Ground Source Heat Pump + Underfloor Heating + Solar Panels

01.matthew

Hi,

We're moving into our first home, which is an old stone property built in 1909. I'm keen on the environment, and want to make the property carbon neutral as possible, whilst being reasonably cost effect.

Property:

- 4 bed, detached, 181 square metres
- Current E on EPC, which has noted room in roof insulation, internal or external wall insulation (which I need to check as some of the solid stone wall houses retain heat better), floor insulation in suspended floor, replace boiler with condensing boiler, solar panels
- Usage: 36714 kWh per yer for space heating, 2337kWh for water heating

My aim is to put in underfloor heating, especially as it works well efficiency wise in the older buildings. I initially thought to just replace the boiler with the most efficient one I could find (which is looking around £3K), but that doesn't necessarily help with the green credentials. So I'm now wondering if a ground source heat pump would be a possible option (I'm not sure yet whether we have enough of a garden for a horizontal one), as inputting these values on the RHI calculator shows a total payment of £28,700? I'm seeing that most information online says GSHP installation could cost upto £20K, so I could potentially do that, and add in some solar panels (I've seen reasonable kits with a battery for around £8K), and effectively this would all be covered by the RHI in the long term?

I understand that the GSHP is technically more expensive than gas, but with the solar panels added on top, and using a variable tariff to store electricity overnight (assuming we don't get everything needed from the panels), has anyone any idea or experience whether this would work out? The property is Bradford, West Yorkshire. 

As a side note, I'm also thinking of a rain water collection system for the toilets/washer/garden hose if anyone has any info and experience on that as well

hollie.weimeraner

I think google is your friend for a lot of what you're asking.  Underfloor heating - there are 2 types either usually installed with the house build which is a water system embedded in the floor or electric which is easier to install post build.  Not sure about the running costs of electric underfloor heating.  Solar panels were a great investment but less so now that the FIT has been removed. The solar system I have saves me about £20  a month over 12 months and with FIT has just about paid for itself in 5 years.  Without FIT I wouldn't have fitted it.

Reed_Richards

• You need a paddock (or equivalent) for a horizontal-array GSHP.  You might want to consider an Air Source Heat Pump as an alternative but current running costs will be greater than gas.
• Don't believe EPC recommendations, it's all done by computer and the computer can't tell what's sensible from what's not.  However if additional loft insulation is recommended you have to install it to get the RHI.
• I have a 12 kW ASHP and under half the energy consumption of your house.  I don't know what happens when the energy requirement is as large as yours.  
• Solar panels don't help a lot with heating because they give most output in the middle of the day in summer and much less in winter - and none in the early morning or evening when you need it most for heating.
• I'm also thinking about a rainwater collection system - but still only at the thinking stage.  I found out that washers often require a pressurised water supply so might not be suitable for collected rainwater.       

shinytop

That's a lot of heating for a (relatively) small house if it's correct.  Solar PV wouldn't even scratch the surface.  Your c.40k kWh at 3p on gas is £1200.  40k kWh of electricity delivered by a heat pump at COP=2.5 is going to be close to £2000 or more depending on your tariff.  Most people on here would say stick with gas.  

Solid stone isn't normally a very good insulator; is there scope to add some internal insulation?

These folks have a similar power requirement to you and have installed an ASHP; there is lots of information/videos available.  Their house is bigger that yours but a bit better insulated and they have a mix of ufh and rads.
https://myhomefarm.co.uk/accuracy-of-our-air-source-heat-pump-proposal

Reed_Richards

shinytop said:

....Most people on here would say stick with gas....  

...But that's probably because this is a forum about saving money, not about saving the planet.

Verdigris

If the house wasn't so large I'd think the OP had just outbid me on my dream house project!

If the exterior aesthetic appearance isn't paramount, then external insulation will help to both reduce the heating load and help you exploit the thermal mass of the building. As a very rough ballpark I'd suggest you'd need three slinky trenches, 40 metres long at 5 metre spacing. Have a look at the Kensa heat pump website. Lots of useful information there.

01.matthew

Hey, thanks for all the replies.

I think the energy consumption is way off re-looking at it. It looks to be some general estimate from the EPC and I don't see how it's correct. Unfortunately I'm not going to be able to get anything more accurate until I move in.

Insulation, I can't do that to the outside. It really is a character property and would destroy the look of the house. I'm going to look at making sure the suspended timber floors are insulated properly (especially where we put in underfloor heating), and also will be doing the roof insulation.

Are there any bodies or a specific trade where I can get someone in to do a more detailed review regarding insulation and suitability for some of these more environmentally options. I want to reduce my carbon footprint, but can't afford to have really high running costs

Verdigris

I was paying my council tax (late), this morning, and there was a link for energy advice on my council website. That might be a good start.

Gerry1

Verdigris said:

I was paying my council tax (late), this morning, and there was a link for energy advice on my council website. That might be a good start.

Councils and energy never seem to go well together...  Robin Hood Energy... Bristol Energy... Your Energy Sussex...

matelodave

You could try the Energy Saving Trust, I found them helpful eleven years ago when I got my ASHP installed, they put me in touch with installers and insulation companies.

You still need to do a lot of legwork yourself and i'd strognly advise that you get yourself clued up before lashing out vast quantities of money on solar and batteries - IMO they dont really match everso well with electric heating as you need most of your energy in the winter when its everso cold, the days are short and the sun doesn't shine al lot but solar panels generate best in the summer when you dont need heating (others may have a different opinion).

As said above you either need a biggish lump of land to install the ground collectors or spend a lot of money on deep bore holes for a GSHP