I haven't used the Alpen product, but they seem to have a well engineered product.

For the price to be less than help I would make sure you are looking at the same specs. From the sounds of it your Marvin quote is for a wood window (maybe aluminum clad?) and Alpen from what I recall is vinyl. So you are not comparing equal product type in my opinion as well. Not saying one is better than the other, just not the same type product.

Also different glass packages for triple pane. Alpen uses Heat Mirror which is a suspended film between two layers of glass, while Marvin is going to have 3 layers of glass.

I agree with the good feedback from the other pros...

-Triple pane is more expensive than heat mirror, and more reliable. Heat mirror technology is very cool in concept, but has a historically high failure rate. Those still selling it will tell you that those issues have been fixed, but I suppose only time will tell. Its lighter, less expensive, and similar efficiency to triple pane so there's not much reason NOT to use it, other than the poor reliability.

-Tilt and turn Marvin's sound like the wood/clad Ultimate (or whatever they call it now)? That's a very pricey window. Very nice, but not cheap. The all-ultrex Marvin would probably yield a closer price comp.

- As WoW alluded to, the Alpen product is generally regarded as well-engineered (except for the aforementioned heat mirror). They have been passed around a few times with ownership though if I'm not mistaken. I believe that they were sold to Obama's Serious Windows for a while, and then that went belly-up and came back to Alpen or something along those lines... May be a concern, may not, but I'd suggest researching all that to ensure that you feel comfortable with their stability.

When Kevin Surace started Serious windows, he acquired Alpen as his flagship company/factory.

When Serious failed and was going out of business, the original owner (who had retired), came out of retirement and bought the company back to save it.

Bit of trivia...the original patent for the heat mirror concept was owned by Cardinal, but they were very concerned about long term performance so they sold the patent to Southwall.

Thanks, everyone. Very helpful!

I'm also looking for good sound attenuation. Does anyone know if the Alpen heat mirror windows have reasonable STC rating? What's the typical STC rating for a classic triple-panel window? My entrance is close enough to the street.

Thanks again.

Generally, if you got a $110K quote from Marvin, you can get a $30K quote from China WDMA.

Marvin price * 30% is wdma price.

Example :

The 43*46 Thermal Break Aluminum casement or awing window with 6mm+12A+6mm fully tempered glass, is about $184.

China Windows & Doors Manufacturers Association, how did we know this SPAM was coming...........................

I got an STC rating from Alpen: 44, if I go with lamination. That is pretty good, right? (I'll have to consider the price.)

When purchasing your windows, pay extra attention to the Solar Heat Gain Coefficient (SHGC). This is the rate at which the windows allow radiant heat to enter the house. The lower the number the less radiant heat is allowed through the glass. This can have a massive impact on comfort, and also on cooling demands of your A/C. Low solar glass also has the added benefit of less fading of interior finishes and surfaces. The U-Value is also very important to pay attention to. This is the insulating factor. The lower the U-Value, the better the insulating performance. If you are in a cold climate, the lower U-Value allows for a warmer interior surface of the glass, reducing that "drafty" feeling you get near windows. Selecting the right SHGH/U-Value for your climate can have a significant impact on your overall comfort, enjoyment and performance of your home. When you are looking at a $50-110k investment, you want to be sure you are happy with the result! My recommendation, do some reading and look to pros in your area (ie: energy advisor, well trained hvac designer, and an informed window rep) to ensure you get the right windows for your home.

One more point, be sure the installers do a proper job of flashing around your window and patio door openings to avoid water penetration into the walls/floors. It can be tricky to do in retrofit, but necessary to avoid damage, rot etc.

David,

STC 44 is exceptionally good.

PSH,

You are in Canada and the general recommendation out of Canada is to use high solar gain coating rather than low solar gain.

Do you disagree with using high solar gain in favor of low solar gain coating in your environment?

The Alpen quote has full-frame NFRC U factor (imperial) of 0.16 ~ 0.17 (R = 5.88 ~ 6.25) and SHGC of 0.17 ~ 0.19. Is that good?

That's an excellent U factor David, as is the STC. Are those ratings from the same glass package though?

The .16-.17 U factor is achieved generally by higher performance windows with triple pane glass and krypton, some top models get it with argon.

As far as the SHGC, that depends on where you are located. As Oberon alluded to, unless you are in a hot climate or have other circumstances that would call for it, a low solar gain glass option is not likely to be the best fit for you. The information that @Pretty Smart Homes seemed to quote applies to that circumstance, but is generally bad/uninformed advice for those of us that spend more money heating our homes than we do cooling them.... Definitely interesting that that post got the "best answer" tag to say the least... good info when properly applied though. I just hope that those folks aren't outfitting many homes north of the border with that low solar gain glass. That certainly would not be smart.

Lastly, take a look at condensation resistance (CR), DP, and air leakage ratings as well. Those are some other factors that you'll want to consider in window performance and are general indicators of quality.

+1. The blanket statement on SHGC recommendations, devoid of any context for climate zone, are entirely misguided. You ALWAYS want a window that is as airtight as possible and with as low a U-Factor as possible...but SHGC recommendations require context like climate, orientation, finishes in the home, design, etc.

The quote is for Alpen's Tyrol series, SolarControl-6, with Heat Mirror tech and tempered glass. In order to get STC rating 44 I would also need to add lamination on top of it (not included in quote).

Overall, Alpen sounds like a pretty good deal, so I've been wondering if there's a catch. The heat mirror tech reliability issue could be the catch, but it sounds like it must have been fixed over the last many years.

(I'm in the San Francisco Bay area, so while it's not really hot it's still good to have low SHGC. I think by code SHGC should be 0.22 or less for my region.)

hi All,

Thank you for your questions/comments. I should have expanded more into why I have commented on the SHGC, and the context. Most people do not pay attention to SHGC therefore my point was bring it to your attention so you can research and select the correct SHGC/U-Value that works for your home and climate.

In Canada, the earlier conventional wisdom (which some still hold today, but awareness is starting to shift) is that using high solar gain windows allows "free heat" into the homes particularly during the cold months. This may be valid in some homes in some areas, but it should not be blanketed across all homes in cold climates.

As our building codes continue to increase in overall energy efficiency and more high performance homes are being built, these builders and the industry as a whole have found heating loads are dropping to very low numbers (20,000-30,000 btus is very common in single family homes (in some areas). In multi's like town homes the numbers can be even lower). With heating loads that low, the home doesn't need the added "free heat" from the high solar windows in the winter. In fact for some time it was difficult to get forced air systems small enough to avoid oversized units and therefore short cycling of the units. We are finding the free heat becomes a detriment in the summer cooling seasons in many areas. With the low load homes, it is becoming common for cooling demands to exceed the heating demands and therefore forced air duct systems that were historically designed for heating loads are now being designed to cooling loads in many cases!! Although the high solar gain windows are adding free heat in the winter which is a marginal benefit, they are actually overheating some homes in the summer, resulting in more demand on cooling units or even having to install larger systems.

Every home is different, with unique orientation, window/wall ratios, insulating types and values, size, geographic location, age, etc. Therefore this is why I recommended seeking out professionals in your area to work through what are the best windows for your home to achieve the overall best comfort for you, and to avoid the pitfall of affecting the operation of your mechanical system.

Point is, pay attention to the SHGC and the U-Factor because they both make a difference. When you are spending that kind of money on windows, you want to be sure you are comfortable in your home.

Again, thank you for feedback. It allowed for the opportunity to expand with more context.

And, Happy Fathers Day to all of the dads out there!

Pretty Smart Homes, thanks for the added context!

Indeed, I'm aiming for a passive house with excellent insulation, low solar heat gain, and heated and cooled by a few mini splits, all powered by solar. (I'll have a gas fireplace, too, but won't need it more than 5 days in a year.) I have large windows facing North-East, and walls facing South-West, with some tree shade on the sunny side. I'm doing my homework to make sure the setup will work as intended. Let me know if there is any other factor to consider. Thanks!

Wow that is fantastic! Best of luck with your project!

Some builders use an air source heath pump for primary heating/cooling, with a gas forced air furnace for the coldest days. ERVs for fresh air supply are also being used.

Congrats, I hope your renovations go well.

You may find these free softwares interesting for your project.

https://www.cardinalcorp.com/technology/applications/comfort-calculator/

https://comfort.cbe.berkeley.edu/

I've thought about having some concrete walls on the south side as the thermal mass (the design allows for it), but wouldn't that make things worse in the summer? Where I am (Northern California), hot summers will be more of a problem than cold winters.

Here's the South-West side (trees exist but are not rendered):

North-East side:

I would NOT put low solar gain windows in a cold climate. Op is in California so non-issue, but that’s some serious salesmanship to try and stretch facts and data to support low solar gain glass in a cold climate in anything but the most extreme circumsyances where a home is super sealed, has the latest and greatest in hvac tech, along with other details to support . Even then, as windows on wash suggested even remedial usage of window treatments can more than compensate. Talk about marginal benefit? Pay for some crap windows that have an attractive u value only because of that super dark and heavy low e coating. Actually no benefit, probably the opposite.