My partner and I live in an 80 year old row house that has a finished, unheated third floor/attic that we have been using for an office. In the winter it gets cold but not too bad, down into the 50's on the coldest nights, and when we're up there a small space heater does the job with no problem. Summer is the bigger problem, it's connected to our CAC (18 years old, apparently done at the same time the attic was finished) but it just can't get the heat out efficiently (and with windows on one side only, there's no air circulation so even on nice days it can get uncomfortably hot).

As part of a home renovation project we are planning to make the attic into a master bedroom suite. This will mean gutting the attic, bumping the roof up, and the back wall out a bit (the attic covers about 1/3 of our house), and adding a full bath and closet space. The total finished area will be about 437 square feet. We're working with architects, and everything will be done to code.

Cooling the new space won't be a problem (hopefully), as we are completely re-doing our A/C as part of this renovation. But how about heating? We have hot water radiators in the rest of the house (boiler in the basement) but don't want to run heating pipes to the third floor, and would like the temperature to be controlled separately anyway. Since our heating needs up there seem to be minimal we are considering radiant heat under the wood floor (new, leaning towards bamboo) in the bedroom and some kind of tile in the bathroom. Are there other/better options? In particular I'm starting to think about electric baseboard heat--would this make any sense at all, and would it make a significant difference in construction costs? (I'm not too concerned about heating costs as our heating season is short and the attic doesn't get terribly cold now, plus the new construction will be properly insulated.)