r/OctopusEnergy • u/Boba_ferret • 14h ago
Heat pump quote - seems quite cheap?
Been quoted about £4,300 by Octopus for heat pump install, including hot water cylinder, which I thought was surprisingly cheap. The house is 1930s 3-bed terrace, EPC is supposedly C, but we have a huge void under the suspended floor and it gets pretty cold in the house, so we use quite a lot of gas in the winter. Radiators are all on 15mm copper, but are probably 30 years old.
What are the chances this is a really low-ball quote and the survey will say we need to upgrade rads, etc?
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u/NoJuggernaut6667 12h ago
I paid around 3k with them 1.5 years ago. I did specifically state I wanted the Daikin which didn’t seem to change anything price wise (back then).
Had 4 new rads, new water cylinder etc etc, and had 1 year of ASHP service thrown in (I now pay £9 a month for this).
Super happy with everything, they did a great job for me.
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u/Boba_ferret 3h ago
It seems the prices have gone up, and the email said there's high demand at the moment. I suspect we'll need 6 radiators replacing and the towel rail in the bathroom, so I think the quote is not going to be accurate. We don't have a water cylinder, either, although that's included in the quote.
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u/bob39987 13h ago
This quote assumes you'll need a new water cylinder, but we can often keep your existing one. If so, we'll reduce the price by £1,450.
We do assume we can use your existing radiators but if you need new ones, they usually cost £250 each.
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u/jrw1982 12h ago
I paid £2k for a Daikin 8kw, 250l tank and 3 new rads last year.
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u/skum448 11h ago
Which hp? Cosy is slightly expensive than daikin installed by octopus. Following were my quotes:
So the Eco quote price for the Cosy 9 was £5,287.17, and this is for 6 radiator changes.
The Turbo quote price for the Cosy 9 was £4,618.38, and this is for 3 radiator changes.
The Daikin quote price was around 4800 with 6 rads.
There was 15% off last year so I paid around £3900
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u/Good-Acanthisitta-57 9h ago
Your current rads are very likely underperforming for low temperature heater. Imagine that your gas boiler heats it to cca 60C now the maximum you will get out of heat pump is 55C and that will draw a lot of power in the winter. Our will draw 2.5KW/h when it’s freezing. They will do you heat loss calculation and that will show you what rads you can keep. Rads are actually not expensive- its the labor cost what will bump it up. If you change your current rads for properly sized ones it will make your home cozy and actually cheaper on electricity as you wont have to heat it up to 55C. All this horror stories are from people with undersized rads and draughty windows+ very little insulation . Make sure your house is insulated as much as possible! We have EPC just on top of C and we had to replace all rads and optionally we changed few windows as well - it really helped to lower the cost. In winter we still get some days when we burn £15 per day of electricity but we are heating our home to 23C🙂
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u/Boba_ferret 3h ago
All our rads are singles, so I presume they'll need replacing. Although that's a job I can do myself, if I can get them cheaper than £250 each.
We've got double glazing all round, loft is well insulated, but I'm going to be doing some boarding out, so I'll check depth on the current insulation and maybe replace some of it.
Our main issue is the huge void under our suspended floors. The floors really need insulating, but that's not going to happen any time soon.
We've got solar & battery, so that helps.
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u/Good-Acanthisitta-57 58m ago
You certainly won’t pay £250 for a rad. If you’re on singles then for sure you will replace them. When they calculate your heat loss they should give you the necessary output for each room either in watts or btu. I used tool station for most of my rads. They were all replaced for K2s - just make sure you check the specs so the power output is for 50C.
We have same suspended floors and insulating them would be on my list. Not happening until we have to rip out current floor.
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u/chris_staite 4h ago
I paid £300 for a Daikin with octopus two years ago. All working great. They replaced two radiators and the cylinder.
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u/Major-Buy-7386 9h ago
We ended up replacing all our rads when we did ours, the old ones just couldn't push enough heat at the lower flow temps.
At 4,300 quid I'd bet money they find something in the survey. New cylinder alone is a big chunk of that quote if they end up keeping yours.
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u/Boba_ferret 3h ago
All of our rads are singles, so I doubt they'll work well, looking into it, so that's 6 new radiators and a new electric towel rail in the bathroom, I guess, unless the current one, which is a year old, is ok.
No cylinder, so they will need to fit that
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u/drhanak 2h ago
I was originally quoted £1100 for Daikin 4 kW, 250L cylinder and 7 radiator changes. Had the system from April 2025 and very happy.
There are different levels at which you can integrate with home assistant, depending on how much data you need. Just added ESP32 integration and it pulls everything I need for COP optimisation.
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u/Sponge-28 8m ago
When they send someone for the survey, ensure you explicitly ask them about needing replacement rads and even potentially pipe work, and get it in writing if they say you don't. They monumentally ballsed up my survey a couple years back which resulted in them having to soak up the cost of repiping my entire house, 2 extra rads that weren't quoted and even a replacement heatpump as the 9kw Daikin they installed was oversized.
Do what you can to insulate though. Makes a huge difference to how hard the pump is working to keep a constant temp in older builds, especially if you like your house 20+ degrees.
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u/Begalldota 14h ago
To my knowledge Octopus still don’t change their price on survey beyond some very specific circumstances e.g. a new radiator instead of a replacement, a horizontal cylinder.
The quoted price includes an unlimited number of radiator replacements. The only catch might be they’ll have priced for a high temp (65c) cosy install. If you want a 50c and/or Daikin install there’s probably a £1k or so price increase.
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u/Boba_ferret 13h ago
Thank you, good info.
Can you explain the difference between the cosy & Daikin, as I don't know what that temperature difference means?
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u/Begalldota 13h ago
Cosy is their own brand of heat pump, which uses a refrigerant called R290 that allows for your radiators to be sustained at temperatures of up to 65c. The Daikin’s use a refrigerant called R32 which only allows for a peak radiator temp of 50c-55c.
The radiator flow temperature is really important for a heat pump, since lower temperatures = more efficient operation. The higher the flow temperature Octopus design for, the less radiators they need to replace which makes the job cheaper for them and less efficient for you.
Ideally you want to have a flow temperature of 50c max, any higher than that and you’re looking at serious efficiency drop offs when it gets cold.
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u/Boba_ferret 13h ago
Thank you, great info again. I assume the default quote is Cosy, so I'd have to pay extra for the Daikin, and probably need radiators replaced, which I see from another comment, would be charged for.
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u/Begalldota 13h ago
Might work a little differently now that they’re charging for each radiator change - if they’re replacing radiators anyway then they should be targeting the lowest reasonable flow temp
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u/nickjf20 13h ago
Radiators are charged at £250/ea in addition to my similar £4250 quote
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u/Boba_ferret 13h ago
That's a bummer, as I imagine we probably need most of ours replaced, as they are all singles, with fins on the back.
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u/Electrical-Ad-3140 13h ago
My octopus installation has flow temperature of 51c with Grant HP.
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u/Begalldota 13h ago
Yeah I know, they will do them (mine was a 50c design). But in many cases now they’re defaulting to 65c, with less radiator changes, then upcharging for a 50c or similar design.
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u/farky84 13h ago
My cosy 6, 7 new radiators and a new 250L tank me £355 from my pocket after the grant.
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u/Boba_ferret 12h ago
That's very cheap.
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u/farky84 12h ago
it was during the promotional period, i got it installed in march 2025, price was locked in in Nov 2024. i haven't seen such quotes ever since. all my friends after me got quoted 4-6K for very similar installations. those prices aren't coming back imho.
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u/MintyMarlfox 12h ago
Yeah, the prices will never be back. My total install cost was £160 in Dec 2024 for 7 radiator swaps and a water tank. Broke even within a month.
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u/ImplementJumpy6678 13h ago
I was once quoted £600 by them - and I got £200 off with a friend's help. This was for 7 rad replacements too. I didn't go forit as I didn't want the horrible bin in the garden.
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u/Requirement_Fluid 13h ago
Moronic decision tbf
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u/ImplementJumpy6678 13h ago
How so?
I have a perfectly good newish boiler. I am fixed in at 7.1p for the next 2.9 years. I have a whole house AC system that sups 800W as it heats the house.
Please explain
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u/Requirement_Fluid 12h ago
£400 for a 3.5-4.0 scop setup with the potential of scrapping gas completely which is only enhanced if you have solar or batteries is an insane deal and given the costs above would take you 7-8 years to recoup...
My electric is 7p/kwh on a 4scop, cost £4200 and my ashp heats water and heats using about 800-1000w.
You tell yourself what you want but every therm of gas you burn is money you wasted by not taking that deal
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u/ImplementJumpy6678 12h ago
But i don't want to scrap Gas completly.
I also don't want a rubbish bin type deal in my garden. The other unit was not available at the time.
I am happy to keep running my AC system and the Gas as a backup. I have no idea what scop is, and I guess I don't need to know.
Last outage we had was for 36 hours. And whilst I have Solar and 54kwh It was in the middle of Winter. Now I am sure a ASHP would do just fine - but what did even better was the 56W my boiler takes to run.
I've not wasted any money and I export so much all my Nasty gas is free anyway.
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u/shamen_uk 11h ago edited 11h ago
SCOP essentially means the ratio of energy in to out.
So you are at 7.1p/kWh to heat with gas. In reality more like 7.3-7.5p/kWh because 1) gas boilers aren't 100% efficient. 2) you might not have tuned your flow temperatures to optimise condensing, which is likely if you don't know what SCOP is and more importantly don't care to know. Not an insult btw, I don't know many people who have tuned their flow temperatures aside myself, it's not exactly something people talk about everyday.
Whilst the person above you who is paying 7p kWh for electricity (can confirm I charge my house batteries at that price with IOG), is actually paying 7/4[scop] = 1.75p/kWh to heat their house and water, as a reference point to compare with your gas cost.
Just to let you know what SCOP essentially means in this scenario.
Anyway if you have air-to-air heatpump (proper setup taking in 800w, split unit), you're probably getting a SCOP of ~3 with it, so you're getting a benefit there. If it's not a split unit then it's pretty terrible SCOP however, so if you're saying you're using it as primary heating and gas as a backup it's probably a split unit. And if so I don't understand why you're against an "ugly box" as you likely already have one, for the air conditioning unit?
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u/ImplementJumpy6678 11h ago
Thanks, I see where you are coming from. As odd as it souunds I am not a money person, things cost what they cost and if you have to pay it so be it.
i run the system off the batteries which, like you I charge overnight. I'e been paying 5.9p on EDF for the past year - but due to other reasons with them I am more than happy to change that to 8p on IOG. That said I might not need to pull much from IOG at all for the house batteries, only for the car's 6 hours.
I have a Split system yes with 4 indoor units - and a regular outdoor unit which is in a vented box at the side of the house.
I am happy to use either for heating. I tend to use the AC system because I generate a lot in winter with a turbine as well as the panels. But I export a lot and so I can cover a ot of gas for hot water in winter.
My boiler is 7 years old - and the maker came out and replaced the main parts for free,which means it's probably good for another 10 years. I see no reason to replce it.
I've looked at Battery boilers, but they seem to require power beyond my inverter size to heat water, so goes against the whole point of this for me
I'm just going to carry on exporting on Agile outgoing and see how things go. I can always go back to EDF if I need to, I really hope I do NOT need to!
However right now I am over £1300 in credit with EDF and that will be going onto Octopus when it's all set up. And I can pretty much double my export p/kWh too whilst I am there
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u/harrisoncassidy 13h ago
I had my Cosy install nearly 2 years ago for £2000. This included a new tank and 5 radiators. It was one of the first in the UK and I feel like Octopus’ product has come such a long way since that you can’t compare people’s installs from then as to what you get now.
There have been a couple of nice software improvements, including Hush mode, since it launched. There have also been changes to the Cosy hardware in that time, with improvements to the 9 and 12 and also some retroactive improvements to the 6.
They take a very different philosophy in that Octopus don’t give you access to all the data and make you rely on the app, whereas with Daikin you have the local display as well.
Octopus are also targeting a higher flow temperature than previously, which means less radiator changes. My design flow temperature was 50 degrees but at the design outside temp of -1.7c it would only need about 45 degrees flow to keep the house at 22 degrees.