Andersen windows: PassiveSun? Heatlock? LowE4?
Anyone know what technology Andersen is using in what they call “PassiveSun”, “HeatLock”, or “LowE4”? These are available as options to some of their windows, even the double pane 400 series.
I pulled their NFRC data [0] and found this test result for a 400 series casement w/out grill with PassiveSun + LowE4:
U-factor = .29
SHGC = .52
I’ve tried comparing this NFRC data with Marvin’s [1] but it’s kind hard not knowing what Andersen’s technology is under the brandname. An Integrity series wood Ultrex casement w/out grill but LowE1 + Argon is:
U-factor = .27-.30
SHGC = .54-.56
I realize this isn’t totally apples-to-apples. Both are double pane casement but Marvin’s Integrity is a “Ultrex” fiberglass frame with wood interior while Andersen’s 400 is vinyl clad though also wood interior, but supposedly they source from the same glass maker? So is Andersen’s “PassiveSun” really just a single layer / Low E1?
BTW: I’m looking at high solar gain + low U-factor combo b/c of the application we have (south facing) and our builder is sourcing materials w/in 500miles as one of our green goals so Marvin & Andersen aren’t just “big vendors” for us but are local.
[0] https://awwebcdnprdcd.azureedge.net/-/media/aw/files/technical-docs/performance/performance-windows-patiodoors-nfrcratings–400series.pdf
[1] https://www.marvin.com/support/energy-data
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Replies
Vapor,
Here is a link to Andersen's web page -- the page that discusses glazing options: Andersen glass options.
I agree that the page is short on details.
Concerning the comparison between low-e windows with a high SHGC and low-e windows with a low SHGC: these differences are usually due to the type of low-e coating chosen by the glass manufacturer. For more on this issue, see "All About Glazing Options."
When Anderson talks about "Low-E4," the company is probably talking about a type of IGU that includes a hard-coat (pyrolitic) low-e coating on surface #4 (that is, the innermost surface of glass facing the interior of the house). The use of a surface 4 coating allows double-glazing to have two low-e coatings, thereby lowering the U-factor of the IGU.
Somewhat paradoxically (counterintuitively?), a surface 4 coating reflects radiant heat energy back into the room, and IGUs with surface 4 coatings have a colder interior surface than conventional low-e double-glazing without the surface 4 coating. The glazing performs better, but the surface is colder. However, if you are sitting near the window stark naked, the glass will feel warmer (even though it is colder).
I believe (but don't know for sure) that both of these vendors are using Cardinal's insulated glass with the LoE 180 high-gain coating. With just one coating it's p probably on surface #3, with double low-E it's on surface #2, with a second pyrolytic hard coat (Cardinal i89) on surface #4.
(Coood be rong, offan am...)
The spacing between panes and gas fill and the frame materials make a real difference in the U-factor, but not nearly as much difference in the SHGC. With air fill the double low-E loE 180 + i89 glass run about U0.24-0.28 at center glass depending on spacing before factoring in the frame, grilles, spacers. With argon fill it runs about U0.20-0.22, depending on spacing.
With just one loE-180 coating and argon fill it runs between U0.26-0.33 at center of depending on spacing.
Martin & Dana,
Ty both for clarifying the technology. I'd read some of your responses and articles here on GBA but, being a layperson, there's a lot of information to digest.
So LowE4 may be a hard coating on surface #4 coating, which makes sense just by the name.
The spacing with Argon over air also makes sense for the U-factor, and I've been aiming for Argon to get at better insulation. We're building a home and I've lived in leaky ones with cold feeling windows before so we want to avoid it for comfort and efficiency reasons.
The Marvin windows are looking better on performance #s, if we can afford them. Marvin lists out performance on their Passive House doc that includes a high solar gain option with U-factors much less than even Andersen A-series. [0]
I've brought this up to my architect as well but wanted to be better informed before discussing it with her. So Ty!
[0] https://www.marvin.com/downloads/request-information/19980669_PassiveBuilding.pdf
The low E coating on surface #4 will be more comfortable to stand next to, even at a higher U-factor, since it's reflecting much of your body heat back at you. With tall windows the lower surface temperature of a LowE4 glazing can result in a perceptible draft, not so much with normal sized windows.
Marvin has surface #4 hard coat glass options too. Theirs is called Low ERS (for Low E Room Side, I guess)
"...our builder is sourcing materials w/in 500miles as one of our green goals..."
500 miles makes the overlap zone between the HQ of both of those vendors pretty big. Got a ZIP code?
Is Pella IA in that radius?
Pella's marketing name for double low-E surfaces #2 & #4 is called "AdvancedComfort". The #2 coating in the AdvancedComfort glass gives it a lower SHGC than some of the other vendors, but they're still pretty good (SHGC 0.35, compared to best in class 0.60-ish for a Cardinal LoE180 + i89 glass, but way better many) , with a center of glass U0.20 in a couple of double-pane thicknesses:
https://www.pella.com/Documents/pdf/professional/features-and-options/3_WinCenterGlassPerf.pdf
There are probably other window manufacturers within your 500 mile radius making pretty-good double panes in the low to mid 0.2s for U-factor and SHGC north of 0.3.
You also might want to check out the 100 Series Andersen. It is a good window for the money.
Dana,
>Is Pella IA in that radius?
Just barely. We're building in the Door County peninsula that's northeast of Green Bay, WI so our a larger than usual radius is because most everything in 50miles is water! :)
I'll ask about Pella Advanced Comfort if not the Marvin ERS, though a quick look finds ERS only in their Infinity line.
Steve,
I checked out the Anderson 100's on a showroom floor because they were on the neary list of makers but wasn't impressed. I'm generally let down by vinyl clad things :)
Jp
Vapor,
The 100 Series is a "Fibrex" composite. The 400 Series is a vinyl-clad wood window. I used three 400 Series sliding french doors on my last house and was generally satisfied with the performance. But the 100 Series was fine everywhere else since we did not want a wood frame on the interior.
I also installed Marvin windows on my first house and found them to be a maintenance headache. You really need large overhangs to protect that product from the elements.
Steve,
Interesting that the Fibrex material on the Marvins isn't holding up to outside exposure. I'll keep that in mind.
Jp
Here are the Cardinal glass stats(glass only, of course) https://www.cardinalcorp.com/technology/reference/loe-performance-stats/
Many vendors are using this glass, but may call it something else.
Omaha, NE is probably out of your 500 mile radius, but Enerlux will use any Cardinal combo in their windows. Maybe some of the Canadian fiberglass window makers are within your range too.
You can play around with the calculator here - you will find that with a room-side low-E coating, drafts are the more significant discomfort issue and are not offset by a small gain in radiant comfort.
https://www.payette.com/building-science/glazing-and-winter-comfort-tool/
I am looking at Andersen's website at the 100 series and the glass options. I'm looking at a 66 x 48 picture window, north facing, Canada. I know that this is probably Cardinal glass and that Andersen comes up with it's own names for the glass coatings that Cardinal offers. I want to know what the "heat lock" coating is, on what surface is it put on, and why isin't it offered as an option by itself ? It seems to be offered only with low-e or smart sun coating.
Without knowing more about 'heat lock", I don't want to cut down on transmitted light but I wouldn't mind some internal heat reflection so I'm really torn between getting clear glass or just low-e. If low-e won't do much in terms of making it "feel" warmer inside on a cold winter day then I think I'd rather have clear glass.
If I had to guess I'd hazard that their HeatLock® is an indium tin-oxide hard coat on surface #4 (if double pane). According to this page o' marketing fluff:
"HeatLock® coating can be added to most of our glass options and reflects heat that likes to escape your home."
https://www.andersenwindows.com/windows-and-doors/options-and-accessories/glass-options/
I would expect that it wouldn't be available on glass that comes with another type of hard coat on surface #4 (such as the i89 coating on several Cardinal Glass glazings), or on glass that has a low-E coating on surface #3, due to the practical difficulties of applying coatings on both sides of a single sheet of glass.
A low-E coating on surface #4 reflects heat back into the room, and body heat back to the person standing next to the window. That FEELS warmer, but the actual surface temperature of the glass is cooler, since it's reflecting rather than absorbing some of the radiant heat. In locations where it dwells below -25C for days on end that can potentially result in copious window condensation, which disrupts the performance & comfort gains whenever the glass is wet.
A clear glass (no low-E on any surface) double-pane will have even colder surface #4 temperatures, more condensation issues, and less comfort than just a single low-E coating on #2 or #3. Any window with low-E on #2 or #3 becomes a net heat gainer (taking in more heat during the day than it loses at night) in most populated parts of Canada (not counting locations north of the arctic circle), unless it's a soft-coat low-E specifically designed for rejecting solar gains.
For cooler parts of Canada the Low-E4® PassiveSun® glass + HeatLock® would be a decent choice. In near arctic cold locations where condensation would be an issue maybe not.
https://weatherspark.com/m/146170/1/Average-Weather-in-January-at-Churchill-Airport-Canada#Sections-Temperature
For a NORTH FACING Canadian window, would having ONLY this "heat lock" coating (and no other coatings) give the best winter performance if I wanted to minimize visible-light reduction?
Any idea why they don't offer it by itself as a coating option?
Edit: I wonder if this "Heat Lock" is Cardinal's LowE 180 - and can they supply it as the only coating option?
The Low-E4® PassiveSun® glass has a visible light transmission of 0.60, which isn't bad. Adding the HeatLock® only knocks that back to 0.58.
A clear glass double pane has a VT of about 0.78 (assuming you regularly clean the windows with religious zeal.) It's hard to tell the difference between 0.60 (or 0.58) and 0.78 unless they're freshly cleaned and side by side.
Compare the VT numbers of the different lowE options here:
https://www.andersenwindows.com/~/media/aw/files/technical-docs/performance/performance-windows-patiodoors-nfrcratings--400series.pdf
You'll note that low SHGC and low VT numbers are highly correlated (and conversely), independent of U-factor.
Heat Lock must be Cardinal's LoE-i89 on the 4'th surface. All their marketing doc's mention it's performance in conjunction with at least one other LoE coating (the lowest being 180). They don't seem to offer it by itself - which is a pitty. I wonder if it can be ordered by itself from any of the window companies.
It's possible to buy single pane storm windows with hard coat low-E one side, which would dramatically improve the performance & comfort of a clear-glass double pane, but even with (double + storm =) 3 panes it would still have a higher U-factor than any decent argon filled low-E double pane, and the low-E coating wouldn't be on the surface in contact with the room air.
VT for plain 2-pane glass is more like 81%:
https://www.allweatherwindows.com/the-pros/architect/glass-performance-chart/
and with 1 low-e coating brings it down only to 79%. Now I don't know what the pane thickness is in that table, or how VT is a function of glass thickness.
VT also depends on the type of glass used. The regular soda lime (looks green from the edge) glass has a lower VT than starfire low-iron glass (looks light grayish from the edge, similar to Pyrex, which is borosilicate glass). You can get low iron glass as an EXPENSIVE option, but it isn’t really worth it until your glass pane thickness gets up around 1/2” or so which is very unusual for residential windows. Pretty much all residential windows will be regular soda lime glass.
Bill