I'm about ready to buy a new electric boiler for my shop and I'm not sure what size would be best. I'm at 960 square feet with 4 200' loops in 4" of concrete. My design calculations indicate that I need about 20k btu's to meet my spec. I can get a 20k boiler or a 30K for close to the same price. Should I go for the extra overhead or keep it close to the calculations. The boilers are modulating. Any opinions would be appreciated.

it's hard to oversize an electric boiler, and more output will give you some better responsiveness. might as well go bigger in that case as long as minimum flow rates or electrical draw concerns are not a problem.

Electric connections, no problem. Flow I'm not sure about. The boiler mfg lists the two boilers min flow at 2 gph for the 20K and 3.1 gpm for the 30K both at 15 psi. Mypanel piping is 3/4" through a 3/4" B&G air seperator and gurnfoss UP 15-42 SF pump into a 1" four port manifold.

Have a look at our new electric stainless steel water heaters. They are about 1/2 cost of electric boiler and approved for space heating. minimal flow 1/2 gpm OK.
Dan

How do I find them? I looked at your website and only see the Thermolecs.

I found them.