The average thermal dispersion for water heaters is between 1 and 2 kWh/24 hr. This means that an electric water heater that is idle consumes between 1 and 2 kWh every hour.
Simply so, are electric water heaters energy efficient?
In the battle between gas and electric water heaters, electric water heaters win out from an efficiency perspective. Conventional gas water heaters typically have EF numbers ranging from 0.5 to 0.7, while electric water heaters can have EF numbers higher than 0.9.
Similarly one may ask, do electric water heaters save?
The U.S. Department of Energy estimates gas-fired tankless heaters save an average of $108 in energy costs per year over their traditional tank counterparts, while electric tankless heaters save $44 per year.
How many hours does a water heater run per day?
The cost of electricity is about 14p/kWh, which means that it would cost about 45p to run a 3kW immersion heater for an hour. Normally though, the immersion will turn on and off via the thermostat so the amount of time they are on fluctuates, depending on the existing temperature of the water in the hot water tank.
Running a 1,500-watt heater for 24 hours will cost $4.80. $11.20 to run per week (8h/day).
According to the Department of Energy, based on the assumption that an electric water heater runs for an average of about three hours per day, a 50-gallon water heater, running at 5,500 watts, with an electricity rate of $0.16 per kWh, will have an annual operation cost of $781.
Now we can start with the calculations: A 40-gallon water heater should have an average 4500 Watt capacity and 240 V emf.
Electric water heaters are less expensive to purchase than gas water heaters. While it’s always possible to buy expensive water heaters in either electric or gas models, if you want a less expensive heater, it will usually be electric.
Uses renewable energy: Solar water heaters are the most energy-efficient water heater options available today.
Efficiency. If you are comparing the efficiency of an electric water heater vs a gas unit, electric heaters are more efficient. Although gas hot water heaters are less expensive to run monthly due to the low cost of natural gas—a gas heater uses more energy to operate and releases waste into the environment.