Is it worth it?

[CotswoldDoItUpper]

We’re not on mains gas and have a 10yr old LPG combi boiler. 
 

It’s an old house with an EPC of 19(!) and a estimated energy usage for space heating of 34500kw per year. 
 

we are adding insulation where practical and changing light fittings to LED etc but want to investigate ASHP further. 

 

I guess we’d be looking at a 16kw unit and an approximate cost of £15-20k installed with RHI payments capped at £1300/yr for 7 years (£9100 in total).

 

it doesn’t seem worth it to me but I want to make the best decision possible. Am I missing something? Is it worth waiting 3-5years to see if the cost of the unit comes down?

 

please convince me either way!

[JamesP]

Not an expert but having but my own house with an EPC of A I would not recommend an ASHP in your property. The electricity cost would be substantial and not sure it would be able to provide you with adequate heating.

I would hang on to gas / lpg for as long as possible before being forced down the electric only route.

 

Edited July 26, 2021 by JamesP

[scottishjohn]

maybe you are starting from the wrong point

 you need to sort the insulation and draft problems first 

can you describe age + type of construction and size of house 

 get the free survey from the energy trust on your house before doing anything 

Edited July 26, 2021 by scottishjohn

[SteamyTea]

1 hour ago, CotswoldDoItUpper said:

It’s an old house with an EPC of 19(!) and a estimated energy usage for space heating of 34500kw per year. 

How big is the place (m²), how much DHW do you expect to use (litres/day), is it detached, semi, terrace, number of stories, is the loft converted to a habitable area? Does it use 34,500 kWh/year (~35 MWh/year) (kW is power, kWh is energy, kw is a nonsense unit, as is kwh, kW/h, KWH).

It may seem a bit snobby and pedantic mentioning the units, but apart from the odd type, if you get a quote that is incorrectly mixing SI units, consistently misquoting derived units, and the worse, mixing SI and Imperial units i.e. kWh/square foot, be very wary of the company.

Edited July 26, 2021 by SteamyTea

[CotswoldDoItUpper]

@SteamyTea

its a 1800s cottage of around 120sqm and a 1987 extension (cavity wall, tho think it’s only about 50mm) of around 100sqm 

Detached, all 2 stories. Loft not converted (yet!).

Double glazed all round, no idea on age of windows, think mid-90s.

no floor insulation, we’re installing that this week. 100mm between joists (not enough space to keep to have more and keep an air gap!) and 20mm above

 

agree with specific units being important. Was an oversight on my part! 

 

@scottishjohn I didn’t realise energy trust did free surveys. I’ll definitely arrange that! 

[SteamyTea]

That works out at ~18W/m², which does not seem excessively high for an old place.

(it is late and I may have made an error)

But it is still ~160 kWh/m².year.

 

A quick google shows this.

https://www.ovoenergy.com/guides/energy-guides/how-much-heating-energy-do-you-use.html

UK average seems to be about 133

Edited July 26, 2021 by SteamyTea

[IanR]

2 hours ago, CotswoldDoItUpper said:

It’s an old house with an EPC of 19(!) and a estimated energy usage for space heating of 34500kw per year. 

 

EPC's aren't necessarily all that accurate, is that 34,500 kWh space heating demand confirmed by how much LPG you purchase in a year? LPG boilers are up to 90% efficient, so that would be around 38,500 kWh worth of LPG annually, plus what ever your DHW demand is. Unless you also have  alternative heat sources, such as log burners, and then it will be difficult to calculate.

 

3 hours ago, CotswoldDoItUpper said:

I guess we’d be looking at a 16kw unit and an approximate cost of £15-20k installed 

 

Where did you get this figure from? and what does it include? Unvented cylinder, buffer, larger radiators and/or wet UFH? Hopefully that figure includes everything you need.

 

3 hours ago, CotswoldDoItUpper said:

with RHI payments capped at £1300/yr for 7 years (£9100 in total).

 

Is that the cap now? Even with low flow temp (35°C) heating emitters?

 

What ever heating system you go with, insulate as well as possible and make the property as airtight as possible. Ideally you'd plan for a low flow temp heating system, so if you don't go for an ASHP now, you won't be ripping it all out if you need to in 10 - 15 years. Low flow temp heating systems require ideally UFH with "good" insulation underneath and/or larger radiators plus a hot water cylinder.

 

2 hours ago, JamesP said:

The electricity cost would be substantial and not sure it would be able to provide you with adequate heating.

I would hang on to gas / lpg for as long as possible before being forced down the electric only route.

 

This I don't necessarily agree with this. I've never had LPG, but it looks like it's around 6.5p per kWh (45p/litre and 7kWh per litre). At 90% efficiency, that costing 7.2p/kWh

 

With electricity at 12.5p/kWh, you've only got to get a COP of 2 and an ASHP is cheaper to run. You'll be far better than a COP of 2, you could probably get to a COP of between 3.5 to 4 for an average throughout the year.

 

The lower you can get the flow temp, the more efficient the ASHP will be. Large heat emitters and large hot water cylinder means lower flow temp.

How much insulation can you get under your floor? Are you considering wet UFH?

 

Are you planning any significant renovation, or are you trying to improve insulation with minimum disruption?

[MikeSharp01]

10 hours ago, CotswoldDoItUpper said:

it doesn’t seem worth it to me but I want to make the best decision possible.

This is the big conundrum - basically in terms of cost it won't be worth it. It only becomes worth it when you factor in the cost / value balance to the planet by seeing your 'best decision possible' in that light. Sadly the general feeling that the planet can be 'saved' without cost to individuals has to be a misnomer and so we are all, the generations alive today anyway, going to have to 'pay' to sort this out and waiting for HMG to find a plan that makes the costs go away is like waiting for a unicorn to be born in Trafalgar square - there is not even a stable let alone a breeding pair!

 

If you do a 'full cost' analysis you may well find that the RHI payments, which you / me / all of us are paying for through our taxes, and lower running cost might cover the differential cost between installing a new boiler and sticking with LPG - which won't get any cheaper in the medium / long term.

[Dave Jones]

10 hours ago, CotswoldDoItUpper said:

We’re not on mains gas and have a 10yr old LPG combi boiler. 
 

It’s an old house with an EPC of 19(!) and a estimated energy usage for space heating of 34500kw per year. 
 

we are adding insulation where practical and changing light fittings to LED etc but want to investigate ASHP further. 

 

I guess we’d be looking at a 16kw unit and an approximate cost of £15-20k installed with RHI payments capped at £1300/yr for 7 years (£9100 in total).

 

it doesn’t seem worth it to me but I want to make the best decision possible. Am I missing something? Is it worth waiting 3-5years to see if the cost of the unit comes down?

 

please convince me either way!

 

get a quote for mains gas. Anything upto the cost of the heat pump id pay to have cheap limitless hot water and heat.

[JamesP]

8 hours ago, IanR said:

With electricity at 12.5p/kWh, you've only got to get a COP of 2 and an ASHP is cheaper to run. You'll be far better than a COP of 2, you could probably get to a COP of between 3.5 to 4 for an average throughout the year.

Please let me know where I can find a supplier for 12.5p/kWh. 

I have just changed supplier to find the rate of 18.97p/kWh who have just announced an increase of 11.7% on the 2nd August.

The Government is looking at delaying the ban on gas boilers to 2040 due to soaring "net zero" cost.

[CotswoldDoItUpper]

@IanR the EPC was done when we bought the house about 2 months ago.
Cost includes a pre plumed UVC, the unit itself and Installation, nothing else. Couple of quotes online to give me a rough idea.

RHI cap from the gvt website, no mention of low temp emitters. We are instilling wet UFH downstairs and will do larger rads upstairs.

we can get 100mm PIR between the joists and 20mm on top. Couple of places we can go to 150mm between, but only basically in the hall!

thanks for those calculations. Good to give some objective data to it!

We’re doing something between significant and minimum disruption. The floors are all coming up, and I’m getting the cavity filled and more mineral wool in the loft. Then it’s kitchens, bathrooms, paint etc.

 

@MikeSharp01 this is the conundrum. We do want to make a good decision, but the cost may be prohibitive. 
 

@Dave Jones nearest gas main is about 3 miles away…. Probably not worth it!

@JamesP we’ve just switched to a ‘cheep’ 14.8p/kWh package. Previous was 11.5p!! Agh!

 

[IanR]

12 minutes ago, JamesP said:

Please let me know where I can find a supplier for 12.5p/kWh. 

 

I've just moved from Symbio to PFP Energy, both are charging 12.5p / kWh. Symbio are terrible though, hence my move.

 

13 minutes ago, JamesP said:

The Government is looking at delaying the ban on gas boilers to 2040 due to soaring "net zero" cost.

 

Have you got a link? the devil's in the detail. Currently announced was that new builds would be net-zero-carbon from 2025. There hadn't been an announcement (to my knowledge) on how they were going to encourage existing housing stock to more away from fossil fuels, only that EPC requirements were going to be ramped-up from 2028 - 2035.

[IanR]

26 minutes ago, CotswoldDoItUpper said:

@IanR the EPC was done when we bought the house about 2 months ago.

 

You'd be better off going by how much LPG the previous owner purchased per year, or paying for someone to do some detailed heat loss calcs. My experience of the EPC's created for house sales are they are a tick box exercise with lots of assumptions, so *could* be wildly out.

 

26 minutes ago, CotswoldDoItUpper said:

Cost includes a pre plumed UVC, the unit itself and Installation, nothing else. Couple of quotes online to give me a rough idea.

 

You should be able to get far cheaper.

 

26 minutes ago, CotswoldDoItUpper said:

We are instilling wet UFH downstairs and will do larger rads upstairs.

we can get 100mm PIR between the joists and 20mm on top. Couple of places we can go to 150mm between, but only basically in the hall!

 

That gets you to a level where the losses won't be too high on the UFH, and if you've already "booked" this cost, I feel the pendulum has swung in favour of going with an ASHP.

 

The job now is to reduce heat losses to permit a smaller ASHP and reduce the install cost further, and that looks like it is already in your plans.

 

Edited to add:

You need your new ASHP heating system commissioned by 31.03.2022 as RHI is finishing.

It does sound like there will be something to replace it, but no details yet.

Edited July 27, 2021 by IanR

[SimonD]

25 minutes ago, CotswoldDoItUpper said:

will do larger rads upstairs

 

Just make sure that these larger rads get sized to the correct Delta T for your future heating system. It's now quite common for manufacturers to provide output data for low temp systems, at 40 & 30 Delta T. If you are planning ASHP at some time in the future, then for efficiency you could need radiators up to double the size and you need to design the heating system according to different flow rates more suitable for the heat pump. There's lots to do to make it work that mostly isn't communicated by installers looking to sell a unit with water tank.

 

Even if you insulate, make sure you take all the necessary airtightness steps - a leaky well insulated house just isn't worth the effort or cost.

 

One thing you can do is design your heating system for a heat pump but buy a low temperatue boiler to use until heat pump prices come down.

 

Predicting how things are going to go in the near term re net-zero heating is nigh on impossible as the government seem to have no proper plan in place to make it happen, nor have they even begun to cost it all out and budget for it.

 

The most important thing I'd like to suggest is that you live in the house for a year before settling on your decision. This will give you the chance to get rid of draughts and sort airtightness, then insulate. You'll then have a much better feel and knowledge of house the house behaves (and costs), making it easier to come to a well informed decision. By then there might even be a new government grant scheme in place. Who knows.

[MikeSharp01]

18 minutes ago, SimonD said:

as the government seem to have no proper plan in place to make it happen, nor have they even begun to cost it all out and budget for it.

No plan - no costing - no budget - no idea(s) - no good.

[IanR]

 

Quote

as the government seem to have no proper plan in place to make it happen, nor have they even begun to cost it all out and budget for it.

9 minutes ago, MikeSharp01 said:

No plan - no costing - no budget - no idea(s) - no good.

 

 

There is the start of a plan, with the high level investment identified

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/945899/201216_BEIS_EWP_Command_Paper_Accessible.pdf

 

And give them their dues, they're already delivering on the actions stated as required for 2021.

[fiaraziqbal]

12 hours ago, SteamyTea said:

How big is the place (m²), how much DHW do you expect to use (litres/day), is it detached, semi, terrace, number of stories, is the loft converted to a habitable area? Does it use 34,500 kWh/year (~35 MWh/year) (kW is power, kWh is energy, kw is a nonsense unit, as is kwh, kW/h, KWH).

It may seem a bit snobby and pedantic mentioning the units, but apart from the odd type, if you get a quote that is incorrectly mixing SI units, consistently misquoting derived units, and the worse, mixing SI and Imperial units i.e. kWh/square foot, be very wary of the company.

As a physics teacher i cannot tolerate incorrect useof units!

[SteamyTea]

3 minutes ago, fiaraziqbal said:

As a physics teacher i cannot tolerate incorrect useof units!

I can forgive students at first, why they came to my lectures.

By showing how the units are derived explains so much.

But when it comes to energy (heat in old money), we should really use joules, it makes so much more sense.

[JamesP]

2 hours ago, IanR said:

 

I've just moved from Symbio to PFP Energy, both are charging 12.5p / kWh. Symbio are terrible though, hence my move.

Have you got a link? the devil's in the detail. Currently announced was that new builds would be net-zero-carbon from 2025. There hadn't been an announcement (to my knowledge) on how they were going to encourage existing housing stock to more away from fossil fuels, only that EPC requirements were going to be ramped-up from 2028 - 2035.

Thanks Ian, lowest rate from PFP  is 16.84p and that's a variable summer rate. Fixed is 20.25p. Do prices  fluctuate that much across the country from the same supplier?

No detail, just current news reports which you are right to be sceptical of.

 

[IanR]

7 minutes ago, JamesP said:

Thanks Ian, lowest rate from PFP  is 16.84p and that's a variable summer rate. Fixed is 20.25p. Do prices  fluctuate that much across the country from the same supplier?

 

They must offer different prices across the county. Here's my current deal with PFP, it is variable, and they're offering a 12 month fixed for a few tenths more. I'm thinking it's probably wise to take the fixed deal.

 

Edited July 27, 2021 by IanR

[JamesP]

3 hours ago, CotswoldDoItUpper said:

we’ve just switched to a ‘cheep’ 14.8p/kWh package. Previous was 11.5p!! Agh!

As noted above it does depend on your location, even from the same supplier the price varies by 30%+.

 

[CotswoldDoItUpper]

2 hours ago, JamesP said:

As noted above it does depend on your location, even from the same supplier the price varies by 30%+.

 

Which is crazy! It means that some people have higher incentives to switch to green energy then others, based on profit rather then necessity or impact.
 

Also feels like we’re being taken advantage of because of no Nat gas supply we’re limited to electricity or oil/lpg tanks. 

 

Our neighbours have a 15yr old 5kwh PV set up which they are ambivalent about. Think they get paid 45p/kWh too. 
 

@IanR this is one of the reasons for waiting. Will the RHI replacement be better/worse then current support? It’s a bit of a gamble. Also, I do feel prices are inflated a bit due to the fact that installers know their clients are getting a bit of cash for it.

[IanR]

 

6 minutes ago, CotswoldDoItUpper said:

 

@IanR this is one of the reasons for waiting. Will the RHI replacement be better/worse then current support? It’s a bit of a gamble. Also, I do feel prices are inflated a bit due to the fact that installers know their clients are getting a bit of cash for it.

 

RHI definitely puts a premium on the prices. Some of it is justified due to the MSC process requiring additional steps from the installers, some of it not.

 

I can only see the grant going one way, so assume what replaces RHI will not be as "generous". The government will tackle new builds first and can do that mostly with stick (legislation) rather than carrot.

For the existing housing stock - rentals and social housing will be first and again they can do this mostly with legislation. It's only when they get to owner-occupied that the encouragement of grants will be required and by then perhaps prices will have dropped a little for heat pumps and increased a little for fossil fuels, so the gap is much reduced that the grant needs to cover.

[SimonD]

7 hours ago, IanR said:

 

 

There is the start of a plan, with the high level investment identified

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/945899/201216_BEIS_EWP_Command_Paper_Accessible.pdf

 

And give them their dues, they're already delivering on the actions stated as required for 2021.

 

I simply do not know where to begin commenting on that white paper. Just looking at the number of caveats and get out clauses, not to mention the rowing back on certain proposals, GHG which died as a farse, then the promise of banning gas boilers in new houses has been rewritten to a promise to 'consult' on the idea. Almost every substantive proposal has something like, if cost effective and practical, or if parliament has the time. Oh and then there's a very comprehensive promise to maintain expenditure, maintenance and development of the gas network to transport gas. The investment cited is a piffle compared to what is really going to be required, but the excuse in the white paper is that the cost will essentially be pushed to the private sector and public, all smoothed over with a platitude that their role in promoting competition will reduce cost. There is no significant investment here by the government.

 

There are some glimmers of sense mixed in the waffle, like they recognise the power distribution networks will need to be significantly modified in light of renewables, but only a minor note that policy and network costs form a significant proportion of cost to customers and that this cost is going to rise. Not much mention of changing network policy to actually further promote transition of energy, something that is holding things back right now and which favours the old boys of fossil fuels.

 

And when it comes to housing, we're still years behind where we perhaps could have been if the government hadn't decided to scrap the zero carbon homes policy that was due to come into force in 2016.

 

At least they're honest in saying they have no idea where things will be and that they are relying heavily on technology that doesn't exist yet, or that has yet to be developed at sufficient scale, which means massive risk.

 

All I can find myself able to give them dues for is publishing a white paper that does seem to acknowledge they're aware they might actually need to do something.?

 

Okay, taking a deep breath, rant over ?

 

 

[CotswoldDoItUpper]

Ok so it’s looking like ASHP is going to be the way forward. The only thing now is timing.

I guess that prices will keep falling over the winter and the cheapest time to install will be jan/feb next year. Just before the RHI runs out. 
 

Has anyone heard of an mcs installer that can ‘sign off’ a Diy installed system to get the RHI payments? It doesn’t seem to be overly complicated, just time consuming, to run and lag the required pipes? Am I missing something again?