A.Registered engineer and sustainable design consultant Marc Rosenbaum, of EnergySmiths, Inc., in Meriden, N.H., replies: Electric radiant heat for a superinsulated small space makes a lot of sense. It gives you a low installation cost and a moderate energy cost; it's highly zonable; and there's no combustion. I assume that the hot water would also be provided by electric resistance.
An alternative might be a combination wall-hung, sealed-combustion, gas-fired water heater coupled to a wall-mounted kickspace heater or two for heat, but that would cost more to install, take up more space, be noisier, and require the location of a vent and a fuel tank.
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