When talking about replacement vinyl windows is it better to have a higher R value number or a lower number to get the most protection in heat/cool loss?
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Its "U Value" when speaking of glazed surfaces and the lower number is what you are shooting for.
Thanks. Have you ever heard of the window companies Lang Exteriors In Chicago or Park Avenue Windows? I was wondering about the windows and how good they really are.
is it better to have a higher R value number
Yes, higher is 'better' in R (some windows are in U, which is 1/R in simplified form; those, you'd want lower).
Now, that beign said, the best window products out there are still only in the R-3 or 4 range--solar gain from shading (or not shading in some climates), is still much more effective.
Also, draft and moisture control are hugely important, too. Given that you're in chicagoland, a well sealed, tightly flashed R3 unit will be a better buy than an average fit R4, over all (acknowledging that the R4's installed tight would be better, still).
actually, you can get better than R4 if you try:http://www.thermotechfiberglass.com/thermotechAdv.htm-------------------------------------
-=Northeast Radiant Technology=-
Radiant Design, Consultation, Parts Supply
http://www.NRTradiant.com
Here in the northeast, u values of .65 are standard if I recall, without looking up paperwork from the last time I filled out an 'energy form' for a build.And definitely in Chi-Town you want to make sure you have a window that has a good U value rating, with low-e glass as well. Argon filled thermal pane holds up longer regular as well.
Thanks for the ideas but what part of the northeast are you? The companies that are quoting me so far are u values of 3.4 and 5.2.
When I saw you have a .65 I am wondering if these guys either don't know what they are talking about or are confusing it with R value.
Ever heard of Lang or Park Avenue Windows?
Don't take my post as an absolute, like I said I didn't look it up, sometimes I should just stop typing -- like talking too much. Here's a link that I think will help you a lot, its from the National Fenestration Rating Council. They rate windows for permeability and energy efficiency:http://www.nfrc.org/I don't know how to make that linkable, but you can copy that and post it in your browser. You'll get more information than you ever wanted!As for u-values and where I am, I'm in New Hampshire and I looked up the values for a thermal pane vinyl window we often sell: clear glass : .50
low-e: .38
low-e/argon: .35So, like I said, I should refrain from thinking I can remember facts by memory:)I'd be interested in knowing if you found the NFRC site helpful at all.
A good U value to go with is a .32 or LOWER. A .32 U value will give you a R value of 3.
Try Builders Supply on Pulaski by Fullerton. They make many windows in their own factory. Ask for the contractor discount.
You might think I'm joking but I'm not. I tell people who ask about windows and heat loss I tell them to go back to the old fashion heavy lined drapes. Fashion has changed over the years and we all want to have houses that look inside like they belong in Florida or California by having flimsy curtains and blinds.
I don't know what the R value of a heavy drape is but it has to be better than a blind.
roger
That's no joke Roger, here in the northeast, energy efficient houses are often equipped with custom made shades or drapes that are actually like a quilted material. The R-value of an 'insulated' curtain or drape can be significant (probably in the R-3 or 4 range)when compared to regular unlined cloth curtains.