Efficient Electric Heaters

[Geffers]

With the exorbitant cost of gas and electricity we are now seeing adverts suggesting some college student or some scientist has developed some super efficient electric heater that can warm a room in minutes for pennies.

My opinion, a kilowatt is a kilowatt, a Dyson 2kW heater costing £200 will heat a room no better than Pifco 2kW heater costing £18.50 Now this might be a slight over simplification and the expensive model may have a better thermostat and perhaps multi speed fan but, if 2kW comes off the element that is all the blower fan has to distribute.

Geffers

 

[Retro]

When it's something like a PC power supply, it might be consuming something like 500W, but only be outputting 400W due to losses, mainly heat. Here, improving efficiency will indeed get more output power for that 500W of consumption, say 430W. Improving the power factor ratio can have a big impact on this.

Now, a room heater is basically just a piece of resistance wire with a current running through it to make it heat up. However, since it's AC power, even here there will be parasitic inductance and capacitance, so presumably correcting for this would increase its power output. However, I think the difference would be miniscule here. Perhaps something about the shape of the heater helps with convection?

As with a lot of things, I think we're seeing big, misleading claims about the products' performance and it would be useful to see an actual ad compared to a review of the product to see just how much BS is in the claims.

 

[Geffers]

I go on the premise that there is no such thing as a free lunch. Bit like our internet plug in thingumebob that gives us free internet.

Geffers

 

[Geffers]

This is one such device advertised.

WellHeater | Stop Overspending On Heating With WellHeater

wellheater.com

Geffers

 

[Retro]

Had a look at that and the gimmick there is the Economy 7 style ceramic tiles that store heat, so it could save money in principle. In practice, I'll bet it saves next to nothing, especially due to its small size.

Bit of a stupid design to limit placement to the exact place where there's a wall socket though.

The website looks beautiful in 4K though, so we know where the development money went on this thing.

 

[Geffers]

Had a look at that and the gimmick there is the Economy 7 style ceramic tiles that store heat, so it could save money in principle. In practice, I'll bet it saves next to nothing, especially due to its small size.

Bit of a stupid design to limit placement to the exact place where there's a wall socket though.

The website looks beautiful in 4K though, so we know where the development money went on this thing.

The only thing with any storage (ceramic) heating is the heat initially gets absorbed by the plates before full heat gets radiated. Bit like the oil filled radiators, longer to initially heat up but then apparently more consistent heat.

I do understand, as you point out, the ceramic tiles store heat quite well.

They are a bit pricey and didn't see any wattage listed.

Geffers

 

[Retro]

It shows 800W in the FAQ. That's quite a low output and putting it in there rather than front and centre shows that they'd really rather not state it. I can't see it heating up a cold room quickly at all and in fact, may never reach temperature if it's not well insulated enough, as there's just not enough heat coming from it.

My ancient electric heater has 2KW and 3KW settings. Fast and effective, but can also blow a fuse if another heavy load like a kettle is used. It's also a fire hazard if not used carefully, ie positioned away from everything and not covered. Put a hand above it and the heat is intense. I only use it for emergencies, in fact.

 

[Geffers]

I often wonder about heaters that have multi kW settings and a thermostat. Guessing at 1kW it'd take twice as long to heat (roughly) as a 2kW. Your mention of blowing a fuse, I notice even at 2kW the plug pins can get quite hot, I seldom have more than one high kW item on the same circuit going. Appreciate a ring main should double the cable capacity but I don't like too much heat in electrical items.

You are right, 800W will hardly heat itself, let alone a room.

Geffers

 

[Geffers]

Another thing that often puzzles me is the advantage or not of blower over plain convection. A blower may spread the heat better but ultimately if 1kW comes out of the heater then that is all it can warm.

Geffers

 

[Retro]

Indeed, warm plug pins aren't too clever and should be avoided where possible. You can be sure that the wiring in the wall has warmed up too, which is an unsettling thought.

Yes, the fan merely helps to disperse the hot air better. It also has the effect of helping to prevent the element from overheating.

 

[Tiffany]

I think it's sad how advertisers make promises that people believe in and they buy the product and obviously the product doesn't deliver ...especially sad when people don't have a lot of money to spare and buy a heater like this hoping there room will be warm from it.