I have a 1922 colonial in Maryland with a finished attic on the third floor. The house is heated by hot water radiators via a gas fired boiler in the basement. In the summer it is cooled with forced central air, which was installed along with the duct work by the previous owner. The air handler is in a closed off area in the finished attic.
I have two problems. First, there are no radiators in the attic. The heat does rise up stairs, but it still gets pretty cold, about 58-60 degrees when the downstairs thermostat is set at 68. I tried closing off all the downstairs air ducts and running the A/C fan, hoping to draw heat upstairs. This had minimal effect. Since I use the room frequently and am considering putting in a master bedroom suite, I am considering what my options are to supplement the heat.
Secondly, this past summer it was very hot in the attic, even with the A/C running all the time and all of the downstairs duct vents closed off to force the cold air upstairs. Part of the problem is that the insulation was placed against the roof sheathing, allowing no ventilation, and the radiant heat passes into the room. I plan on tearing down enough of the insulation to install passive soffit and roof venting behind the insulation. This should help, but maybe not eliminate the problem.
Any suggestions on what to do? My thoughts are:
1. Install supplemental heat of some kind, perhaps electric baseboard, heat lamp in proposed bathroom, etc., to be used when needed. Install window A/C for summer heat if necessary.
2. Since the A/C air handler is in the attic, retrofit it with a heat pump to supplement the upstairs. Still use the window A/C if necessary.
3. Install a separate window or wall unit A/C/heater combination of some kind for the attic. Don't know much about such a product.
There may be other better solutions also, which I am open to. My first goal is to minimize costs, which is why I'm leaning towards #1, but I'm not sure how long term power costs would compare between the various options. Please provide some feedback.
Thanks for your time.