Can a recirculation loop off a tankless water heater (which decreases how long you have to wait for hot water) be used to heat a basement ??
What is the heat loss of your basement? That will answer your question in a hurry.
Just a follow-up on tankless thread. I have an radiant heat set-up with staple up between joists and in slab for garage. Overall there is about 1000 feet of 1/2 inch tubing throughout including garage. Using recirc with tankless. Option on tankless is set-up for monitoring of temp every 1/2 hour by tankless unit and automatic firing of boiler if temp is greater than 9 degrees below set temp. I have set temp at 135, but temp only gets up to 111 degrees after running about 12 hours plus. I have two 1/25 hp pumps on system, one pushing water on suply side and other pulling on return. Both pumps are hot at 12 hrs+. Do I need bigger pumps? Do I need to up the set temp? Any input would be appreciated