If I have a fish room I would also enclose the room with lots of insulation. I would run this rooms heating hooked up to my boiler system (gas supply)with its own zone. I would just throw out all the heaters and control the room ambient temperature. Electric heating are too expensive and not economic in the long term..
I can't advise you on which heating system to use, but personally I would use a ceramic space heater just because its cheap and there's no installation involve. Plus it's easy to return should it prove not strong enough.
One thing I never understood about heating the room is how you can stand being in the heated room to watch the fish in your tanks. I know it is the most economical approach, but then I feel like your time with your fish ends up being limited. I know that for me, I like to keep my house 65-69 degrees but I compromise with my wife and live with 70. I can be comfortable in 70 but as soon as the house hits 71-72 I start sweating. Then, on the hot days in summer it will occasionally hit 75 and that is unbearable for me to the point that I have my shirt off laying under the ceiling fan on full blast. How are you guys with rooms heated up to 80-82 degrees able to spend any length of time with your fish?
