Higher CFM after window replacement

Ask replacement window questions & get answers!
Post Reply
Message
Author
stkevinsverve
Posts: 2
Joined: Thu Jun 27, 2024 1:17 pm

Higher CFM after window replacement

#1 Post by stkevinsverve »

Hello,

I recently performed a blower door test on a client's home after they had their windows replaced. After testing and consulting the previous CFM, the CFM actually increased by 600 CFM. Is there anyway to explain this? I was the analyst that performed the pre-project BDT and also made sure conditions were the same both times I tested. The only reasoning I can put to this is much like a leaking dam. One leak was patched and put pressure on another causing a much bigger leak than the sum of the two before the repair. Has anyone else ever experienced this?

User avatar
toddinmn
Posts: 1096
Joined: Tue Jan 06, 2009 9:02 pm

Re: Higher CFM after window replacement

#2 Post by toddinmn »

Details on the old windows and the new would help .
Old windows painted shut can be pretty air tight.
New windows with low quality and Poor installation can be factors. I’d focus on the windows if nothing else was done .

stkevinsverve
Posts: 2
Joined: Thu Jun 27, 2024 1:17 pm

Re: Higher CFM after window replacement

#3 Post by stkevinsverve »

The old windows were painted shut and were pretty drafty. The new windows are Anderson and installed very well. It is just baffling.

User avatar
Randy
Posts: 1224
Joined: Fri Oct 08, 2004 7:26 am
Location: Houston, TX

Re: Higher CFM after window replacement

#4 Post by Randy »

Are the Andersen windows their 100 series?

User avatar
TheWindowNerd
Posts: 2302
Joined: Fri Apr 17, 2009 3:05 pm
Location: SE PA & NJ; DFW/Metroplex

Re: Higher CFM after window replacement

#5 Post by TheWindowNerd »

AW windows are very leaky.

User avatar
Windows on Washington
Posts: 5397
Joined: Fri Oct 27, 2006 11:23 am
Location: DC Metropolitan Area-Maryland/Virginia/DC

Re: Higher CFM after window replacement

#6 Post by Windows on Washington »

That's no good.

We actually did a CFM 50 test on a home, before and after, after an install of about 28 Okna 800 windows, and the CFM number dropped by 1400 cfm. Home actually got to minimum ACH number.

User avatar
toddinmn
Posts: 1096
Joined: Tue Jan 06, 2009 9:02 pm

Re: Higher CFM after window replacement

#7 Post by toddinmn »

You could tape off the windows to see if they were the source. From the air infiltration data I have seen , Andersen windows performed surprisingly well. I have no data on Renewal by Andersen by the the way.

User avatar
Windows on Washington
Posts: 5397
Joined: Fri Oct 27, 2006 11:23 am
Location: DC Metropolitan Area-Maryland/Virginia/DC

Re: Higher CFM after window replacement

#8 Post by Windows on Washington »

+1.

Tape them off and see if you can get a blower door infiltrometer and run some smoke and volume tests.

I think the regular series do pretty well. I have heard about some high numbers out of their replacement series windows. HomeSealed has specifically gone in and replaced "new" RBA units that were performing like crap and the client would watch the curtains move like the windows were open.

User avatar
TheWindowNerd
Posts: 2302
Joined: Fri Apr 17, 2009 3:05 pm
Location: SE PA & NJ; DFW/Metroplex

Re: Higher CFM after window replacement

#9 Post by TheWindowNerd »

What series of AW?
The following test results from AW reports
WDH = .16 AI
TW= .10
A series= .08
100 = .05
The only one that gets close to our minimum is the 100 single hung.

User avatar
toddinmn
Posts: 1096
Joined: Tue Jan 06, 2009 9:02 pm

Re: Higher CFM after window replacement

#10 Post by toddinmn »

IMG_2006.jpeg
IMG_2008.jpeg
IMG_2007.jpeg
I got different numbers than you.
It is almost Impossible to get any air numbers from Andersen now.

Post Reply