Do I just go with the lowest quote for my heat pump?
Octopus are coming around at the end of the month to survey my house. Their quote is half the price quoted by BG.
I have had two heat loss surveys and they agree fairly closely with my own from Heatpunk at around 4kW.
They would both remove my boiler and put in a slimline tank and a Daikin Heat pump. BG quoted at 45C and Octopus will, I understand, at 50c but I may be able to get Octopus to quote lower.
My thinking is that if Octopus are happy to install I would go for that and see how things work out this winter. I would then have the difference in cost to spend on upgrading or adding radiators if needed even if Octopus do not want to replace any.
Basically it is the same hardware with the same pipes so why pay thousands more?
Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.
I would agree with you so long as the pipe work isn’t going to be changed.
Swapping a radiator or two isn’t expensive and well within the scope of a competent diyer.
House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60
Have you checked for any extras on the Octopus side? For example I had to either get artex removed or lift floorboards for an alternative pipe route - both at my own cost above their fixed quote.
@gunboatdiplomat Yes when I have had the survey and report I will check. The BG one was pretty perfunctory with little detail except that it is up to me to provide piping and cabling under the path.
Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.
@jancold since you’re choosing between BG or Octopus, basing your decision on price makes sense if they’re both offering similar installations. However, design remains the most crucial component. I’d definitely evaluate this and see if either is proposing a buffer tank. BG is supposed to be phasing these out from their designs and proposals, which could result in hardware savings as well as long-term running cost savings.
Buy Bodge Buster – Homeowner Air Source Heat Pump Installation Guide: https://amzn.to/3NVndlU
From Zero to Heat Pump Hero: https://amzn.to/4bWkPFb
Subscribe and follow our Homeowners’ Q&A heat pump podcast
@editor Yes my BG quote includes a buffer maybe as a thermostat or TRV was suggested downstairs (which I did not want had it been explained). I am questioning whether my BG man was an installer as he did not seem to be able to suggest, for instance, what I needed to provide for running the services under the path. He talked of piping but no mention of cables which are also rather necessary! I don't know if BG will produce a more detailed report after paying my deposit but anyway OE will not be surveying till 31st July. I wish I had started this process so much earlier as time is rushing by.
Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.
@jancold Just a thought, when you say the Octopus quote was half BG, what are we talking about here? Not £500 v £1000 I take it 🙂 If it was then of that order then the system designs would need to be scrutinised closely.
House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60
@bontwoody It is £2300 for OE (assuming they do not alter it in the survey) and £4200 for BG which was down from £5900 initially. As you say I have to wait for the OE Survey and detailed report.
However if the boiler flow temp reading was reasonably accurate: I ran it 24/7 for the last two winters at an indicated 40C and only on the coldest days it fell below 19C. I know the Kitchen /Diner rad and Bathroom towel rail is far too small and maybe I need a rad at the top landing (according to the MCS rule book).
Since no piping changes were suggested the only changes can be the radiator output/size? and the system setup. About which I need to learn to understand before I even think about fiddling with it.
Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.
@jancold To me its a no-brainer then, a max 40C flow temp should give you a very pleasing SCOP. You seem aware that a buffer tank isnt usually a good idea so its not a plus point for BG.
What I managed to do in my house to keep costs down was change the largest radiator I needed to and then shuffle the others down to the next smallest room so pretty much everywhere got an upgrade.
I used 15mm plastic pipe to feed the rads which made for a very easy install and they have a large enough diameter to allow 1.89 kW at DT5 at 0.9mps flow (versus 2.75 kW for 15mm copper pipe)
House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60
Octopus have now surveyed. He was very thorough and for instance felt the need to contact his electrical expert on a possible problem with my supply: thankfully all was good. All his measurements and photos are then passed to chair jockey designers so he suggested that if I am in disagreement with something to say no and make a counter proposal they want to please the customer.
I now await the detailed report but his heat loss was a lot higher than BG at 5.25 (BG 3.46) my heat punk result was 4.9 which agreed more closely. Also the radiator changes on the ground floor are closer to my Heatpunk predictions but as they require two new radiators they may want to charge me for them. So I guess it will be a 6kW Daikin.
They will also supply a larger towel rail though it has not got the required output. I may query this as I am not against a radiator and like a warm bathroom.
They will lay a gravel base for the Heatpump BG won't. I provide a trench for the pipework they do the rest. Surely If I made up an insulated pipe there could be problems with the warranty? BG made no mention of how to route the electrical supply or data cable.
I could have gone for the Cosy6 but he admitted it was not quite as efficient so I'm sticking with Daikin. It was suggested using the immersion in the summer and switch the heat pump off, that does not make sense to me.
Has anyone had a bathroom towel rail on the DHW circuit to dry towels all year round? Is this a bad idea?
I mentioned I would like a design temp of 45 and it was noted and, if necessary taken up with sales.
There will be a volumiser which he sometimes calls a buffer "to help with the defrost cycle" is this bull**It?
The property is about 2 meters above the road and he was concerned about lifting the heat monster up! I said I could rig a derrick (no not Derek M) or rent a Telehandler or platform surely that can be overcome fairly easily!
So now it is another wait...
Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.
@jancold The only reason i can think of to suggest using the immersion in summer would be to turn the heat pump off completely to avoid its standby losses, but I would be very surprised if they were large enough to make it profitable to do given the extra energy needed by the immersion.
Re the towel rail, do you mean just have the towel radiator heated when the DHW cycle is on, which would only be for an hour or two a day? The rest of the day it would be cold, so it doesnt seem like a good idea to me.
My understanding of a volumiser is to ensure that there is always enough volume of water in the system for the heat pumps minimum requirement to smooth out cycling and provide energy for defrosts. I dont have one as I know I have sufficient volume in my pipes and always open radiators
House-2 bed partial stone bungalow, 5kW Samsung Gen 6 ASHP (Self install)
6.9 kWp of PV
5kWh DC coupled battery
Blog: https://thegreeningofrosecottage.weebly.com/
Heatpump Stats: http://heatpumpmonitor.org/system/view?id=60
@jancold We have an ‘oversized’ radiator in the bathroom as we wanted an elevated temperature compared with MCS guidelines. We achieve the 25 - 26 degrees C. - our installers took note of my requirements on this matter. We also have a towel rail above the radiator; we have a ‘dual fuel’ fitting and use the immersion element in it during the summer (approx. 300 watt consumption per hour) I close one of the towel rail valves if we want to heat the rail to the higher temperature in the winter. The element heats the rail to a higher temperature than the ASHP circuit would. I close the valve so that I am not returning hotter water to the ASHP system than it would expect to see as this I feel, would cause confusion to the control circuitry. The electrical element is controlled via a Myenergi Eddi; we use the relay board and I programme that to give power to the rail for 3 hours in the evenings. Anything else I can tell you - please ask! Regards, Toodles.
Toodles, he heats his home with cold draughts and cooks his food with magnets.
- 22 Forums
- 2,054 Topics
- 44.8 K Posts
- 32 Online
- 3,287 Members
Join Us!
Trusted Installers
Struggling to find a reliable heat pump installer? A poor installation can lead to inefficiencies and high running costs. We now connect homeowners with top-rated installers who deliver quality work and excellent service.
✅ Verified, trusted & experienced installers
✅ Nationwide coverage expanding
✅ Special offers available
Latest Posts
-
RE: Battery sizing - How low can you go!
My own experience with connecting four batteries to thr...
By Transparent , 4 hours ago
-
RE: Yes, the "zoning with ASHP" topic again...
Hi James,Thanks again for your detailed thoughts. I app...
By HarryRea , 4 hours ago
-
RE: Plate heat exchanger considerations
Work on 2-3 percent per degree. This is a reasonable e...
By JamesPa , 14 hours ago
-
RE: Advice for ground source heat pump in new build with PV and batteries
The useful bit is the bit that specifies the heat loss ...
By JamesPa , 14 hours ago
-
RE: Volumisers in Heat Pump Systems: Does Placement Matter?
You’re absolutely right that during defrost the refrige...
By Mars , 16 hours ago
-
@editor thanks Mars that’s the same table I found in th...
By Gary , 21 hours ago
-
RE: Tariff and charging strategy advice please
They haven't asked me to prove that I have an EV (I do)...
By JamesPa , 1 day ago
-
RE: Solar Power Output – Let’s Compare Generation Figures
Took a while to find on the OFGEN site: ”The FIT sche...
By AgentGeorge , 1 day ago
-
RE: why solar diverters for HW instead of the heat pump?
For me there are few factors why you may want to heat w...
By Johnmo , 1 day ago
-
RE: Hydronic plinth heaters and ASHPs
@editor yes I think so. It will be a while until I get ...
By benson , 1 day ago
-
RE: Aira Heat Pump: Stylish Scandinavian Heating
I’m an Aira customer with a 6kW Outdoor Unit in a small...
By KevinPotts , 2 days ago
-
RE: Is your heat pump insured?
@richard24738 good to hear. I’ll also review them this ...
By Mars , 2 days ago
-
RE: Warm weather and heat pumps.
Just looked at my WC setting, it is programmed for 25 D...
By Johnmo , 2 days ago
-
RE: How to disable radiator heating in LG HM161MR
Just to add to above,when adjusting WC heat pump should...
By JamesPa , 2 days ago
-
@johnmo yes I can believe that. It seems to be human na...
By SUNandAIR , 2 days ago
-
RE: Help optimising my system!
I would be doing things a little more simply. Your heat...
By Johnmo , 2 days ago
-
RE: Renewables & Heat Pumps in the News
If you want to read a huge amount of speculation, fabri...
By Judith , 3 days ago
-
IVT Greenline high pressure switch and electrical cassette errors
I have an IVT Greenline HT Plus C heat pump that is con...
By tdudgeon , 3 days ago
-
RE: Additional Battery v Wind Turbine v Ripple
There was a call today for Ripple investors and amongst...
By Judith , 4 days ago