Electric Heaters

[Andy Allen]

We have an all electric house. No gas supply to the village and dont want to go to the hassle of installing an oil tank. All of our heaters are wall mounted electric heaters. Some are not working and we have been advised that purely because of their age (26 years) we should replace them all with modern day heaters that if nothing else will be cheaper to run. Does anybody know of any web sites or suppliers where we can look up details of modern electric heaters. Thanks a lot.

[SC]

Hi,

this page:

http://www.leroymerlin.fr/mpng2-front/pre?zone=zonecatalogue&idLSPub=1101743929

and the links are pretty comprehensive.

Don't fit heaters that are higher wattage than the old ones without checking that the circuit and cables will support them.

Steve 

[Andy Allen]

Very informative. Thanks very much.

[Anton Redman]

Provided the heaters have thermostats I do not understand how an electric heater can be more or less expensive to run unless it is a heat pump.Anybody enlighten me ?

[powerdesal]

Anton, looking at the OPs post, I think you are looking at possible improvements in material technology over the years. If the heaters are storage v radiant then material tech is very relevent.

[Gyn_Paul]

Yes but Anton's right: assuming they are ordinary convector heaters then 1kw of electricity produces 1kw of heat, and it all ends up in the room just the same.

p

[BJSLIV]

 

 

[BJSLIV]

I suppose there also the radiant versus convector business. 1 Kw of radiant heat might feel warmer, especially if you haven't got to heat a 10 foot high ceilings worth of void first!

 

[SC]

I agree with everything that has been said about some electric heaters being cheaper to run than others, electric heating is more or less 100% efficient regarding input / output, although I haven’t studied claims made regarding reversible air conditioning. Also that there is a difference in comfort between the different types.

 

Here's a few things to consider:

 

If you want to heat the whole house with electricity your bills will be very high unless it is exceptionally well insulated and / or you have a log burning stove as the main heat source during the evenings and cold days.

 

Ordinary electric convectors that have an element will dry the air, this can make some people feel uncomfortable and require a humidifier. Those with mechanical thermostats, starting at about 20€, maintain temperature (near the heater) within a degree or so;  If you are light sleepers, remember that these heaters make expansion and contraction noises and their thermostats click when operating and spark when they get older. Electronic thermostat versions are a little dearer, hold temperature to within a tenth of a degree, and the thermostats are virtually silent.

 

The panneau rayonnant type convect about 70% of their heat and radiate the other 30% forwards, so if you are fairly near the heaters, you will benefit from the radiated heat while the rest of the room may be at lower temperature than you would normally require. Probably a good choice for living rooms if the budget is tight, and as far as I know, they should be virtually silent in operation.

 

Radiateurs à inertie and oil filled radiators hold their heat in the body of the radiator while the thermostat cuts in and out, and therefore feel more like a wet central heating system. I believe oil filled radiators (ideally controlled by a central thermostat) to be the best electric substitute for a conventional central heating system, but cannot understand why they are so expensive to buy in France compared to the UK.

 

If you have an open plan living area, having an electrician fit a central programmable thermostat and contactor to control all the electric heaters will enable you to control the room temperature and on/off times at one place. Heaters with timers are useful for bathrooms, landings, and bedrooms.

 

If wall insulation is poor, you can buy insulated reflecting panels to fit behind the heaters.

 

Regarding reversible air conditioning systems, this is from Wikipedia:

 

“The technologies are developing rapidly: COPs (coefficient of performance) have risen from COP=3 to COP=4 or even COP=5 over the last five years. Heat pumps are now becoming popular choices for home-heating as well as for cooling — especially in areas with less severe winters.

Those buying air-source heat pumps should look closely at its COP, the outside temperature range in which that COP is effective, the cost of installation, how much heat it can move, and how much noise it generates.

Air-source heat pumps do not work well when temperatures fall below around −5°C (23°F).”

 

Does anyone know if reversible a/c unit efficiency figures are based on raising the temperature of the outside air, or (recycled) interior air?

 

Steve

[Gyn_Paul]

If you are considering storage heaters, and have access to a van, I can recommend buying them in the UK and bringing them out here. The cost savings make it a no-brainer.

I had an encounter with a salesman from a well-known French/German company some years back who was trying to sell me what were -essentially - a thin brick storage heaters. Having poked around the house a bit he declaired that we would need 9kw to heat the three main rooms (not unreasonable; just over 90sqm) and we could have these 4 heaters at a reduced price of €12,000 (more or less) but only at this bargain price if I signed up there and then.

I invited him to inspect the exterior of the front door. Then got on the internet, and ordered 4 of the big buggars, with about the same total rating, to be delivered to our UK address for about £600.

p

[Anton Redman]

"Does anyone know if reversible a/c unit efficiency figures are based on raising the temperature of the outside air, or (recycled) interior air? "

Thye measured rate is the amount of energy the put into the inside of the house.  On the outside of the house your have a cooling coil which absorbs energy from outside.  This is linked by two pipes to a radiator on the inside where the gas releases the energy into the room. There is no between the outside of the house and the inside.  Crude analogy outside the hoiuse you have a deep freeze with the door open. Inside the house you have the grill at the back off of the deepfreeze which always feels warm.

[SC]

Thanks for that Anton, worth considering them then, some are not particularly expensive.  Neat analogy!

Steve

[Chancer]

I combine new technology storage heaters (well not much is actually new in this world really!) which I brought over from England with a reversible heat pump air con unit that I "stole" from Brico-Depot for 129 euros.

In the coldest of cold snaps (or on the cold evenings a few weeks ago before I switched on the night storage heating) I use the aircon unit in heat pump mode, it is very efficient and gives out 2750 watts while consuming around 900 and actually feels like a lot more. Because of the sweeping fan action it doesnt need to be on for long to make the area comfortable, it can take up to 10 minutes to kick in but warms the room much quicker than would fans or convectors. The heater worked fine at -4 degrees last year, I have recently read that they work down to -7 or -15 for the dc invertor type.

Last winter I was very pleased with the EDF factures.

[Gyn_Paul]

The received wisdom has always been that air-to-air (or indeed air-to-anything else) systems get less and less efficient as the exterior temp heads towards zero.

I was chatting to a chap who used to import various types of heat pump the other day, and he explained to me that the fall-off is due to the water vapour in the air causing icing on the evaporator fins. Once the temperature has dropped below zero there is no more water vapour and the plunging efficiency curve levels off.

I still can't help thinking you'd get more heat out of the ground. However I will admit that the capital costs of 1 box bolted to the wall  v  miles of planted pipe does tip the equation somewhat!

p

[Chancer]

I also understood the theory as a good friend now runs a ground source heat pump firm.

I was expecting the thing to either work intermittently (between defrost cycles) or give out less heat as the outside temp fell to -4 degrees but it was not at all noticeable.

Perhaps the unit was using more power to convert the heat but that goes against my understanding of the system, I will ask my friend next time we meet.

You would have to have steal most of the equipment and not pay for labour to equal my capital cost of 129 euros!

I keep expecting it to pack up or leak out the gas but so far so good - famous last words!

[Gyn_Paul]

I bought a pair of Brico Depot split packs at the start of the canicule in 2005. The ones with the tubes you flush out with the excess gas charge as opposed to the ones with the pre-filled pipes. Either way, you are stuck using the pipes at the supplied length, unless you are very confident of your ability to flare copper and make high pressure joints . For the first one, I carefully threaded a metre of pipe back into the bedroom and connected it up to the inside unit allowing the coiled remainder to sit behind the ext unit, made the conections and purged the system. It worked faultlessly all summer, and was pressed into service as occasional heat during the following winter. The other unit needed to be mounted in a mirror image and was absolutely vile. I ended up crushing one of the pipes (don't ask!)  and having to try and bend it back into shape with gas spanners. There was nobody more astonished than me when it worked; - and continues to work.

The first one, however clearly needs re-gassing although its plumbing was far less suspect.

'Go figure' as the americans would doubtless say.

Anyone had experience of having a home re-gassing experience?

p

[Chancer]

[quote user="Gyn_Paul"]I
Anyone had experience of having a home re-gassing experience?

p
[/quote]

 

I would like to know that as well, the bumpf that came with it gave a price for recharging if I accidentally discharged the unit while fitting but it was more than twice the cost of the unit, my neighbouring restaurant threw away a perfectly serviceable commercial beer cooler (like I use as a workbench) because the recharge man wanted 800 euros hors taxes to change the compressor and recharge, the recharge was nearly as much on its own.

In the UK someone would (and many already have) see the gap in the market and start up a man in a van recharge service, its not likely to happen here or would be prohibitively expensive as would mobile oven cleaners, paint chip retouchers etc etc, the list goes on.

What are your symptoms of loss of refridgerant and have you tested the pressure? - so I will know when my time comes!

[Gyn_Paul]

[quote user="J.R."]

What are your symptoms of loss of refridgerant and have you tested the pressure? - so I will know when my time comes!

[/quote]

Fans, compressor etc work, but the air coming out is neither hotter nor cooler.

No, I haven't tested the pressure: no idea what it should be so the reading would be meaningless.

p

[Chancer]

I did see in a motor trade supply warehouse in the UK a kit consisting of an aerosol for recharging partially discharged auto systems, a bit of a bodge as the system should really be evacuated under vacuum and refilled with a certain weight but I believe that it works OK as a top up. It came with a slow bleed valve and a pressure guage so it may work on a house AC unit.

I will look next time to see what gas it used, mine is R407 I believe.

If you find you have some residual pressure, retighten all the joints and it doesnt fall any further perhaps it will be recoverable?

[Anton Redman]

UK regassing for car Air Con is now £ 75 in London including the call out fee. One of my two units was empty. I had it regassed almost two weeks ago and still have not had the bill, will post when I know how much.  

[Gluestick]

A fully mobile de-gasser/gasser, vacuum tester is less than £600.

Refrigerant isn't that expensive either.

Must be a businesses opportunity in this activity in France?????????

 

 

[Anton Redman]

Invoice arrived today :

1 Kilo of Gax r407 = Euros 25, Time  = Euros 33, plus 19.6 TVA = Grand Total 69,37

 

[Chancer]

Anton

That was for regassing the car aircon on their premises no?

I was very excited for a while then, as for effectively the same service but on site (home aircon units)we are expected to pay 5 times that.

If indeed it was the car its interesting to compare the UK£ prices versus the Euro price.