Window R-value testing

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#1

Originally Posted By: Stang
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Fellow inspectors,


I need some input regarding windows in a 2 year old house. I was called to inspect a problem with condensation on kitchen and bath windows. It is a very well built house, but even with somewhat high humidity, my feeling is that there should not be constant condensation running down on to the wood trim. At extreme cold temps, there is a frost buildup on the glass. I did a test by covering one pane of glass with an R-one Styrofoam and the condensation disappeared. Is there a way to test a window for proper R-value?


Michael

#2

Originally Posted By: jrice
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What material are the window frames made of? If they are vinyl, maybe the glass does not have gas in between the panes. Or the glass may leak air if they are a less expensive window. Saw a house once were the windows were cheap vinyl and the seal was poor. They got condensation on inside window pane.


Jeff

#3

Originally Posted By: Stang
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The windows are suppose to be good quality, Pella wood frame. Condensation builds on inside of window and only occurs in the winter.

#4

Originally Posted By: rcloyd
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Pella has one of the best warrantys in the business. Have the owner call them to come out and take a look at the windows. If it is a manufacturing defect, they will usually replace them.


Regards,

--
Russell G. Cloyd
Intra-Spec Home Inspections
& Code Consulting, LLC
859-586-4591
www.intra-spechomeinspections.com

#5

Originally Posted By: lgerving
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It depends on the humidity levels in the house and the outside temps.


You didn’t state where you were at. In the colder climates this is common even with the best windows. There are several things that can come into play here. One is humidity another is what type of heating system is in the house. With out proper air movement around and in front of the window condensation is going to happen when the humidity levels are above 45% and the outside temps are below freezing. There could be several other reasons for this if you are not in the colder areas. One trick I have found that works is to remove the screen window in the winter months, this allows better air flow around the glass.


LWG icon_biggrin.gif

#6

Originally Posted By: mbartels
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Beautifully put Lynn!


The problem is not with the windows but with the high humidity in the house. As stated, with very high humidity on one side and very cold temps on the other, even the best windows will do this.

#7

Originally Posted By: Stang
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Thank-you for your response regarding the Pella windows. This house is in the snow belt of western NY where the last winter was quite cold. The house has a forced hot water heating system so the humidity levels are higher anyway. The problem windows are in the kitchen and master bath and bedroom. The rest of the house is not a problem. All the windows were the same temps at time of inspection. My 1st suggestion was to turn on all ceiling fans to move air around, which helped but did not solve problem. This inspection was called for to settle a dispute between homeowner and Pella windows. So my thought is to find a way to actually test the true R-value of an existing window. My main concern is a ice buildup when exterior temps are very cold.


Michael

#8

Originally Posted By: psabados
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Michael


Well, you hit the nail right dead center on the head. Heating type, poor air movement and the areas that would have even higher levels of moisture, kitchen and baths.

I'm betting no venting in the bathroom to the exterior and probably a recirculating vent in the kitchen. No way for the moisture to leave the dwelling. More of a ventilation problem rather than a window problem.

They need to exchange some air.

Paul