British Gas versus Octopus: Two possible heat pump routes - how to evaluate them?
Posted by: @jancold@broadsman Unfortunately this does not seem to have trickled down to the surveyor who still added one to my quote even though I mentioned I did not want one.
But do you have room thermostats? You can only delete the buffer if you ditch the room thermostats and most TRVs (keep bedrooms only) as well.
@broadsman I think there may be a few old buffers on the board…
Toodles.
Toodles, he heats his home with cold draughts and cooks his food with magnets.
@johnmo Ah yes he did say something about a TRV downstairs not a room thermostat but why would I need that? I want the most economic system controlled by the heatpump and WC don't I?
Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.
Posted by: @jancoldTRV downstairs not a room thermostat but why would I need that? I want the most economic system controlled by the heatpump and WC don't I?
You do.
Are your bedrooms downstairs? TRVs will strangle flow just as easily as a zone valve. If your normal living space needs TRVs your flow temp is too high and the TRVs could easily close of big bits of the circuit and flow. You only have them in bedrooms to act as a limit stop - to stop bedrooms getting too warm.
State you want a fully open system in all living spaces, TRVs only in bedrooms and no buffer.
@johnmo Thanks , bedrooms upstairs. A fully open system is what I want, I must specify that to Octopus surveyor.
Daikin 6Kw ASHP.
MG4 EV
1926 Semi with loft and wall cavity insulation, all radiator.
Posted by: @jancold@johnmo Thanks , bedrooms upstairs. A fully open system is what I want, I must specify that to Octopus surveyor.
The only time that you may wish to have a TRV in the living area is in a room or rooms that suffer from high solar gain. While in an open system, the temperature in each room would be set by adjustment of the lockshield valves, because the effect of solar gain is not consistent it is quite possible that the temperature in certain rooms may increase on cold, but sunny, days. This can unbalance the temperatures around your home which you may not find desirable.
If a TRV was installed in such a room, it should be set as a temperature limiter so that during normal system operation the TRV is fully open so does not limit overall flow rates.
OK! An update from 🐙 I'd be very interested in your opinions please.
They are now proposing a Daikin 6kw but were going to leave everything else the same.
My response - I agreed that it was a borderline HP size case but emphasised that my focus was on running costs and efficiency as well as heating output.
I pushed back on design flow temp and made a formal request for 45º noting that Octopus has designed this way for other clients.
I also pushed back on the hallway design heating temp of 18º pointing out it was a CIBSE box tick but my hallway is a square central room that is used for multiple reasons including kids play area and yoga.
I did the same for my bedroom office and noted it was a workspace and needed to be designed to be warmer.
Sales first tried saying 'turn the heating up' [🤦🏻♀️] and then asked what I thought it needed. My response: higher design room temp & rad upgrade.
I thus requested 2 x rad upgrades - hall & bedroom/office.
I am supplying and fitting the bathroom radiator.
Dunno about the 4kw v 6 kw bit - and I made that clear in my response.
What do you all think?
They are, in theory, coming back to me on this later today after meeting with the installations 'big boss'.
@lucia Sounds to me as though you have made great progress (and I suspect, Octopus staff have learnt a few things about customer’s want and needs and heeding them!). Did you manage to get them to design out a LLH or buffer tank? Though I could not employ Octopus to install my system (as relayed ad nauseam elsewhere), I still think they will install a good system at a good price - and at least they are a company that listen and have the resources behind them to rectify any problems. Regards, Toodles.
Toodles, he heats his home with cold draughts and cooks his food with magnets.
Posted by: @toodles@lucia Sounds to me as though you have made great progress (and I suspect, Octopus staff have learnt a few things about customer’s want and needs and heeding them!). Did you manage to get them to design out a LLH or buffer tank? Though I could not employ Octopus to install my system (as relayed ad nauseam elsewhere), I still think they will install a good system at a good price - and at least they are a company that listen and have the resources behind them to rectify any problems. Regards, Toodles.
Quite agree, @toodles.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
Posted by: @toodles@lucia Sounds to me as though you have made great progress (and I suspect, Octopus staff have learnt a few things about customer’s want and needs and heeding them!). Did you manage to get them to design out a LLH or buffer tank? Though I could not employ Octopus to install my system (as relayed ad nauseam elsewhere), I still think they will install a good system at a good price - and at least they are a company that listen and have the resources behind them to rectify any problems. Regards, Toodles.
I agree @toodles that for me with limited resources they are the best deal - plus I really liked the lead installer (who may not be my installer -dunno yet).
But I don't know if I have made great progress ... that's the problem. 6kw is the result BG came up with if designing for no cavity wall insulation.
4kw was borderline for Octopus.
My question - brain knot - is am I better going 4KW with more /bigger rads or 6kw with more/bigger rads (hall/bedroom as identified by me above)?
I need to keep running costs as low as possible without getting cold. 🤔
It hasn't got a buffer it has a volumiser and I'm not pushing back on that.
I don't want the short cycling probs of a too big heat pump but I don't want a too small one working flat out when it's cold or wet.
-
Vaillant arotherm plus heat pump frost protection
4 months ago
-
Daikin Octopus installation update - I saw my first defrost. 😍😂
4 months ago
-
Daikin Error Code 7H05
6 months ago
-
Vaillant aroTHERM plus not level or flat - what base is best under an external unit?
6 months ago
-
Vaillant Arotherm monobloc error f.788 - ASHP is not working!
7 months ago
- 22 Forums
- 2,073 Topics
- 45.5 K Posts
- 41 Online
- 3,354 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: Solar Power Output – Let’s Compare Generation Figures
510kWh of solar PV from my 4kW Hyundai panels and SMA S...
By JulianC , 14 hours ago
-
RE: Is my Samsung heat pump working too well?
Thats in itself is interesting. I have a Vaillant heat...
By JamesPa , 15 hours ago
-
RE: Jokes and fun posts about heat pumps and renewables
@transparent Not a swell season then ☹️
By Toodles , 18 hours ago
-
RE: 5 Star Service from Havenwise
Oh good! I was wondering when/if you might pick them ...
By Transparent , 2 days ago
-
RE: Air Changes per Hour - ACH and the MCS requirement
update - my old installer insisted on a heat loss of 11...
By MatWin , 2 days ago
-
I agree it's not very helpful. Generally, the max heat ...
By Old_Scientist , 2 days ago
-
RE: Commencing on an ASHP Installation Process
I think therein lies the problem. Ratio of quotes to i...
By JamesPa , 3 days ago
-
RE: Why Your MCS-Certified Installer Might Not Be As Competent As You Think
Hive and most other smart thermostats don't play well w...
By JamesPa , 3 days ago
-
RE: Enabling WiFi: Samsung ASHP on Smart Things App
Thanks for the input. I've been running various experim...
By Grahamh-uk , 3 days ago
-
RE: Radiators downstairs are cooler at the bottom after ASHP install
@melonbuffet Hi, this sounds great is you are getting 5...
By ASHP-BOBBA , 3 days ago
-
RE: Ripped Off: How UK Homeowners Are Paying Gas Prices for Wind Energy
I believe there's another reason that network upgrades ...
By Transparent , 4 days ago
-
RE: What’s the modern take on advised types of insulation?
@jeff I am sorry @jeff if I have misunderstood what you...
By Toodles , 4 days ago
-
RE: Getting the best out of a heat pump - is Homely a possible answer?
@editor Cobbler’s Mantra that!
By Toodles , 4 days ago
-
RE: Renewables & Heat Pumps in the News
Australia Blue, the first wind farm in Western Victoria...
By Morgan , 5 days ago
-
RE: Flow rate discrepancy between ASHP and manifold
That's useful thanks, I hadn't seen that table before. ...
By AshRolls , 5 days ago
-
In principle I agree, @johnmo, but with provisos. The...
By Majordennisbloodnok , 6 days ago
-
RE: Heat pump installation and BUS Grant timings
@jamespa Thats how I understood it too. 🙂
By ASHP-BOBBA , 6 days ago
-
RE: Antifreeze top up for my heat pump - is this a rip off?
@sallyl That sounds about right if they are re-filling ...
By Brendon Uys , 6 days ago
-
I wouldn't be so sure about that. Heat pump designers ...
By JamesPa , 7 days ago