I’m planning to build a passive solar designed house. I’m having difficulty finding a source for south facing windows (low u factor & high shgc). I’ve researched a couple dozen companies so far and H window is the only one I’ve found that sells them. Does anyone know of other sources? Thanks, Aeon
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
There are a number of ways to achieve a level foundation and mudsill.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
Greetings aeon,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
well, let's try this again.
bump
"being human is a complicated proposition"-DavidxDoud
---Never show a fool a half finished job---Grampsy
I feel like a bunny in a hillbilly meadow at noon..........jjwalters
For what you want the best thing is triple glazed non-coated windows.
The triple glazing will give you the low U value without a low-e coating, and no coating give you maximum SHGC.
Now just find a company that offers triple glazing, and spec it with plain uncoated glass.
I don't have an answer to your question but am curious how are you planning to handle the potential for overheating in the summer?
With passive solar design the idea (in the winter) is to collect the solar heat in thermal mass that is incorporated in the structure (concrete floors, structural masonry) which then gives off the heat at night. Too much glass and not enough t-mass will cause dramatic temp. swings (temps to high in the day and no heat storage to help you through the night). That's in the winter. For the summer, you need to design the structure to provide proper shading on the south side to prevent over heating. The angle of the sun allows you to do this with roof overhangs. You can also incorporate various shading devices or seasonal plantings.This is a simplistic explanation. But the idea is to design it right from the beginning. The science has been around for awhile, but in practice it's still not that common. A very good resource is "The Passive Solar Energy Book" by Edward Mazria, Rodale Press, 1979. I don't think it's in print any more, but if you Google it you could find a used copy. This book is packed with relevant information and is very easy to understand.
Thanks for the info. So ideally, there'll be optimally located deciduous trees, or some well thought-out overhangs to provide shade in the summer? Kudos to you for your efforts. Keep us posted on what you learn.
I too have found only one source of "passive glazing":
Hurd with "hard coat lo E"
Which manufacturer did you find?
BTW triple "clear" glazing is OK, but the performance curves aren't as good as a high SHGC and lo E double glazed window. The main reason is increased reflected energy from the third sheet of glass, and the fact that the U values are pretty close.
I've found 3 other manufacturers. In the US, Alpen from Boulder, CO. In Canada, Thermotec and Fibertec. http://www.alpeninc.com ,http://www.thermotechfiberglass.com, http://www.fibertec.com. I'm still deciding on who to go with, but I'll check out Hurd again. My local window guy that carries Hurd told me that they had stopped making this kind of window.The plans for the house should be finalized soon. Ground breaking in the spring.~Aeon
I asked Marvin rep about passive solar at a home show last spring. He claimed that their new low-e glass allowed the heat from low angle winter sun to pass through. Since this was a salesman talking I don't know about the truth of this statement.
Typical salesman BS. The SHGC rating is what to look at. The Hurd hard coat is over .5, but most Lo E windows are closer to .3That means that the hard coat is letting in roughly 80% more energy.
Unless price is a big issue, I wouldn't buy Hurd, only because it's a wood window. I've had a little mold from sweating when my wife cranks up the humidifier.