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I have no clue what it is---so it can't be very important.

By
Home Inspector with Charles Buell Inspections Inc.

Since 1991 in Washington State, some means of bringing fresh air into the home has been required by the Washington State Energy Code.  This requirement is for new construction as well as significant remodels.  So, as an inspector, I am always looking for these systems.

Window air intakesOn remodels it is common to find these systems missing.  When they are missing it is one of the indicators that work was done without proper permits.

When they are missing in new construction it is usually because someone forgot to install the timer and simply installed a regular toggle switch to operate the fan.  Obviously in this case it is not a difficult repair.

There are several means of meeting the requirements of the code and the simplest of these is accomplished by installing a timer-control on a Bathroom exhaust fan or the Laundry exhaust fan.  Other approaches involve being integrated with the heating system ductwork.  Sometimes it is done by means of a Heat Recovery Ventilator (HRV).

These systems don't just exhaust the air, they also require locations for bringing fresh air into the home when the fan is operated.  With no means of providing air to the home, the home would be placed under negative pressure and air would could then be pulled into the space down chimneys and the vents of other fuel burning appliances.  Some jurisdictions used to allow for leakage around doors and windows to be the source of this make-up air.  Obviously not the best solution to the problem.

The other thing to keep in mind is that when any exhaust fan is operating (kitchen, bathroom, dryer etc) make-up air must be provided.  The lack of adequate air intake when exhaust fans are running is often evidenced by dark "ghosting" at carpeting around exterior walls of the home or by "ghosting" at poorly fitted exterior doors and windows.  It can cause smoke to be drawn into the home from fireplaces and it can be related to back-drafting of gas appliances like water heaters.

Fresh air intakes are a REALLY good idea---and will help your home have balanced air pressure---neither negative pressure or positive pressure.  Balanced air pressure within the home is good for avoiding moist air from either being drawn into walls or driven into walls.  In energy efficient homes these considerations become more critical.  In old drafty homes it is done more or less automatically---along with emptying your wallet and supporting the oil barons.

Some windows (like the one in the picture at the beginning of this post) come with little vents in the windows that can be opened to allow air to enter the home----or even leave the home if for some reason a positive pressure was created.  Most home buyers have no clue what theses things are---if they noticed them at all.  During the inspection they are almost always closed---consistent with the homeowner not having any clue what they are or what they are for either.

On a recent inspection I found another common type of air intake.  

Air intake---through the wall type

When this type is installed the inspector will usually find one in each room of the home.  This ensures that fresh air will be drawn into all areas of the home when the exhaust fans in the home are operated.  These are mounted on the wall and have a screened cap at the exterior.  These screens must be maintained free of debris and easily clog with lint because they will act as a filter for the air moving through them.

Sometimes they suffer from house painters that also have no clue what they are for.

Painted air intake

This one, in brand new construction, will need to be replaced due to being heavily painted.

 

 

Charles Buell, Seattle Home Inspector

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Comments (18)

Donald Hester
NCW Home Inspections, LLC - Wenatchee, WA
NCW Home Inspections, LLC

Charlie,

Great blog. It is amazing how many people do not know what the vent on the window is for. I have pointed this out many many times.

May 23, 2011 03:55 AM
Peg Barcelo
Fluff My House! Home Staging Inc. 250.486.6369 - Summerland, BC
The FlufftasticStager from Summerland, BC

Chahhlie, I understand about fresh air intake, we do have one (on the furnace), but to have  (basically) a hole in the wall when it's -30 celsius, does not make sense to me. How do they work? Are they sealed shut until the pressure from a - or + opens them? We spend so much time and money insulating our homes here to keep them warm, to have one in every room... I need to research how they work I guess.

May 23, 2011 04:15 AM
Cynthia Larsen
Cotati, CA
Independent Broker In Sonoma County, CA

Huh ... our utility company has made my Mother-In-Laws apartment so air tight it's stifling. But her electric bill is $13 a month.

May 23, 2011 04:31 AM
Jason M. Keith
Caliber Home Loans - Parker, CO
Equal Housing Lender

That last picture looks suspiciously like sub-contractor work!  Just spray it on and let it dry...

May 23, 2011 04:57 AM
Atlanta's Home Inspector, David Lelak IHI Home Inspections
IHI Home Inspections 404-788-2581 - Canton, GA
Experience the IHI Difference

Great information.  As always, a great affirmation as to why new homes need inspected just as much as older ones... Keep up the good work.

May 23, 2011 05:04 AM
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

Don, yup---and they are almost always closed it seems

Peg, air is only going to be moving through them when the home is under either negative or positive pressure.  Any amount of heat lost is going to be easily offset by the benifts of mainitaining good air quality

Cynthia, there still needs to be some way to change the air

Jason---certainly careless work

David and Bonnie, no question about it

May 23, 2011 06:23 AM
William Feela
WHISPERING PINES REALTY - North Branch, MN
Realtor, Whispering Pines Realty 651-674-5999 No.

Not something we have in Minnesota.  The fresh air is but not that type of vent

May 23, 2011 08:48 AM
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

William, I am pretty sure that this energy code requirement is not common in other parts of the country---but will likely become more common as we become more and more concerned with indoor air quality. 

May 23, 2011 10:35 AM
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

I just inspected an Energy Star Rated home. No HRV or any means of make up air was present. The last three new energy efficient homes I inspected lacked any means of fresh air intake. BUT it is not required here. Most contractors and homeowners have no clue about this. Sound familiar?

May 23, 2011 11:27 AM
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

Jim, it sure does.  In a really humid climate with the AC cranked up in the Summer that can amount to a lot of moist air being sucked into the building envelope.  Of course if the house is tight enough it can amount to a lot of exhaust fans merely "spinning their wheels."

May 23, 2011 11:43 AM
Steven L. Smith
King of the House Home Inspection, Inc. - Bellingham, WA
Bellingham WA Home Inspector

Mr Charles,

I thought that, when you inspected, you always brought lots of hot air into the mix.

Nutsy

May 23, 2011 04:43 PM
Robert Butler
Aspect Inspection - Montreal West Island, QC
Montreal Home Inspector | Aspect Inspection

Then there is the completely old school, old fashioned notion of opening the window. The equipment is already there you just have to use it.

May 23, 2011 05:07 PM
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

Nutsy, I do my best to keep up to you but never succeed.

Robert the minimum requirements of the energy code insures air quality even when the person is to incapacitated or ignorant to do it themselves :)

May 23, 2011 05:45 PM
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

These fresh-air vents bring in cold, wet air when something else is turned on?  Really?  In every room?  Really?

Wow, Billy needs to get on this one!

May 23, 2011 11:26 PM
Steven L. Smith
King of the House Home Inspection, Inc. - Bellingham, WA
Bellingham WA Home Inspector

Charlie,

I think you pretty much got figured out, nailed, and brought down to your own size by Nutsy.

May 24, 2011 10:01 AM
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

Jay, we don't have wet air here :)

Steve, who is Nutsy?

May 24, 2011 11:53 AM
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Delivering the Unbiased Truth.

Just putting a timer on the fan satisfies the fresh air requirement?  Interesting.  'Round here, an acceptable substitute for an HRV is a continuous exhaust fan in the bathroom; one that runs at low speed all the time, and kicks in to high gear when needed.

May 25, 2011 02:46 PM
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

Reuben, probably a smarter idea in your neck of the woods---you guys only get to go outdoors one month a year :)

May 25, 2011 03:00 PM