hawgeye wrote:

"Furry" wrote...


We have a 1200 sq ft full basement that we're heating via radiant heat.
There are 4 runs of Pex. We're very happy with it but I'm worried that
there is something wrong with the system. When the basement calls for
heat the pump turns on and I can see the temperature gauge go up to
around 100-110 degrees. There's no gauge on the return but feeling the
Pex it's obvious that the water coming back is pretty cool. The
problem: It takes at least an hour, sometimes 2, for the basement to
warm up enough that the thermostat stops calling for heat. 1200 sq ft
is a lot of concrete to heat up but isn't that a long time?

Any thoughts much appreciated.


As others have stated, the drawback to radiant heat is it's slow warm-up.
OTOH, it has a slow cool-down. Depending on how cool it was to start with,
2 hours is not a long time for that area to warm up to temp. However the
boiler shouldn't be running continuously. The boiler should cycle and only
fire up once the water reaches a certain temp.
You really can't have your basement set at 60 then adjust your thermostat
for 70 and expect it to heat up quickly. I've found that if you set the
thermostat lower (say 65) and leave it, the area will eventually warm up
beyond that point and the boiler will only kick in every once and a while.
Assuming the radiant heat is installed in the floor, you can also get away
with a lower temp setting on your thermostat because since the heat is lower
it actually feels warmer.

Yes, slow cool down is one of the other disadvantages, but it is really
the same phenomenon. I have a friend with a radiant heated home and he
often has to open the windows in the spring and fall when the temps
cycle dramatically from day to night. When the sun comes up in the
morning and the temp outside rises from 20 to 50 in four hours, the
house simply can't release the stored heat quickly enough so you end up
throwing heat away via open windows.


Matt