"Edwin Pawlowski" wrote in message
news:UV8Hd.1413$cx2.530@trndny03...

"twfsa" wrote in message

If you are using a boiler to heat your home, and are going to replace
the
driveway a manifold type control to limit the amount of warm water that
would be circulated thru the driveway seems the way to go, it does not
have to be heated to 70degs, once warmed the concrete should hold the
heat.I would think 35 degs would be sufficient.

If you use the boiler, you'd have to go to a glycol system or drain the
lines when not in use. I don't think that would be the most practical
system.



I used to go to a church that priced a liquid (glycol?) driveway system when
they were going to replace their boiler, as the electrical driveway system
was too far over the church budget to ever operate. They decided that, even
with members (a cement contractor) removing and replacing the asphalt at the
steepest part and replacing with concrete and tubing at cost (no labor) the
added expense to the boiler project was just too high.

I do not know specifics (and we left that church over the right wing
nutballs moving in, so I can't ask)... but I remember very well the
discussion surrounding the special unit that would be attached also taking
up some of the space of a storage closet right next to the boiler.
Considering how much smaller that stuff is today I thought that was notable,
but as I said... I really do not know the specifics... just that there is
such a critter available somewhere out there but pricey.