1500 watts will heat spaces up to about 150 square feet and can help you stay warm and toasty in a medium-sized room, office, kitchen, or modest-sized living room.
Heater Room Size by Watts
Answer: 10 watts of heating power per square foot is recommended for electric heaters.
A 1,500-square-foot home will require between 45,000 to 90,000 BTUs. A 1,800-square-foot home will require between 55,000 to 110,000 BTUs. A 2,100-square-foot home will require between 65,000 to 125,000 BTUs.
For example, a 300 square foot room typically requires 7,000 BTUs to maintain a comfortable temperature, while a 1,000 square foot room requires 18,000 BTUs.
Running four hours a day, a 73-watt TV costs about a nickel per day to operate, or a little more than $17 per year. And that doesn't include vampire energy. In comparison, a 1,500-watt space heater running four hours a day costs nearly $1 per day, or about $88 for three months of daily winter usage.
Using a space heater to target rooms you're using instead of heating the entire house is a surefire way to trim money off of your monthly energy spend. Space heaters cost about 20 cents per hour to operate, give or take, which is a whole lot cheaper than central heat for a home of almost any size.
The more insulation, the less wattage is needed to effectively heat the space. But with that said, you are going to need somewhere between 5-10 watts per square foot. And Home built within the last 10 years only require around 5 watts/sqft because of increased insulation standards in building codes.
x 24 ft. garage has 528 square feet, so the easiest way to estimate the required wattage is to multiply by ten. 528 x 10 = 5230 watts, so a unit like the NewAir G56 Electric Garage Heater (5600 watts) would be more than enough to keep it warm.
HVAC contractors use a rule of thumb to allocate 20 BTUS to every square foot of space inside your home.
Such a heater consumes 36 kWh of electricity. Running a 1500-watt heater for 24 hours will cost $4.80. $11.20 to run per week (8h/day). $48.00 to run per month (8h/day).
A 6,000 BTU mini split system will be able to handle a 12 x 12 room. Once you go over a 260 square foot room, you're going to need to go up to a 9,000 BTU mini split system. A 6,000 BTU mini split can usually handle up to 6,500 BTUs.
High wattage means more power is consumed. Because of this most of the time we are trying to build and use appliances that use less power and have lower wattages. Higher wattages however are good when you particularly need to turn electricity into heat. The higher the wattage the hotter the heater.
A heater that is too large for the space will not heat the space more quickly. A heater that is too large for the room will continue to heat for an extended period of time beyond the temperature set point, wasting energy. We call this a temperature swing.
In other words, a 10x10 room (100 square feet) will require 1,000 watts of electric baseboard heating. This heating can be provided by a single baseboard heater mounted on the wall. For larger rooms, the total wattage can be provided by two or more heaters.
Garage Size
A good rule to follow for choosing an adequate garage heater is for every 10 watts of output, you can heat 1 square foot of space. For instance, a 150-square-foot garage or shop will be fully heated by a 1,500-watt electric garage heater.
A good rule of thumb to follow when choosing a garage heater is that for every 10 watts of output, you can heat 1 square foot. In this case, a 1,500-watt electric garage heater can heat a 150-square-foot garage or shop.
Single-car garages up to 450 square feet should use a heater with 2,000 to 3,000 watts or 6,800 to 9,000 BTUs of airflow. Two-car garages between 450-700 square feet need a heater with 3,600 to 7,000 watts or 12,000 to 24,000 BTUs.
BTU's are equal to Watts x 3.413.
In our case 1500 watts x 3.413 = 5119 BTU's. Most manufacturers of 1500 watt heaters generally say they provide 5120 BTUH's or British Thermal Units per Hour. Now, the colder your average climate, the greater your heating needs will be.
Therefore, a 1500 watt space heater (120 volts) can heat an area of 150 square feet, and a garage heater rated at 5,000 watts should be able to comfortably heat an area over 400 square feet.
Never leave your space heater alone in the room
The best way to prevent a fire is to never leave a space heater running in a room unattended—that way, if anything does go wrong, you can take action quickly.
According to experts at the Energy Saving Trust, the idea it's cheaper to leave the heating on low all day is a myth. They're clear that having the heating on only when you need it is, in the long run, the best way to save energy, and therefore money.