Any on got these flat panel wall mounted heaters. I am working in a new build that has them in every room and they seem to give of a good heat, they are meant to be cheap to run.

Exactly the same as any other electrical heater – 100W is 100W regardless of the source.
Remember these are “directional” too hence you’ll find them on the ceiling normally.
Classed as “Snake Oil” by everyone I know

When you say snake oil do you mean all bullshite.

😉

New build = cheapest way of doing EVERYTHING.

Remember, electric heating is 100% efficient. But some are more effective at getting heat to you than others. eg infrared heats you not the air which might be full of damp.

But if one heat source costs 1/4 of the price per kW then it has to be a lot less efficient to lose all that cost advantage and modern gas boilers certainly arent that.

Also radiators and similar will cause air currents to form this circulating the heat and ensuring there are few cold spots.
Infrared don’t do this and they have been known to allow huge cd areas, damp/mould in high corners, etc.
Have a read on some of the consumer forums – posts there going back a few years and most seem to now have expensive ornaments or places to hang stuff in the garage…

But if one heat source costs 1/4 of the price per kW then it has to be a lot less efficient to lose all that cost advantage and modern gas boilers certainly arent that.

Is it just me? I kind of understand what you’re saying, I think. Use of double negatives perhaps?

Are you saying: That the panel heaters are 75% cheaper to run and whilst they are not as efficient as gas boilers, they are not 75% less efficient?

Is it just me? I kind of understand what you’re saying, I think. Use of double negatives perhaps?

Are you saying: That the panel heaters are 75% cheaper to run and whilst they are not as efficient as gas boilers, they are not 75% less efficient?

Nope, what I am saying is gas can be up to 1/4 of the price per kW – ie 75% less (I prefer to say 25% of the cost)compared to electricity so to cost the same in use would have to be 25% of the efficiency which they are certainly not.

Thus with any electric heating you are always going to be at the mercy of electricity being horrendously expensive in the UK.

Err, electric heating isn’t 100% efficient.

It is – the device outputting that heat might not be though….

So if an infra red heater heats you not the air, then that is not good or efficient. If you are warm but your surroundings cold then heat will transfer from you at a much quicker rate, so you need the heat source on you all the time. If you’ve got a well insulated house and convection heating it only needs to be on for a couple of hours to heat the space and then switches off and the insulation keeps the house warm for longer.

Err, electric heating isn’t 100% efficient.

What are the losses then?

Nothing is anywhere near 100% efficient. There are losses in the generation of the electricity from fossil fuels in the first place, losses in the distribution, losses in terms of the heat energy emitted from the heater as heat vs the energy input into the heater, so on and so forth. The overall efficiency of that whole system will not even break 50%.

Ignoring the misdirection about generating electricity in the 1st place – as that’s never asserted, the rest is a basic physics misunderstanding. –

“losses in terms of the heat energy emitted from the heater as heat vs the energy input into the heater, “

What are these losses? Where do you think this energy dissapears to? You can’t create or destroy energy, all the energy that get’s emitted by a heater turns into thermal energy. Hell even if you’re heater creaks a bit with thermal expansion, that noise still gets converted to thermal energy. Entropy init.

An electrical heating element only generates heat when it’s upto temperature and just getting the element upto temperature takes a good slug of electrical energy – so energy being pumped into the element which isn’t generating any heat energy from it. This amount of electricity is required to run constantly to maintain the temperature of the element. Then you’ve got electrical resistance of the rest of the unit. So this accounts for a chunk of energy before you’ve even started heating the room. Then once you’ve got the the element upto temperature you’ve got the usual heat conduction losses through the chassis of the heater and into the wall/floor acting like a big heat sink – which applies to any heat source e.g. A normal gas heated radiator.

Ian Munro is correct and is aware of the physics behind this. We don’t care about upstream effects, all we’re interested in as consumers is in terms of inside our system – which I define to be inside my house.

“getting the element up to temperature” – that’s still heat being added to the system. “electrical resistance of the unit” – put a current through a resistor and it generates heat. “heat conduction losses” – that’s heat being given out. all within the house.

basically if you take the heater as a unit – 100% of the energy that goes in (that you’re paying for) comes out as heat (inside the house). if you take gas, the calorific energy that goes in, not all of it comes out. heat goes out of the exhaust outside of the house, combustion isn’t complete, and so on.

motivforz beat me too it 🙂
An electrical heater is 100% efficient. Nothing you’ve said counters that. The fact that it doesn’t produce full heat immediately where you are sat does not have any bearing on it’s efficiency. Electrical resistance does not effect efficiency, it’s what generates heat. It’s resistance that generates the thermal energy in the first place (the square of the current multiplied by the resistance). Heat conduction sources have nothing to do with how efficient a heater is, it’s a reflection of the environment you’ve chosen to put the heater in.
To repeat – an electrical heater is 100% efficient – any other figure would require physics of the universe to be different to how we understand them.

Energy balances hey, it’s all about what you draw your box around.

Surely some of the electrical energy will also be converted into light? Even if it’s only a small amount?

Also there will be kinetic energy as the metal expands and creaks? Again a small amount but not 100% is converted into heat?

No offense taken, it’s what I like about discussions like this it forces you to review your own understanding of how things work and clearly it seems my own understanding falls short big time in this case.

I guess what I was thinking is how much heat you feel as a consumer from an electrical heater, they don’t feel that efficient when the electrical meter is clicking up KWh like a circular saw and you don’t feel much benefit. It just seems like there is a lot of electricity going into the thing but not much heat coming out despite what the physics says. I’ve only lived in one property that was electrically heated and I was always freezing and had a huge electricity bill.

Would this be a good time to mention that a dehumidifier is >100% efficient? 😆

Indeed a small amount will be converted to both light and sound – which both in turn produce thermal energy.
If you shout at a cup of coffee enough you can warm it up again 🙂
http://www.physicscentral.com/explore/poster-coffee.cfm

Will take some time though.