Electric wet heating

[WannadoDIY]

Having no central heating for 10 years, now is the time, but we find that having gas connected to the house is way too expensive and no where to install a gas boiler, so have decided to have an extra phase electricity connected and run the central heating by Electric boilers feeding rads run on Economy 10. The house is a chalet type bungalow, wood frame at top, brick below, having had recent cavity wall installation.

Two questions - who has this type of heating and what do you think of it? and secondly, do I instal single skin rads or double skin. Appreciate any comments so I can move onto the next stage.

 

[simond]

Are you a bat? Economy 7 only runs in the middle of the night. 12 till 6 I think.

The rest of the time you will be paying 11p per kWh. Ouch.

 

[Nixt]

Try a simple solid fuel system with maybe a solar open vented cylinder for free HW on sunny days.

 

[Bahco]

Storage heaters may be the way to go for you as an electric boiler will cost you double than a gas one to run.

Maybe a direct cylinder for your DHW.

 

[oilman]

Are you a bat? Economy 7 only runs in the middle of the night. 12 till 6 I think.

The rest of the time you will be paying 11p per kWh. Ouch.

Time you did some homework. The 3-phase heaters are a massive storage block, so store the heat which is then distributed by a heat ex through a wet system. The OP said Economy, not Economy 7, so this gives a low rate afternoon boost.

I was approached to remove similar system and replace with oil. I explained the economics, and recommended the electric system should have a thorough overhaul if the owner really wanted to spend money. The only maintenance the system needed in15 years was a new pump, and servicing for both gas and oil will add significantly to their fuel costs.

 

[simond]

My homework was up to date, thanks.

We have found that the storage systems you allude to need 1000-1500 litres of stored water to be charged during the off peak rate period.

On colder days the heat has all gone through the rads by late afternoon, necessitating using the electrical heaters at peak rate electricity for the rest of the day.

The charge time for a mid afternoon boost is very long because of the large water volumes.

Bearing in mind this is at 300-400% more than off peak the savings are soon negated.

We have pulled two of these massive heatstores out in as many years, the users have been very very disappointed with the running costs of them.

All they do is use water rather than bricks to store off peak energy.

I think your advice to overhaul them was poor and ill-considered. There is almost nothing you can do to make this type of system more efficient, an 'overhaul' would not achieve anything.

Do you offer a brick night storage heater overhaul service too? Sounds like a con to me.

 

[simond]

Oilman

Can you also explain the merits of 3 phase heater vs single phase ones?

You imply that the use of 3O makes it more economical.......

 

[oilman]

I had not alluded to a wet heat storage, but a brick store which stores at a much higher temperature of 600 to 800 C.

The three phase is to get the power in and not present too much of an imbalanced load to the generator. This has a hidden benefit in that when the electricity boards were promoting this heating, you got a 3-phase connection thrown in.

Why do you think Economy 10 afternoon rate is 3 to 4 times the cost of overnight? (I note you have to use the verbose notation).

Why offer a brick night storage heater overhaul? Your suggestion is pointless. Night storage heaters are a reasonable option for many people.

I don't install or maintain them, so I have no vested interest in suggesting them. All your suggestions seem to have a vested interest.

The overhaul for the large system is mostly for the wet side, but elements may need replacing in the store.

 

[WannadoDIY]

I am none the wiser yet on whether to have or have not the electric wet heating. It would seem that I do not have a choice. Solid fuel is out - as after cowboy firms supposedly "lined" the chimney and it eventually disintegrated and was finally removed and the solid fuel boiler also sprang a leak!!! Solar power seems a good idea, but we have not a south facing roof area. East and West only

Gas is out, supply to house too expensive - so no alternative other than go ahead with electric wet heating.

So - are you saying that they are not economical - oh yes I know the price is sky high, but that has not been unusual in the past years with convector fires!

And - my final question - for electric wet heating - does one use double skin or single skin radiators? I have come to a standstill as nobody in the plumbing world can advise me types of rads for electric wet heating.....

Appreciate more help.

 

[chr15]

And - my final question - for electric wet heating - does one use double skin or single skin radiators? I have come to a standstill as nobody in the plumbing world can advise me types of rads for electric wet heating.....

The reason nobody in the plumbing world can advise you whether you need single or double radiators is because we have no way of knowing what the heat losses are in the rooms you wish to put these radiators.

Whether you have single or double is not a valid question, you first need to know the heat loss of each room and then your radiator outputs can be worked out from that.

 

[gas4you]

The radiator size is worked out exactlly as if fitted to a gas boiler as Chr15 says.

I assumed (rightly or wrongly) that your were refering to an electric boiler such as an Amptec.

These will be very, very expensive to run as they do not store heat but heat it as it is demanded, just like a gas boiler.

I would vaguely guess that you would need a 9Kw or possibly a 12Kw boiler. If it was a 12Kw boiler, then apart from the 3 hours during the day that is cheap rate you will be paying 12 X 11p/hr =£1.32/hr to heat your property. If you were generous and thought that the boiler would only be on for about 65% of each hour that would cost 86p/hr and if it was on for around 7 hours a day, 7 days a week would cost about £42/week. In a standard quarter this would equate to £546/quarter electric bill just for heating

 

[WannadoDIY]

55,000 BTUs for the whole house - which I understand is 16.5 Kw, so we are talking about two boilers.

Currently electricity in the house is costing me £100.00 per month now anyway, taking in summer lighting/hotwater and winter lighting/hotwater and 4 convector heaters. This is a strain on the current electricity supply anyway, as there are the rest of the appliances too. I am aware of the expense, but what other choice do I have?

As the two convector heaters leave many cold pockets downstairs, I am hoping that the radiators will give constant heat throughout (around 16 degrees would be comfortable for us). If not we just put on an extra woolly!

I have still the old radiators on the walls from the Solid Fuel days and they are heavy! If I measured these and halved the size for a double skin that should be OK shouldn't it? I intend to replace them for a lighter radiator.