Are there any standards or ratings for storm windows?

[hdrider_chgo]

I am looking into several lines of manufactured storm windows, trying to compare them, and trying to figure out how they are rated. I have to admit, I am very confused.

1. It appears that no storm windows are Energy Star rated.
2. None seem to be rated by the NFRC.
3. Most manufacturers offer no performance data. However upon inquiry, one manufacturer told me:
-----------------------
The only testing we’ve had done on our windows is the ANSI/AAMA 1002.10-93 Which the window passed with .65 air infiltration. The amount allowed is 1
-----------------------

Another gives the following data in their marketing literature:
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Paragraph No 2.3.3.2 Air infiltration measured 0.29 CFM/FT Allowed 1.0 CFM/FT
0.56 psf (15 mph) measured 0.76 CFM/FT Allowed ----
1.56 psf (25 mph) measured ---- Allowed -----

Done by a national certified testing laboratory
-------------------------

Don't really know what any of this means, and I haven't been able to locate anything online to explain it.

3. Whether storms are eligible for the Federal Tax credit seems to be a gray area. The DOE says on their web site:

Yes, there is a tax credit for storm windows and doors in 2009 and 2010 that meet this criteria:

"Storm Window. A storm window that, in combination with the exterior window over which it is installed-

(a) Has a U-factor and SHGC of 0.30 or below; and

(b) Meets the prescriptive criteria for such component established by the IECC"

How the heck would anyone be able to tell THAT?

http://www.energystar.gov/index.cfm?...ts.tx_index#c1

So, what I am wondering is how you compare the performance of one storm window to another? Is there a way?

[mrd999]

A brief description of AAMA standards may help: http://www.aamanet.org/upload/CMB-1-98.pdf

[Martin Holladay]

HD Rider,
The tax credit criteria for storm windows are a mess -- poorly crafted, with no guidance provided by the Federal government.

You might want to check out
http://www.kaufmannwindow.com/2009energytaxcredit.htm

For those of us who live in cold climates (IECC climate zones 5-8), we need the storm window plus original window to have a combined U-factor of 0.35 (if we want to apply for a tax credit). That's a tough criterion. There's simply no way that a storm window over a single-glazed window will ever qualify.

In most cases, a low-e storm window over an existing double-glazed window will probably qualify, but good luck convincing the IRS if they ever ask you to document how you calculated the window U-factor of the storm plus window combination. Your best bet is to refer to ASHRAE Fundamentals, Chapter 27, Table 5. Good luck!

Martin Holladay, senior editor
www.greenbuildingadvisor.com

[hdrider_chgo]

For those of us who live in cold climates (IECC climate zones 5-8), we need the storm window plus original window to have a combined U-factor of 0.35 (if we want to apply for a tax credit). That's a tough criterion. There's simply no way that a storm window over a single-glazed window will ever qualify.

I'm not clear on this... "original window" meaning what, a double-glazed unit? "Original windows" here would mostly be single-glazed dating back to 1800's. Some of these must be retained per Landmark criteria. And how would you ever verify the combined performance, since there is likely no performance data available for an existing window.

Also, by that criteria, you are really relying on the U-value of the existing window to determine whether the new storm window is eligible. A storm window would provide the greatest benefit over an old, leaky single-glazed unit, but in that situation may not be eligible because the combined U-value is too low. While installing a storm over a new, state-of-the-art double-glazed window WOULD qualify because the combined U-value would meet the criteria. Even though adding the storm in this case provides minimal benefit. That makes no sense.

How do you go about comparing manufactured storm windows? There seems to be no rating system other than AAMA, and none of the manufacturers I have talked to seem to comply with it. I am currently trying to get more info from AAMA, it's not looking good so far.

[J.Buesking]

Around here storm windows are a major no no.

They shorten the life of the existing window tremendously.

They leak, then the sun heats up the space between the the two and litterly steams the glue and glazing around the window.

[Martin Holladay]

HD Rider,
By "original window," I simply mean the existing window -- whatever is in the house before you decide to install a storm window.

If the existing window is single glazed, forget the tax credit. The storm window will never be eligible -- certainly not in Zones 5-8.

If the existing window is a decent double-glazed unit, a low-e storm MIGHT be eligible for the tax credit. But as I have already written, good luck documenting that fact if you are ever challenged by the IRS.

Energy modelers use default values when calculating the U-factors of existing windows. There are simple techniques for determining whether existing double glazing includes a low-e coating. Once you know whether or not the double glazing is low-e or not, you simply use default values for the existing window.

You're quite right -- the storm window tax credit makes no sense.

[Martin Holladay]

J. Buesking,
I strongly disagree with your generalization that "storm windows ... shorten the life of the existing window tremendously." The majority of homes in Vermont have had storm windows for 100 years, and the storm windows have not shortened the life of the primary windows. In fact, there is plenty of evidence that primary windows last longer when protected by storms.

[Dick Seibert]

Martin:

I think what Josh is referring to is installing storm windows over windows with IG units, most manufactures void their warranties if storm windows are installed over them because of the heat build-up Josh describes; Hell, they void the warranty if you put solar film on windows with IG units because of heat build-up between the glass.

[hdrider_chgo]

Martin:

I think what Josh is referring to is installing storm windows over windows with IG units, most manufactures void their warranties if storm windows are installed over them because of the heat build-up Josh describes; Hell, they void the warranty if you put solar film on windows with IG units because of heat build-up between the glass.

That's interesting, because some manufacturers, such as Marvin, sell triple-glazed units which are essentially an insulated glass in the sash, with a manufactured storm window applied to the outside of the jamb.

[J.Buesking]

J. Buesking,
I strongly disagree with your generalization that "storm windows ... shorten the life of the existing window tremendously." The majority of homes in Vermont have had storm windows for 100 years, and the storm windows have not shortened the life of the primary windows. In fact, there is plenty of evidence that primary windows last longer when protected by storms.

I'm not much into building science but "around here" they do more damage than they prevent.

Humidity is real bad here. Vermont probably not so much.

I've pulled several off that had moisture still between the original window and storm and it hadn't rained in days.

[Dick Seibert]

Harley:

I use triple glazed glass almost excursively, interestingly the IG unit manufacturers will not put coatings on both the #2 and #3 surfaces in a dual glazed units becasue of heat build-up, yet they will put coatings on both the #2 and #5 surfaces on triple glazed units, I've never understood that and have asked, all I get is that testing shows that the triple glazed survive and the dual glazed don't. I suspect that a lot has to do with the spacer, a metal spacer like Intercept with a minuscule coating of butyl or silicone allows for no expansion, a full butyl rubber or silicone spacer will take quite a bit of expansion/contraction before failure. In the above image you can see how the rubber can expand in the left and center IG units, and how the seal would fail with expansion in the right.

BTW, never use Intercept spacer, I just got off the phone with a customer of 12 years ago with more seal failures, it seems that I'm going to be spending the rest of my life replacing failed IG units, the manufacturer warrants the units for life, but I had to supply the labor to replace them, had I know how bad these things were I wouldn't have applied my normal lifetime guarantee for my work. Energy efficiency comes at one Hell of a price, both to the initial consumer and to responsible contractors who warrant their work. It's best to tell customer right out front, that windows are no-longer lifetime investments, they are like paint and roofs, or tires on a car, they must be routinely replaced.

[NW Architect]

Stick a single-glazed, perimeter-gasketed storm window over a drafty, wood sash, single glazed window and you will have condensation on the back of the storm, rotting the sash.

Stick a double glazed storm over the same existing window and, if the storm has adequate U-value, the inside of it will stay warm enough to avoid the condensation

Open the drafty, original window a bit, and enough air circulates to avoid, or mitigate any condensation problem.

If the original window is not drafty, and the preimeter frame is not permeable, the condensation problem won't occur.

If the storm leaks in the rain, condensation will occur no matter what.

. . . IMHO

[hdrider_chgo]

I finally got to the bottom of this (if anyone else cares). The only standard that applies to storm windows is from the American Architectural Manufacturers Association (AAMA), standard 1002.10-93. And it's virtually unused.

Initially the AAMA tried to tell me there was no such standard. But I pressed on and got to their chief engineer for certification who explained the situation (see below).

I also spoke with the National Fenestration Rating Council (NFRC) at the Remodeling Show in Indianapolis last week. They also told me there were no standards for storm windows. I told him I thought this was ludicrous, since it has been well-established that storm windows are a much more cost-effective and architecturally sensitive solution than window replacements, with nearly the same energy savings. And with no standards there is no way for the consumer to do any comparison shopping. He finally admitted that the Department of Energy is after them because they feel this situation is unacceptable as well.

This is a joke. If you go to the AAMA web site and pull up storms as described below, you get a list of one.

I visited a large apartment building on the west side of Chicago last week, built in the 1920's. In the 1990's, they removed all the original heavy wood sashes and installed vinyl windows, destroying the architectural look of this solid brick building. Now, they are replacing all those vinyl windows (hundreds of them), which are already broken and failing, with another round of new "super high efficiency" vinyl windows. The general approach we are taking to windows in this country is madness.

The answers are ‘embedded’ with your questions, below.

In answer to your second question: Very few storm products are authorized for certification. This isn’t because very few pass testing to AAMA 1003 or AAMA 1002.10; very few manufacturers are interested in certifying these products separately. The AAMA website Certified Product Directory (CPD) is not searchable by the standards used for certification. The only way to search the CPD for storm products is by Operator Type.

AAMA 1002.10, Voluntary Specifications for Insulating Storm Products for Windows and Sliding Glass Doors specifies the following Operator Types:

FWE Storm Windows-Fixed, External
HWE Storm Windows-Horizontal, External
VWE Storm Windows-Vertical, External
SGE Storm Doors-Sliding Glass, External
FWI Storm Windows-Fixed, Internal
HWI Storm Windows-Horizontal, Internal
VWI Storm Windows-Vertical, Internal
SGI Storm Doors-Sliding Glass, Internal

In the on-line AAMA CPD, the pull-down list of available Operator Types from which to select is populated by the contents of the database that runs the CPD. You’ll notice that, of the several Operator Types listed above, only VWE is currently available for selection in the CPD pulldown. This is because only VWE products are currently authorized for certification.

Regards,
Dean Lewis
Chief Engineer, Certification Programs
American Architectural Manufacturers Association
1827 Walden Office Square Suite 550
Schaumburg, IL 60173
www.aamanet.org



1. If a storm window product meets your standard 1002.10-93, is it considered "certified" by AAMA? It is considered authorized for certification; technically/legally, AAMA only authorizes certification, and the manufacturer actually certifies the product in the act of applying the AAMA label. Products that are tested, authorized, and listed are still certified only if they’re labeled. Is that why the Larson storm window referred to below is appearing in your certified products database? In the context of the previous answer, YES.

2. If this is the case, how can I use the database or other means to pull up a list of all storm windows that meet the 1002.10-93 standard? See my extended explanation, above.

3. Does the manufacturer apply a sticker label to the product to show that it has been certified by AAMA, or has met the 1002.10-93 standard? In the context of the first answer to your Question #1, YES. If not, can I contact the AAMA to verify that the product meets the standard?

[m beezo]

I was at my supply house today and asked about storm windows. Of course they would rather sell you a new window than a storm, They had no idea if they were rated for anything at all. They also told that storm windows no longer qualify for any tax credits. I guess they used to but not now.

Someone posted a while back about another brand of window but do not recall the name. They were mainly in the Northeast and were not interested in shipping windows to me so they were not an option. Sounded like a good window tho.

[Dick Seibert]

The general approach we are taking to windows in this country is madness.

Good research Harley, I've been saying this for the last 12 years. At first there was the WDMA, a trade association of wood window manufacturers, and the AAMA, a trade association of the aluminum window manufacturers, eventually the vinyl and fiberglass window manufacturers were admitted into the AAMA. These trade associations were in the business of promoting the products of their members. Because of all the misinformation (bordering on fraud if not fraud) the government created the NFRC to standardize window ratings, yet many aspects of windows were left to the two trade associations, the buyers had to look for two labels, and know how to read them, for example, the biggest factor in window efficiency, air-leakage, was left with the WBMA and AAMA, it was suppose to appear on the NFRC stickers eventually, but to this day you are hard-pressed to find air-leakage on the NFRC sticker (it is now on some). Another problem with the NFRC is taht the dues paying members are the window manufacturers, and it too has become the fox guarding the henhouse.

When I was coming across evidence that many dual pane window installations were actually less efficient than the single pane windows they replaced I started digging into it, you are lucky to even talk to Dean Lewis, when I was talking to him he shut off the conversation by actually telling me that he couldn't talk to me anymore since I was in and out of court testifying against window manufacturers.

Because both the WDMA and the AAMA are fighting over the composite windows, and composit windows are under attack in California for their formaldehyde emissions, the two organizations have joined in fighting California style regulation spreading nationwide, the EPA is attempting to get California style regulation of engineered woods (read toxic woods) nationwide, here is an example of their collaboration fighting toxic products regulation.

I tried my best to expose these frauds about 10 years ago, even the scientists at the Daylighting Institute at the Lawrence Berkeley Laboratories told me: "Good luck in taking on an entire industry singlehandedly."

Martin Holladay once got a vinyl window manufacturer to admit that U.S. window products were inferior to European products because of price competition, Paul Fisette once stated that the problem with American windows was the "Price at the Pump mindset" of the American window consumer. The west coast representative of a window seal manufacturer once told me that there is no such thing as a good window made in the Untied States, you have to go to Canada or Germany to get a good window, yet architects continue to specify, and contractors continue to buy, off-the-shelf windows without specifying the design.

As you are seeing, we are already replacing many PVC windows installations, in many cases I've replaced them soon after installation and even gotten the money back for the consumer, the deeper you dig the more you'll find, but I frankly got tired of the fight.