Author Topic: Electric Central Heating.  (Read 1947 times)

Jocko

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Electric Central Heating.
« on: May 15, 2021, 03:47:30 PM »
As some of you already know I am moving to the family home shortly. The central heating is courtesy of a gas combi boiler. My wife has decided she wants it moved from its location in the kitchen, a few feet along the wall, and into the downstairs toilet.
Because the boiler is a few years old now we are considered replacing it with a new one, as there is not a great difference between the cost of fitting a new one in the new position and moving the old one to the new position.
I think, with the way things are going, this would be an excellent opportunity to change to electricity. I am looking for suggestions from the learned members of the forum as to how to proceed.
The questions are: Boiler or heat pump? If heat pump what sort? Running costs compared to gas? Makes to consider?
Feel free to chip in. As a well-known camp guard once said. "I know nothing".

John Ratsey

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Re: Electric Central Heating.
« Reply #1 on: May 15, 2021, 05:52:38 PM »
Heat pumps need well-insulated homes designed for low temperature heating (ideally under-floor, otherwise oversized radiators) so that the house can be kept warm by tepid water. The hotter the circulating water then the less efficient the heat pump. A few months ago I did some analysis based on using a hybrid system https://www.vaillant.co.uk/specifiers/products/arotherm-hybrid-air-source-heat-pump-53953.html#specification and concluded that I first needed to further improve the insulation (although walls and loft are insultated and windows are already double or triple glazed) and fit bigger radiators in some rooms before considering heat pumps further.

I would note that better insulation and bigger radiators also enable central heating using a gas boiler to be run at a lower temperature which improves the efficiency while thermostatic radiator valves make it easier to have have different rooms at different temperatures. If there is scope to reduce the heat losses from the house then you may find that you can get a new boiler with a lower rating. One annoyance I have with my boiler is that it can't reduce the heat output enough (the minimum is 10kW) to match the heating demand of the house once it has done the initial daily warming up. The result is that the boiler shuts off the heat until the temperature of the circulating water drops by 10C which can be 15 minutes or more which causes significant changes in radiator temperature.

Worcester Bosch and Vaillant are reckoned to be the most reliable brands of gas boilers. Many boilers also support an outside temperature sensor which enables the boiler to adjusting the water temperature to further improve efficiency - hotter water on cold days and warm water on warmer days.

Perhaps you should try to resist moving the boiler until you have spent a winter in the house and have a better understanding of the heating performance. If you get a smart meter producing half hourly consumption data then you'll have a much better understanding of how the gas consumption chances with the weather and even during the day. The smart meter in-home display also lets you see the instantanteous gas (or electricity) consumption.
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embee

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Re: Electric Central Heating.
« Reply #2 on: May 15, 2021, 06:37:41 PM »
It might depend a bit on what your priorities are. Some factors to consider -

up front installation costs
fuel costs (including various tariffs, off peak etc)
maintenance costs
flexibility of control
"green"
reliability
future-proofing

Some excellent points made by John above. Insulate first (reduces amount of heat required), look at zoning (only heat the places which require it and when they require it), look at system efficiency (boiler and rad sizes etc). There are a lot of zone control possibilities now, each rad valve can be programmed for example.

richardfrost

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Re: Electric Central Heating.
« Reply #3 on: May 15, 2021, 07:07:41 PM »
Like electric cars, I don’t thing the tech is ready yet. The advice to live through a Winter sounds great to me.

Jocko

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Re: Electric Central Heating.
« Reply #4 on: May 15, 2021, 08:59:06 PM »
The boiler cannot stay where it is. The bulk of the kitchen is 1950s, with the sink and units around it 60-70s. The central heating was originally run off the coal fire and back boiler but the combi was put in several years back under a grant scheme and the clowns who installed it fitted the boiler over part of a double socket!
A new fitted kitchen is a must.
The house is well insulated with full double glazing windows and doors, cavity wall insulation and generous loft insulation. The loft had been insulated, but at the time the combi was installed new thick insulation was placed over the top of the original insulation. The radiators are not microbore and are all fitted with thermostats, though manual and not programmable. Mum used to have the house like a hothouse and her monthly gas bills were never that high.
The technology for an electric combi boiler is anything but in its infancy. It appears to be a tiny self-contained immersion system for the central heating, with a flash boiler for the hot water system. I am currently waiting on a Fischer catalogue arriving but there are several other makes I am looking at.
When I had my own house we only ran the heating in the lounge, downstairs hall (the one that was on continuously), and bathroom. The only time heating was on in the bedrooms were if someone was in bed, unwell, or when my daughter used her room as her study.

guest9236

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Re: Electric Central Heating.
« Reply #5 on: May 16, 2021, 06:50:29 AM »
The boiler cannot stay where it is. The bulk of the kitchen is 1950s, with the sink and units around it 60-70s. The central heating was originally run off the coal fire and back boiler but the combi was put in several years back under a grant scheme and the clowns who installed it fitted the boiler over part of a double socket!
A new fitted kitchen is a must.
The house is well insulated with full double glazing windows and doors, cavity wall insulation and generous loft insulation. The loft had been insulated, but at the time the combi was installed new thick insulation was placed over the top of the original insulation. The radiators are not microbore and are all fitted with thermostats, though manual and not programmable. Mum used to have the house like a hothouse and her monthly gas bills were never that high.
The technology for an electric combi boiler is anything but in its infancy. It appears to be a tiny self-contained immersion system for the central heating, with a flash boiler for the hot water system. I am currently waiting on a Fischer catalogue arriving but there are several other makes I am looking at.
When I had my own house we only ran the heating in the lounge, downstairs hall (the one that was on continuously), and bathroom. The only time heating was on in the bedrooms were if someone was in bed, unwell, or when my daughter used her room as her study.

This all sounds very expensive to me  if the boiler and general heating/hot water are and have been working ok, Why  not  wait a while to get an idea of existing costs whilst proceeding to cost up the work possibly needed with estimates and possibly any grants available.
Anyway good luck in your new abode  hope this all works out ok for you.

Kremmen

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Re: Electric Central Heating.
« Reply #6 on: May 16, 2021, 07:34:50 AM »
What's worrying is that 'they' are going to force us all on to electric heating as they outlaw gas.

I've got a very good built in warm air system and my house isn't engineered for radiators.
Let's be careful out there !

guest9236

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Re: Electric Central Heating.
« Reply #7 on: May 16, 2021, 08:35:35 AM »
Have just perused the following from today’s Daily Telegraph
Might be interesting reading Jocko.

https://www.telegraph.co.uk/technology/0/tech-clinic-ultimate-guide-buying-new-boiler/

Jocko

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Re: Electric Central Heating.
« Reply #8 on: May 16, 2021, 12:15:57 PM »
Thanks, that is most interesting. So the choice today is basically a new gas boiler or an electric boiler. Heat pumps just too expensive.
Interesting that houses changing to electric heating (heat pumps or boilers) is a bigger worry to the abilities of the grid than electric cars!
So I now need to get prices for boilers and compare running costs. I am not sure of the capacity of the current combi boiler but I will get that information once we start work in the house. I know the shower is cr@p.
The kitchen will require a complete rewire so wiring for a boiler will not be a problem.

John Ratsey

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Re: Electric Central Heating.
« Reply #9 on: May 16, 2021, 12:54:02 PM »
The house is well insulated with full double glazing windows and doors, cavity wall insulation and generous loft insulation. The loft had been insulated, but at the time the combi was installed new thick insulation was placed over the top of the original insulation. The radiators are not microbore and are all fitted with thermostats, though manual and not programmable. Mum used to have the house like a hothouse and her monthly gas bills were never that high.
One kW of electricity for heating (unless you use a heat pump) costs about four times the cost of one kW for gas heating so that even if you halve the amount of heating you might end up with double the bill. The electricity cost could be reduced using storage heating using either individual room heaters and/or a big insulated tank heated using cheaper night electricity. However, given that you have a radiator system in good condition then a new gas boiler looks to be the prudent option.

At the present rate of progress a substantial part of the UK electricity generation will be using gas for the remainder of our lifetimes so it's more efficient and less CO2 overall to continue to use gas for heating until such time as homes are better able to benefit from heat pumps and there's a lot more reliable low carbon generation capacity. I don't want to live in a house which needs the wind to be blowing for the heating to work.
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culzean

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Re: Electric Central Heating.
« Reply #10 on: May 16, 2021, 12:54:31 PM »
Thanks, that is most interesting. So the choice today is basically a new gas boiler or an electric boiler. Heat pumps just too expensive.
Interesting that houses changing to electric heating (heat pumps or boilers) is a bigger worry to the abilities of the grid than electric cars!
So I now need to get prices for boilers and compare running costs. I am not sure of the capacity of the current combi boiler but I will get that information once we start work in the house. I know the shower is cr@p.
The kitchen will require a complete rewire so wiring for a boiler will not be a problem.

Given that the equivalent electrical output for most UK gas boilers ( depending on number of radiators ) is in the region 24 to 35KW, replacing gas with electrickery is going to impact the grid a lot.   24KW is about the size of average TOTAL supply to a house in UK ( 100 amps ) - government is considering making underfloor heating mandatory in new houses, but any problem with heating may well mean digging up flooring.  Totally sealing up a house will mean lower heating requirements but is it good for health ?

As John Ratsey says,  a KW of electricity is at present 4x cost of a KW of gas, and our eletrickery supply is getting less and less stable and more at the whim of nature ( the fans on sticks have made very little input to grid in over 4 weeks now - and a I write this is down to 4.5% ).
« Last Edit: May 16, 2021, 12:58:47 PM by culzean »
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Jocko

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Re: Electric Central Heating.
« Reply #11 on: May 16, 2021, 01:26:56 PM »
The more we are looking at it the more gas seems the way to go. A new gas boiler should be good for 12 - 15 years, which may well be longer than me and possibly my wife. If we outlive the new boiler then hydrogen ready boilers may be considerably cheaper by then.

peteo48

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Re: Electric Central Heating.
« Reply #12 on: May 16, 2021, 02:57:34 PM »
Just on heat pumps I know a chap who is pretty clued up on energy issues generally. He worked for Bentley for a time with a remit to enhance fuel efficiency but later worked for British Gas and then on a committee set up to advise governments on energy matters.

He is not without a bob or two and his wife has had her own successful career. Last time I spoke to him we talked about what he had done to his house and he said he had spent £25,000 on a heat pump but had also done a huge amount to the house in terms of insulation. We are talking triple glazing, the elimination of draughts completely (there is ventilation but the system heats incoming air - he did explain how this worked but he lost me at that point. I think some cladding might have been involved as well.

This confirms everything John has said above. I can't remember what the total bill was only that it was north of £50,000. His energy bills, however, are miniscule - £25 per month all in but he freely admits it won't pay for itself in his life time.

culzean

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Re: Electric Central Heating.
« Reply #13 on: May 16, 2021, 03:49:04 PM »
Just on heat pumps I know a chap who is pretty clued up on energy issues generally. He worked for Bentley for a time with a remit to enhance fuel efficiency but later worked for British Gas and then on a committee set up to advise governments on energy matters.

He is not without a bob or two and his wife has had her own successful career. Last time I spoke to him we talked about what he had done to his house and he said he had spent £25,000 on a heat pump but had also done a huge amount to the house in terms of insulation. We are talking triple glazing, the elimination of draughts completely (there is ventilation but the system heats incoming air - he did explain how this worked but he lost me at that point. I think some cladding might have been involved as well.

This confirms everything John has said above. I can't remember what the total bill was only that it was north of £50,000. His energy bills, however, are miniscule - £25 per month all in but he freely admits it won't pay for itself in his life time.

Mechanical Heat recovery ventilation (MVHR or HRV ) work by grabbing warm air from upper floors of house, also warm humid air from kitchens, air from bathrooms and  pumping it through a heat exhanger to outside of house, the air on other side of heat exchanger is fresh air coming into the house ( the two airstreams never mix ),  the outgoing stale warm air heats up the cooler incoming air so saving energy but getting fresh drier air into the house. The fresh pre-heated incoming air is normally pumped back to downstairs floors.  Can reduce heat loss by almost 90% and vastly improve air quality in a house, as well as tackling condensation ( the damp air releases condensation inside heat exchanger as it is cooled by incoming air, the heat exchanger will drain the water away. 

As You say costly.. the old payback period rears its head again.  In a 5 bedroom detached house our monthly gas bill in winter is no more than £60 ( in summer about £20 ), and that includes heating house, heating water and cooking - so with a saving of £35 a month during colder months ( say 6 months = £200 ) would take a hell of a long time to pay back say a £30K investment in a heat pump and ventilation system - which would not last for ever and would need replacing at some point.

http://cchrc.org/whats-a-heat-recovery-ventilator-hrv-and-why-do-i-need-one/
« Last Edit: May 16, 2021, 03:58:52 PM by culzean »
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Jocko

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Re: Electric Central Heating.
« Reply #14 on: May 16, 2021, 04:03:34 PM »
In one factory I worked in we had fans, just under the roof, ducted to tubes that came down to almost floor level. The heat from the process collected in the roof spaces and was blown down to floor level where the temperature was considerably lower. The energy recovered was more than the energy to power the fans.

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