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Energy Auditor


Eric Gans
Certified Energy Auditor


Residential Comfort & Energy Efficiency

Sunday, June 21 2020
How a Gas Furnace Can Cost You in Summer

One of the greatest benefits of being a home energy auditor is that I get to visit so many different style homes and hear about so many different types of issues that I have gained a library of information about how to advise people on what they can do to solve just about any comfort problem. When you fix comfort problems - you save money on your bill too!

Let's talk about gas furnaces for example and why they can be problematic in summer.  Not all homes have gas furnaces and not all homes with gas furnaces will have this issue, so take a look at yours to see if this applies to you.  

A gas furnace is a combustion appliance.  It must evacuate the harmful gases that it creates when burning fuel to heat your home.  As a result, a furnace has a flue or chimney that must go to the "outdoors".  In order to do that, the builder must plan for space inside the home for the flue to run through the conditioned space, up through the attic and out at the roof.  This is known as a chase or conduit.

How does this relate to comfort and high energy bills in summer?  Check out this video to get a better understanding of the problem this can cause.


Generally, warm air follows cold air.  If you open your front door on a warm, humid summer day, warm air from outside wants to come inside.  In winter, the warm air inside wants to go right out.  With that general idea in mind, if the cavity created for the furnace chimney is open at the attic floor (like the one in the picture) then guess what happens...the 150 degree air in your attic wants to seep down into the conduit and wreak havoc on your life!

What do do?

If you have a flue that runs through the attic, you will need a professional to take a look.  Blocking and sealing around a flue at the attic floor requires taking the correct precautions to be sure it is correctly fire rated since the flue gets very hot.  

Another tip:  typically, houses that have an open flue chase at the attic floor also have several other common problems that can easily be corrected.  Another thing I learned from doing so many audits - many people think that they have to live with being uncomfortable.  Not true!


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