Heat Pumps: anyone have one/thought about it?
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You’ll need to talk them through all the insulation work you’ve done and nudge them in trunking for external pipework if you want it. The default is external pipework clipped to surface and insulated.
1970's. Sds'ing is always good fun. It's the tidying up and making good afterwards that's the issueHow old is your house?
If it’s newer than mid-90’s then it should have some insulation under the floor.
No need to read, grab an SDS and find out
Soldato
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We inquired with JK before we knew we had a bit of insulation.
They said we could get away with it, but recommended 100mm pipe centres. Then I found we have 25mm of xps so JK said 125-150 would be fine (knowing about the heat pump we were getting.)
We opted to have 100mm pipe centres anyway to which they obliged and it’s been working brilliantly.
That’s on a suspended block and beam floor though, where I guess the air gap isn’t as thermally conductive as soil if your slab is poured direct.
They said we could get away with it, but recommended 100mm pipe centres. Then I found we have 25mm of xps so JK said 125-150 would be fine (knowing about the heat pump we were getting.)
We opted to have 100mm pipe centres anyway to which they obliged and it’s been working brilliantly.
That’s on a suspended block and beam floor though, where I guess the air gap isn’t as thermally conductive as soil if your slab is poured direct.
Heatpump man just left. A bit of a damp squib unfortunately - despite a 2M side return (and my neighbors having 2M as well), there was no suitable space to install the pump. He reckons the noise calcs will fail. Also, regardless of the noise issue, he was suggesting the only place to put it was right in the middle of side return rendering the whole space pretty useless.
The only sensible space therefore is down the garden; which involves a 750mm deep trench by 500mm, by about 4meters. Business case bust now - and needs to be part of the larger patio job; which is constrained by the larger extension/side return job.
Turns out wall mounting above 30cm isn't something Octopus can do.
Gas it is for the foreseeable then!
The only sensible space therefore is down the garden; which involves a 750mm deep trench by 500mm, by about 4meters. Business case bust now - and needs to be part of the larger patio job; which is constrained by the larger extension/side return job.
Turns out wall mounting above 30cm isn't something Octopus can do.
Gas it is for the foreseeable then!
I doubt you’ll find many installers willing to wall mound any higher than a few guys can realistically lift a 150kg heat pump. You need proper lifting equipment to fit them and servicing becomes a bit of a pain. If there are access restrictions also, that will put installer off also.
All might not be lost, if the noise calcs are the issue, Daikin is actually on the nosier side of the spectrum and another brand may work. Eon fit Vailent who’s official ratings are quieter. Likewise a local installer could fit any brand.
The government just published a bunch of changes to heat pump planning regs which is worth having a look at.
All might not be lost, if the noise calcs are the issue, Daikin is actually on the nosier side of the spectrum and another brand may work. Eon fit Vailent who’s official ratings are quieter. Likewise a local installer could fit any brand.
The government just published a bunch of changes to heat pump planning regs which is worth having a look at.
Soldato
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Our heat loss calc was 9.68kW
Our heat pump is 12kW
Our house is 180m^2
For the month of November we have used ~800kWh more this year than last year with no heat pump. Does that sound about right? (Our unit cost for electricity is around 20p/kWh)
Our heat pump is 12kW
Our house is 180m^2
For the month of November we have used ~800kWh more this year than last year with no heat pump. Does that sound about right? (Our unit cost for electricity is around 20p/kWh)
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How much gas did you use last year and what was the average temperature last November where you live?
Edit the month is not over yet but I’ve used 336kwh in the heat pump bt my heat loss is smaller than yours at 5.6kw, I have a 6kw heat pump.
Edit the month is not over yet but I’ve used 336kwh in the heat pump bt my heat loss is smaller than yours at 5.6kw, I have a 6kw heat pump.
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Soldato
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We were on oil so had no month by month consumption data.
No idea what averages were like this year compared to most although it seemed we had an unusually long cold snap below zero.
Our up to date EPC says 13000kw/year for heating and 2000kW/year for water so by their stab in the dark we’re doing extremely well.
Is it as simple as adding up all of the total heat pump consumption figures through the year should equate to somewhere near the 9.68kW heat loss figure?
No idea what averages were like this year compared to most although it seemed we had an unusually long cold snap below zero.
Our up to date EPC says 13000kw/year for heating and 2000kW/year for water so by their stab in the dark we’re doing extremely well.
Is it as simple as adding up all of the total heat pump consumption figures through the year should equate to somewhere near the 9.68kW heat loss figure?
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No, the heat loss figure is how much heat you lose from your house when it is -2 outside (or which ever temperature they used during the survey, -2 is usually the max, they can use a colder temperature).
Also don’t forget those EPC numbers are the heating amount, that you have quoted is your electricity amount. When you push the electricity through the heat pump, you should be getting 3.5X that number out in heat.
Does your heat pump report any performance numbers, that’s probably the overall metric you need to worry about out rather than overall energy consumption. There are too many viable to consider like how warm you are heating your house and if that’s equivalent or not to before.
A SCOP of 3.5-3.7 will be equivalent to a decent gas system in terms of cost for the same amount of heating.
This thread is mostly about monoblock heat pumps attached to traditional wet central heating systems.
I think what you are referring to is the indoor unit from a split air to air heat pump?
In any case, you only get mould where there is excess moisture that’s allowed to fester. Make sure the condensate drain is clear, clean/service it regularly.
You’ll get better efficiency and less condensation when running it for longer at lower power levels. Depending on how intelligent your system is, the power level is usually linked to fan speed, so low fan speed is lower compressor power.
Try not to turn it off after it’s been working at a high power level as the internals will be very wet, run it on fan only mode if it has one to dry it out before switching off.
800kWh just for November sounds painfully expensive! In comparison we have a 1890s Victorian house, solid walls and a 36kw Vailliant boiler and used £78 of gas in November to keep the house at 21c - took a lot of effort!
For November our total usage was 767 kWh.
We have a 12kw eco Dan for a 5 bed house, we also have a full ev and battery set up. We’re on intelligent octopus go so our unit cost was an average 9.6p
Associate
Had my rattly old gas boiler replaced this year, and I am impressed with how quiet the heat pump is. Don't need to think about any smart scheduling, just set your preferred temperature and let it do it's thing.
The image shows how much energy it takes for hot water and heating my mid-90s 3 bedroom semi-detached house.
It's not saving me any money, yet, but that is due to gas being much cheaper than electricity.
This coming year I'll be looking at getting solar panels and a battery fitted to lower the average cost of the electricity I'm using.
The image shows how much energy it takes for hot water and heating my mid-90s 3 bedroom semi-detached house.
It's not saving me any money, yet, but that is due to gas being much cheaper than electricity.
This coming year I'll be looking at getting solar panels and a battery fitted to lower the average cost of the electricity I'm using.
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Associate
We have an 8kw Nibe heat pump from 2018. Our house is 100 year old (no cavity walls) but well insulated, with underfloor heating, double glazing throughout and a 4 kw solar panel array. The heated floor area is something like 170 m^2. We used 806 kwh in total for november, and 465 of that was for the ASHP.
Last november we used 759 kwh in total, and 530 of that was for the ASHP.
The Daikin MMI does a lot of rounding up, the issue is that it rounds up, rounded up numbers so it can be an overestimate.Had my rattly old gas boiler replaced this year, and I am impressed with how quiet the heat pump is. Don't need to think about any smart scheduling, just set your preferred temperature and let it do it's thing.
The image shows how much energy it takes for hot water and heating my mid-90s 3 bedroom semi-detached house.
It's not saving me any money, yet, but that is due to gas being much cheaper than electricity.
This coming year I'll be looking at getting solar panels and a battery fitted to lower the average cost of the electricity I'm using.
According to Daikin, I’ve used 75kwh so far this month, I’ve actually used 67kwh according to a separate energy monitoring device I have on it.
Last month it reported 372kwh, my actual was 343kwh.
Deffo get that solar on, it’s well worth it.
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Soldato
I've recently became intrigued by heat pumps due to the government grant and whatnot. Octopus have quoted about £4k and considering I've been wanting to move my boiler out of bathroom into utility room, a heat pump install might save the faff.
Does anyone know if they repipe any radiators or move radiators if necessary? It could be an opportunity to get a bunch of things moved about to save me doing it anyway.
Does anyone know if they repipe any radiators or move radiators if necessary? It could be an opportunity to get a bunch of things moved about to save me doing it anyway.
They will replace radiators for bigger ones as required by the heat loss survey. If there needs to be any re-piping that will be extra but it’s unlikely that will be required. The re-pipe of the flow and return out to the heat pump is included, as is any minor tweaks needed to make a bigger radiator fit to an existing position.
If you want more work doing than a like for like install (like rads moving to new locations), you may be better off going elsewhere but you’ll pay a lot more for the privilege. Ironically, it may be cheaper to get octopus to install and get someone else in to move the radiator after (or before).
Don’t forget, if you have a combi boiler, you’ll need somewhere for a hot water cylinder, this can be the loft if needed and it will fit through the hatch.
If you want more work doing than a like for like install (like rads moving to new locations), you may be better off going elsewhere but you’ll pay a lot more for the privilege. Ironically, it may be cheaper to get octopus to install and get someone else in to move the radiator after (or before).
Don’t forget, if you have a combi boiler, you’ll need somewhere for a hot water cylinder, this can be the loft if needed and it will fit through the hatch.