Economy 7 Usage Limit?

Broadview_2

I wonder if anyone can answer my question. I have an Economy 7 meter and am considering changing my oil fired boiler for new Electric boilers, with the Economy 7 I can therefore heat water overnight.
My question is...... Is there a limit on how much Economy 7 electricity I can consume either overnight or monthly/quarterly etc? Have tried to get an answer from my power company but failed. I don't want to find there's a xxkwh limit on consumption as the electric boiler is about 18KW
Andy

Cardew

Welcome to the forum.

There is no limit on the amount of Economy 7 you can use.

What sort of Electrical boiler are you thinking of getting?

An immersion heater to heat domestic hot water is no more than 3kW.

If your 18kW boiler is for a thermal store, you will be using a lot of electricity at daytime rates.

Broadview_2

Thanks for your reply Cardew.
Have been looking at AMPTEC electric boilers. For my place I'd need 2x 9KW boilers, these would heat water for a Megaflow HW tank and also supply the central heating system.
Am interested in these new electric boilers as I'm currently on oil as there's no mains gas around here and the price of heating oil is going through the roof and I can't see it ever coming down again. The other pluses are that the whole system can go in the loft, it's silent apart from the pump, and there's no ugly oil tank in the garden.

Cardew

How much electricty do you feel will be used at daytime rates?

I would think that the cost of running these will be a lot more than oil! - despite the 60p a ltre price.

Broadview_2

This is the $64,000 question, nobody can really advise me how much electricity I'll consume, too many vairiables around heat loss and insulation. I love the idea of a silent tucked away electric boiler and no ugly storage tank but am frightened I've been mislead by manufacturers blurb and I end up with electric bills as big as the debt of a small 3rd world country. Add to that the question of underfloor heating v regular rads.... it's all so confusing and at the moment I'm doing nothing for fear of doing the wrong thing!

mute_posting

Broadview wrote: »

This is the $64,000 question, nobody can really advise me how much electricity I'll consume, too many vairiables around heat loss and insulation. I love the idea of a silent tucked away electric boiler and no ugly storage tank but am frightened I've been mislead by manufacturers blurb and I end up with electric bills as big as the debt of a small 3rd world country. Add to that the question of underfloor heating v regular rads.... it's all so confusing and at the moment I'm doing nothing for fear of doing the wrong thing!

If you are thinking of an electric boiler I think you will be (probably) better off on an E10 tarrif, where you get midnight - 5am, 1300-1600 and 2000-2200 off-peak...

The units will probably cost slightly more than E7 units, but you should save bacause you are getting more off-peak throughout the day.

This kind of tarrif is reccomended by electric boiler manufacturers as the cheaepest way to run the boiler AFAIK

From my research into E10 tarrifs, it seems the only one that is almost universal (in knowing what you are on about and being ably to supply/bill it) is Scottish & Southern group, in different areas other companies may be able to supply but I had no joy with them even though E.on and others are supposed to be able to supply it in the Norweb region.

As to the heating, assuming you are installing from sratch, a underfloor system is generally cheaper to RUN but installation may be more.

HTH

MP

Cardew

Broadview wrote: »

This is the $64,000 question, nobody can really advise me how much electricity I'll consume, too many vairiables around heat loss and insulation. I love the idea of a silent tucked away electric boiler and no ugly storage tank but am frightened I've been mislead by manufacturers blurb and I end up with electric bills as big as the debt of a small 3rd world country. Add to that the question of underfloor heating v regular rads.... it's all so confusing and at the moment I'm doing nothing for fear of doing the wrong thing!

If you do a search there is a thread about this type of 'wet' electric off-peak CH with a large thermal store,

I think you are wise to think very hard about such a system - the blurb from the manufacturer will certainly be misleading!!!

Premier_2

Theres no limit to the amount of E7 you can use, but you might be hitting a problem with the overall current you could be potentially trying to pull.

e.g. my property is protected by a 100A fuse (I think) partially to prevent me frying the incoming supply lines and partially to ensure adequate supply is available to other properties served locally.

That means a maximum power draw of 24kW at any one time. If you are thinking of pulling 18kW on heating alone, could there be a possibilty that 100A maximum current wouldn't be enough?

Attempting to increase the maximum current allowed on your supply could be a big expense in itself.

mute_posting

Premier wrote: »

Theres no limit to the amount of E7 you can use, but you might be hitting a problem with the overall current you could be potentially trying to pull.

e.g. my property is protected by a 100A fuse (I think) partially to prevent me frying the incoming supply lines and partially to ensure adequate supply is available to other properties served locally.

That means a maximum power draw of 24kW at any one time. If you are thinking of pulling 18kW on heating alone, could there be a possibilty that 100A maximum current wouldn't be enough?

Attempting to increase the maximum current allowed on your supply could be a big expense in itself.

I almost posted something similer the other day (along with the number of units you coulf theoretically use in the 7 hours assuming you pulled full load throughout), but thought it would just confuse things. :rotfl:

It is a valid point though, but in a larger all electirc house with IH and storage heaters, there could easily be 18Kw total load during off-peak so isn't much difference IYSWIM?

peat

Your first step should be to contact your supplier to verify that there is an adequate supply of electricity coming in to your property to cope with the potential peak demand when using a wet electric system.