Reduce your heating bills – seal your ducts

This is wasting more energy than leaving a window open

I admit it – I go crazy when I see leaky ducts. I’m not talking about ducts that have little leaks, I’m talking about problems that cost you hundreds of dollars per year and could be fixed in a few minutes with a piece of tape.

Incompetent heating contractors hate me. Why? Because I’m on a mission to give you the information you need to know when they’re ripping you off.  On the other hand, quality contractors love my information because I arm you with knowledge so you can tell the difference between the good ones and the bad ones.

Sound interesting? Read on!

How does a forced air system work?

  1. A big fan, usually installed in your basement or attic, sucks air from one part of your house
  2. The air passes through a filter
  3. The system heats or cools the air
  4. The blower pushes the air through the ducts back into the house

This is simple, right? Anybody can understand this principle. So why do so many heating contractors do such a crappy job of installing these systems? Because they’re in a rush and they know nobody is looking over their shoulder checking their work. So even though you may have just installed a super new $30,000 geothermal heat pump or efficient furnace, the installer’s negligence could be reducing the system’s efficiency so much you would have been better off sticking with that 30 year old system.

Think I’m exaggerating. Sadly, I’m not.

Take a  look at the photo at the top of this post. You’ve got a huge fan to the right of the filter. Where do you think it’s sucking air from? It doesn’t take a genius to know that if you have a big hole, a lot of air is going to get sucked from the attic or basement where this is installed instead of from the house (connected to the ducts to the left of the filter).

What are ramifications of an open air filter?

This single problem can cause so many problems, it boggles the mind.

  1. During the winter, the system sucks cold air from the attic instead of air from the house. Then it has to try to heat it, wasting a lot of energy. How much? At night, the attic might be 30F. Normally the system is sucking 70F air from the house. So every bit of air sucked from the attic might require at least twice as much energy to heat as the air from your house.
  2. During the winter, outdoor air is much dryer than indoor air. When you mix that cold, dry air with your household air, you create uncomfortably dry conditions, leading to nosebleeds and cracked woodwork, among other problems associated with low humidity. You probably run a humidifier in the winter to replace that humidity, costing you even more money.
  3. If you’re like many people, you have your blower thermostat set to “on” instead of “auto” during the winter because you want to even the temperatures out around the house. If you’re sucking 30F air from the attic, that’s going to be like an air-conditioner running in your house during the winter, driving your heating bills up even more.
  4. How effective do you think that air filter is? You’re sucking dusty air from the attic. Air filled with fiberglass and other contaminants. Then you’re spreading that around your house. Is your house always dusty? It’s probably because you have leaky ducts.
  5. During the summer, system will suck 130F air from the attic instead of 80F air from your house. Your air conditioner lowers the temperature of that air about 20F, so that 130F air becomes 110F air. Normally, it takes 80F air and drops it to 50F air. So most of your air conditioner energy is going to trying to cool off attic air instead of your house. This can easily double your air conditioner bill.
  6. During the summer, outdoor air that is ventilating your attic, is hot and humid. A big reason for having an air conditioner is to dehumidify your air. Instead, you’re sucking in humid air and blowing it your house. This leads to uncomfortable conditions and maybe even mold and the associated health risks.
  7. You know that mice love to crawl in those openings and build their nests where it’s warm. Do you want to be breathing the air from a mouse that’s living in your ducts?

How to deal with an open air filter

  1. First, fire your heating/cooling contractor. If any company has worked on your system and hasn’t fixed a problem like the one above, they’re totally incompetent. Seriously. I don’t care if it’s your brother-in-law and you’ve been using him for 30 years. He’s probably cost you thousands of dollars in wasted energy and made you sick because he was too lazy to install the right sized filter and cover the filter port.
  2. Buy a properly sized filter that fits entirely within the slot.
  3. If there’s a cover, check the weatherstrip and make sure the cover seals air-tight.
  4. Wipe down the sheet metal around the filter port with a dry paper towel. Get it nice and clean.
  5. Go to the hardware store and buy some foil tape to put over the filter port so it’s really sealed air tight.
  6. Take some of that money you’ve saved and send me a donation so I can keep producing these energy efficiency tips.

There you go. You’ve just saved a few hundred dollars a year on your heating/cooling bills and it cost you five minutes and a few cent worth of tape.


1 thought on “Reduce your heating bills – seal your ducts

  1. Pingback: Understanding and Evaluating Heat Pumps « Ted's Energy Tips

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s