[Greenbuilding] distribution of radiant heat

[John Straube]

If you have a source of domestic hotwater, a small circulation pump moving domestic hot water through a 1/2" PEX line and heating the exposed tile floor could quietly and easily heat the bathroom to whatever temperature the clients desire.

Depending on the clients goals, engagement, and space constraints, you could even use the fireplace to preheat DHW by coiling a bunch of copper pipe next to the fireplace on the way to the DHW tank.

Finally, assuming 65F for the bathroom temperature is likely as low as most clients will want their bathroom, and I dont blame clients for wanting the aesthetics of a gable end fireplace: there is no reason that they cant have the fireplace and very good performance.

On 2011-01-08, at 12:03 PM, Chris Koehn wrote:

> Hey Corwyn, If you'd like more info before jumping to conclusions just ask:
> 
> The "open fireplace" is not open: it's an enclosed, sealed combustion unit with outside combustion air and heat circulation. Not my preference, but again, I'm not the architect.
> The clients have in place a 12 KW propane generator. We won't be powering the home exclusively with solar;  solar will be used to top up the batteries when the genset isn't running.
> I am building a case to revamp the design to abandon the fireplace (on a gable wall- largely aesthetic) in favour of a centrally located masonry heater.
> Propane has to be barged over, so it's usual cost and efficiencies are not applicable here. 
> There is currently no heat source called out for the bathroom, so your assumption that we're starting with 65 degree air is invalid.
> We are working with 4500 HDD but heating typically starts in late September and ends in early June. It's oceanfront, so there's a really big 45 degree mass out there.
> It may prove to be more efficient and practical to provide a separate propane heat source for the bathroom area but the clients have asked me to look for alternatives and so I am.

Dr John Straube, P.Eng.
Associate Professor
University of Waterloo
Dept of Civil Eng. & School of Architecture
www.buildingscience.com