work, maybe we can figure out something else which could be causing your problem.

Regards,
Home-Wizard.com
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