growing in a cold attic

Anyone ever try to use a waterbed heating pad to raise the temp in a cold attic grow room? I'm trying to keep the wattage down and a space heater is 700 - 1500w.

Thanks

never tried to use a waterbed heater although i have heard of people using similar stuff to warm cutting etc . . . but i just go for a standard green house heater simple easy cheap lol

Thanks, any recommender brands? The ones I saw were expensive and/or uses a lot of wattage.

Thanks