Energy consumption is based on wattage, so your heat bulb wattage affects how much you pay to operate it. Heat bulbs often range between 125 and 250 watts; you can find your exact wattage by looking at the bulb. The wattage will be printed on the front of the bulb or at the top of the metal threads where it screws into the socket. Because heat bulbs convert their filament energy primarily into radiant heat rather than visible light, they use only the power rating of the bulb, which is much lower than most forced-air space heaters.
Step 1
Find the kilowatt-hour charge on your electric bill. If you cannot find this listed, call your electrical service company and ask what their kilowatt-hour rate is. Some companies charge varying rates depending on how much energy you use, but you can get a good estimate of your heat bulb's consumption using the base rate.
Step 2
Divide your lamp wattage by 1000 to get the kilowatts.
Step 3
Multiply your answer by your local kilowatt-hour rate.
Step 4
Multiply the answer by the number of hours you use the lamp per day. If you only use it for a half-hour daily, that would be 0.5 hours. Round to the nearest 15 minutes (0.25 hours) for your calculations.
Step 5
Multiply your answer by 365 to get the annual cost of operating your heat bulb, or by 30 to get the average monthly cost.