Nothing seems more difficult than finding efficient windows(and doors) for a new build. Some threads have turned into Pi$$ing matches, and I’m not looking for that obviously. I have read all the available threads here and also GBA to get a handle on it.

I am also looking for “Inbetweenie” installation details for SIPS and ICF. (I have the Building Science detail) . I am also waiting for Intus to update their installation recommendation. Install details are very important. Will probably use the Tremco Trio expanding foam or EPDM gaskets.

I am in in MI,
• 47.2° mean annual temp,
• 1529° degree F days,
• 2000 air freezing index.

Looking for windows that are Goal:
• ~$50.00/sf or less
• U <.24;
• VT >.40;
• SGHC >.40;
• Air lnfiltration < .02cfm.

Here is my shortlist so far: Simonton (Reflections 5500), Softlite (Imperial LS), Sunrise(Elements) HiMark, Okna 800, (.25 U-value, .01 AI, and a 60 DP.) Strassburger, Alpen, Wasco, Loewen, Intus upvc, Bieber, Unilux, Marvin (Integrity), Kolbe, Accruate Dorwin, Inline, Fibertech, Thermotech

Most of the PHI rated windows are above my priceline. Ideally I would like to get windows that I can go look at before I plunk down $15K so Euro windows are not at the top of my list. USA or Canada manufactured are more in my gameplan. What makes this the most difficult is that prices are not listed online. Anybody have price/sf experience with my “short” list?

I haven't heard of most of the windows on your "short list" but I can tell you that the Intus uVPC triple pane windows will price out in your range. The only way to find out the real numbers is to get a bid on the windows. Operable will cost more than fixed and you are better off getting one large window vs. two smaller windows. This is design dependent and should be incorporated when choosing window size and location.

Here is one datapoint in central Arkansas: This year, my Marvin Integrity All-Ultrex fiberglass frame single hung windows with Cardinal LoE 180 w/Argon high solar heat gain glass came in for a delivered price of $334 each for my 3'x5' windows and $351 for my 3' x 5'6" windows. The windows on the front of the house had grids between the glass (GBG) and that added ~$50/window.

From the sticker on the windows:

U-Factor = 0.31 (U.S. / I - P)
Solar Heat Gain Coefficient = 0.55
Visible Transmittance = 0.63

LC - PG40 DP +40/-40

I could have gotten glass with lower U value for same/similar price, but I would have had give up the high SHGC and VT and I wasn't willing to do that.

That is quite a short list.

By my quick count you have eight American companies, six Canadian companies, and three Euro imports on your list.

You also have a mixture of vinyl, fiberglass, and wood manufacturers as well as variations in available glass packages.

Do you have other criteria (sash/frame material preferences, for example) besides those listed that might break down your options?

Among your choices, Sunrise is in your backyard while Kolbe and Wasco are right on the other side of the lake, with a couple of the Canadian companies are just across the border north of you...if that makes any difference.

Thanks Guys,
Yes my Prime Directive is U-Value, and price. Of course everything else can also be significant if it is too far from my goal data. My only problem with Intus is the screens seem to be an afterthought so LBear, yes fixed is the way to go there. I almost ruled Marvin out as the AI is a bit up there compared to say Okna but their price point seems good. Zola is high quality but appears to be also high priced, so I dropped them earlier. Some of my other Euros may fall off the list once I find price points for them. Canada is pretty close to Michigan so shipping should not be outrageous, Canadian windows have a good chance. I recently added Strassburger, (Canada) as they have a Michigan presence as well as good numbers. (Thanks GBT user Stuie!) I will probably try to visit the Sunrise factory as they are pretty near me. My only problem with them is that they only offer sliding patio doors. I can get swinging doors elsewhere I suppose. Their website only shows double pane Doors at U = .29, but perhaps they can make a triple. If anyone has some recs on particular glass packages I am all ears.

The only other main constraint is the ability to install “Inbetweenie”. That means I don’t really need the nailing flange as it only leads to a larger hole in the wall to accommodate it. The Euro data and thermal imaging pictures I have seen seem to show the optimal place for windows is the middle. With thick SIP/ICF walls that leaves about 3-4” on each side. It is estimated 10% greater efficiency over “Innie” or “Outie”(most typical).

Window screens are a "necessary evil" and I have yet to see a window screen that wasn't a pain to deal with. The friction fit ones I have on my Milgard are a nightmare to deal with. The Intus screens are actually pretty decent. They use screws to attach to the window frame and can be easily removed if needed.

If you are looking for U-Values <0.25 then you need to step-up to triple panes or use the heat-mirror technology (which is pricey). In the end the only way to make a good decision is to get bids. Pick your top three choices and get bids.

My favorite is Intus uPVC. I have yet to find a window that offers the level or performance, build quality, for the price. It is the best bang-for-buck out there in high-performance triple pane windows. If you visit Green Building Advisor you will see Intus is used in many PH and high-performance energy builds. They have a DP70 rating and the window secures like a bank vault door. Once you see and operate such a window, you will never want to install a run of the mill US window ever again. It's a night and day difference in quality and performance.

Digging Deeper!

Argon is roughly $20 xtra per window for a ~ .05 reduction of UV but Krypton is $100+ per window for an additioonal ~.03 lowering of the U-value so I will stick with Argon.

Perhaps I should look from a different viewpoint and look at North American Flat Glass Manufacturers and decide on a glass package first
• Pilkington (nsg) OH
• Asahi Glass (AGC) GA
• Cardinal MN
• Guardian MI
• ACH Glass Operations (Visteon) OK
• PPG PA
I found info on Cardinal so far:
http://www.cardinalcorp.com/technology/reference/loe-performance-stats/
For 1 3/8” triple pane I get the following sets of numbers for coatings. .

LoĒ-180 (#2) / LoĒ-180 (#4) / i89 (#6) has VT 68%; Uip= .12; Heat Gain Coeff .50
LoĒ²-272 (#2) / LoĒ-180 (#4) / i89 (#6) has VT 62%; Uip=.11; Heat Gain Coeff .30.

Most of the windows are West facing and not South due to the view. There will be however plenty of white reflective snow covering the ground in the winter. Should I go with the 272/180/i89 because of the better U-val?

If I pick a glass unit first and then find a window manufacturer with good construction and low Air Infiltration (and of course price) that can manufacture the window with the glass pkg I want.

http://www.optiwin-usa.com/builders.html


not sure if these were mentioned but someone brought them up to my attention at some point, they have some incredible claims and supposedly certified, I don't wuite buy it I tinkered a bit modeling windows could not even come close, guess they know what they are doing?


as for prices? I did not have the guts to ask, bet its all custom quotes,

keep us posted I'll have to cross this bridge at some point myself

Thanks Georgec,

Optiwin had been on my "long list" but I had a few issues with them. They are a German designed window but were sold and manufactured for a time by French Bieber. You can find some references at GBA and look up edgewaterhouse.



The good thing about Euro design is the triple seal that tilt and turn and other Euro designs have is the low Air Leakage value. My issue are:

• Euro measures U-value differently than US, no NFRC/ comparison

• Not sure if the building/shipping issues have been worked out

• Price is not well known, zero data points available online

• Shipping could be a lot

I have kept Euro windows like Intus on my list as they (Intus at least) have solid data points referencing price comparisons to other window bids, as well as some happy reviews and owners. So Summing up, there were just too many unknowns about Optiwin for me to continue perusing info about them. They may well be a good value for other people to consider.

Trying to understand the various coatings. Here is my table so far

	U	VLT	shgc
PPG
Sungate 600 (1)	0.29	0.73	0.7
Sungate 500(1)	0.31	0.76	0.7
Sungate 400(1)	0.28	0.68	0.68
Cardinal
LoĒ³-366(1)	0.05	0.65	0.27
LoĒ-180(1)	0.29	0.79	0.69
LoĒ² – 272(1)	0.16	0.72	0.41
LoĒ²-270(1)	0.14	0.7	0.37
	AIR/AR
LoĒ-180, LoĒ-180, LoĒ-i89	0.21 / 0.17	68%	0.5
LoĒ²-272, LoĒ-180, LoĒ-i89	0.21 / 0.17	62%	0.34
LoĒ²-270, LoĒ-180, LoĒ-i89	0.21 / 0.17	60%	0.3
LoĒ³-366, LoĒ-180, LoĒ-i89	0.21 / 0.17	56%	0.22
AGP
SolarPlus (CL/CL/EPS)	0.21	68%	0.66
SolarPlus2 (EPS/CL/EPS)	0.15	62%	0.62
Guardian
ClimaGuard 80/70+80/70	0.23/ 0.18	73%	0.58
ClimaGuard 80/70 + 71/38	0.22/ 0.17	64%	0.46
RLE Residential Low-E
Pilkington
Energy Advantage Low-E(1)	0.5	84%	0.77
LOF (Libby Owens Ford)

Posted By kb on 18 Feb 2014 04:31 PM
I am in in MI,
• 47.2° mean annual temp,
• 1529° degree F days,
• 2000 air freezing index.

Looking for windows that are Goal:
• ~$50.00/sf or less
• U <.24;
• VT >.40;
• SGHC >.40;
• Air lnfiltration < .02cfm.
...snip...

The "1529° degree F days" has me puzzled. When I look at heating degree days for the past year for Detroit, MI, I get 6774, which sounds a lot more reasonable than 1529. Is the "1529" a typo, or are you in the "sunbelt" of Michigan, wherever that might be??

You mention in this post wanting SHGC > 0.40, but in a later post you ask about the tradeoff of U-value and SHGC. Going from low to high SHGC usually results in about 0.03 (or less) increase in U-value (in U.S. units). If your solar exposure is not blocked by trees, the high solar gain windows are recommended as providing a little more heat gain than the 0.03 in U-value differences in your area (http://www.residentialenergylaboratory.com/window_codes.html), at least on windows other than the north side. If you want to see hard numbers, you can model the proposed house with BEopt or whatever.

I would stick with windows that have an NFRC rating. It makes for easier comparisons, plus building codes generally require the NFRC stickers.

Thanks Lee, The 1529 is for the coldest month. I used that for some calculation involving the amount of heat I would use in the coldest part of the year. For a yearly value my number is 8067.

I agree it is difficult to compare Euro numbers to North American NFRC. I do believe they would be close in the final comparison as they have access to the same coatings we have in the US. There is a good chance the Air Leakage numbers could be slightly better on the Euro designs like tilt turn etc.

I like the triples Cardinal LoĒ-180, LoĒ-180, LoĒ-i89 and ClimaGuard 80/70+80/70 Units the best so far, but it is difficult to find the information at most of the various glass manufacturers websites. The NFRC notes and codes are quite cryptic and time consuming to wade through. I am wondering about the longevity of the i89 coating on the final interior surface, but in Cardinals words "When used on the # 4 glass surface in a dual pane IG unit or # 6 glass surface in a triple glazed unit it will reflect roomside radiation back into the room."

Posted By kb on 23 Feb 2014 09:41 PM
I agree it is difficult to compare Euro numbers to North American NFRC. I do believe they would be close in the final comparison as they have access to the same coatings we have in the US. There is a good chance the Air Leakage numbers could be slightly better on the Euro designs like tilt turn etc.

The Euro values are often for the glazings only, while the NFRC values are for the total window, so the Euro values look better, even though the physics of window coatings do not change depending on location relative to the Atlantic Ocean. The temperature differentials are lower for Euro than for North America, so that typically also results in slightly better looking values. And I would agree that the tilt-turn windows generally seal better than the slider designs.

I like the triples Cardinal LoĒ-180, LoĒ-180, LoĒ-i89 and ClimaGuard 80/70+80/70 Units the best so far, but it is difficult to find the information at most of the various glass manufacturers websites. The NFRC notes and codes are quite cryptic and time consuming to wade through. I am wondering about the longevity of the i89 coating on the final interior surface, but in Cardinals words "When used on the # 4 glass surface in a dual pane IG unit or # 6 glass surface in a triple glazed unit it will reflect roomside radiation back into the room."

The Cardinal LoĒ-i89 is a new coating, and I have not looked for or seen durability data.

The LoĒ-i89 coating operates, of course, just like the other coatings do. All these coatings transmit most visible radiation, and are good reflectors in some portion of the infrared spectrum. The wavelengths where they are good reflectors, they are also poor radiators. So you could say the i89 coating reflects the heat back into the room, but at the same time it also limits the radiation from that surface outward (or inward) toward the outer glazings (or toward the room). The difference in performance between the different coatings, like low versus high SHGC, is the reflectivity in the very near infrared portion of the spectrum. The low SHGC is reflective in that region, while the high SHGC is clear in that region.

According to the Cardinal info online, i89 is unaffected if you use windex or normal window cleaning fluids. Abrasives/Razorblades are a nono. Does anyone have kids? They occasionally put stickers and mark with crayons, so good luck at getting that stuff off the window surface. There are other IGU's that have coatings on the inner glass surface, layer 4 on double, or layer 6 on triple, I think Pilkington has had inner surface coatings for a while, Sungate 600 is rumored also to have that coating since 3/28/2012. Any data out there on those? I imagine 90% of the homeowners/window buyers have no ideas which coatings are on what surfaces of their windows.

I spent a few hours digging through the NFRC website cherry picking data and I thought I would try to share my results. I was specifically looking for the Cardinal triple 180/180/i89 IGU as well as the 272/180/i89 version with ARgon as the fill in both gaps (no grid). I expected to be able to compare the abilities of various window manufactures, as they are all the same IGU/coatings. Since NFRC is a whole window rating, a lower U-value would mean a better construction/design. A lower VT would mean more glass to sash area. (I am not sure what the different SHGC's mean.) I could not find the info for some manufacturers that use Cardinal glass units but only put a non-traceable number into the database. It is interesting that Simonton had 10 pages of Krypton/Krypton fill or KR/AR or AR/KR but I did not find the AR/AR I was looking for so my data has one of their KR/AR filled units. I just took Marvin Integrity's best U-value data. Several of the listings contained outdated 270 glass which has been superseded by 272.

Windows U-factor SHGC VT Condensation Resistance
Otasco TG,SS-D,LoE180/LoE180/i89,Arg90%,G1-MB,G1-CB2,G1-DIMB,S1-SDL 0.17 0.36 0.45 61
Otasco 272-arg-Cl-arg-180, xl 0.18 0.25 0.41 77
Simonton 325-325; CA; SF; 00; G00; 042613; E180; kry; clr; arg; E180; DS/DS/DS; 1.000 " 0.19 0.37 0.45 73
Sunrise LoE270/LoE270/i89; ARG 0.15 0.20 0.37 63
Sunrise LoE180/LoE180/i89; ARG 0.15 0.34 0.43 62
Strassburger 272-arg-180-arg-i81, xl 0.17 0.22 0.36 62
Strassburger 180-arg-Cl-arg-180, xl 0.19 0.36 0.45 75
Marvin Integrity, CCAAckac0000000 best Casement Operator/Stationary (CCAA) MAR-N-250 Fiberglass/Wood Combination/Fiberglass/Wood Combination, Fill 1: ARG/AIR (90/10),Fill 2: ARG/AIR (90/10), LowE, CL, No Grid 0.20 0.27 0.45 68
Jeld Wen 180-arg-Cl-arg-180, xl 0.20 0.37 0.45 76
Inline Cl-arg-HS1-arg-HS1 3se Foam 0.17 0.41 0.48 77
Intus Eforte Climaguard 4mm arg Fixed 0.16 0.37 0.55 77
Intus TiltTurn Climaguard 4mm arg 0.21 0.37 0.48 71

So from this rather informal data gathering it appears that Sunrise is the clear winner in U-value, but there are other things to consider.

Only if we have a complete price list from all the manufactures could you possible make a smart choice.....

Perhaps you may be looking too deeply into specific coatings and glass configurations. While glass-only performance numbers are an excellent way to compare between various IG configurations, that data is not typically going to translate very well into finished windows depending on window sash/fame material, sash/frame configuration, quality of manufacture, quality of installation, and so on.

I would suggest that you really should be looking at finished product where you can compare performance values, warranties, reputation, between window companies rather than glass suppliers. Ultimately you are paying for a complete window rather than a glass package. Let the window engineers and designers worry about what's in their sash, thats what they get paid to do. A superior window company is almost always going to offer a superior glass package because their reputaion rests on it, it is part of what they do. While a less than stellar window company might offer a great glass package but if the window isn't very good then whats the point?

You can have an identical IGU configuration with two different windows companies, or even between different window styles within the same company, and have a surprising difference between finished window performance numbers.

Personally I would never recommend high solar heat gain package for west-facing windows unless there is some way to block spring, summer, and fall solar heat. South-facing absolutely go for high solar gain windows, it's worth it, but ensure that they do have adequate summer shading. Even north-facing windows can benefit from high solar heat gain, but I would maximize U value for those first. East-facing is a coin-flip between highest solar and lowest U. Personally I like morning sun and I would go for moderate solar gain and moderate U value, depending on climate.

Lee Dodge's comment on surface 4/6 coatings is spot on. Per ruggedness of the I89 coating, some might suggest that the coating is actually tougher than the glass that it's applied to. It can certainly be scratched, but then so can glass.

Another side benefit of the I89 coating is that I89 is "smoother" than raw glass that its applied to meaning that it's actually a bit easier to clean than raw glass and things like tape and crayon come off easier leaving less residue behind.

Is that a selling point? No. Is it advertised? No. Is it real? Apparently it is per testing results that I have seen.

Finally, LoE²-270 is still a very active coating that was not superceded by 272. They are both readily available to window manufacturers.

Posted By Oberon on 25 Feb 2014 11:26 AM
Perhaps you may be looking too deeply into specific coatings and glass configurations. While glass-only performance numbers are an excellent way to compare between various IG configurations, that data is not typically going to translate very well into finished windows depending on window sash/fame material, sash/frame configuration, quality of manufacture, quality of installation, and so on.

I would suggest that you really should be looking at finished product where you can compare performance values, warranties, reputation, between window companies rather than glass suppliers. Ultimately you are paying for a complete window rather than a glass package. Let the window engineers and designers worry about what's in their sash, thats what they get paid to do. A superior window company is almost always going to offer a superior glass package because their reputaion rests on it, it is part of what they do. While a less than stellar window company might offer a great glass package but if the window isn't very good then whats the point?

You can have an identical IGU configuration with two different windows companies, or even between different window styles within the same company, and have a surprising difference between finished window performance numbers.

Personally I would never recommend high solar heat gain package for west-facing windows unless there is some way to block spring, summer, and fall solar heat. South-facing absolutely go for high solar gain windows, it's worth it, but ensure that they do have adequate summer shading. Even north-facing windows can benefit from high solar heat gain, but I would maximize U value for those first. East-facing is a coin-flip between highest solar and lowest U. Personally I like morning sun and I would go for moderate solar gain and moderate U value, depending on climate.

Lee Dodge's comment on surface 4/6 coatings is spot on. Per ruggedness of the I89 coating, some might suggest that the coating is actually tougher than the glass that it's applied to. It can certainly be scratched, but then so can glass.

Another side benefit of the I89 coating is that I89 is "smoother" than raw glass that its applied to meaning that it's actually a bit easier to clean than raw glass and things like tape and crayon come off easier leaving less residue behind.

Is that a selling point? No. Is it advertised? No. Is it real? Apparently it is per testing results that I have seen.

Finally, LoE²-270 is still a very active coating that was not superceded by 272. They are both readily available to window manufacturers.

Oberon, I really respect your information. I assume you are the same knowledgeable Oberon I have seen elsewhere on the web regarding windows. Thanks for correcting me on the LoE 270. Cardinal offers both coatings, they have slightly different characteristics. I noticed LoE-180 superseded LoE-179, which superseded LoE-178 … and I assumed the same was true for272/270. Thanks also for the data point on i89 ruggedness.

Reputation is always hard to get real data that has any degree of accuracy or precision. (my NO DRAMA proclamation) Bigger companies with more sales have a higher chance of someone with a negative account or experience. If one person in 10 complains it has the same impact as 1 person in 1000. IMHO 50+% of the internet complaints are likely due to user/installer issues rather than manufacturing problems. Local reputation is very limited and likely to have “statistics of small numbers” errors. Let the buyer beware. There has been at least one highly rated North American window company recently come and go (seriously). Another has changed their product construction methods and they still try to live on their old reputation (fibertechnically speaking).

One of the reasons I picked Cardinal is because my perusing of the NFRC database showed Cardinal Glass as always having lower U-values than other glass units that were otherwise available in the same package. I agree that I need to compare performance values, warranties, etc, between window companies, but I want to compare apples to apples. I can’t go out to buy a new vehicle and compare a Ford Escort to a Chevy 4WD. So, with numerous variables I am holding one constant (glass package) and now I can move on to compare the other variables.

I am still trying to get my head around your west window low heat gain idea. My best views will be to the west and a high VT is preferred. In general high VT means higher SHG to some extent. (180/270/272 glass has higher VT) In Michigan we have 3 months of warm and the remainder shoulder seasons and winter. So those west windows would only damage cooling potential for a small segment of the year. They could gain useful afternoon solar heat for over half the year. Reflections from the white snow could also add to the amount of solar gain. There will be a few trees to shade things in the summer.

Oberon's advice about using low solar heat gain windows on the west side is in general agreement with what most folks on this forum recommend. For my location and climate, I chose to go with high SHGC on the south and west sides, half high SHGC on the east side (would have gone all high SHGC except for cosmetic reasons), and low SHGC on the north side.

In my case, the modeling results of a similar "generic" house said that compared to using all low SHGC windows on all sides, using high SHGC on south only would reduce heating and cooling loads by 8.7%, while switching to high SHGC on the south, east, and west sides would reduce energy use by 15.3%. (Table 4 results for Alamosa, CO of http://www.residentialenergylaboratory.com/window_codes.html)

I think the choice of low versus high SHGC depends on many factors, including the following:
Climate: I am in a mostly heating climate, and do not even have an A/C. Plus, anybody that has been in the Colorado Rockies in the summer knows that almost every summer afternoon it clouds up, reducing the heat gain in west-facing windows during the summer.
Active versus passive: I am an active homeowner, and don't mind using cellular shades to block undesired solar gains (although I leave small gaps at the top and bottom of the shades to avoid window overheating).
Deciduous trees: If you have deciduous trees around the house, they can help cut solar gains during the warmer months.

Therefore, I would feel free to make your own decisions about low versus high SHGC windows on the west side.