Garage heating - water or glycol

NYplumber

Hey there wallies

I have two garage jobs, one being radiant new construction and the other a remodel. The remodel job will have either a home made radiant wall panel, radiant ceiling or hydro air coil.

On the new construction job, the heat will most likely be radiant slab.

Im well aware of the horror storries of radiant slabs freezing and scrapping the loop or doing big repair work. In the case of low mass radiant of the retrofit job, i would assume the garage can get pretty cold albeit it being under the bedrooms.

Im spec'ing glycol for garage loops due to the door possibly being left open. Would you consider water? These houses are in upstate NY where design day is around 0f.

Thanks in advance

kcopp

I did a in slab job a couple years ago for a 2 car garage. I used water only. The house has a generator for back up. If they lose power the lab would have a couple days before it really cooled to the point that it could freeze anyways.
As far as the doors being left open... can you really prevent people from being silly and forgetful all the time?
I would give the homeowners the option.. here are the pluses and minuses of using glycol. Here is what can happen.
Let them make the decision.

SWC

Siegenthaler goes without and he is upstate NY

Near bottom of page from: Less antifreeze

http://digital.bnpmedia.com/article/John+Siegenthaler/1556535/0/article.html

Tinman

On attached garages with the radiant panel in a 4" slab, I've always used water.

If it were a fan coil, most cases I would use glycol.

SWEI

Howler alarm on the garage door, in series with an OAT snap switch.

NYplumber

Thanks for the replies guys. Water it is as there will be a generator. I can also put a set point sensor in the slab or heated wall for any time it approaches close to freezing to turn on the heat.
Thanks for that link to siggys article.