ASHP Cost

[iMCaan]

Hi

 

Re-considering ASHP for a self build house including UFH on two floors. How much would it cost to install a ASHP (5 residents, 3 wet rooms and UFH)?

Thanks

[HughF]

Got a heat loss calc yet?

[Dave Jones]

and ditch all those zones.

[Mr Punter]

Could scrap the UFH upstairs and just have towel radiators.  Once you know you heat losses and DHW requirements you can work out system sizes and costs.

[ProDave]

To "install" an ASHP broadly the same as installing a gas or oil system boiler, perhaps a little more if the installer has not done many so more reading of the installation manual needed.

 

Whether you can find a plumber and electrician to do that is another matter.

 

To have the whole lot supplied and installed as a package probably a lot more, but whatever you choose you will be having the same UFH the same bathrooms etc so are you just trying to compare the cost of a gas or oil boiler with the cost of an ASHP?

[JohnMo]

Start with heat loss calculation, that will give you your ball park ASHP size. Number and bathrooms will determine the cylinder size.

 

Once you know the cylinder size and heat loss, the rest will fall into place. 

 

But really you are comparing the actual cost of an ASHP and comparing to a boiler. Just every bit of plumbing will be the same, either way.

[iMCaan]

Thank you all.

 

Need to rethink the upstair UFH.

How do I calculate/get the heat loss calculation?

 

Thanks

[nod]

As Mr p has already stated I’d ditch the UFH for the first floor You will never need it 

 

I was speaking to a heat pump installer yesterday Who has been supplying and installing HPs for 22 years 

He stated that a gas boiler versus a HP in a well insulated house will be cheaper to run He also said that BG promising that bills will drop by £380 per year in a poorly insulated home is nonsense 

 

[JohnMo]

  On 12/09/2023 at 18:02, nod said:

stated that a gas boiler versus a HP in a well insulated house will be cheaper to run

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Which are you saying is cheaper gas or ASHP?

 

I have two years heating data on gas, will have an ASHP running this winter. So can tell you the real world comparison.

 

What you can't do with gas is use off peak energy. Now I have a battery, time of use tariff or even E7 make sense. You can batch charge the floor most of the heating season in the 7 hours, you take a slight hit in CoP, but the electric is half price and you only need to run the heat pump for 7 hours.

[nod]

I’ve had three quote All have said HPs are more expensive to run 

Pretty obvious really as electricity is far more expensive than gas 

The guy I spoke to wasn’t looking to sell me a HP But did point this out 

[ProDave]

Anyone who claims a heat pump is cheaper to run than a gas boiler is a brave man.

 

My view is an ASHP running with a COP of 3 and electricity at 3 times the cost per kWh of gas, the ASHP could equal the cost of heating with gas.  So for a property that does not have gas, it is a way to equal the heating costs if you had gas available.

 

An ASHP will be better for the environment eventually as more electricity is generated by renewable means.

 

Re the heat loss from the building.  How technical are you?  How much do you know about the building design and proposed insulation (if's all buried in the SAP report if you have the full report not just the summary)  Then have a look at this.

 

 

[iMCaan]

Thank you all.

 

I think it's better to put ASHP on future list along side solar panels.

 

Thanks

[George]

  On 12/09/2023 at 19:42, ProDave said:

Anyone who claims a heat pump is cheaper to run than a gas boiler is a brave man.

 

My view is an ASHP running with a COP of 3 and electricity at 3 times the cost per kWh of gas, the ASHP could equal the cost of heating with gas.  So for a property that does not have gas, it is a way to equal the heating costs if you had gas available.

 

An ASHP will be better for the environment eventually as more electricity is generated by renewable means.

 

Re the heat loss from the building.  How technical are you?  How much do you know about the building design and proposed insulation (if's all buried in the SAP report if you have the full report not just the summary)  Then have a look at this.

 

 

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CO2 per kWh delivered is already a lot lower for ASHP, thanks to the '200%' of energy coming from the ambient air.

 

Mains gas is probably cheaper for the next few years but that could change. In my calculations oil and LPG were more expensive, especially if you have solar panels/battery/smart tariffs. 

[JohnMo]

  On 12/09/2023 at 20:18, George said:

CO2 per kWh delivered is already a lot lower for ASHP, thanks to the '200%' of energy coming from the ambient air.

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Current energy mix for my post code

 

A modern A-rated gas boiler will emit 215 grams of CO2 per kWh of heat delivered.

 

So on face values pretty similar, except the SCoP of a heat pump should be over 4, so CO2 emmisions a 1/4 of gas.

 

[Lofty718]

Most gas boilers aren't running at 100% efficiency, more like 80%

[JohnMo]

  On 12/09/2023 at 21:36, Lofty718 said:

Most gas boilers aren't running at 100% efficiency, more like 80%

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Same is true for a lot of heat pump installs they are not 400% efficient, but get rid of zones, run on weather compensation, no reason they shouldn't run at over 100% efficiency for gas and 400%+ for a heat pump.

[Dave Jones]

the reality is a ASHP install is at least treble the cost of a combi, you have the hassle of tanks so you dont run out of hot water and the noise as silent they are not.

 

But if you can build airtight and reasonably well insulated so you can run at a low flow temp then your long term costs are comparable. If you cant run low flow temp it WILL cost you an absolute fortune to run hence the horror stories in the press.

 

 

[JohnMo]

  On 13/09/2023 at 07:01, Dave Jones said:

reality is a ASHP install is at least treble the cost of a combi, you have the hassle of tanks so you dont run out of hot water and the noise as silent they are not

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OP base case was gas system boiler and cylinder (although stated on another thread).

 

Granted the cost of a combi install would be cheaper. But it's a huge house, not sure a combi would be the best fit. So would be having a cylinder either way anyway 

[Happy Valley]

We have an ASHP which cost around £10000 to install including the hot water tank. £5000 came back in the form of govt grant. The house is new and fairly airtight. We didn't want gas as was uncertain as to it's long term future and the possibility of changing the boiler for a new hybrid one. Also gas boilers generally have a poor reliability record, are expensive to fix and rarely last more than 10 years in our experience.

 

We have no gas which means we save on the daily standing charge which in our area is £0.30 per day or £110 a year. 

[Bramco]

  On 12/09/2023 at 18:30, JohnMo said:

You can batch charge the floor most of the heating season in the 7 hours, you take a slight hit in CoP, but the electric is half price and you only need to run the heat pump for 7 hours.

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Agree - but except for really cold weather we only have to run the ASHP for up to 4 hours on the Octopus Go tariff which is a less than a third the price of the normal rate.

 

Simon

[HughF]

My current costs to upgrade a 40yr old back boiler system... Still got to buy some copper, and some electrical items. Probably another £500...

 

I'll probably use half those press fittings (I bought a job lot, I'll adjust the costs afterwards once I know what I used)

Edited September 13, 2023 by HughF

[Bramco]

  On 12/09/2023 at 20:50, JohnMo said:

Current energy mix for my post code

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What app is that? - the national grid one doesn't look like that.

[JohnMo]

  On 13/09/2023 at 09:32, Bramco said:

 

What app is that? - the national grid one doesn't look like that.

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It's linked to my Givenergy App for the battery. You do national average or by post code.

[Blooda]

You are where we were 4 years ago, thinking you need loads of zones.  We ended up with 5 downstairs. I am just going through the process of reducing the Zones from 5 to 2 for this winter.  [i don't like changing too much at once as SWMBO won't be too happy if I make a mistake, and can't rectify it.

 

You seriously need to rethink the number of zones.   

 

Each one of those zones will cost you at least £100 in build - When you take into account, Thermostat, Thermostatic actuator, cabling, commissioning. etc etc.

 

Ours is a similar sized house, maybe similar spec,  and the fact there arre not really any cold areas. We have UFH down stairs and Rad's upstairs. Rad's hardly come on and when they do not for long.  The only "cold" spot is the vaulted bedroom over the integral garage, and that's because it is too far way to benefit from the UFH down stairs.  It can run about 1 or 2 degree colder when it is freezing outside, but an hour on forcing the rad's on will sort it out for 24 hours [probably easier just to but a fan heater.

 

I am just going through the process of reducing the Zones from 5 to 2 fo

[Conor]

Our 315m² house is two zones. It would be one, but we keep the basement separate as it doesn't need cooling at all and very little heating in winter. We tweak room temps sby simply changing the flow rates in the loops.

Edited September 13, 2023 by Conor