And high voltage can melt resistance elements.
I use space heaters. I modified the RV to run 'em (Installed a pair of proper 15/20 amp outlets each fed with genuine 12ga wire each from a circuit breaker that powers ONLY that outlet, one 15 amp one 20) Standard RV wiring is not up to 1500 watt heaters long term.
I'm currently in S.E. GA where it hit 35 last night here (30 offically but 35 was my lowest) and I used only 2250 watts 750 in the living room (Thermostat added over last 2 days but it is still on as I type) and 1500 in bedroom.. Got a bit cool here. but, as it happens, I like cool when I'm sleeping. I could have 2 or 3 more heaters in storage if I need 'em.
Average cost per heater is in the 20-25 range (The 750 watt "Fireplace" was I think 30 before I added the Thermostat, Which was about 30 as well) (Nice Honeywell LINE VOLTAGE Thermostat, This unit is NOT affected by power flowing through it or by the heat of the heater so it works real well) So replacement is simple and low cost when they fail.. Most last several years. Oh and the 750 Watt. Standard RV wiring is more than up to that.. But watch out for chained outlets (only one to a breaker folks)
Home is where I park it!