Electric space heaters are energy hogs and can cost as much as $100.00 per month to run for each space heater.
So if you run the electric space heater that uses 1500 watts per hour then it will cost you around $3.50 per day per space heater to run 24 hours.
I used 3 electric space heaters before to heat a few rooms while waiting for my furnace to be repaired and in one month of running those 3 electric 1500 watt each space heaters my electric bill went to $350.00 which was way more than what my natural gas heating bill cost me each month to keep the house really warm.
Heating my home with my natural gas furnace cost me around $150.00 per month to stay warmer.
Space heaters are really good for supplement heat to help warm up some cooler rooms however they're not meant to actually heat a home as the sole source of heat.
Also space heaters can be dangerous and a loose outlet connection can cause the heaters plug to get hot which could start a fire so always make sure the space heater is firmly plugged into the outlet and not loose.
Always periodically feel the plug and it's normal for the space heater plug to be a little warm but not too hot where you can't touch it.