Should this be 90kW?
Electric house heating - any new tech savvy members?
- Thread starter Lorenzl
- Start date
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Just had a look at Google maps and the new house is orientated North east to south west with the back on the south side. There are some lean-to buildings there that I would be happy to put some solar panels on at 28m2 so about 4kW. £4,800 + inverter and whatever else I would need. They need re roofing anyway.
Phil Pascoe
Established Member
That rate is better than I could find here four or five years ago.
I assume he extracting from the bathroom rather than heating it, other wise there was no point in going to the apex of the roof ........... come to that, why go to the apex of the roof anyway?
Phil Pascoe
Established Member
Only if he lives in a railway station.
Phil Pascoe
Established Member
Only if the stove is closed down too far. I go to open it up before my wife who is in the room knows to do it.
Terry - Somerset
Established Member
Figures could be refined for orientation, installation complexity, sunshine hours/location:
Seems a good deal with the price cap of 28p, but can only be used when generated. Surplus energy (little in winter, lots in summer) can be sold back to the grid - currently at rates below ~5p kwh.
The overall cost kwh produced by PV will greater than 14p - probably 20-25p making PV alone financially dubious. Using all energy produced requires storage - battery, hot water, recharge EV - yet another level of complexity.
- the average 4kw PV array produces ~3400 kwh pa
- cost including installation is ~£7k
- life of PV system is ~20 years
- probably inverter replacement mid term + other maintenance/cleaning (say) £150pa
Seems a good deal with the price cap of 28p, but can only be used when generated. Surplus energy (little in winter, lots in summer) can be sold back to the grid - currently at rates below ~5p kwh.
The overall cost kwh produced by PV will greater than 14p - probably 20-25p making PV alone financially dubious. Using all energy produced requires storage - battery, hot water, recharge EV - yet another level of complexity.
If and when we move (much more "when" rather than "if", thank goodness), the new place is about double the habitable area of our current house and has oil because there is no gas in the village.
The current owners have removed all of the radiators and all but two rooms have wet underfloor heating. The other two rooms, both receptions, have wood burners. The house is a hybrid of cob, Victorian stone and block cavity - because it has been extended over the centuries. The current owner says that it's decently well insulated although one reception could do with dry lining (as it hasn't been modernised) and the one accessible roof space has insufficient insulation. The other is inaccessible and a bit more is vaulted - so I'm a bit stuck there. The whole house is double glazed with low E glass - somehow, the place escaped listing - which I am not complaining about! The garaging has 4Kw of solar but the inverter doesn't have battery. The FIT rate isn't magical, but it all helps.
We will have to see how the energy bills work out.
Each room has an individual thermostat so can be controlled pretty effectively, we think.
I have a PV dump system in this house whereby surplus solar energy, having been counted for export, is then routed to the immersion heater. It works well here aside from stratification which limits how much of the tank can be heated. The new tank is a modern dual coil one with an immersion heater inset half way up. I'm hoping it will heat more of the tank than the current one via the PV dump. I also looked at a solar array with a water feed to the second coil in the tank. It seems, for now, that the PV dump is cheaper and easier to implement.
We plan to insulate the remaining walls which will benefit from it. Interesting thoughts about engaging a specialist to do it rather than a normal builder.
I looked at adding solar batteries but my maths suggest that the pay back is excessively long. We will wait and see how things pan out with battery technology and increasing per unit costs of electricity. There is space form battery and it may help with a BEV car, when we finally give in.
We have a nest thermostat in our current house and this works fairly well (except when it goes off on a crusade to try and save us cost). The new place probably wont benefit as each room is individually controlled. It would be an expensive toy to simply control when the hot water is heated.
We've looked in ASHP and GSHP. Time will tell but both don't appear viable at the moment - certainly we want to give it a year while we gather data. Some of the old incentives offered by the Government would have been helpful but the new scheme seems excellent at hype and less excellent at financial incentivisation. We have the space for a GSHP but the thought of digging up hundreds of square metres of a field are not very palatable. Sinking vertical bores are prohibitively expensive. The house derives its water from a vertical bore hole and it may be possible to run a GSHP via this (but it's expensive to do). Equally, it may be possible to utilise the adjoining river as a GS - but I'd have to investigate this with an expert.
ASHP is less disruptive and it feeds nicely into the wet underfloor heating. While I accept that it is about 300% efficient, it's still a massive outlay and the variation in air temperature (as opposed to the relatively constant temperature of the ground) concerns me - when really cold, energy being made up with electric heating (which is still expensive) and I cant use the solar PV as the yield is typically low in winter. Perhaps an ASHP could be combined with the existing oil boiler rather than electric ? I need to consider the space requirements.
We've also considered biomass - at the moment I'm not convinced that we have the space for a boiler and a hopper. We do have a ready supply of wood on the land to run the wood fires but I doubt we have enough to run a biomass.
We also looked at wind turbines. They would complement the solar but I was amazed how expensive a decent turbine is. Once again, the ROI is long.
This, I feel, is the big conundrum for all of us: we are all stuffed with increasing costs of energy for our homes. Aside from the low, but very effective, hanging fruit such as wall and roof insulation, most of the other systems have a pretty big outlay, are massively disruptive to install properly in older homes and suffer from a pretty long payback time. Government incentives and grants, while helpful, go a long way to hype the politics and green credentials but do a lot less in really helping with the up front costs. Much of it seems like window dressing. Especially now, where wallets are under pressure, adopting this new stuff for ecological reasons requires deep pockets and adopting it to save money needs very careful investigation before pressing the button.
The current owners have removed all of the radiators and all but two rooms have wet underfloor heating. The other two rooms, both receptions, have wood burners. The house is a hybrid of cob, Victorian stone and block cavity - because it has been extended over the centuries. The current owner says that it's decently well insulated although one reception could do with dry lining (as it hasn't been modernised) and the one accessible roof space has insufficient insulation. The other is inaccessible and a bit more is vaulted - so I'm a bit stuck there. The whole house is double glazed with low E glass - somehow, the place escaped listing - which I am not complaining about! The garaging has 4Kw of solar but the inverter doesn't have battery. The FIT rate isn't magical, but it all helps.
We will have to see how the energy bills work out.
Each room has an individual thermostat so can be controlled pretty effectively, we think.
I have a PV dump system in this house whereby surplus solar energy, having been counted for export, is then routed to the immersion heater. It works well here aside from stratification which limits how much of the tank can be heated. The new tank is a modern dual coil one with an immersion heater inset half way up. I'm hoping it will heat more of the tank than the current one via the PV dump. I also looked at a solar array with a water feed to the second coil in the tank. It seems, for now, that the PV dump is cheaper and easier to implement.
We plan to insulate the remaining walls which will benefit from it. Interesting thoughts about engaging a specialist to do it rather than a normal builder.
I looked at adding solar batteries but my maths suggest that the pay back is excessively long. We will wait and see how things pan out with battery technology and increasing per unit costs of electricity. There is space form battery and it may help with a BEV car, when we finally give in.
We have a nest thermostat in our current house and this works fairly well (except when it goes off on a crusade to try and save us cost). The new place probably wont benefit as each room is individually controlled. It would be an expensive toy to simply control when the hot water is heated.
We've looked in ASHP and GSHP. Time will tell but both don't appear viable at the moment - certainly we want to give it a year while we gather data. Some of the old incentives offered by the Government would have been helpful but the new scheme seems excellent at hype and less excellent at financial incentivisation. We have the space for a GSHP but the thought of digging up hundreds of square metres of a field are not very palatable. Sinking vertical bores are prohibitively expensive. The house derives its water from a vertical bore hole and it may be possible to run a GSHP via this (but it's expensive to do). Equally, it may be possible to utilise the adjoining river as a GS - but I'd have to investigate this with an expert.
ASHP is less disruptive and it feeds nicely into the wet underfloor heating. While I accept that it is about 300% efficient, it's still a massive outlay and the variation in air temperature (as opposed to the relatively constant temperature of the ground) concerns me - when really cold, energy being made up with electric heating (which is still expensive) and I cant use the solar PV as the yield is typically low in winter. Perhaps an ASHP could be combined with the existing oil boiler rather than electric ? I need to consider the space requirements.
We've also considered biomass - at the moment I'm not convinced that we have the space for a boiler and a hopper. We do have a ready supply of wood on the land to run the wood fires but I doubt we have enough to run a biomass.
We also looked at wind turbines. They would complement the solar but I was amazed how expensive a decent turbine is. Once again, the ROI is long.
This, I feel, is the big conundrum for all of us: we are all stuffed with increasing costs of energy for our homes. Aside from the low, but very effective, hanging fruit such as wall and roof insulation, most of the other systems have a pretty big outlay, are massively disruptive to install properly in older homes and suffer from a pretty long payback time. Government incentives and grants, while helpful, go a long way to hype the politics and green credentials but do a lot less in really helping with the up front costs. Much of it seems like window dressing. Especially now, where wallets are under pressure, adopting this new stuff for ecological reasons requires deep pockets and adopting it to save money needs very careful investigation before pressing the button.
In the past have (self) put in 2 gas systems with home built electronics linking circulating water temp to external temp / tank temp. I presume this is standard now on wet systems. For the last 30 yrs we've had no gas available, and have been all electric storage heaters - 10 in all spread over 3 phase (£100 to install & handy for the workshop) for the first 10-15 years reasonably competitive with gas, if you include annual servicing and boiler replacements. The 30 year old heaters are still going strong with zero maintenance. Their electric input is regulated by the weather. The main disadvantage of economy 7, is 24 hour heating. However for the last 20 yrs we have been retired and need heat all day. There are apparently economy 10 packages out there, which can give daytime top ups, and new storage rads have better insulation and release heat by controllable fan, whenever you want it.
If you have a wet ground source heat pump with the works all indoors, the heat output would require 4x the amount of kWhrs from a conventional electric radiator. This makes the pump amost 100% efficient, as the waste heat from the motor and compressor are retained in the house. This is lost with external air heat pumps. Because of the low rating of pump systems they need to be running all or most of the time, using normally priced electricity. Storage systems chaarge at night on a cheap rate - but you do pay more for day time units - they get you one way or another! A heat pump would be a total waste of £ in a badly insulated house, sadly, most of the UK housing stock.
If you have a wet ground source heat pump with the works all indoors, the heat output would require 4x the amount of kWhrs from a conventional electric radiator. This makes the pump amost 100% efficient, as the waste heat from the motor and compressor are retained in the house. This is lost with external air heat pumps. Because of the low rating of pump systems they need to be running all or most of the time, using normally priced electricity. Storage systems chaarge at night on a cheap rate - but you do pay more for day time units - they get you one way or another! A heat pump would be a total waste of £ in a badly insulated house, sadly, most of the UK housing stock.
Jameshow
Established Member
Could you link a couple of stoves with back boilers to a highly insulated tank. That way you can heat up water when you want it at night ready for a morning shower.
Here in BG the most common form of heating uses wood, either woodburner or pellet boilers. Gas is available in the cities and larger towns but it's expensive - and now non-existent thanks to "Uncle Vladimir".
Electric boilers are used by most people for hot water - there are also wood-fired stove/boilers one can install in a bathroom plus dual-fuel models (electricity and wood).
When we renovated our house about 7 years ago we installed 2 80-litre electric boilers and one 100-litre; they were fancy Italian ones with 5-year warranties and right on cue they all died just after the 5 years were up. We've since discovered that a single 80-litre one us enough for the two of us.
We also installed aircon on the two main living floors, and serious external insulation on all the walls; the roof is uninsulated. Our HW/heating bills are much lower than those of our friends and neighbours, and the same is true for a couple of apartments we rent out with electric boilers and aircon heating/cooling.
We're certainly happy with what we've got and will do the same if we ever move to another house
Electric boilers are used by most people for hot water - there are also wood-fired stove/boilers one can install in a bathroom plus dual-fuel models (electricity and wood).
When we renovated our house about 7 years ago we installed 2 80-litre electric boilers and one 100-litre; they were fancy Italian ones with 5-year warranties and right on cue they all died just after the 5 years were up. We've since discovered that a single 80-litre one us enough for the two of us.
We also installed aircon on the two main living floors, and serious external insulation on all the walls; the roof is uninsulated. Our HW/heating bills are much lower than those of our friends and neighbours, and the same is true for a couple of apartments we rent out with electric boilers and aircon heating/cooling.
We're certainly happy with what we've got and will do the same if we ever move to another house
Woody Alan
Established Member
Slightly off topic but must put balanced view. Firstly my wife and I don't have many big meetings in our house so do not stretch the boiling tap beyond capacity. I was cynical based on work type boiling taps always breaking down. However fitted a Grohe tap with I think 4 litre tank and it has been fantastic, make a hot drink whenever without messy kettle standing about and it tastes good which was also a concern, would never go back to a kettle. Grohe filters are stupid price but if I could be bothered I could swap out for cheaper make, but don't change them that often once a year maybe.
On topic gradually insulating main external wals in my house and where done the difference is very noticible in warmth comfortable ambient temperature.
Same with our house; perhaps they didn't think it was worth saving!
On the subject of air source heat pumps I am told they are basically re invented air conditioners and nobody wants to develop them into a better product. I can't say how I know but there are a lot better more efficient options if a company redesigned them from scratch. Better efficiency, smaller, quieter, better looking and possibly cheaper.
We built a bungalow about 20 years ago and paid a token value of about £200 each for electricity, telephone and water. They all came and installed temporary connections in that price. BT managed to put the pole in the wrong place and came back and moved it. I was speaking to a guy having a house built for him and the water company want £15,000 to make a connection and he has to lay a pipe to where the connection will be. I think he said the electricity company wanted about the same.
We can tell when our filter needs changing as the nozzle starts furring up. I use the cheaper filter from Amazon and they work OK.
Woody Alan
Established Member
I have had a lot of dealing with UKPN for power to lay connection to the DSLAM broadband cabinets and their general rule is if your point of connection to a serving main is 43 metre or less they just charge for a service connection, if it's is over that they charge you for extending the network for them and it runs into big money depending on distance of course. Openreach are similar they can/will/maybe charge for network costs to get from curtilage down to your property e.g a farm with long track. They don't usually charge for extending the network within public highway unlike UKPN.
It's certainly a possibility, although the pipe runs may prove to be a little problematic - but it could, theoretically, use the second coil on our tank - interesting! thanks
clogs
just can't decide
we have a duel fuel boiler, wood n oil...never ever gonna use oil.....
bare with me.....
this winter was the worst in 30 years.....comparable to a mild to cold winter in the UK....
we also had a lot of rain so the damp was the same.....
we burnt 3 ton of hard wood....mostly Olive as per the norm....a norm winter we use 1.5ton....
this also does the hot water...the only benifit on a nice winter day is the water solar panels....it just raises the temp a bit.....
plus point with using wood we support the local economy....
the wood is €130 per ton....del pre cut to 35cm's
I have a mate in Poland with solar water heating panels...and it works for him there....
we did bring a large glass fronted woodfire with a back boiler just in case.....
it will get used in a micro home, WHEN we build it.....
so not sure of the future about wood fired boilers in the UK, but might be a good semi perm fix til the day the gas gets shut off....esp if out in the country.....
hopefully by then the GSHP might be cheaper/better...
Here there's not gonna be many bore holes as were on solid rock......
bare with me.....
this winter was the worst in 30 years.....comparable to a mild to cold winter in the UK....
we also had a lot of rain so the damp was the same.....
we burnt 3 ton of hard wood....mostly Olive as per the norm....a norm winter we use 1.5ton....
this also does the hot water...the only benifit on a nice winter day is the water solar panels....it just raises the temp a bit.....
plus point with using wood we support the local economy....
the wood is €130 per ton....del pre cut to 35cm's
I have a mate in Poland with solar water heating panels...and it works for him there....
we did bring a large glass fronted woodfire with a back boiler just in case.....
it will get used in a micro home, WHEN we build it.....
so not sure of the future about wood fired boilers in the UK, but might be a good semi perm fix til the day the gas gets shut off....esp if out in the country.....
hopefully by then the GSHP might be cheaper/better...
Here there's not gonna be many bore holes as were on solid rock......
I’ve done exactly this on my 1885 granite walled property. We had Icynene permeable foam poured into the space between the lathe & plaster and the external walls. You should research this foam and the few companies set up to install it. Our home is transformed: draughts gone (esp around windows), massively warmer and quieter. We sprayed Icynene between the roof trusses also and so have a warm clean and dry loft. There’s lots of ignorance and doubt about this type of permeable foam, and you’ll find a lot of people have not heard of it, or are very sceptical. Check out the 10yr+ research done by Scottish Heritage to validate it’s effectiveness at isolation and also in avoiding damp.
woodieallen
Established Member
Do you have any sources to back that up, please?
And as an aside, for any given pipe radius there is a sweet spot as to insulation diameter. It's a fallacy to think that the thicker the better because the surface area also increases which increases the heat loss.
Jameshow
Established Member
https://forum.buildhub.org.uk/topic/14036-ashp-pipework/
Basically common knowledge....
Basically common knowledge....
woodieallen
Established Member
That's what we have done. We were burning through a full tank each month. So night time temperature reduced from 15 to 12 degrees. Daytime to 16.5 degrees. Heating only on for a few hours early morning and a couple at night. Result? Three months on and the tank is still half full. Caveat...we do have an unlimited supply of wood to burn in our delightfully inefficient but lovely open fire. We did install 4" of Celotex seconds on the inside of our very thick stone walls. But allowed our indulgence of Georgian single glazed windows with beautiful narrow glazing bars.
Could I please ask that you refrain from using bulleted lists in your posts as it makes replying and quoted effing difficult !
