Our quest for Net Zero one year on

NedS

https://forums.moneysavingexpert.com/discussion/comment/82057986#Comment_82057986

We were lucky enough to have the ASHP and initial solar install done on an ECO4 grant, at zero cost to us, so I can only estimate the costs of that.

Savings per year are around £3,000 - our previous running costs for oil and electricity, which are now zero. So if the total cost were around £30k (not unreasonable estimate), total payback would be 10 years* Obviously we didn't pay that, so our payback will be around 4 years. Savings would have been a lot higher this year as heating oil more than doubled in price in March due to the Iran war, which reduces the payback period further.

ASHP installation costs can vary wildly. Some installations are near covered by the £7,500 BUS grant whereas others can cost upward of £10k after the grant, so each case will be different. Hopefully I've shown what can be achieved.

On the financial side, one of the driving forces for us was to reduce our regular outgoings in retirement. Reducing our outgoings by £3k year, and insulating us from the continual ravages of fuel inflation was a big part of our retirement planning.

*maybe less, as a new oil boiler would likely have cost us £5k, and that would never have 'paid' for itself as the savings associated with that would have been zero.

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/82058038#Comment_82058038

@NedS While I am not too familiar with your heat pump set up, I have helped around a dozen or so with theirs. BUS Grant factored in, the average price averages to £8K for a Heat Geek installed Heat A2W Vaillant pump (10 KW or less) with new Vaillant DHW cylinder and a half dozen replacement radiators.

An 8+ KWp (16 X 515W) bifacial solar panel system with a Tesla PW3 should cost ~£12K installed. Adding both together, that's £20K (give or take 10%) all inclusive for a Solar + heat pump set up to achieve a similar net zero outcome. Prices and outcomes will vary across the country but this is entirely achievable at that price point.

This obviously doesn't factor in the cost(s) of any replacement FF boiler.

QrizB

BUS Grant factored in, the average price averages to £8K for a Heat Geek installed Heat A2W Vaillant pump (10 KW or less) with new Vaillant DHW cylinder and a half dozen replacement radiators.

Are yo saying it costs £500 + grant? Or £8k + grant? Those are two quite different numbers.

If £8k + grant, then the cost of (heat pump + solar + PW3) is closer to the £30k that NedS estimated.

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/82058221#Comment_82058221

After grant deduction; it’s £8K out of pocket. Add £12K for solar and battery and the homeowner pays £20K or thereabouts.

Martyn1981

https://forums.moneysavingexpert.com/discussion/comment/82058289#Comment_82058289

I'm guesstimating about the same for my setup. I paid more, but that was over time, with changes and revisions.

From now, I think two A2A units and a HW tank should be about £4k and up, let's say £6k to allow for 3 units, and variations in cost.

My PV set up is messy with 4 arrays, but basically two main roofs, then bits and bobs at lower level (no scaffolding costs), so 9kWp of mixed orientation, or perhaps equal to 7.5kWp south facing, plus ~20kWh of batts, should be ~£14k (just to make the maths easier). So ~£20k all in. No subsidies, but hopefully they will become available soon.

I won't include any cost for the BEV's, as you can now buy SH, and hopefully similar prices to an ICEV, so no significant differential cost to include.

So net leccy bill of ~£100pa (v's old leccy + gas + petrol), sounds like a decent payback IMO on £20k(ish).

So that's an alternative approach, a bit messier, and ad-hoc, but ending up at a similar cost/investment.

I sincerely hope that with PV now cheap(ish), and battery costs tumbling, plus cheap tariffs, especially if EV's are involved, that more and more folk can do this. Not everyone, and not yet, but more people every day.

And with my really thick rose tinted glasses on, hopefully folk with batts, EV's and HP's, will help to reduce costs for everyone, by reducing peak demands through time shifting (batts), or even boosting supply through VPP's (virtual power plants).

NedS

https://forums.moneysavingexpert.com/discussion/comment/82058289#Comment_82058289

Sounds reasonable, and in our case the savings are in the order of £3k/year so a payback of just under 7 years, or less if you factor in the cost of a new FF boiler that would provide zero savings (IOW, if you would have had to spend £3-5k anyway, you've only really invested an additional £15-17k, not the full £20k, reducing the payback period to 5-6 years.

On another note, I am amazed that modern FF boilers appear to need replacing every 10 years. I am hoping our ASHP will last significantly longer than that, but we will see.

jimi_man

There is some information missing here, so could I ask? What sort of temperature do you heat your house to? If you only have your heating on to 18c for example then that will make a huge difference.

For example, we have a 2008 four bedroom detached house with a fairly new kerosene boiler and in the winter we keep our house around the 21c mark - 20c during the day and 21c in the evening - sometimes 22c if it's cold. It's very well insulated being a modern and well built house and we burn 1000 litres of oil a year which is around £6-700 a year. (We didn't buy in the Iran high period). Electricity is £850 a year. So £1500 a year on energy which will take a fair amount of time to payback with an ASHP/Panels.

A further point is that if it takes 15-20 years to 'payback' then it's reasonable to assume that the ASHP/battery/controller may also need replacing during that period which will add to the payback time. Life expectancy of 15-20 years for an ASHP, 10-15 for a battery and controller. Now obviously an oil fired boiler would also need replacing within the similar time as an ASHP but they are a lot cheaper and can last longer - certainly longer than gas ones.

So I'd posit that with a long period of 'payback' time, you'd probably never do it and it would be more expensive. Now of course, that's not the main thing - the idea is to save the planet so cost shouldn't come into it and in this situation there probably wouldn't be much in it. Even if it's slightly more expensive to 'go Green' then great, but it's worth doing the long term sums.

I'd like solar panels but we don't have a South facing roof, only East and West though we are in Dorset, so we are reasonably far South but the direction is key in solar energy.

Screwdriva

Hi @jimi_man. Not sure where the following assumptions are coming from?

1. 15-20 year payback?
2. E/W roofs in Dorset is unsuitable for Solar, especially as you appear to import over 4000 KWh per year?
3. Heating Oil price spikes are limited to the Iran conflict (vs. nearly all Geopolitical shocks)?

jimi_man

https://forums.moneysavingexpert.com/discussion/comment/82058855#Comment_82058855

Hi

1.The OP suggested that £30k wasn't an unreasonable estimate, so divided by £1500 a year is 20 years. Of course you may get a grant which I think at £7.5k brings it down to £22.5k, so 15 years.

In that time, with a life expectancy of 15-20 years for an ASHP you are likely to have to replace it and with no grant now. My f-i-law has had an ASHP put in last year in his 3 bed bungalow at cost of £14k (less the grant). Our payback period is 15 years and if we said that ASHP lasts the upper end - 20 years - we'd only need to add 3/4 of that so lets say £10k. Plus a replacement Tesla battery with similar life expectancy, 3/4 of that - another £7.5k. So add costs of £17.5 k versus an additional £5k for a replacement FF boiler and there is £12.5k difference to add into the payback period.

Servicing according to Google is more than for FF boilers, but we'll ignore that as it might get cheaper if there are more and more engineers as time goes on.

The point I'm making is that when calculating the payback time one needs to calculate the ongoing costs, not just the one off system install costs and it might produce less of a saving than you might think. Solar panels have a life expectancy as well, cleaning etc.

2. No I don't think they are unsuitable, just not as good and also you would need more panels to achieve the same output which will obviously cost more. I'm still investigating it, but it's trying to find someone to get in to assess it who isn't biased! Most companies just want to sell me an installation and so will tell me anything to get me to agree.

3. I was just going on the 20 year average which seems around 70p a litre. I'm actually just about to order some, I haven't looked at the price recently.

Martyn1981

https://forums.moneysavingexpert.com/discussion/comment/82058804#Comment_82058804

Hi. I don't think we're talking 15-20yr payback. In my case, gas, leccy and petrol, probably £2.5k+ pa. And I forgot to include a £3k(?) replacement cost for a new gas boiler as ours was ~25yrs old.

But I appreciate that the 'big' savings really kick in when you've done most/all of the changes, as each part leans on the others. As Ned said - "This is very much a case of the sum being more than the parts."

Regarding temps, with the GCH we probably had the living room at 20C to 21C. Now it's more like 21C to 22C, as in my situation, I want the A2A units to spread heat through the house, so the living room door is now wide open, rather than ajar. I think it feels about the same, due to a bit more airflow.

As another example, the kitchen now has no direct heating, I've even removed the radiator now when re-painting. It's heated via air coming in from the small window linking it to our small conservatory where an A2A unit is. The internal window is at one end of the kitchen on a SSW facing wall. We measure the temp at the kitchen external windowsill at the other end of the room, on a NNE wall. That temp sits at 18C to 20C.

Our house is a 3bed 1930's semi, with a loft conversion. Loft stairs are covered in a heavy insulated curtain during the winter. As a very rough guess, for a 4bed detached property, I'd suggest you'd probably need two multi split A2A units, so four internal units. But probably better to go for a 'proper' wet ASHP, using the existing rads. As I believe the heatpump grant is £9k for detached properties with oil?

I'd like solar panels but we don't have a South facing roof, only East and West though we are in Dorset, so we are reasonably far South but the direction is key in solar energy.

My situation is similar, my house has E/W roofs. There is however a plus side to that, hope I explain it adequately.

So, E or W roofs will generate about 80% of what a south facing roof will, pa. But you have two of them (typically a north facing roof isn't worth considering).

Doing two roofs, and doubling the amount of panels, won't double the cost. Scaffolding will be more, but not double. A larger inverter may be needed, but the cost won't be much more, and the internal A/C work should be roughly the same. So you will probbaly find that doubling the PV, only adds ~60% to the cost.

So you pay 160% (v's south facing), but generate 160%. The downside is that they will perform even worse than south facing in the winter …. but that's where cheap rate leccy and batts come in, plus you'll earn more export during the summer, to help pay for that winter import. I would suggest that my E/W house will generate quite a bit more pa, than neighbouring houses with a south facing roof. That's gross generation, not more efficiently, of course.

And then I went and added a steep pitched south facing ground mount in the garden for winter gen.

Absolutely not belittleing £20k, and I think it's safe to speak for Ned and Screwdriva on that too, but even putting aside the green and ethical issues, I do think it's a good investment.