12,000 sq ft plus 6' in my aprons in front of all the doors for snow melt.
There is about $35,000 in copper in my building since it is big enough all the runs could not come back to the boiler direct, it all had to manifolded off and plumbed. Add that to the $14,000 in insulation for underneath the slab to help hold the heat in the slab instead of wasting it heating dirt.
But, I'm now heating that 12,000 sq ft on $1250/month average. It's expensive, but efficient one done.
You can see some of the overhead plumbing up in front of the windows.
It's a big space
Chris