Todays 5Live 'Wake up to money'. Guest says old leccy heaters are not 100% efficient

I could have sworn that I wrote "software" where that double space is above. :-(

Chris

A shot of brandy every five minutes ....

All electric heaters are unavoidably 100% efficient.

However heat pumps driven by electricity can deliver around three times the input power.

Electric heaters are ideal for intermittent heat, eg we have a wall mounted electric fan heater in the bathroom. Only needs to be on for ten minutes.

They are also cheap to install.

(1) Storage heaters, except as below, are 100% efficient but less than 100% effective, as they generally deliver some of their heat when it is not needed. But they are beneficial to the wallet, as they get their energy substantially more cheaply than direct heaters usually do.

(2) If un-curtained windows are present in line-of-sight of the heater, so that the heater is visible (in any wavelength) from outside, then a cheerfully-glowing heater loses more energy to the outside than an inconspicuous storage one does. The effect is unimportant in practice, but necessarily exists.

(Z) An OT thought : Microsoft have omitted what might have been included --- surely, when a PC user opens & closes Windows, or windows within Windows, one should see Curtains moving likewise (or Blinds/Shutters for some localisations)?

Nothing is 100 percent efficient, if it were you could use the heat to power the heater. I was always thought that the primary fuel was always best assuming you can use it efficiently. all by products are inefficiencies. However electricity does not occur naturally in the environment in a usable form so every time you convert energy from one form to another you lose some. Its what you might call, bleedin obvious.You lose through losses on the power lines in the efficiency of transformers and at the generation stage due to the inefficiency of the engines and friction. When you heat thing with electricity you are merely dissipating energy into the medium you use. In a storage heater you are heating a brick. It would be more efficient to use some other form of energy storage these days, as you really cannot control the output of a hot lump of brick unless you shove it in a vacuum flask, now can you!

Brian

Isn't producing heat when and where it is wanted the correct measure of efficiency? After all a gas fire or even an open coal fire is close to 100% efficient at converting chemical energy to heat, it just uses a lot of it to heat exhaust gases.

Not very "effective".

Depends where you define as the start point. There are transmission losses from the power station to the 13 amp plug on the wall.

Since you're allowed (worst case) 5% voltage drop on the wiring, this would limit efficiency to 90%, although in practice most of this lost heat would heat the house. But not very usefully at 3am.

But I suspect your parents house had single glazing, possibly solid

Probably a Johnson and Starley system, which were quite effective when electricity (off peak) was a lot cheaper.

More likely back to wearing the correct clothing to keep warm and only keeping one room vaguely 'warm' in cold weather.

Plenty of people over a certain age will rmember those days.

People who just wear T shirts and pants in the house in mid-winter are in for an expensive shock.

Not really. It may be a measure of how well it works to heat your house which most might call efficient.

A 60 watt tungsten light bulb produces near 60 watts of heat, so is a very efficient heating device. But not much use for heating the house.

they are inefficient in the the timing of the release of their stored heat

For many people, they over heat the house during the day when no-one is there so that they have enough heat left in them to heat the house in the evening when you are there.

tim

The radiative heater on my man-cave wall is radiating on to me. That's why I picked it.

Andy

And also onto the walls behind you, and out through the window.

I'm rarely in here long enough for it to warm the walls very much, and I doubt much gets through the latest spec double glazing.

I used a fan heater as a topup over the winter; too noisy to want to use much. A convector will heat the air from the top down, and take a while to get to me. I get the IR immediately. Well, some of it.

I'm sure some soaks into the wall and the floor (not the ceiling; it's not pointed that way). And some will be lost to convection, heating the layer of air above my head. But it's silent and immediate which is good.

Andy

No open fire comes close to 100% efficiency.

Lots do. They're called flueless.

NT