Steven L. Smith, Bellingham, WA Home Inspector (King of the House)


New Furnace, Service It!

When inspecting a new home, the professional home inspector might have to call for service at a new furnace -- even if the furnace is only a few months old. The problem has to do with wet weather. At least in the wet climate of Bellingham and Whatcom County, builders cut wood and drywall in the garage during the fall and winter. They do so, logically so, to get out of the cold and wet. But guess what is located in the garage at many houses. Yep, the furnace.

And all of that sawdust, shavings and drywall dust ends up inside the furnace and/or the heating ducts and system. The photo below is a classic example of this scenario at a furnace that is only six months of age.

Manufacturers' state that a furnace should be serviced annually but, when a new house is being sold, I usually recommend HVAC service at that time if the furnace is in obvious need of cleaning. Sure, the service might be three our four months shy of one year since installation, but better to get it taken care of sooner rather than later since the device is obviously crusty inside. Estimated design life of a furnace is 15 to 20 years.

Steven L. Smith

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Comment balloon 14 commentsSteven L. Smith • February 16 2014 07:40AM


Steve, This is not all that uncommon and technically could void the warranty of the unit.

Posted by Donald Hester, NCW Home Inspections, LLC (NCW Home Inspections, LLC) over 6 years ago

I also see this a lot.  Once the contractors took the filter out of the unit so the filter would not clog completely and prevent the unit from blowing air!

Mason, your hand sure has grown!  I bet you're a big kid now!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 6 years ago

I've seen the amount out dust and debris that can be generated early in the life of a home Steve, It may be the toughest time for that new furnace! Service it early.

Posted by Tom Arstingstall, General Contractor, Dry Rot, Water Damage Sacramento, El Dorado County - (916) 765-5366, General Contractor, Dry Rot and Water Damage (Dry Rot and Water Damage Mobile - 916-765-5366) over 6 years ago

This isn't a matter of the calendar.  This is a matter of risk.

I recommend to new home buyers  that they change their filters once a month for the first year as long as the builder is still building.  

At least LOOK at the filter from time to time.

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley,, MD & VA Homes and Real Estate) over 6 years ago

Wood can be dirty too if air filters not exchanged.

Posted by Andrew Mooers | 207.532.6573, Northern Maine Real Estate-Aroostook County Broker (MOOERS REALTY) over 6 years ago

I have every new home inspected by a licensed state inspector. It is not just the furnace that might need a bit of tweaking and afterall, these homes are made by subcontractors and the last time i checked perfection is not a possibility.

Posted by Joe Pryor, REALTOR® - Oklahoma Investment Properties (The Virtual Real Estate Team) over 6 years ago

Many manufacturers void warranties if ductwork and furnace components are not protected from infiltration of debris during construction.  Very difficult because the furnace is such a handy thing to heat a house with

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) over 6 years ago


Sawdust can get almost everywhere on a construction site.  I wish there was a way to wrap a furnace during construction phase and protect it from sawdust infiltration.

Posted by Andrew Payne Realtor® Richmond VA Homes For Sale~804-938-5257~, Richmond, VA, Real Estate, SRES®, NAR Green (Piedmont Real Estate) over 6 years ago

Happy this is somethng I don't have to dealith in Florida. Just one more thing to check. A/C systems not generally fired up until al that kind of construction is completed.

Posted by Bill Reddington, Destin Florida Real Estate (Re/max By The Sea) over 6 years ago

I never had thought of this type of issue with new construction.  Thanks for the heads up.

Posted by Joan Whitebook, Consumer Focused Real Estate Services (BHG The Masiello Group) over 6 years ago

One more good reason to have eyes open when doing Real Estate

Posted by Richie Alan Naggar, agent & author (people first...then business Ran Right Realty ) over 6 years ago

Bill, I am always surprised when I think of states that do not require heat. Up here is it just a given, yet the A/C is not.

Thanks for the comments everyone.


Posted by Steven L. Smith, Bellingham WA Home Inspector (King of the House Home Inspection, Inc.) over 6 years ago

Hadn't thought of construction dust effecting a new furnace.

Posted by Brian Clinger, Brian Clinger ABR, GRI, CRS, SRES (Coldwell Banker AJS Schmidt) over 6 years ago

Makes sense. Might want to ask for the ductwork to be cleaned out if you think the builder didn't seal everything off.

Posted by Aaron Hofmann, aka Mr. Smyrna Vinings (Atlanta Communities) over 6 years ago