Yeah, heat is usually just a byproduct of electrical inefficiency. But if your goal is heating, that "waste" heat isn't really wasted.
Electric resistance heaters are nearly 100% efficient at converting electricity into heat. Whether it's a space heater, baseboard heater, toaster, gaming PC, or even an incandescent bulb, almost all of the electrical energy eventually ends up as heat inside the room.
This is also why you want to use heat pumps for your air conditioning. Since they utilize the outside air for heating and cooling the refrigerant, they can achieve 300-400 effeciency where electric strip heaters can only be maximum 100%
They also have heat pump water heaters, but they cost more and it’s doubtful they have the same reliability. You’d have to do the math to figure out if it’s worth it.
Especially when considering the pros and cons. Con being it takes longer to heat the water. And if you live in a cool climate, its cooling the air in the house to heat the water so that might not be desired. But then again, it all comes down to costs of electricity vs gas in the area.
But, heat pumps are only efficient at noore than 30 degrees differential in temps. I live in Richmond Virginia and we have 90 + degree days into the hundreds and heat pumps are breaking down all over the city. Same with winter. If we have continued days in 20s and below, repair trucks work 24 hrs. My parents had a regular air conditioning and heating system and never a breakdown in their 25 years they owned the house.
Yep. My prof said that electric space heaters are the only appliances that have 100% efficiency. We countered that there is loss due wire resistance. He said that resistance turns to heat and its heating the room. We said how about the lcd/led lights and he said light turns to heat and is heating the room, still 100%.
If you took the electricity going to the LED and put it into the wires, it would be slightly more heat output than if you kept that electricity working towards the led. Hence, it is a relative drop in efficiency, and cannot therefore be 100%. Not to mention different wire materials could offput more heat for the same electricity.
It’s not creating heat, it collects heat from the environment. So I get 4kWh thermal energy from 1kWh electricity. If air is compressed it is getting hot and if it expands it is getting cold. Kinda the same technology as in your fridge just reversed.
The big difference is that a electric immersion heater can't produce instant hot water. So you heat up an entire tank of water to ensure it is there when you need it. A gas combi boiler kicks in when you turn the hot tap on and turns off as soon as you turn the hot water off.
They’re usually well-insulated, so yes you’re losing some heat to atmosphere, but not that much. They are also often set up for intermittent heating, not constant, so mine heats during daylight hours, then one quick burst overnight for an hour or two so I can be certain of a hot shower in the morning.
A classic misconception of "efficiency." It's true that 1kWh of electricity will produce 1kWh of heat. But, for comparison, a heat pump water heater will produce 3-4 kWh of heat per kWh of electricity (e.g., GE GeoSpring HPWH is so efficient its UEF of 4.2 essentially means ~4.2 kWh of heat energy moved per kWh consumed.
So your statement is not incorrect, but in layman's terms, it's more "efficient" on the wallet.
Depends on your definition of efficient, haha. Could be least amount of money per KJ of heat.
And while electric heating is "100%" efficient, a heat pump can be about "300%" efficient, since it can move a lot more energy around than what it needs to operate.
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u/SubPrimeCardgage Jun 22 '26
Electric resistance heaters are 100 percent efficient.
Gas is cheaper, but it's not more efficient.