Which electric heater would you recommend?

[HappyHippyDad]

A customer wants me to fit an electric heater with timer control integral to it.

There seems to be really cheap ones (screwfix) ranging up to £100's, so it's a bit difficult to make a choice. Is there anything wrong with the cheaper ones? They seem to have reasonable reviews on screwfix.

This is to heat an extension 3m x 3m. Does anyone have any recommendations?

Also, their existing plug in heater is 2kW. they don't feel that gives enough heat. However, the heating calcu;lations for a 3m x 3m come out at around 1kW max. Is this because the plug in ones just don't give as much heat per watt?

Cheers all.

 

[James]

All electric heaters give out the same amount of heat per watt.
if they are not getting the room warm enough with 2kw then 3kw will give out 50% extra heat.
if the recommended heat input to the room is not enough, it is probably down to poor insulation or excessive heat loss by other means.

 

[overskilled]

You really need to do a calc on heat loss to get a u value (iirc) I did it when I built my garage (5.8x3) and 500w will slowly raise the temp, 2 will raise the temp a lot more swiftly and I've seen 35C in the depths of winter when I forgot to turn it off...
Would take less heat if the front doors had a tighter fit...

 

[HappyHippyDad]

All electric heaters give out the same amount of heat per watt.
if they are not getting the room warm enough with 2kw then 3kw will give out 50% extra heat.
if the recommended heat input to the room is not enough, it is probably down to poor insulation or excessive heat loss by other means.

I kind of thought the old 2kW heater may not be 100% efficient, whereas a modern heater will be.

Meaning that the btu of the older heater may be less than a 2kW modern heater. Is that possible, or even if it was, perhaps It would only be negligible and I need to be looking at other factors (as you suggested) which would be influencing the warmth of the room.

 

[Pretty Mouth]

(Someone else can probably explain better/more accurately than I can)

It's to do with converting energy. You can't create energy, you can't destroy it, you just convert it from one form to another. And it tends to be very easy to convert most forms of energy to heat, whether you want to or not.

Take for example, an incandescent light bulb. Most of the electrical energy used to light one up is wasted as heat.

For a heater, it all gets converted to heat, none of it gets converted to light, kinetic, and so on

 

[ferg]

I kind of thought the old 2kW heater may not be 100% efficient, whereas a modern heater will be.

Meaning that the btu of the older heater may be less than a 2kW modern heater. Is that possible, or even if it was, perhaps It would only be negligible and I need to be looking at other factors (as you suggested) which would be influencing the warmth of the room.

All electric heaters are 100% efficient at point of utilisation.
The only things that differ are the controls, aesthetics, quality of manufacture and marketing.

 

[Avo Mk8]

I kind of thought the old 2kW heater may not be 100% efficient, whereas a modern heater will be.

Meaning that the btu of the older heater may be less than a 2kW modern heater. Is that possible, or even if it was, perhaps It would only be negligible and I need to be looking at other factors (as you suggested) which would be influencing the warmth of the room.

Another factor is how long the occupiers want to have the heater on for!
If they are happy to leave it on 24/7, then 2kW should eventually get warm enough, unless there are multiple outside walls or windows, or the insulation is poor.
Since they ask for a timer, presumably they want heating for a specified period, so the radiator will have the job of bringing the room up to temperature in a limited time. So a higher power could be needed to achieve that.
I don't believe there is any disadvantage to going for a higher power heater than you necessarily need (other than perhaps purchase cost). It would cope better in the 'quick warm up' scenario. It could take more amps but that would be for a shorter time, so running costs similar, well the same in theory.
As has been said, these things are effectively 100% efficient, so no difference between brands other than quality of engineering and perhaps reliability.

And now I apologise for a ramble - there are at least two different styles of convector heater. One has coils of element wire that heat the air directly to a high temperature. The other type look more like traditional hot water finned radiators, that heat the metalwork over which the air convects to a lower temperature, but because there's a lot of surface area, they have the same heat output. To me the second type seem 'gentler' on the air quality, and I prefer them. But they can be a lot more expensive.
Then there are radiant panel heaters, that give more direct IR that you can feel on your body. Some people prefer those as one can feel a bit warmer even though the air temperature is cool.

We have some cheap Screwfix floor standing convectors (without timer) at home, and have been entirely happy with them ?

 

[rapparee]

Do it right

Stick in a Glen Dimplex PLXE or Nobø Panel Heater

If you get a Nobø top outlet you can even get a clip on glass to make it more attractive

Make sure whatever heater you get is Lot20 compliant

 

[DefyG]

However, the heating calcu;lations for a 3m x 3m come out at around 1kW max.

So it has already been properly calculated what the heat loss will be?
2kW may be an overkill but better to be over sized than under.

 

[ferg]

Do it right

Stick in a Glen Dimplex PLXE or Nobø Panel Heater

If you get a Nobø top outlet you can even get a clip on glass to make it more attractive

Make sure whatever heater you get is Lot20 compliant

Should you be declaring a conflict of interest here?

Having said that Dimplex are my go to brand.

Customers will rarely pay the cost of the Quantums though.

 

[mattg4321]

I quite like and often fit Haverland