Reuben's Home Inspection Blog

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Don't Ruin Your Furnace

When I think of homeowner maintenance, the first thing I think of is changing the furnace filter. Most homeowners know about this regular chore, and at least one out of five homeowners is diligent about doing this.  As for the rest of you...

Do you really know why you're supposed to change your furnace filter?  Hopefully your dad, your real estate agent, or your home inspector told you about doing this regularly.  There are a couple obvious reasons to change your furnace filter - your heating or cooling system will run more efficiently and the air in the ducts will hopefully be cleaner, but those aren't the most important reasons for changing your furnace filter.

The most important reason for changing your furnace filter is to preserve the life of your furnace.

Dirty furnace filter

To make it very simple, your furnace works by passing relatively cool household air over a big hunk of metal, which is called your heat exchanger.  As the cool air passes over the heat exchanger, it gets warmed, which dissipates heat from the heat exchanger.  This warm air gets distributed throughout the entire home, and this is what keeps the indoor air temperature at 70 degrees when it's -10 degrees outside.  That heat exchanger is responsible for transferring a lot of heat to the rest of the house.

Now think about what would happen to that heat exchanger if it couldn't transfer it's heat to the rest of the house:  it would get extremely hot, much hotter than it was ever supposed to get, and it would probably fail (i.e. -crack) prematurely.

When you operate your furnace with a dirty filter, this is what you're doing to your furnace.  You're preventing the cool household air from passing over the heat exchanger, heat doesn't get dissipated the way that it should, and the life of your furnace gets reduced... besides costing you more money in heating bills.

In other words, don't forget to change your furnace filter.  It's not just about indoor air quality.

Reuben Saltzman, Structure Tech Home Inspections

        

Comment balloon 20 commentsReuben Saltzman • December 21 2010 06:16AM

Comments

Thank you for the post. Good reminder to change the filter often.

Posted by Gita Bantwal, REALTOR,ABR,CRS,SRES,GRI - Bucks County & Philadel (RE/MAX Centre Realtors) over 7 years ago

Gita - thanks, and good morning.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Good Morning Reuben. Thanks for the post and information. Have a great day.

Posted by Patrick White, Driven to bring New Yorkers home (Home Driven Realty, Inc) over 7 years ago

And, diligently, I replace my filter every single Christmas, at the same time I change my clocks.  Getting ready again to do it this weekend!

Thanks for the reminder...

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 7 years ago

Patrick - thanks, you too.

Jay - good man.  You're doing your part to help keep your furnace technician employed.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Thanks!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 7 years ago

Hi Reuben - My husband is a real stickler for regularly changing the furnace filter, so we're good on that. But how cool to know more of the reason about why it's so important to do so! Thanks for youre informative post.

Posted by Judy Klem, Home Staging, Senior Move Management, Fairfield/New Haven counties (Transition Stage LLC) over 7 years ago

If you use outlook that's a good way to remind yourself of these things. I'm crazy about changing my furnace filter and check it more often than I need to.

Posted by Vince Santos, Southeast Michigan Home Inspector (StepByStep Home Services LC) over 7 years ago

Jay - thank you.

Judy - now your husband should have even more reason to be a stickler.

Vince - great idea.  I use your method - I just check it every time I think about it, which is often.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Jay, no wonder you are running late (or is that early) if you wait until Christmas to change your clocks.

Reuben---the same with electronic filters too---gotta keep them clean.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) over 7 years ago

That filter is nasty. I love the filters when there are pets in the house. Sometimes they look like a squashed cat.

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) over 7 years ago

Reuben or Charlie - what time Saturday is best to do the change?  The clocks I mean...

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 7 years ago

Charles - I think a lot of people don't even know that their electronic filters have pre-filters.

James - not a cat fan?

Jay - that sounds like the first line of a Laffy Taffy joke.  

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Knock, knock...

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 7 years ago

Hi Reuben, as always, great information.  How often have you come across a furnace that's been plumbed with air ducts that block the area where you would remove the filter?  I came across one last week that had never been changed since the furncace was installed!  Thankfully, it was "only" two years since the install.

Posted by Frank Cawley Nebraska Home Inspector (BrickKicker Inspection Services) over 7 years ago

Amen to that. I had to change my heating system last Christmas for exactly that reason, a cracked heat exchanger.

Now the system was 20 years old an nearing the end of the life expectancy period, but with more diligent maintenance, it could still be operational today.

RB

Posted by Robert Butler, Montreal Home Inspector | Aspect Inspection (Aspect Inspection) over 7 years ago

Great post - clearly written and information.  Thanks again.

Posted by Peggy Chirico, REALTOR® 860-748-8900, Hartford & Tolland County Real Estate (Prudential CT Realty) over 7 years ago

I don't know how I missed the previous comments...

Frank - I've several filters that had to be bent up to be changed, but I've never found one that was completely blocked in.  I'll bet that two-year-old filter you found was nasty!

RB - yes, regular maintenance surely would have helped your furnace.

Peggy - thanks for reading.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

My split system A/C and furnance share filters and I don't change them as often in the winter (it's about the hours of use I hope) because we primarily heat with a wood burning stove.  It really is about the hours of use and not the time gone by right?

Posted by Tammy Lankford,, Broker GA Lake Sinclair/Eatonton/Milledgeville (Lane Realty Eatonton, GA Lake Sinclair, Milledgeville, 706-485-9668) over 7 years ago

That's correct, Tammy.  

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

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