Low-e tempered glass for shower doors
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I’m looking for ways to stay warmer in the shower (that don’t involve hotter water or more of it). Since thermal comfort depends on both the air temperature and the radiant temperature, it seems reasonable to reduce the radiation heat transfer by putting in a low-e glass. Does anyone know where one could find tempered low-e glass? I’d prefer not to put on a film on the outside, because I always end up with bubbles and creases.
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Replies
I think any insulating gain of that loE shower door will be overwhelmed by the heat loss from natural convection currents and air movement around the shower door. This is the basic “air leaks are more important than insulation” issue. A small air leak can cause a LOT of heat loss.
A bette option for you may be radiant heat in the floor and possibly also the walls of the shower. The Schulter membrane system for tile makes this pretty easy to put in.
Bill
>"I think any insulating gain of that loE shower door will be overwhelmed by the heat loss from natural convection currents and air movement around the shower door. This is the basic “air leaks are more important than insulation” issue. A small air leak can cause a LOT of heat loss."
It isn't about heat loss- it's about the mean radiant temperature in the shower.
Hard-coat low-E on the shower side surface of the glass reflects the heat radiating off the occupant back at the occupant, independent of how much convective heat loss is going on.
FWIW: Some manufacturers of wood stoves use tempered low-E glass in the view window doors, with a hard coat low-E facing the firebox side. By reflecting a fraction of the heat back the fire burns a bit hotter & more cleanly, and it's easier to keep smaller fires going.
That's a great place for me to look. Thanks.
My guess is the most important factors are
1 Air tightness, if the warm air can escape the top it will and takes the heat with it.
2 Size the smaller the space the faster the water will warm it.
3 Mass walls and floors made of heavy material like tile will absorb a lot more heat than light weight ones like fiberglass.
Walta
Hi Kathryn: Larry Schlussler of Sunfrost Company has some ideas for thermal comfort and efficiency for showers:
http://www.sunfrost.com/energy_efficient_shower.html
Thanks very much for the replies! I agree that I need to make it more airtight and heat the floors. I've already done this, I just didn't mention it. I'd love to put in heating in the walls, but that's not permitted by code (I guess they're worried someone might drill into it) otherwise I certainly would have.
funny....we do the opposite. we're careful to always stop the glass at least 8" from ceiling at top so that humidity in shower can dissipate. On occasion, we've done steam showers with Mr. Steam generators....they need to be closed, but we've provided an operation panel at top to vent shower afterwards....Are we doing the right thing? I dunno, but personally, I don't like being in totally enclosed showers.
Hugh,
You absolutely need to ventilate the shower, but only after you're done using it. Venting it after use allows everything to dry out and not get moldy so fast. But during the shower, you can get away with a relatively sealed enclosure. Vents like the transom vents in a steam shower are great for this, as some people like more fresh air than others in the shower. But any airflow carries heat and moisture out of the shower, decreasing comfort and increasing the moisture deposited on bathroom walls and ceiling. I'd attack the airflow first, before looking at low-e glass for the door. That said, a layer of hardcoat low-e could certainly help, especially if the bathroom is kept relatively cool.
I don't even have a shower door............
I don't think heating the floor will do much good. The hot shower water warms up the floor right away anyway. Limit the airflow and keep the shower stall area smallish & the hot water will warm it up. If that isn't enough, a radiant ceiling panel might be nice.