Most places in North India experience extreme climates during summers and winters. Summers are extremely hot and winters are extreme cold. This makes it important to have both air conditioners as well as room heaters. It’s a common knowledge that air conditioners consume a lot of electricity and cause increase in electricity bills. But in northern India electricity bills due to heating in winters can be as high as that for cooling and in fact can be more. A recent trip to New Delhi provided us some opportunities to measure room heaters for power consumption that gave us the idea to write this article.
Room Heaters and their wattage
An analysis of room heaters suggests that wattage of room heaters vary from 400 W to 2000 W (or 2 kW). If the wattage is less, it will emit less heat, if the wattage is more, it will emit more heat. It is important to note that if a 400 W heater runs for 1 hour it will consume 0.4 units whereas a 2000 W heater will consume 2 units if it runs for 1 hour. So more the heat, more the wattage and thus more the units consumed.
Impact of wattage
The heat moves in the room through thermal conduction, which in turn depends on the temperature gradient in the room. If a 400 W room heater is used, the heat from it will not spread wide and thus one has to be close to the heater to feel the warmth. It will be good for a smaller room. A 2 kW system instead will be far more effective in heating a bigger room, as it will emit more heat.
Benefits of a room heater with thermostat
As we have discussed in a previous article on ideal air conditioning temperature, ideal temperature for thermal comfort of humans is 25 degrees. But if we leave a heater on for longer duration, the temperature might increase beyond that. This not only makes the environment un-comfortable but also increases electricity consumption. A room heater with thermostat with temperature setting will cut off power consumption when the desired temperature is reached.
We measured a room heater without thermostat by keeping it on for 8 hours; it consumed 10 units and was consuming electricity at a constant rate of 1.3 kW (or 1300 W). 10 units at average rate of electricity in the country of Rs 5 are about Rs 50 per day or Rs 1500 per month. (You can check per unit rate applicable to you using our calculator: Online Electricity Bill Calculator – For all states in India). Had we used a room heater with thermostat, electricity consumption would have been lower because the room was quite hot after 8 hours.
A room heater with fan
A fan will help heat reach out to a larger space, as it will increase airflow and heat flow. If the room heater does not have thermostat but has a fan, then it is better to keep room heater at lower temperature. Fan will make sure that hot air reaches across the room and lower temperature will make sure that the power consumption is less.
A room heater with variable wattage knob
Many room heaters have a variable wattage knob using which wattage can be adjusted. As we discussed earlier, higher the wattage, more will be the heat from the heater and larger the reach of the same. So if knob is kept at higher number the room will heat faster and will heat more, but the electricity consumption will also be more as compared to lower knob setting. So to save electricity it is better to keep room heater at as low settings as possible. Keeping it close to the people sleeping can help reducing the wattage (just make sure that the distance is safe and no one gets burnt).
For room heaters it is always better to buy one with thermostat as it keeps temperature in control and reduces excess electricity consumption. It also makes sure that the environment is comfortable for humans to sleep. Also it is important to keep the right insulation in the room to keep the electricity bills for heating in control.