Hi All.

I am looking to have a heat pump and 250l cylinder installed in Somerset. I have had 2 heat loss calculations and two quotes. Both come to over 12k for a 4/5kw heat pump and cylinder system. The flow and return pipework is already in. UFH and manifold on the ground floor. I don't know how they can justify that cost but unless I can find an alternative I am going to have to go with it. I have already had the BUS voucher (which has expired but I am eligible). I have wasted 6 weeks while my useless plumber goes back and forth with the plumb centre and they are quoting to install a pre plumbed cylinder with a buffer tank. I absolutely don't want/need a buffer tank or zoning. I have had to take out a bridging loan to complete the build so every month wasted is costing a fortune so I am looking at all options, one of which is forgetting the BUS grant/MCS and just getting someone to get on with it, hence my question here. I am all ears if anyone can recommend an alternative course of action.

The heat loss for the house is 3.2 - 3.4kw. MVHR is installed. It is a 3 bed detached new build with UFH on each floor (the first floor is yet to be done but I have a design and think I will get the builder to do this.)

4kW Hiaer heat pump £2050 incl VAT from Wolseley (you may need to buy an indoor unit also now). You will 2x anti freeze valves an isolated valve and couple of flex hoses. Install direct to UFH manifold.

Buy a direct cylinder and just heat via immersion about £500. Any plumber can install your cylinder.

About £3k for parts plus labour to install.

Edited Wednesday at 18:253 days by JohnMo

Not directly relevant or anything to do with us, but just to introduce Otter South West

When we moved here (South Somerset) in Oct '25 we inherited a Daikin ASHP which we decided we'd like serviced and they are one of the local approved co's...

But the point I wanted to make was that the guy Chris who came was professional, extremely knowledgeable, helpful and did a great job for us well beyond a service. If you need someone like that then you could ask them if they could help...

If I do some form of DIY install is there any issue with getting building regs sign off for a new build? That was my plumbers excuse. Is the BCO going to demand an MCS cert?

1 hour ago, jimseng said:

If I do some form of DIY install is there any issue with getting building regs sign off for a new build? That was my plumbers excuse. Is the BCO going to demand an MCS cert?

No issue if you comply with building regs! For a heating system you'll likely need a part P spark to sign off electrical work or ask and pay for BC to inspect it. If you're installing an unvented cylinder you'll need that signing off by a qualified plumber. No MCS cert needed but it would likely be accepted by BC as evidence of compliance with regs

Whether you can get tradesmen to sign off work they haven't done is a different matter!! BC are obligated to inspect electrical work that you've done but I don't know about pressurised cylinders.

Edited Thursday at 07:303 days by Dillsue

You may may need an MCS noise certificate, but zero reason not to do that yourself, MCS provide all the guidance. But don't provide it not specifically asked.

What does you planning permission actually ask for?

9 hours ago, JohnMo said:

What does you planning permission actually ask for?

I don't think there is anything particular in the planning consent, just a heat pump location specified by the architects and to be installed "by specialists".
I have seen the kit list from City Plumbing now and they have specified a 6.5Kw heat pump which is too big for my house. I don't think they took into consideration the MVHR. It seems to me the MCS/Heat pump industry is a mess and it is no wonder people who aren't paying attention end up with poor performing systems.

So nothing stating MCS, position of heat pump is defined by agreed plans, so that's not moveable.

So not many variables left except size of heat pump, which isn't stated on plans.

As mentioned above Panasonic are good, a small version of that would be fine. But you don't need a lot of the bits they will want to sell you.

Feet, flex hoses, isolation valves and anti freeze valves. I would really consider a direct cylinder. Especially if going for PV and/or battery, so you can make good use of ToU tariffs.

Edited Thursday at 17:542 days by JohnMo

On 22/10/2026 at 18:53, JohnMo said:

I would really consider a direct cylinder

Why is this? The heat pump can heat hot water at at least 150% can it not? I do intend to use TOU and I have a quote for a great economy 7 rate and 32kwh of battery storage so I am hoping to make the system cheap to run. But I also intend to use the immersion element when it is expedient to do so.
What is the advantage of a direct cylinder vs a typical UVC?

An UVC can be direct or indirect, so immersion or cylinder coil.

A heat pump cylinder can deliver reported CoP of about 5 (Heat Geek Cylinder), we got a reported 3.6 most the time from our normal ASHP cylinder. But when you start to compare the actual electricity input, yes the immersion does consume more but surprisingly not a lot more. We were heating the cylinder twice per day and using about 2kWh per heat (4kWh a day on average), getting a CoP of 3 to 4.

Doing it directly via immersion. I was doubtful so did a one test, dismissed it, then a month or so later did a longer test over about 4 day and then left it like that as I wasn't seeing much change in energy usage. The immersion is set to run twice per day it does one heat that takes an hour and other time the immersion comes on for 10 mins a couple of times over 3 hours. So I am using about 4kWhs, somes 5kWh. So really not that much difference in reality

On E7 you have a 7 hour spell to heat your water and ideally heat the house, yes you can use the battery but most of the year you can heat the house in the 7 hours. But you will struggle to heat house and heat DHW in the same window with the heat pump. Doing one DHW per day on a small heat pump can take 1.5hrs and that is 1.5hrs less time for heating.

Cost, a direct UVC cylinder is £5-600, it can be way smaller than a heat pump cylinder also. A basic heat pump cylinder is £1500 and heat geek ones start at £2500. That cost difference alone buys a lot of E7 electric.

If you are a heavy hot water user (especially if that means you need to heat the water during expensive electricity hours) then heat pump will heating will likely win. But if, as John is, you are able to heat the water overnight (and potentially use solar to heat the water during the summer) then the install would be significantly simpler and cheaper using direct heating.

This all assumes you are not getting the heatpump grant. If you want that you have no choice, you have to have the heatpump heat your water.

7 minutes ago, -rick- said:

This all assumes you are not getting the heatpump grant. If you want that you have no choice, you have to have the heatpump heat your water.

Not really - design wise and plumbing wise the heat pump has to be capable of heating the water - but, of course, once installed, you can set the heat pump to heating only. We do this.

1 minute ago, Bramco said:

Not really - design wise and plumbing wise the heat pump has to be capable of heating the water - but, of course, once installed, you can set the heat pump to heating only. We do this.

Sure, but if you do that you've still paid for the heat pump cylinder and all the valves/plumbing involved.

You are not saving on installation this route.

On 22/10/2026 at 18:53, JohnMo said:

As mentioned above Panasonic are good, a small version of that would be fine. But you don't need a lot of the bits they will want to sell you.

Feet, flex hoses, isolation valves and anti freeze valves. I would really consider a direct cylinder. Especially if going for PV and/or battery, so you can make good use of ToU tariffs.

If using a Panasonic, you don't need flexis and you don't need the feet, just bolt down to a slab, but feet are okay if you haven't got choice, or they sell a metal stand up frame. But also and more importantly, don't narrow down your choices on the DHW cylinder. Also, the Panasonic system by default use the DHW for defrost, although you can switch it to use the CH circuit, but DHW cylinder is a good way to deal with it.

40 minutes ago, JohnMo said:

A basic heat pump cylinder is £1500 and heat geek ones start at £2500. That cost difference alone buys a lot of E7 electric.

Heat pump cylinders from Gledhill have gone down a lot and ex. VAT are around £800 for a good family sized cylinder. For the sake of a few hundred, it's just not worth it long term with a direct. If you ever want to change, you're then talking either a new heat pump cylinder or a plate load kit and you've lost a lot of money compared to just going for an indirect cylinder to being with.

On 22/10/2026 at 06:27, jimseng said:

If I do some form of DIY install is there any issue with getting building regs sign off for a new build? That was my plumbers excuse. Is the BCO going to demand an MCS cert?

Heat pump installations do require building regulations approval, which like with all things you can pay for through your BCO, or use an installer who's registered with a competent person scheme to do this.

On 21/10/2026 at 18:20, jimseng said:

Both come to over 12k for a 4/5kw heat pump and cylinder system.

Is that over 12k after the grant or before it? And what heat pump and cylinder did they specify. And then what control system?

5 minutes ago, -rick- said:

Sure, but if you do that you've still paid for the heat pump cylinder and all the valves/plumbing involved.

You are not saving on installation this route.

See above, a 3-port diverter for your cylinder is about £100 and then you just need flow and return pipework to the cylinder, D2 and a sensor back to the heat pump.

I don't think a direct cylinder is even a sensible option. Does the OP have family? What's the likely DHW use. For example, we're a family of 4 and have dhw on continuous top up, no schedule through the heat pump. Our dhw cost us a mere £129 for the last year using our average electricity cost, or it would be £220 if using our expensive rate of 30p/kWh

I had some more thoughts but something else is distracting me now so forgot......

1 hour ago, SimonD said:

you don't need flexis and you don't need the feet, just bolt down to a slab, but feet are okay if you haven't got choice, or they sell a metal stand up frame.

Just need to make sure you have suitable snow clearance, same with most modern heat pumps, feet are an easy way to get that. Mine are hard plastic about £16 each. Flexible hoses aren't really needed at all now, but is nice insurance that you aren't going to get any vibration driven noise going into the house. Maybe not an issue when a heat pump is shinning and new, but you never know in 10 years time.

2 hours ago, SimonD said:

Heat pump installations do require building regulations approval, which like with all things you can pay for through your BCO, or use an installer who's registered with a competent person scheme to do this.

I think the OPs is a new build so building regs should already be approved??

I took it that the OP was asking if he could do the install himself, which I'm sure he can with a spark signing off the mains wiring....not necessarily ELV/control though.

1 hour ago, JohnMo said:

Just need to make sure you have suitable snow clearance, same with most modern heat pumps, feet are an easy way to get that. Mine are hard plastic about £16 each. Flexible hoses aren't really needed at all now, but is nice insurance that you aren't going to get any vibration driven noise going into the house. Maybe not an issue when a heat pump is shinning and new, but you never know in 10 years time.

So just to be clear here, I was specifically referring the the Panasonic installation requirements as you mentioned Panasonic in your post. Other heat pump manufacturers will have different requirements which may stipulate the necessary use of rubber vibration isolating feet and the use of flexis. For example, I wouldn't even dream of installing a Grant heat pump without rubber feet and flexis due to unit vibration - the Panasonics are in a completely different league here.

52 minutes ago, Dillsue said:

I think the OPs is a new build so building regs should already be approved??

I took it that the OP was asking if he could do the install himself, which I'm sure he can with a spark signing off the mains wiring....not necessarily ELV/control though.

Installing a heat pump is notifiable work.

So this is a new build. When I say do the work myself, it isn't something I would take on but employ a plumber. My plumber suggested we could do the install under the (what I have now discovered is called) umbrella scheme. However the plumber went to city plumbing and after waiting for 6 weeks I have seen a quote that includes a 6.5kw heat pump, which is too big. So I have no faith in the plumber or city plumbing and I am struggling to just get on with this. I have been quoted 12.k for a system from Installio before the BUS granthas been deducted, which leaves me with a 4.5k bill, which seems like a lot for such a simple job. The flow and return pipes are already in place and I don't need anything sophisticated in terms of control. I can't believe how much incompetence there seems to be in the industry, or am I being unfair? I am at a loss as to how to get this done, wither through the BUS route or via the Umbrella scheme.