I’m trying to decide if upgrading to superinsulated windows is going to be worth the money. My usual is a double pane low-e2 (U=.30). I’m looking at various heat mirror products, hoping to maximize heat gain and minimize loss. I’m in Idaho at 6000′ (it’s snowed something like 14 days in April so far this year!), so retaining heat is usually a worthwhile endeavor.
Anyone with experience with the heat mirror products? Competing window salesmen claim they can warp with age. Ever run into that problem? Argon gas and the like aren’t available here because of the elevation. Maybe I’m better off with an insulating blind? Let me know what you think.
thanks
Replies
Dan,
I did a study when selecting windows for my own home in northern IL. To make a worthwhile evaluation, you need to know:
Annual energy use or HDD (heating degree days) for your location;
Cost of fuel at your location;
Cost and U values of the various windows you are considering;
And the overall total quantity of glass.
For me, the cost of the Lowen triple glazed, versus the Pella Smart Sash II, at the cost of fuel for me (no NG, only LP at an average of $1.00/gal) would have had a payback of some 35 years, or so. I decided it wasn't worth it. BTW, a U of 0.3 is pretty good. Your milage may vary, but do the math and see what you get. Unless there are energy conservation incentives that apply, a straight payback of over 20 years is not worth it, 10 or 15 years, worth considering and less than 10 year payback would be money well spent.
As far as the other stuff, I can't help you there, except I do use "window quilts" in spare rooms and the like (where I don't care to see out) that helps limit the heat loss.
Don't forget to take into consideration the "opportunity cost" of tying up the money that could have been invested elswhere.
Steve
Thanks for the input. I'm working on the calculations now. It seems like I'll just stick with the Pozzi low-e2, and get some insulated blinds. They add about another R=3.5 to the windows. I was curious if anyone had experience with the Heat Mirror products though.
Strictly anecdotal:
I did a 4 Seasons sunroom kit with heat mirror in the roof glass but not in the wall glass. I could feel the difference when I was near a wall panel vs, near a ceiling panel.
The room was pretty good at not gett ing unbearably hot even though it was a western exposure.
Steve
Was the difference that you got less heat gain, or less heat loss. They make products tailored for both, TC88 to allow solar gain and SC75 to block out solar gain. Which did you use? Anyone heard anything about the Heat mirror deforming over time?
Our concern was heat gain in the summer, being that it was a western exposure. I don't recall the specification, but it was supposed to be the product that reduced heat gain in the summer.
Steve