Replies

1. 
   David_Thomas | Jan 18, 2002 09:11pm | #1

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   The window manufacturer might be able to help you with the temperature differential issue. 155F might be more than they design and test it for. My windows see 110F differential (-40F outside, 70F inside) with no problem. One would see a 130F differential in Fairbanks and I've heard nothing about problems there. I would have too, since the "Arctic Engineering" course I needed for reciproicity on my PE addressed all aspects of dwelling construction and two of the profs were from Fairbanks.

   A storm window would help. The outer glass of the double pane would not get as cold. It would be 30-35 degrees warmer and that would bring the temperature differential into a range that I know works.

   The max temp (170F) is probably okay, especially since it is for short times. A 120F day in Phoenix would give surface (sun-lite) temperatures of 150F or so, depending on color. But the manufacturer should be able to provide specific data.

   Are they going to run from the 170F sauna and jump, naked, into a snowbank? That's the temperature differential I have the most trouble with. -David

1. 
   Barry_LaDuke | Jan 19, 2002 03:22am | #2

   *David:In your studies, did you ever do anything with a product called Heat Mirror(tm)? It is an insulated glass unit with two air spaces and a low-e coated film suspended between the two lites of glass. It can be used with any combination of glass types (tinted, low-e, tempered, whatever). They used it to build the glass Boeing Flight Museum in Seattle.It is reputed to have wonderful insulation values compared to regular insulated glass, and would be a compact solution to the differential issue Mr. T raised in this thread.I don't know who makes it any more, or if it is even available. It was kinda spendy.... Originated from Palo Alto, CA.

1. 
   David_Thomas | Jan 19, 2002 08:28am | #3

   *Yes, I'm aware of the product. The interior film creates two more air films on the inside of the double-pane giving it insulation similar to a triple-pane window. And the film can be specified to reduce solar input (not a problem up here, except at 11 pm in June).The temperature differential issue I'd be concerned about, in Mr T's case, is that the interior pane will expand while the outside pane will shrink. Yet they are joined together. How much bending is allowable? And how much force can the seal between the panes take? An interior film would help overall energy loss, but not reduce the inside-outside temperature differential.Storm windows would. Interior shades or curtains, if tight-fitting, would as well. But insulation on the inside increases condensation which will already be huge. -David

1. 
   Rob_Susz_ | Jan 20, 2002 01:13am | #4

   *I see no way around heat mirror or triple panes. The dewpoint of the indoor air will be above 100 degrees or so. Just a guess, I dont have the psych chart on the wall anymore - rearranging the office.Plan on these things being a condensation machine unless you do something very heroic.-Rob

1. 
   david_thodal | Jan 21, 2002 07:49pm | #5

   *I have no experience in using insulated glass on an outside wall. I have used the glass for sauna doors, tempered with no problems. But then again, the inside dressing room temp was maybe 90 to 120 difference maximum.I have built a number of saunas and have used single pane glass or glass block with no problems. I can not see the advantage of one insulated window for a sauna in terms of heat loss. walk gooddavid