Electric house heating - any new tech savvy members?

[Lorenzl]

In our next house I am looking for a water heating and radiator system as there is nothing installed at the moment. Half renovated and the seller took out the oil tank; not that I wanted to use oil.

There is no gas available and I don’t want oil, propane tanks or a heat pump so it will have to be all electric.

I intend on using some IR panels in a couple of the rooms but want old looking rads in the rest of the house to blend in with the oldish building.

Has anyone had any experience of modern water heating systems they could share?

300m2 floor area and to heat and with an electric boiler I would need a 30kW unit which would need to be 3 phase and the largest single phase is around 14.4kW and 35A. The main fuse is probably 60A although I might be able to get it increased to 80A

Looking at thermal stores with a immersion heater and Sunamp is the only current item I can find on sale and might have two instead of one and a boiler.

 

[gcusick]

Why not a heat pump? We have a 270m2 house which we heat with a single-phase (9kW) ground-source heat pump.

 

[Old.bodger]

I have had to deal with several properties with electric ‘boilers’. They have proved to be massively expensive to run. Some, we have taken out and gone back to oil. Not very green but the tenants can (could) afford to run them. All the time electricity is 4 plus times the cost of gas per Kw (I know direct comparison is difficult) electricity is really a non starter. I think you will find the quote from the DNO for a three phase supply ‘shocking’.

 

[mikej460]

Search for electric boilers, there are plenty out there. They are considerably more efficient (99%) than oil or gas so fewer kWhs are used for the same heat output. The boilers are also a lot cheaper than oil or gas and a lot smaller. The downside is obvious, electricity cost per kWh is off the scale and you will need a100A supply.

We live in a very old, badly insulated, stone cottage and inherited a very old oil boiler that was condemned by the heating engineer and we don't have gas. An air source heat pump was a ridiculous £12k with no chance of payback even with RHI so we opted for wood pellet biomass with an 7 year RHI payment that covered the high cost of wood pellets. The RHI grant ends this year leaving us facing the £395 per month cost of pellets in winter (just increased from £305) so we are considering what to do next.

I am looking at the possibility of a thermal store heated via economy 7 or 10. Also look at modern storage heaters as you don't have radiators.

 

[mikej460]

Why not a heat pump? We have a 270m2 house which we heat with a single-phase (9kW) ground-source heat pump.

Unfortunately heat pumps are said to only work effectively in very well insulated modern homes. What type of house do you have?

 

[eribaMotters]

I'm interested in following this post.
We are moving to a new build bungalow late summer. It has an EPC rating of B and a score of 88. Loft has 400mm fibre insulation, walls 100mm in cavity and underfloor is 50 or 60mm of foam board. It has an air source heat pump for heating and hot water. I was initially concerned but on reading up now happy. Heat pumps generate hot water for at a lower temperature than a conventional boiler. because of this you need larger radiators so as a retro fit they are not a good idea as you would need to replace all the radiators. In a new build it is a different issue as our heating will be underfloor. This concrete screed floor will act as a large battery and store heat, theoretically reducing energy you require.
Air source heat pumps can get heat out of the air when temperatures are as low as -10c, how is wizardry to me.
Electricity was until recently 3 to 4 times more expensive per Kw than gas so electric as a source of heat was expensive. The best gas boiler are about 90% efficient, air source electric heat pumps are 350% efficient, so now they are cost effective.
At present we are paying £92 a month on a similar size bungalow for gas and electricity combined, I just hope all this information I've been told is correct as I know costs will rise.

Colin

Edit, the electrician has told me the house is future proofed with 3 phase [3 x 80 amp] running to my meter area, although only one phase is being used/ran through the meter.

 

[Jones]

Electric boilers make some sense for water heating though expensive but not much sense for heating a wet system. If you want to go electric there's electric radiators in various styles and underfloor mats which will at least save you plumbing costs, if not running costs

 

[Sachakins]

Underfloor electric heating probably best option, lower heat kwh as heat rises, so runs cooler.
Then separate water heating, say electric shower and at source heaters, like a Quooker tap.
https://www.quooker.co.uk/catalog/c...002op5UFkjB8xI1Xn7CP68APYDNlKqsUaAqaEEALw_wcB

 

[Sandyn]

Half renovated? Insulate, insulate, insulate, insulate! then add some more.

 

[mikej460]

Half renovated? Insulate, insulate, insulate, insulate! then add some more.

I agree and in our old place we've had double glazing installed (I speak from experience when I say don't buy cheap double glazing and if you afford it get triple glazing) and I'm slowly internally dry lining all outside facing walls with YBS Superquilt counter battened with 50mm PIR Plasterboard. The roof is a challenge as it has semi vaulted ceilings with no loft access and I can't insulate them properly without pulling down the ceilings as we'd lose too much headroom if I just dry lined them. At the moment 2 bedrooms only have thin layers of 1980's yellow insulation.

 

[Lorenzl]

All good points and as to heat pumps:
Pros: cheap to run
Cons: need a storage cylinder, only heat to 40/50C, expensive to install, best with underfloor heating or large rads @eribaMotters , needs a well insulated house @mikej460

My preference at the moment is two Sunamp phase change batteries and when econemy 7 is available again use that. They can use solar, or grid supply and only need ~10A
A few rooms I plan on using IR panels.

 

[Lorenzl]

@Sandyn You are right about insulation but I don't have a lot of room in the roof without loosing to much headroom. I intend on insulating between the joists and then over the top as well on the horizontal areas.
Walls I have not decided on as some people say they should breath and others say they don't need to!

Currently all windows are single glazed and in keeping with the look of the building we want to use timber windows rather than UPVC.

 

[Jones]

You'll never regret spending money on insulation. There's the right type for various applications, if you want thin but effective and money is no object try aerogels. That looks an impressive joist span unless it's just the wide angle lens.

 

[Sachakins]

@Sandyn You are right about insulation but I don't have a lot of room in the roof without loosing to much headroom. I intend on insulating between the joists and then over the top as well on the horizontal areas.
Walls I have not decided on as some people say they should breath and others say they don't need to!

Currently all windows are single glazed and in keeping with the look of the building we want to use timber windows rather than UPVC.

Walls breathing and insulation can be achieved quite easily with the right vapour membrane type.
Unfortunately, people often assume all walls are made equal and they just slam on the "normally used stuff".
But brick with cavity, double brick, granite, sandstone, slate, cobbles, flint etc all require a different approach.
If its not traditional brick construction, I would get the advice from a stone specialists, not a builder, surveyors or the like. Many a damp issue in no standard brick construction buildings has been exacerbated by the wrong internal insulation, incompatible plaster, render even mortar types! Just as with the assumption damp proof course is a necessity, in some building materials a DPC can cause issues.

I think what I am trying to highlight is that you are trying something outside of the norm, which is commendable, but seek specialist advice, it will be cheaper in the long run.

Good luck.

 

[chris.s]

at source heaters, like a Quooker tap.
https://www.quooker.co.uk/catalog/c...002op5UFkjB8xI1Xn7CP68APYDNlKqsUaAqaEEALw_wcB

I would avoid like the plague if the recent batch of instant hot water taps advertised for the domestic market are anything like the Zip hydrotap that were being installed in government buildings about 15 years ago, they quickly used very expensive filters and couldn't cope with the rush after a meeting ended, kettles had to be reissued as backups. This was at the same time as they installed the overpriced and useless Dyson hand driers.

 

[gcusick]

Unfortunately heat pumps are said to only work effectively in very well insulated modern homes. What type of house do you have?

I agree, up to a point, but any form of heating will perform better in a well-insulated building. The main reason why heat pumps fit better into new buildings is the lower output temperature they provide. This means either much bigger radiators (than a boiler-based system), or underfloor heating, which is what we have. But if electricity is the power source, a heat pump will produce ~3-4 times as much heat for each unit of electricity than a simple electric heater.

 

[Lorenzl]

I would avoid like the plague

We have one at the moment which the wife like as it is instant hot water and no kettle. It seems a bit of a waste to store very hot water 24/7 for a couple of cups of tea, coffee etc. but I will have to install one

money is no object try aerogels

I did look at those when looking for thin efficient insulation and they look very good but from memory expensive as you say ~£200 for a 1.2x2.4m sheet. It might be worth it in a couple of areas where there is little space.

Walls breathing and insulation can be achieved quite easily with the right vapour membrane type.

I have been looking over the last couple of weeks and you are correct. The roof area should be OK as the air can flow over the insulation. The inside wall are going to be left as bare brick with a lot of cleaning and repointing; luckily I am retiring soon. I think the outside walls may look a bit odd with a very flat surface and there are breathable foam insulation and plasterboards. I have found breathable lime renders containing cork which are supposed to be good insulators and one that contains voids which is half as good as the cork version.
We will have 9" solid brick walls with lime mortar.

 

[Jameshow]

Insulate insulate insulate ....
Large bore piping with increase efficiency too - insulated if course..

A thermal cylinder like a megaflow will be efficient for water on demand.

 

[Spectric]

You need to have a thermal mass with electric underfloor heating, ie at least 75mm of screed over it. This way it may take time to heat up but then it just ticks over to maintain. Electric is never going to be cheap, but as James has said it is insulation that may help reduce the cost, but do not scrimp on fitting it as it may not be cheap initially but you will save over time.

 

[Fitzroy]

I've been mulling similar of late as I have an old granite house with a combi gas boiler, Scotland plans to get rid of all gas heating in the next ten years. My thoughts/understanding in this area:

• The highest heat demand on the gas boiler comes from DHW rather than CH, so the 'boiler' size can be reduced via a HW tank which can be charged with hot water when CH is not demanding.
• The energy demanded to heat the house is independent of the source of heat, it's a result of the level of insulation and how warm you keep each part of the house. Total cost = total energy x cost per unit x efficiency
• Heat pumps use a reverse refrigeration cycle and some extra energy to move low grade heat to high grade heat, the better the source of low grade heat the more efficient the heat pump can be, hence ground source is better than air source as the ground has a higher average temperature than the air. Typically they put out 2-4x as much energy than they use, so can be said to be 300% efficient. Heat pumps put out lower temperatures than traditional boilers so need more heating area to be effective, eg UFH or more radiators.
• Modern combi gas boilers are 90+% efficient
• With gas prices at 1/3 electricity prices the yearly cost will be very similar, but a GSP will cost £10k+ to install and a new boiler c. £2k+. If gas prices rises quicker than electric, which could happen as more electric comes from renewables then the balance could shift and a move to electric heating could pay for itself overtime.
• Insulation will reduce operating costs of any system, but how to insulate a lath and plaster, solid granite wall construction. Put on a jumper and turn the thermostat down.

Fitz