Low-e Glass in Storm Windows
Our old farmhouse had the sash in the original double hung windows replaced about 15 or more years ago. Some of the windows also have old cheap aluminum framed storm windows. We are considering putting new storm windows on all the double hung windows in the house and I have more questions the more I look. For example, Larson makes a couple of lines of aluminum framed storm windows that look better than what are on our house now. They are also promoting the use of low-e glass in the storm windows. Is it worth getting low-e glass in this kind of window? Does anyone have recommendations based on experience and perhaps records of heating costs, for any particular type/brand/model of storm window?
Our goal is increased comfort and lower heating cost.
Any suggestions will be appreciated.
Jim Erdman, in Menomonie, WI, zone 6A
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Low-e storm windows are a cost-effective measure in your climate zone. The original research on this issue was conducted in Chicago in 2007 by S. Craig Drumheller. Here is a link to the relevant paper: "Field Evaluation of Low-E Storm Windows."
Drumheller concluded, "Reduced total heating energy was significant for both the clear storm windows (13%) and the low-e windows (21%), as were the installed costs ranging between $1,344 and $4,691. In order to determine how cost effective the energy retrofit measures are, a simple payback analysis was performed on the four homes with well correlated data."
The average payback period for the low-e storm windows was 4.3 years. See also the table below from the Drumheller paper.
Drumheller's findings were confirmed in a 2015 study conducted by researchers at the Pacific Northwest National Laboratory (PNNL). For information on the PNNL study, see "Low-e Storm Windows Are Big Energy Savers."
Finally, you may want to read this GBA article: "What Should I Do With My Old Windows?"
The tightest storm windows on the market seems to be Harvey Tru Channels and they have a hard-coat low-E glazing option, but they're a northeastern regional player, probably not available in WI, but it doesn't cost anything to look:
The best grade Larsons are pretty tight too, and can probably be ordered through the same box stores that carry their lower-priced stuff.
Provia has distribution in the midwest, and has a low-E glazing option for their storms. I can't personally vouch for them, but it's worth taking a closer look to compare.
It looks like Harvey no longer offers a storm window.
HD and Lowes carry Larson exterior storms, but don't seem to stock them in-store and I haven't been able to find a display unit so far. In general anyone manufacturing exterior storms doesn't offer much in the way of photos or information about how to order them, etc., making it difficult to evaluate build quality and cost.
Have interior inserts like Indow mostly taken over this market? Is there anyone else I should be looking at for exterior storms or should I keep pulling the Larson thread? I'm in the Seattle area.
I used Larson gold (or whatever they're calling the highest level of Larson storms now), bought from Lowes/Home Depot/a local hardware store. I cannot say if they improved performance over old storms (I have only one room left with old storms). I did get low-E -- it was not much more, maybe $30 on a 72-inch tall window? This was before inflation...
My biggest problems were that the big box stores will not install, and I did not have the ability to install on second floor; and that a lot of the windows broke in transit! I had to re-order repeatedly.
I'll be ordering storms soon myself (w/ the low-e option). Eastern MA.
Prefer a double track profile versus Harvey's triple (moot point ... left the biz).
The options I am working ...
- Larsen. IIRC no shipping charges through big box store.
- Quanta. I thought a slightly better build than Larson. But $100s in shipping.
- Allied. The best, have a single track option. Big bucks.
- Monray and Coastal recently got on my radar when Harvey left the biz.
- Probably will take a quick look at Provia (mentioned by Dana).