Low wattage electric wall panels, help please

Sailor

I live on a houseboat in the Ca. delta region and it's cold here. I have a couple of 1200/1500 watt space heaters but it's costing too much to run them. I'm a disabled Namn vet and my income just about covers dock fees and groceries. So someone told me to get some low wattage electric wall panels that basicially run full time to keep you warm but don't cost that much. The boat is three small rooms plus the head, a 14x10,12x10 and 6x10, roughly 315 sq. ft. So can someone tell me how many of what kind of these wall panels I need? I've onlt been able to find one company that makes them Econo Heat and the reviews I read about their service and product doesn't seem that good. Are there other cmpanies that make these low wattage panels? Someone told me about a company that sells an electric wall panel unit that comes with a starter kit of a thermostat and 4 90watt strip panels that plug together and more can be added if need be, this sounds great but he didn't remember the name of the company. Please any help in finding the product or experiences with low wattage panels would be appreciated. Shivering in the delta.
Sailor