Electric boilers

[Chippiepat]

I am thinking of using an electric boiler to run central heating & hot water in a three bedroom barn conversion.Has anyone first hand experiance of electric boilers re; efficiency etc, not too concerned about running cost.

Many thanks,Pat

[oglefakes]

We have one, 151 Litre. More than enough for a family of four. We've never run out.

One trick with the electric units (or maybe any large 'tank') is to drain them once a year to get rid of the crud that builds up. I've seen several twenty+ year old units and the owners have told me that they do an annual drain religiously. 

Rods (heaters) are reasonably cheap these days and short of a rupture, are the only real repair needed.

Best bet is to look at the spec sheets of a gas unit then compare.

Cheers

[powerdesal]

[quote user="oglefakes"]

One trick with the electric units (or maybe any large 'tank') is to drain them once a year to get rid of the crud that builds up. I've seen several twenty+ year old units and the owners have told me that they do an annual drain religiously. 

[/quote]

Do you really need to be on your knees and praying whilst draining is taking place  [:P]

[BJSLIV]

We have one, 151 Litre.

Do you really get hot water and run radiators from an electrically heated  tank that size?

I cannot see the point of heating water by electricity to run radiators. it would seem to be far more controllable to run individual electric radiators, especially if running costs are of no concern. You can get good programmers that will control the radiators at least as effectively as your average wet system.

[Jc]

Had an electric boiler years ago in a factory to supply hot water to a piece of machinery-powerful(10Kw),heated up quickly,low maintenance-as long as cleaned annually but cost a fortune to run.In France we get our hot water from a tank heated by electricity(1.7Kw) and it is very good-supplies sink,basin and shower but to heat a house I would estimate you would need a boiler with about 30Kw. output.And you would need 3-phase supply.

[Nick Trollope]

[quote user="Chippiepat"]

I am thinking of using an electric boiler to run central heating & hot water in a three bedroom barn conversion.Has anyone first hand experiance of electric boilers re; efficiency etc, not too concerned about running cost.

Many thanks,Pat

[/quote]

As I've said before, you can't, in France at least - the power supplies simply aren't large enough. Electrically-heated wet systems are, as BJ points out, more inefficient than direct electric radiators (fewer losses).

Electric HW heating is the norm in France. This is the sysem that ogleflakes has, I suspect.

[Jc]

To heat a whole house with electric radiators is unlikely to work - given the resriction on supply;you would only be able to have a few on at a time;oil or gas would seem the obvious route to take.I had storage radiators in the UK running on "cheap" electricity-even they cost a fortune to run-the  gas system fitted later was infinitely better.

[Nick Trollope]

[quote user="Jc"]To heat a whole house with electric radiators is unlikely to work - given the resriction on supply;you would only be able to have a few on at a time;oil or gas would seem the obvious route to take.I had storage radiators in the UK running on "cheap" electricity-even they cost a fortune to run-the  gas system fitted later was infinitely better.[/quote]

Sorry, but as an Electrician I have installed several electric-only heating systems, all of which work and all of which have no backup other than a woodburner. Electric heating is marginally more expensive to run (than oil, cheaper than LPG) but significantly cheaper to install.

 

 

[oglefakes]

[quote user="BJSLIV"]

We have one, 151 Litre.

Do you really get hot water and run radiators from an electrically heated  tank that size?

I cannot see the point of heating water by electricity to run radiators. it would seem to be far more controllable to run individual electric radiators, especially if running costs are of no concern. You can get good programmers that will control the radiators at least as effectively as your average wet system.

[/quote]

We only use it for hot water. Heating is via a hot air (heat pump) system.

[Chippiepat]

just trying to avoid gas or oil tanks,seemed easy to me, install boiler & plug in?

Have tried to research a bit & found many boilers for domestic use, whats throwing me a bit at the moment is calculating b.t.u's required & k.w's.required to give b.t.u's (if you see what I mean).Guess I'll go & pick the brains of my plumber & electrician mates.

Pat 

[oglefakes]

[quote user="Jc"]And you would need 3-phase supply.[/quote]

I'm no electrician, but that's not true (he says in a non confrontational tone) as we have had much bigger tanks than that without 3-Phase.

The only time we needed that was when we had In-Slab heating, on a 168 sqm house and even then the electrician said we had only just gone over the limit and there was enough spare capacity to light a tennis court, not enough yard, but enough power [:)]

[Jc]

You may have bigger storage tanks but I was talking 30Kw. boiler.

[Nick Trollope]

[quote user="Chippiepat"]

just trying to avoid gas or oil tanks,seemed easy to me, install boiler & plug in?

Have tried to research a bit & found many boilers for domestic use, whats throwing me a bit at the moment is calculating b.t.u's required & k.w's.required to give b.t.u's (if you see what I mean).Guess I'll go & pick the brains of my plumber & electrician mates.

Pat 

[/quote]

1Kw = 3413 BTu/Hr

If you need a (say) 35Kw boiler (average 4 bed house IM), then you are talking about a supply that will give you 1 spare Kw from the largest available domestic supply (although I know of noone who can get a 36Kw supply).

[Jc]

Exactly-to supply hot water and heating to a large house you are looking at a boiler of 80,000-100,000BTU or as I said about 30-36 Kw.

[Quillan]

The type of unit you are talking about have been available in the UK for a few years now but I can't find much information on them in France. They are around 99.8% efficient and can replace an existing gas or oil boiler. The more common type are 'instant' heaters and replace 'combi' boilers. There are also versions that hold a small hot water tank to give really instant hot water. My interest is that we already heat electric as we have no gas or oil. I have seen mixed reports as to their running costs and to how good they are. There is a very definate two sided vision, they are either really, really good or really, really bad and nothing in the middle. However many councils have installed these systems for their tennats in the middle and north of England.

One running cost I found for an all electric house (with the ocupants at work during the day) was around 750 to 800 pound a year.

You might find some of the following links interesting.

http://www.heatandplumb.com/acatalog/Trianco_Aztec_Classic_Electric_Boiler.html

http://www.discountedheating.co.uk/shop/acatalog/Heatrae_Sadia_Elecromax_Combi_Boiler.html

http://www.nef.org.uk/energyadvice/storageheating.htm

http://www.dealec.co.uk/acatalog/electric_boilers.html

http://www.buildingdesign.co.uk/facil/atlantic-boilers/index.htm

From The Energy Saving Trust

http://www.est.org.uk/cafe/forum/index.cfm?mode=view&topic_id=36

I then used some of the links in these posts on their forum some of which give running costs.

40968 BTU is around 12kw which is around 50A on a 240V supply or 55A on a 220V supply (I am saying the boiler is 100% efficient, I mean whats 0.2% really). The largest published single phase supply advertised on the EDF website is 60A although I am told by our local electrician that you can now (recently) get a 90A single phase supply now.

Hope this helps.

[Chippiepat]

Quillan,

thanks for the links, notice that you posted regarding the same in January, seems to me the problem is getting a supply large enough to run the system,my knowledge of electricity extends to changing a fuse in a plug.Still feel I want to go the way of heating electric though, have you seen the water filled plug in rads www.easy-heat.co.uk

Would be interested to hear what you finally decide on.

Pat.

[oglefakes]

They look like a great alternative, but ....

The outer casing of the radiator does not exceed 43 ^oC, 

I get warmer than that, sometimes.

providing a safe enviroment for the elderly and children.

Normally they would only touch it once.

Have you seen these working for yourself Pat?

If they are effective, they could be a great alternative to spending a fortune on a traditional radiant system, but there is a little bit that says:

Research has shown that in a modern, well insulated

home, electric heating can often be cheaper to run than gas or other fuels for

a number of reasons:   

Exceptional efficiency

levels

In a

traditional fossil fuel system, as much as 30% of the heat produced is

vented to atmosphere through the flue.

As Easy-Heat radiators units are independent

all power consumed is converted into heat.

Maintenance free

With

virtually no moving parts Easy-Heat are reliable, maintenance free and

unlike other systems, do not require annual safety checks.

This is an

obvious saving when considering the total running cost of an electric

system.

Comfortable and

Controllable

Electric heating provides unmatched levels of comfort, 24 hours a day.

With Easy-Heat individual room temperatures can be adjusted to suit

occupancy ensuring a relaxing living environment.

Reliable and safe

Since

Easy-Heat do not produce carbon monoxide or any other harmful gases,

there is no risk of explosion or danger from poisonous fumes.

Easy-Heat are

maintenance free which ensures complete peace of mind for all of our

customers.

 

I would think that if you had a "Modern, well insulated home" you probably wouldn't be looking at this type of heating?

cheers

[Gluestick]

[quote user="oglefakes"] 
I would think that if you had a "Modern, well insulated home" you probably wouldn't be looking at this type of heating?
[/quote]

And, as the bard said, "Aye, there's the rub!"

One of the problems with houses is they have become a series of compromises. In the 1960s the big "new" thing was picture windows, to allow occupants to live in light.

Then with focus on energy costs, window appertures became far smaller!

And so on.

If a house or appartment was a new build and enjoyed the latest optimal insulation, then sure, a different and far cheaper approach to heating could be adopted.

The reality is, sadly, however, that a majority of French houses - of the type beloved by emigree Brits. - are going to be horribly energy-inefficient!

Short of losing considerable internal space, I cannot insulate my external walls. there is a new german system of exterior cladding which provides significant insulation: a friend has had it fitted to his newish villa in Southern Spain, mainly to avoid rising temps and higher aircon costs, it must be said!

I shall reserve my judgement until I have seen it!

Thus in conclusion, most of us are stuck with chucking considerable amounts of raw energy into heat and losing much of it as fast as it arrives!

Our place has electric rads fitted - expensive German controllable, all singing all dancing. Hopeless. And expensive!

Oil fired CH is the only real answer.

 

[Quillan]

My initial figures which are a total guestimate for running a unit that provides 98,000 BU and running continuous at 80 deg C at 150 ltr per hour for 5 hours a day 365 days a year would cost around 3,000 Euros (just for heating) a year using the AVC E-Tec S boiler it also has a 127ltr tank for domestic hot water. Of course once the rooms are up to temp it's not going to be running all the time so I thought 5 hrs for 365 days seems reasonable.

What I would like to know is what is the biggest 3 phase domestic supply in France and how much the price is per kwh. I have looked on the EDF site but it's either not there (unlikely) or I don't understand their website and am looking in the wrong place (highly likely). Once I have those figures (plus the standing charge) I can get a better idea. Help anyone?

The problem with oil is the price swings and there are two many variables that effect it.

 

[BJSLIV]

Assuming that you would want to run it on an off peak tariff

les tarifs Métropole* (au 15/08/2006)

or you could play Russian roulette on the Tempo tariff

le prix du kWh selon le niveau de tarif

Jours bleus Heures Creuses	Jours bleus Heures Pleines	Jours blancs Heures Creuses	Jours blancs Heures Pleines	Jours rouges Heures Creuses	Jours rouges Heures Pleines
0,0452	0,0561	0,0922	0,1092	0,1709	0,4781

They don't seem to be displaying the monthly charge for Tempo at present, which may indicate that it has / is going to be withdrawn for new customers, presumably all part of the run up to competition this summer.

 

[Nick Trollope]

[quote user="Quillan"]

What I would like to know is what is the biggest 3 phase domestic supply in France and how much the price is per kwh. I have looked on the EDF site but it's either not there (unlikely) or I don't understand their website and am looking in the wrong place (highly likely). Once I have those figures (plus the standing charge) I can get a better idea. Help anyone?

[/quote]

As I say above, 36Kw supplies are not available, except (I guess) on new bits, close to distribution points/power stations or in cities. Has anyone got one (that is not commercial or a farm)?

& judging by the standing charges, I'm grateful I can't get one!

 

[Quillan]

Well it would seem that the electric boiler in France is going to be a no no. To get 90,000 + BTU you will need a 3 phase supply of around 12 to 14 kva per phase. Single phase boilers just don't give out enough to heat a house, OK for one or two bedroom flats but that’s about it. It's not really the fault of the boiler so much as the inability of EDF to give a big enough supply. If you could get the supply it would not be as expensive as you might first think to run but you can't so it's a pointless exercise going any further. Shame really but never mind [:(] .

My next ‘great idea’ then is to look a burning willow which I have heard is very quick to grow, is sustainable and there are boilers that are specifically designed to burn it. Any thoughts or pointers on this idea?

[Nick Trollope]

[quote user="Quillan"]

My next ‘great idea’ then is to look a burning willow which I have heard is very quick to grow, is sustainable and there are boilers that are specifically designed to burn it. Any thoughts or pointers on this idea?

[/quote]

Tina is determined to try this - she has worked out that by planting a 200M hedge of willow (which we need anyway) we can be self-sufficient and keep the cows out of our garden.

 

[Owens88]

[quote user="BJSLIV"]I cannot see the point of heating water by electricity to run radiators. it would seem to be far more controllable to run individual electric radiators, especially if running costs are of no concern. You can get good programmers that will control the radiators at least as effectively as your average wet system.[/quote]

I cannot yet comment on efficiency/cost but...

 

I had a wet  rad CHsystem in my gite and a dead oil boiler. Options: 1) replace oil boiler 2) Individual electric heaters option 3) elec boiler to feed wet rad CH system.

1) was ridiculously expensive.

2) required a combination of Convevtors and Radiators to achieve a sensible balance of comfort and speed and space heating. If living there full time I would have had a storage heater or two as well.

3) was slightly less expensive than 2) and seemed to offer a 'sweeter' heat. Comfort and programmability.

 

In a brand new installation 2) would probably win my vote with some of these air conditioning/air heat source 'splits'

 

 

 

[Quillan]

[quote user="nicktrollope"][quote user="Quillan"]

My next ‘great idea’ then is to look a burning willow which I have heard is very quick to grow, is sustainable and there are boilers that are specifically designed to burn it. Any thoughts or pointers on this idea?

[/quote]

Tina is determined to try this - she has worked out that by planting a 200M hedge of willow (which we need anyway) we can be self-sufficient and keep the cows out of our garden.

[/quote]

Funny enough Nick it was Pat who saw it on telly some time back (OK so it's not really my idea) and there are boilers designed to use it. The one I am interested in is sawdust. We have two big lumber mills near us and they burn the stuff outside as they are now charged to have the stuff taken away. So I was wondering if there is a boiler that burnt this stuff as it would be a free source of energy. Mind you it had entered my mind to charge them half the price the others charged to take it away but then I might be pushing my luck and it might blow back on me oneday.

The way I understood the willow thing is that you need two or three areas in which to grow it and use one per year. You don't have to do anything to the soil between crops but it takes around 3 years to get a suitable quantity. Although not being an expert on this (more of a novice eally) I could be wrong. If this is correct would you not loose part of your hedge every winter? The boilers are not that expensive but going from manual to automatic feed costs a bomb and you really need to go that route apparently. The wood chip ones (not sawdust as I can't find any domestic ones yet) you can buy your own machine to make the chips, again another large expence. Having said that if you can get free fuel the boilers only burn around 70 to 100W in electricity so the time to get your money back is very quick compared to other systems. You could also facture in a solar panel to thelp hings along.