This ^^^ Even with a fully insulated interior, it wouldn't be enough to heat the building. Dealership I work for has liquid floor heat in the shop's dyno room and wash bay since they aren't heated, and it does nothing to regulate room temps. And these are well insulated bays, too. The rest of the shop has NG radiant and it works great. Even with bay doors going up and down all day through the winter, it keeps the shop about 65 degrees on average. No idea what company installed the systems, but it's industrial sized equip since our building has 30 ft ceilings and 26 bays, so it was definitely expensive.