Posted by: @derbygraham

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I have been quoted for a Midea R290 4kW unit

The installer has gone for midea over a Vaillant, as the unit will be located under a window and midea would fit better

Its good kit the Midea and significantly cheaper, you would get maybe £500 - £700 off compared to Vaillant.

@editor That's great - thanks so much.

Just FYI in case anyone can help us as I would really appreciate some guidance - I'm weighing up replacing my old oil boiler (we're not on gas, the boiler was installed in 1992 and is temperamental) with either

(a) a new combi oil boiler (approx £4.5k install), or,

(b) ASHP.

I have a three bed semi detached 1940s-ish house. Cavity walls. Double glazed. We're doing an extension and renovation. The extension will be up to required building regs for insulation, and we will internally insulate external walls in the existing house. The extension will have under floor heating, but I'm not sure I can afford it for the main house (it would be the overlay underfloor heating if it was anything, but looking like it might just be radiators). There's two adults and three kids. We have solar panels and a 10 kW battery. Because we have an extension under way a lot of installers have said to wait til it's built, but, we'll need to remove the old boiler to allow the build to take place so would be left without hot water in the meantime, and part of the questions we have are where the internal units and water tank would go, which is best dealt with before we've decided on wall placement and built up the floors and walls etc.

EDF and Aira were happy to quote. I was given a quote from EDF of £7,500 after the BUS grant, on the basis of the BUS grant being £7,500 (they seemed to think it would be OK to delay the install until the £9k becomes available, so maybe £6k in total). The system they offered:

DAIKIN LOW TEMP EDLA 8KW HEAT PUMP
250L PRE PLUMBED R32 CYLINDER
PIPE WITH FITTINGS AND ELECTRICAL CABLING
COMBI CONVERSION / CYLINDER RELOCATION UP TO 5M
EXTERNAL TRUNKING
HEATING CONTROLLER
RADIATOR REPLACEMENTS (five)
BIOCIDE 500ML
28MM X 13MM BLACK OUTDOOR PIPE LAGGING 2M

Otherwise I got a quote for £8,300 after the £7,500 BUS grant from Aira, but they would have installed a buffer tank and from the information on here I steered away from that; plus it was more expensive. I'm waiting for a quote from Ovo. Heat Punk were wanting £800 just for planning, which is too much for us.

I'm very nervous about moving to an ASHP. We had the battery and solar panels installed about three years ago and frankly were royally screwed over by the installer, so I'm very very nervous of (relatively) new tech that makes promises. We've wasted thousands of pounds on that, which we can't recover without court action (which I only very briefly considered after running out of road on all other options, but isn't actually an option) and the battery does not do what we wanted it to. I have no idea if it would integrate (in a 'smart' sense) with an ASHP system - it's a PureDrive battery (since bought by Duracell).

I also watched the (very helpful!) video on the Renewables Hub YouTube which said "Don't install a heat pump unless..." and then listed loads of things that I just realistically wouldn't have time for - monitoring the system, energy prices, outside temperature info etc. Without wanting to sound like a complete numpty - if I can't just turn it on and have it work, we will struggle. I can't afford to have this not work.

Thanks for any guidance etc.

And thanks again for offering to pop over details of local installers. I think the more information I have the better at this stage.

Actually - sorry - I did also get this quote from Ovo:

£6,363 with the £7,500 grant already removed (so about £13,863 in total).

@little-lights sorry to read your bad experience with PV & Battery.

Larger brains than mine in here but from recent experience:

1. Only choose an installer who has reckonable experience, sourced from a 3rd party;  else walk away
2. You are in a good place here.
3. ASHP is not relatively new tech: it is about inexperienced/ untamed plumbers, sadly a few  unqualified rogues too, that are new to the tech.
4. Do try educate yourselves to become 'smart customers'. You will also be able to ask  more questions in here and get better informed answers. Buy Mars' RHH books: the best £33ish you will invest. You will digest much more than a YT video, and it's easier to reference info later.
5. Aira: I approached them at an energy and renovation show: 'Gucci' stand and slick sales pitch with litlle technical substance to back up their 'facts'. I moved on quickly.
6. Over-floor retrofit UFH wet system looks good in the glossy and on video but it really has to be right for your home. We opted for JK Floorheating in-concrete throughout the GF: Admittedly, more disruption upfront but easier to manage the aftermath: viz. Internal/ external doors, skirting, ceiling height, decor, etc. But, whatever works for you.
7. Ask in here for any recommended installer in  your area. @editor has curated a list.
8. Lastly, caveat emptor.

WIshing you a brighter and hopefully green future. 

@colinc Much appreciated - thank you. Similarly... I asked the chap at Aira who ran through a remote quotation with us about the buffer tank, and he admitted to not really knowing why someone would want or not want one, but despite that was pretty sure they were good. 

Since we're renovating throughout the ground floor, the floor height and doors/skirting etc is all a movable feast to some extent at the moment. I need to look into the overlay underfloor heating a bit more, I'm hoping my builder (very good local reputation) will have a helpful opinion as to how it would work in our house. As always likely to come down to cost to a large extent. Thanks for highlighting the grinding option - I'll take a look at that, too. 

@little-lights 

Done properly an ASHP will almost certainly give you greater comfort for similar or lower running costs even in 'normal' times without a battery.  Given current/near future given oil prices or just the fact you have a sizeable battery, almost certainly lower running costs, possibly quite a lot lower.  Simple scheduling will be enough to get these savings - a lot of fuss is made of 'smart' but if you choose a tarrif with cheap periods at fixed times, eg Octopus Cosy or (if you have an EV Go) 'smart' is not necessary. 

I made my switch initially for environmental reasons, but now for comfort reasons alone would not go back to a boiler willingly, having experienced just how good low temperature heating, which is what you get with an ASHP, is.  Basically the whole house is comfortable 24x7, and I touch the controls perhaps 2-3 times a year (actually its quite a lot more but only to look at the display of outside temperature, because its not not possible to tell what the OAT is from the house temperature). I never achieved anything close to this level of comfort with my boiler even though it was fairly modern.

Done badly an ASHP will be a pain.

Fortunately its become abundantly clear over the past few years what 'good' and what 'bad' is so we can help if you want.

According to the largest independent survey by NESTA in 2023, satisfaction rates for ASHP installs and boiler installs are essentially the same.  The problem is that both are only around 80% satisfied, and of course people who get an ASHP blame it on the tech not the variability in quality of our heating industry. 

We cant make the decision for you, we can only help you maximise the probability you are in the 80% and if you aren't initially help you shift to the 80%.

If, on that basis, you want to proceed (and before we discuss the quotes) please tell us a bit more.  how much oil do you burn annually, what is your heating 'pattern', is the house basically warm all the time or do you allow it to get cold during night/day, whats the floor area of your house.  

If you do wish to proceed can I suggest you read this article which is a no jargon introduction.

Please post again if you want to proceed with an ASHP.

@little-lights, a good point wrt flooring. We too are doing a complete makeover. All the flooring: tiles and carpet, is as installed in 2001.

Our quotes for retrofit GF UFH, from install through to ready for the LVT 'latex' pour;  JK were actually cheaper than Wunda and Nu Heat over-floor systems. Whatever you decide, do engage your heating installer early; to ensure correct pipe sizing calcs for flow rates, heat energy requirement. etc. If your UFH installer doesn't understand about ASHP and Heating Power calculations: this is a Red Flag, find one who does. Siting the UFH manifold can be a key decision too, in terms of loops and optimal distance to/from HP. The DHW and Rad pipework size and distances also need  consideration.

We decided early on in planning to install 'glue down" LVT (not the Click variant); the same LVT throughout the GF.

Our carpet installer suggested to consider the same carpet for 1st floor, stairs and landing (not bathroom and enuite shower). Buying a roll as opposed to 'room by room' m² is a significant saving (@25% in our case). Flooring uniformity is not an issue for us. 

To be blunt: "... failing to plan is a plan to fail"

Hope that helps.

Posted by: @little-lights

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@colinc Much appreciated - thank you. Similarly... I asked the chap at Aira who ran through a remote quotation with us about the buffer tank, and he admitted to not really knowing why someone would want or not want one, but despite that was pretty sure they were good. 

In general they aren't and he is wrong.  End of in almost all cases. 

That said Aira are essentially vertically integrated so can actually set up the system so that a buffer tank does no harm (unlike most), and the reports here suggest that they probably do.  There is still no evidence that it does any good though even for an Aira system correctly set up.

Posted by: @little-lights

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@colinc Much appreciated - thank you. Similarly... I asked the chap at Aira who ran through a remote quotation with us about the buffer tank, and he admitted to not really knowing why someone would want or not want one, but despite that was pretty sure they were good. 

In general they aren't and he is wrong.  End of in almost all cases. 

That said Aira are essentially vertically integrated so can actually set up the system so that a buffer tank does no harm (unlike most), and the reports here suggest that they probably do.  There is still no evidence that it does any good though even for an Aira system correctly set up.

@jamespa Great, thanks - I've had a quick look at the article and will have a proper look later this eve/tonight. I wonder if for me it's a case of once bitten twice shy, but I can see the sense of a heat pump overall. I went with a small installer last time - I'm hoping the larger companies (EDF, OVO) will have better installation skill/support. I'll come back with the info you've asked for once I've digested the article. Thank you! 👍

@jamespa Thanks so much for the support so far. I've read the article you linked to, which was helpful - thanks.

You'd said... "If, on that basis, you want to proceed (and before we discuss the quotes) please tell us a bit more.  how much oil do you burn annually, what is your heating 'pattern', is the house basically warm all the time or do you allow it to get cold during night/day, what's the floor area of your house."

Here we go:

1. If you want to proceed...

I like the idea of a heat pump, and I'm nervous of the reality, I think partly because people have advised us against it (... aunt, mother, neighbour, oil boiler engineers) so - quite apart from any heating problems a future heat pump might serve up - it'd be very annoying to have a litany of "told you so's" as a side order. Anyway. 

2. How much oil do you burn annually...

Oil: Approx 1,250 litres. Bit of a guesstimate. We supplement with electric heating and kettles for hot water when the oil boiler fails (not infrequent maybe approx. 2.5 weeks in total across the past year, in fits and starts, during the winter months).

Electric FYI: 1st Jan 2025 - 31st Dec 2025 we used 3,248.699 kWh (and exported 1,598.19 kWh, obviously mostly in the Summer)

3. What is our heating pattern...

March to Sept - no or very limited heating through the radiators - put on a jumper if it's chilly, which isn't often. The back of our house is South facing, and if it's sunny in the morning it warms up quite quickly from that. The North facing side of the house is cooler, which is actually nice in Summer.

From Sept through the March, we've used heating as and when we've needed to, which through winter is every day. We tend to heat if the kids are with us, so early mornings, evenings, weekends, and holidays. Sometimes on an evening (esp when the kitchen is warm from cooking) we will use an electric oil radiator to heat the main room only, or very occasionally have the log burner in the main room, to avoid using the heating system too much. We work from home so winter day-time is cold, and at times we've resorted not only to socks and jumpers but coats as well.

Our oil boiler was installed in 1992. There is no thermostat, there are no thermostatic controls on the radiators in the rooms, no dials indicating 1-5 for power/heat output etc. The heating is either on, or off. The temperature of the heating is dictated by the temp of the water. We have our water temperature set at 78C at the moment. The temp we need to set it at varies, for reasons I can't quite work out, I think the boiler loses efficiency over time (?) so in-between services or repairs we've needed to increase the temperature setting to get actual hot water. We've had it set to 65 in the past, and that's the lowest it's ever 'worked' at. The boiler 'leaks' quite a lot of heat into our utility area (where it's housed), the under stairs storage where a lot of pipework is (always like a sauna despite the pipes being insulated), and our main bedroom above the utility area (mainly heat rising from below, and maybe a bit from the hot water tank which is in that room). 

4. Is the house basically warm all the time or do you allow it to get cold during night/day... we allow it to get cold. Night time - no heating, so in colder months it's cold. Winter day times - cold. 

5. What's the floor area of your house... 43 meters squared downstairs. For some reason, 36 square meters upstairs... can that be right?. There's a porch and entrance way downstairs that we don't have upstairs. Those figures are for the existing property. When we've done the two storey side extension, there will be approx 100 square meters in total across the two floors.

Just FYI, I think I could get an oil combi boiler for about £5k installed. Maybe less. I'd be paying about £1,250 a year on oil thereafter (based roughly on current prices).

I think EDF are looking most likely, because albeit OVO have quoted cheaper, they haven't actually yet spoken to me, despite a couple of requests for a call.

Thanks as ever