Heat pump quote

70sbudgie

I have recently had a heat loss survey from a heat pump installer and I have many questions. From reading this board, I think I have more!

The heat loss surveyor also did a new EPC for us and for ~£200 for both this seemed good value.

The sales guy quoted ~£16,000 (before the £7,500 grant), before the survey and I felt a little like he might have been adding things in to his colleague's design to stop the price dropping after the survey. (Seeing as the 2 extra radiators came out).

EPC came back as A (just, score of 92). Heated floor area of 160sqm. We have 2 large zones of UFH and 12 radiators.

The initial price was described as a "package price" with an Ecodan 11.2kW monobloc HP, 250l tank and 10 radiators. The two extra radiators were extra as was a 'low loss header'. (Which I am sure was in the original quote, but seems to have been added in again)

Heat loss survey identified ~14,000kWh heating per year and ~1800kWh DWH. (This mostly correlates with our annual gas usage of ~18,000kWh.)

Only 2 radiators were identified as needing replacement. Some radiators have microbore pipes (according to the sales guy - how do I check this?), but I was told that shouldn't be a problem. The salesman did ask if I wanted any other radiators changing as it wouldn't impact the price (which includes 10 changes)

Design temp 47° at -3°. Giving a design SCOP of 3.85 - which I was told is good for a house of this size.

Resulting in an annual electricity consumption (for the HP) of a bit over 5,000kWh a year. 

-3° is a fairly common occurrence here, so I am interested in how the HP operates in cold weather. I have been running our gas boiler at 50° and it hasn't been too cold except for the snap of -8°. I have also been trying to balance the radiators over the last couple years (without a thermometer). I know I haven't got it right, but it is not wrong enough to motivate me to try again, yet.

I've noticed that there aren't very many mentions of Mitsubishi Ecodan on this board and wondered why that is. 

I've also read up on the low loss header (including the HG "avoid" article) and am a little suspicious. The surveyor didn't look at the UFH manifold because it is in the back of a cupboard and was taking me too long to empty. I wonder if there is one there, from what I've read. 

Red flags for me - applied to the DNO and for the BUS before giving me the heat loss survey results. Wanted me to sign on the spot (I managed to deflect that and they've sent a Docusign). I've already had an email reminder for the BUS verification, even though I have until the 18th. Tried to convince me that the BUS grants might disappear. Kept telling me the house is perfect for a HP. Have booked me in for an install date (I managed to push this to the end of the month to give myself time). Wanted to dig up my patio to install a soak away when there is a (albeit solid) drain cover less than 10cm from the expected front of the external unit. I pointed this out and they have amended the design, but still no specifics of what they are going to do to my patio. They haven't mentioned anything about planning consent, but the contract small print puts the liability on me. Haven't yet sent me the design /heat loss assessment despite the salesman offering to. I have found Heat Punk and intend to have a go at running the numbers myself, just haven't had a chance yet. Also without their assessment, I'd have to measure everything again.

I know our house is not typical, but £16,000 seems a lot more than others on here seem to have been quoted. Especially if it is so "perfect for a HP". 

I accept that maybe I am being a bit paranoid, but £8,500 is a lot of money, especially with doubts.

QrizB

£16k seems a lot of money. Just for comparison, what do Octopus quote you? https://octopus.energy/order/heat-pump/

Mitsubishi Ecodans have a good reputation, and I think were the most common brand mentioned on this forum before all the budget installers started using Daikin.

70sbudgie

Thank you @QrizB that was a good suggestion. Last time I looked at Octopus, I didn't have a valid EPC. I can't find that I got any figures.

The instant quote gives £13,772.95. 

Where do they get the information from because I didn't have to complete any details about my house?

70sbudgie

Octopus must have enough information in my account, as I logged in for the quote.

They just phoned me to follow up. I said an hour was a bit to quick for me to be able to think about moving forward!

QrizB

70sbudgie said:

The instant quote gives £13,772.95. 

Was that after the £7500 grant, so ~£21k before? Of before the grant, so ~£6k after?

70sbudgie said:

They just phoned me to follow up. I said an hour was a bit to quick for me to be able to think about moving forward!

They emailed me about mine (I might've ignored the calls, I don't recall). I told them that I wasn't able to proceed right now!

TroubledTarts

Mitsubishi have been in the heat pump market for a long time and one of the better brands imo. They might not be the most efficient on the market but from other groups like Facebook etc there are some good old units still cracking away nicely.

But that quote does seem a bit heavy given the grant of £7500

greenbee

Your setup with two UFH zones and 12 radiators sounds very similar to ours (we've got a total floor area of 340 sq m (although that includes an unheated double garage that is due for conversion). My Octopus 'instant' quote after the subsidy was around £12k. 

We're hoping to use a recommended local installer (when we get round to it!) who can undo the 4 separate zones we currently have set up - but have been warned by a neighbour who did a lot of research that most of the people he spoke to have no understanding of how to design heat pump systems (apparently I know more about it than all the installers he spoke to... so I'm hoping he'll help with the design and we'll then use his installer to implement it. 

My current plumbing/heating engineer is just starting to get interested in heat pumps, so is being helpful in making sure that any new radiators and pipework are sized appropriately, but may not be in a position to do the installation when we're finally ready to go ahead. 

70sbudgie

QrizB said:

70sbudgie said:

The instant quote gives £13,772.95. 

Was that after the £7500 grant, so ~£21k before? Of before the grant, so ~£6k after?

70sbudgie said:

They just phoned me to follow up. I said an hour was a bit to quick for me to be able to think about moving forward!

They emailed me about mine (I might've ignored the calls, I don't recall). I told them that I wasn't able to proceed right now!

Both quotes are without the grant. So £8,500 vs £6,200. 

70sbudgie

greenbee said:

Your setup with two UFH zones and 12 radiators sounds very similar to ours (we've got a total floor area of 340 sq m (although that includes an unheated double garage that is due for conversion). My Octopus 'instant' quote after the subsidy was around £12k. 

We're hoping to use a recommended local installer (when we get round to it!) who can undo the 4 separate zones we currently have set up - but have been warned by a neighbour who did a lot of research that most of the people he spoke to have no understanding of how to design heat pump systems (apparently I know more about it than all the installers he spoke to... so I'm hoping he'll help with the design and we'll then use his installer to implement it. 

My current plumbing/heating engineer is just starting to get interested in heat pumps, so is being helpful in making sure that any new radiators and pipework are sized appropriately, but may not be in a position to do the installation when we're finally ready to go ahead. 

It does sound very similar. The unheated double garage was ignored in my case.

There does seem to be a bit of disconnect between heat pump installers and good heating plumbers. I'm still not sure whether my money will get my heating set up properly (as opposed to the HP being set up properly).

Thank you for your replies, they have been reassuring.

70sbudgie

It has occurred to me that I might be able to make more of the quote I have had. For example by taking up the offer to change up to 10 radiators. Would this allow me to run the HP at a lower temperature (and therefore more efficient) or would my microbore pipework limit that regardless of the size of the emitter?

I've seen a few mentions of buffers /volumisers, but not enough about low loss headers to understand whether I would really need one. 

Thanks.

FreeBear

70sbudgie said:

It has occurred to me that I might be able to make more of the quote I have had. For example by taking up the offer to change up to 10 radiators. Would this allow me to run the HP at a lower temperature (and therefore more efficient) or would my microbore pipework limit that regardless of the size of the emitter?

There is a limit to how much water can be pumped through a pipe. This restricts the volume of heat that can be delivered to a radiator. With a gas boiler running with a flow temperature of 70°C, 15mm will deliver ~6kW, whilst 10mm is restricted to ~2.5kW (with a ∆T20°C across the radiator). As flow temperatures drop, so does the ∆T, possibly as low as 5°C, so your 10mm pipe is only good for 1.15kW. 8mm pipe is even worse at just 750W.

If you can not increase the size of the pipe, you either need to increase the flow temperature (and the ∆T) or the flow rate. Increasing flow rate needs a more powerful pump, increases wear, and increases the amount of noise you'll hear. But... even with 8mm pipe running with a low flow temperature & ∆T, a 750W radiator is still going to be quite big. The T21 600x1000mm radiators that I have here are rated at ~1300W with a 70°C flow temperature. Drop to 40°C, and they only output 400W each - Well within the limits of 8mm copper microbore pipe.