Every year around this time stores begin selling electric heaters. The boxes boast how much money you’ll save if you switch to their product. You can save half of your winter heating costs by spending a mere sixty dollars! What a terrific deal!

Unfortunately, many people have discovered how insubstantial these claims are. Often to the detriment of their already strained budget. We will walk you through the math to determine if one of these electric heaters will save you money or end up costing you more. I’m warning you now, I have tried to make this as simple as possible. There is a lot of math involved to understand what’s going on. Casey had to educate me on a lot of different details and triple check my work to explain what I don’t fully understand.

• BTU: is a measurement of heat output.
• CCF is one hundred cubic feet, the measurement of natural gas used as shown on your meter
• CF is one cubic foot, equal to 1,000 BTU
• 1 US Therm equals 100,000 BTU

The first thing to keep in mind is that these heaters run on electricity. In California, natural gas is available almost everywhere. Rate structures are designed with the understanding people will use more of a utility in a specific season. People will use more electricity in the summer for air conditioners. They will use more gas in the winter for heaters. Yes, there are electric only schedules. You would have to replace all gas appliances with electric, and then have the electric company come out and inspect your home. Once approved, you’ll receive more baseline allocation each month.

The utility companies change the baseline to allow more usage for the appropriate season before you get into the higher rates. If you are using an off-season utility, like an electric heater during the winter, it's going to put you into tiers fast. The Gas Company and PG&E Gas change over to winter baseline effective November first each year. The average PG&E summer baseline for gas is 0.59 and the average winter baseline is 1.96. That is an increase of 40.97 US Therms each month.

For real-world numbers, we are using the Lasko 6405 Designer Oscillating Heater. You may buy it on Amazon for about fifty dollars. Here comes some math:

The equation is electric heater wattage rating x 3.413 (maximum efficiency) = BTU output

The Lasko 6405 is rated for 1500 watts. 1500 x 3.413 = 5119.5 BTUs or 0.05 US Therms

Next, you need to know how much it will cost to run the electric heater. You can read this article about how to calculate kilowatt hours. For the sake of brevity, we’ll give you the numbers. This electric heater will run at 1.5 kWh per hour. Assuming you run it for 2 hours in the morning and 4 hours in the evening, that’s 6 hours per day or 9 kWh per day. That works out to 270 kWh per month. If you run it longer during the weekend days, that’s going to cost more.

The electricity rate is a trickier since that will depend on how much electricity you use each month. Most calculations will use the baseline amount for simplicity. But, that can lead to a gross understatement of the actual amount the electric heater will cost. You can already see it is going to cost quite a bit to run this electric heater for a few hours daily. Winter baseline allocations range from 270 to 500 and running it for part of the day will cost most of your baseline. Now, what about the rest of your usage? Lights, television, refrigerator, computers, and everything else that runs on electricity? All that is charged at the higher tiers.

For our example, we will assume the baseline allocation for the month is 330 kWh. We'll use the rates for PG&E. It is usually safe to assume that you need the allocation for your daily needs. Test calculations should be on the second tier or higher, depending on your individual usage.

At standard second tier usage, the heater will cost 270 * $0.28478 = $76.89 per month.

At standard top-tier usage, the heater will cost 270 * $0.44095 = $119.06 per month.

At CARE second tier usage, the heater will cost 270 * $0.18075 = $48.80 per month.

At CARE the top tier usage, the heater will cost 270 * $0.27987 = $75.56 per month.

Output

Okay, this furnace is rated for 50,000 BTU per hour. Remember, a single foot of natural gas puts out about 1,000 BTU and equals 0.01 on a CCF gas meter. So, when running, this heater will use about 50 cubic feet per hour. That translates into about 0.50 CCF per hour on your gas bill. Remember though, your heater won’t run for 60 minutes at a time. It will take about 20 minutes to heat up the home in the morning or when you get home from work and then periodically afterward. This site references average run times to be 2 – 3 cycles per hour and 10 – 15 minutes each. I have seen about that in my own home, so we’ll use those numbers. On the low end, that means your furnace will run for about 20 minutes per hour. On the high end, it would be 45 minutes per hour. That’s a range of about 0.20 to 0.45 CCF per hour. Whenever possible, adjust your thermostat so it runs on the lower end of this range for greatest savings. We’ll use an average of 0.325 CCF per hour as our number. That works out to about 234 CCF per month (0.325 per hour x 24 hours per day x 30 days). This is California, so the likelihood of it running 24 hours a day is pretty low. The highest gas bills I see are less than half of that.

Gas Tier Rates

So, assuming the low end of 0.20 per hour at 10 hours a day, you’re looking at 60 CCF per month. That is on par with most of the gas bills I see out here in the dead of winter. We will use baseline rates for gas because they are designed to provide some heating at the lower tier. For PG&E rates, it would work out to the following:

At standard baseline rates, the furnace will cost 60 CCF * $1.28806 per unit = $77.283 per month.

At standard excess rates, the furnace will cost 60 CCF * $1.84870 per unit = $110.92 per month.

At CARE baseline rates, the furnace will cost 60 therms * $1.02915 per unit = $61.75 per month.

At CARE excess rates, the furnace will cost 60 therms * $1.47766 per unit = $88.66 per month.

So how can you really save money on heating?

All that math is helpful for calculating your own heating usage, but how does it compare on an apples to apples basis? The conversion of therms to kWh will provide that.

1 US Therm equals 29.3 kWh.

1 US Therm of gas at standard top tier costs $1.84870.

29.3 kWh of electricity at standard 2nd tier usage costs $8.344054.

So, there it is: using electricity to heat your home costs about four and a half times as much as natural gas. Now, using an electric heater to supplement your heating will be most likely to save you money. If you are in the front area of the home, there is no reason to heat the back rooms to a comfortable temperature. And, if you are in the back of the home, there is no reason to heat the front rooms to a comfortable temperature. You can save money on heating if you set your thermostat at 60 and run an electric heater for a few hours during the morning and evening. Add an extra blanket to your bed if it's too chilly. Don’t be afraid to experiment. Try different combinations of thermostat temperature and electric heater time for a few days each. Track the usage.

If you haven’t already read our article about saving utilities and downloaded them, sign up here to get our utility usage trackers and use those to help figure out the best combination for you.