I'm considering how to provide some heating to an extension. Off the
kitchen, it's a utility room with shower room beyond, total area about
7m x 2.5m.
There is CH to the kitchen but I haven't yet determined whether it can
be extended to provide radiators.
I'm looking at electrically-powered underfloor heating (area will be
all floor tiles). However, as the roof gets a lot of sunlight I also
wondered if solar panels used to run warm water might be a viable
alternative.

Any observations from anyone who has done something similar?

(johnty) wrote in message . com...
I'm considering how to provide some heating to an extension. Off the
kitchen, it's a utility room with shower room beyond, total area about
7m x 2.5m.
There is CH to the kitchen but I haven't yet determined whether it can
be extended to provide radiators.
I'm looking at electrically-powered underfloor heating (area will be
all floor tiles). However, as the roof gets a lot of sunlight I also
wondered if solar panels used to run warm water might be a viable
alternative.

Any observations from anyone who has done something similar?

Electric costs around 3x gas to run.
Flat plate solar space heating is far cheaper than costly water
heating systems. This is the one form of solar that has very
reasonable install cost and pays back well. See alt.solar.thermal.

NT

N. Thornton wrote:
(johnty) wrote in message . com...

I'm considering how to provide some heating to an extension. Off the
kitchen, it's a utility room with shower room beyond, total area about
7m x 2.5m.
There is CH to the kitchen but I haven't yet determined whether it can
be extended to provide radiators.
I'm looking at electrically-powered underfloor heating (area will be
all floor tiles). However, as the roof gets a lot of sunlight I also
wondered if solar panels used to run warm water might be a viable
alternative.

Any observations from anyone who has done something similar?


Electric costs around 3x gas to run.
Flat plate solar space heating is far cheaper than costly water
heating systems. This is the one form of solar that has very
reasonable install cost and pays back well. See alt.solar.thermal.

NT



I am working on replacing my forced air heating with floor radiant
with solar assist -- I've found these sites to be helpful for
understanding whats involved in all the various radiant heating options:

These sites offer a lot of installation and design
documentation (you may have to dig around through the architect,
designer, professional pages to find the good stuff):
http://www.radiantec.com/installation.htm
www.ipexinc.com
www.warmrite.com

These guys do both electric and hydronic:
http://www.warmzone.com/otherproducts.asp

Some interesting products:
http://www.wirsbo.com
http://www.warmboard.com/

Gary

(johnty) considered:

how to provide some heating to an extension... total area about 7m x 2.5m.

About 23'x8'.

...as the roof gets a lot of sunlight I also wondered if solar panels
used to run warm water might be a viable alternative.

You might check out unglazed solar roof panels from Energie Solaire, or
replace the roof with a layer of polycarbonate glazing over two layers
of polyethylene film over a polycarbonate ceiling. The space between the
film layers could be filled with air during the day and soap bubble foam
at night from a shop vac blowing air through a pipe full of holes in a
10% detergent solution. The vac might turn off when foam begins to push on
a screen over an air return near the top and the screen pushes the arm of
a microswitch.

In Phila, 620 Btu/ft^2 falls on the ground on an average 30 F January day,
so a square foot of room with an R2 cover and 80% solar transmission might
collect 0.8x620 = 496 Btu and lose 6h(70-30)1ft^2/R2 = 120, for a net gain
of 376 Btu, or 8x23x376 = 69.2K Btu/day, under an 8'x23' roof. You might
get some sun in south windows as well.

You might keep the room an average 65 F on a 30 F day if 24h(65-30)G 69.2K,
ie G = 680/R 82.4, which makes R = 8.26, ie US R-value 8.26 (metric U0.69)
walls and ceiling, like 2" of white foamboard. You might store 69.2K Btu in
69.2K/(70-60) = 6920 Btu/F of thermal mass cooling from 70 to 60 F, eg an
8'x23'x1.5' thick concrete slab, or a thinner layer of overhead warmer water.

Nick

Thanks for the responses.
I shall follow them up, and put Nick's reply into babelfish to get the
English translation...