Brain Dump IV – Should we buy an Air Source Heat Pump or New Boiler? Plus the GDHIF
In today’s Brain Dump we are covering such exciting topics such as Air Source Heat Pumps, Boilers, and the government scheme called the Green Deal Home Improvement Fund (GDHIF). When we moved house in October we didn’t really consider how old the boiler was but having had a few qualified people come round to have a look they reckon it’s knocking on 30 years. It would probably survive for another year or two but I recently read about the GDHIF and that you can get up to £1,000 off a new boiler installation, plus a further bonus £500 if you moved house in the last 6 months. With a possible £1,500 up for grabs I thought it was the ideal time to look into getting the rusty old thing replaced! As usual with these things it turned out to be far from simple with a myriad of options, ways to pay and save with government schemes, and so on. I’ll try to summarise it as clearly as I can below, in case anyone else is also in need of an upgrade, this might come in handy!
Overview of boiler replacement options
After reading around a bit I narrowed down the high level options as follows:
- A new, higher efficiency condensing boiler (Gas)
- A new, higher efficiency condensing boiler (Gas), with up to £1,500 cashback from the GDHIF
- An Air Source Heat Pump (I will call this ASHP to save typing it out every time from here on in!)
Option 1 and 2 are fairly self-explanatory as I am sure most readers are familiar with a gas boiler. The newer models are around 90% efficient whereas the old one is probably around 70% so we’d be looking at a cut to our bills and Carbon footprint of about 20%. Therefore this isn’t an investment as such as it wouldn’t pay for itself over it’s expected lifetime of say ~20 years (hopefully), barring a horrendous gas price increase (in which case I would be wishing I’d gone for the ASHP option anyway!). But looking and listening to the old one, creaking and cranking away, worries me a little, and apparently it’s not installed in an ideal spot either, so it needs to go and we might as well just get on with replacing it.
The Green Deal Home Improvement Fund
You might also be wondering why anyone would go with option 1 over option 2, surely I would jump at the chance to get £1500 off right!? Not so fast young Firestarter 1!
It turns out that the GDHIF is an overly complicated scheme. A government program with many rules, caveats and hoops to jump through? I know, inconceivable isn’t it?
So to get the money, you actually have to complete two home efficiency improvements from this list here.
The most feasible improvement would have been the addition of a Flue Gas Saver which takes extra heat from the Flue and recycles it back into the system for even higher efficiency 2 but this added nearly a grand onto the quote, so we are pretty much back to square one on price and I think the savings would end up being negligible. Add in the extra ball ache of filling all the forms in, having to go through a Green Deal qualified installer (see further reading section below for help on this!) and so on, it quickly became obvious this wasn’t really worth the effort for our situation.
Having said that, it is still a great scheme if you have other more worthwhile improvements to make such as cavity wall installation, so if you were thinking of doing those anytime soon then now seems like the time to do it! The schemes get pulled quite quickly and at short notice, so get your arse into gear now if you think it will benefit you, time is of the essence!
What the frack is an Air Source Heat Pump?
This leaves the other option as the Air Source Heat Pump. From what I gather they are pretty much a refrigerator in reverse, they take “heat” 3 out of the air outside your house, and use heat exchangers and refrigerant liquids to convert that into useful energy to heat water or air inside your house. Pretty darn clever.
They run off of electricity and because of the conversion process they can generate up to 4 kWh of heat for each kWh of electricity input. For this reason it is said they are over 100% efficient. In fact if the ratio is 4 to 1 then the efficiency is said to be 400% 4, which is often called a Coefficient Of Performance (COP) rating of 4.0. This is what makes them a “renewable energy source”, because they are generating heat out of a renewable source, which is latent heat in the air. And this is why they have a lower carbon footprint than a gas boiler, in fact if you know the electricity to run the ASHP comes from solar or wind power, then you have a (nearly) completely carbon neutral heating system 5. Good stuff!
As I’m no expert in thermodynamics, I’d rather leave the technical side of things there, but for more information read here or trusty old wikipedia, which will explain how these things work in far better detail than I can! If you have any questions though please ask and I’ll try my best to answer them.
Renewable Heat Incentive Payments
The main benefit of getting an ASHP right now is that the government are running a scheme to entice people into buying and installing this more efficient and climate change friendly heating systems, as part of their drive to meet the carbon emissions cuts they’ve agreed to by 2020, 2030, and beyond. The higher your needed heating demand the quicker your payback period will be on your investment. This obviously doesn’t mean you can turn the thermostat up to 30 degrees and sit there in your bermuda shorts, coining it on your way to early retirement. You would still end up losing money that way as the payments are only a percentage of the heat you generate, so don’t try pulling any funny business, right? 🙂
But the RHI is a great scheme and it makes the ASHP option much more attractive at current prices, which are otherwise expensively prohibitive for most installations.
The additional pros and cons of the ASHP will be discussed further below!
The Finances
Here are the quotes and my estimates for other costs for the 3 options
| Boiler | Boiler + GDHIF | ASHP | |
| Cost up front | £3320 | £5724 | £6933 |
| Other costs involved | ~£1000* | ||
| Money Back now | £1500** | ||
| Money Back via payments | £4185*** | ||
| Servicing**** | £800 | £800 | £200 |
| Final cost over 10 years | £4120 | £4574 | £3948 |
Notes
*Apparently we need some newer, better radiators to work properly with the ASHP and to qualify for the RHI payments. I am guessing a middle figure for this of £1000 at £100-£200 per radiator depending on whether we can go with standard ones or have to go with these fancy fan convection ones.
** I am assuming we’d get the full amount back, which I think is pretty doubtful anyway!
*** You get the payments over 7 years so this would work out as £597 per year. This is an estimate from the company that we got the quote off of, so not sure how accurate it will be.
**** I am assuming £80 per service for the boilers over 10 years. Apparently you just need to do a basic check yourself for ASHP with a service every 3-5 years, so I am totally guessing £100 per service on that one.
So as you can see, the boiler with the GDHIF actually works out slightly more expensive and that is assuming we’d get the whole of the allowance money back, which as I say I think is doubtful, so we are pretty much set on knocking out option 2 straight away. So this just leaves Boiler vs ASHP.
Weighing up the Pros and Cons
The price over 10 years looks pretty much a wash, so let’s review the other possible pros and cons of each system:
| Boiler | ASHP |
| Higher carbon footprint | A more sustainable way of generating our hot water needs (as recommended by Sustainable Energy without the hot air) |
| Trusted technology | Kind of an unknown quantity |
| Gas prices could rise steeply over the next 10 years | Generating electricity with Solar panels and heat via electricity with ASHP seems to hedge fairly well against this |
| Gas is ~4 times cheaper per kWh than electricity right now… | Electricity prices could rise… |
| … although yearly running costs should still work out higher due to lower efficiency | … although RHI payments are index linked so should be protected from this for at least 7 years, plus yearly running costs should be lower due to higher efficiency |
| Fits nicely into our airing cupboard | Noisy / bit of an eye sore, plus there is an outside component |
| No messing about with government schemes. Costs are well known from the offset | Are the RHI payment figures accurate!? No real way of knowing until the system is installed and the first payment comes in. The system for calculating this seems horrendously complicated |
| Incentive to switch off heating and use less gas, to use less and save £££ | Less incentive to turn off the system as you are paid on how much heat you generate (I find this a bit weird!) |
| Generates lower temperature water |
|
| Fairly easy and quick job for installers. Recommended option. | Bigger and more complicated job to organise, radiators need replacing as well, etc… Non-recommended option! |
There seems to be far more red on the ASHP side of the table but a lot of them are just minor quibbles and are more based on unknowns, however they still need to be considered.
The “Less Incentive to turn off the system” one is a bit silly for a start, because even though we’d get 7.3p per kWh of renewable heat generated (63% of total heat according to our survey), you are still paying more than that for the electricity. But you can’t get away from the fact that the more heat you generate (that is actually needed, or would have used anyway) then the better the pay back will be. If we are very frugal with our heating and hot water usage, then we’ll get less benefit than someone who is naturally more wasteful, which is a bit of a paradox!
Similarly, the hot showers point might be a load of rubbish, I have no idea what temperature my shower runs at and maybe I don’t need the power of gas to get a nice one!? Google to the rescue here again, it looks like around 40 degrees C is fine for showering. I’ll cross that one out then 🙂
A bigger red cross on the ASHP column for me is the fact that the this solution is actually not recommended for our current house set up. Yep you read that right! If you are on gas mains and have a relatively small house the recommended option is indeed to insulate and get a high performance gas boiler. ASHP are generally recommended to replace oil boilers/biomass boilers for people who are living out in the sticks, not townies like myself.
However, the green pros in the ASHP column are pretty big ones for me. I like the idea of trying to get on the sustainable bandwagon early doors even if we end up paying a little bit more for it in the medium term. Likelihood is that in 5 years time these things will be half the price! But we need a boiler replacement now. Also I like the idea of hopefully future proofing ourselves against a possible steep rise in gas prices. This could end up being a massive win over the course of 10 years, but it is a bit of a punt and could go either way. Long term (20 years time) I think these things will be everywhere anyway, so we could just get a boiler this time round then replace it when that one goes kaput in 15 years time, or we might not even be living in our current house by then. Oh, the future! You elusive blinder, you! 🙂
Opportunity costs
The final thing that should be considered is the opportunity cost of not having the money that would be saved by going with the cheaper boiler option invested over the 7 years. To make it fair we’ll assume we would invest the income from the RHI payments as soon as we receive them as well, so let’s see how does that work out?
Boiler: Lump sum of £4613 over 7 years @ real return of 4% = £6100.
Total returns = £6100 – £4613 = £1487
ASHP: Monthly investment of £49.82 from the RHI payments over 7 years @ real return of 4% = £4820
Total returns = £4820 – £4185 = £645
So as you see the cheaper boiler option returns an extra £842 over the 7 years, not to be sniffed at! This should pay for the yearly servicing for example, which works out pretty nicely. It is worth bearing in mind though this return is not guaranteed, and it could end up being negative! Whereas the RHI payments and a more efficient heater are guaranteed returns (just the amount we receive is still to be 100% determined)
Conclusion
To be honest I am still somewhat undecided. The fact that the total cost of the systems are so similar, even if the RHI payments don’t quite work out quite as much as in the estimate out I am sure we’d break even over time anyway. But I also am surprised that the difference in cost invested generates such a large amount! Maybe the point it boils down to is principals. I’d like to think I am a man of them, therefore the ASHP is the only real option, if that is the view I am taking.
As always I’d really appreciate others input on this one! What would you go for? Has anyone got an Air Source Heat Pump out there that can vouch how amazing they are? Or has anyone faced a similar decision and gone with the gas boiler option (or other), and what were your reasons?
Further Reading / Resources
If you are interested in the Green Deal Home Improvement Fund the following links might come in handy:
Government’s Green Deal main page – https://www.gov.uk/green-deal-energy-saving-measures
Find local Green Deal Assesors, Providers and Installers – http://gdorb.decc.gov.uk/
Find more companies here… – http://www.greendeal-directory.co.uk/
And here… – http://www.thegreenage.co.uk/find-local-green-deal-assessor
Important Note: It was very hard to get someone to come out and give you a quote for work done without getting an EPC (Energy Performance Certificate) or Green Deal assessment which cost around £150!!! This was another reason why I was put off of going along with this scheme, as there is no guarantee you will get any money from it up front and you may decide that you dont want the work done anyway. If you are certain you want work done it’s not such a big deal as you will get some of the money back off the work anyway, but it is certainly something to bear in mind and I found it rather annoying if I’m honest!
More on heat pumps
http://www.superhomes.org.uk/resources/are-heat-pumps-cost-effective/
You can also get Ground Source and Water Source heat pumps! You need either a big garden or, surprisingly, a water source. Here is some info on the other options – http://www.betterplanet.co.uk/ground-source-air-source-or-water-source
RHI payments info – https://www.ofgem.gov.uk/environmental-programmes/domestic-renewable-heat-incentive/apply-domestic-renewable-heat-incentive
Notes:
- Quite a relevant name with all this talk of combustable gases isn’t it? 🙂 ↩
- In fact, this isn’t even listed on the list, so not even sure it would count anyway ↩
- (in quotes because they still work somehow even when the temperature is below freezing, they are just less efficient at lower temperatures ↩
- The X-Factor judges would have a field day with that one! ↩
- Barring the obvious footprint of manufacturing and transporting the thing to your house, which is not insignificant. ↩
Hi,
Interesting stuff.
I am in no way an expert from I’ve looked at air source previously and understood that it doesn’t really make sense retro fitting it into a system with tradition radiators. As you’ve said the water doesn’t get that hot so unless you have underfloor heating it makes no sense.
As stated I’ve no experiance in this so don’t take my word for it! Good luck!
Hi UTMT,
The general consensus seems to be that if you retrofit you will have to upgrade your radiators to larger ones, or ones with higher radiating surfaces, or convector fans to help radiate heat faster / more efficiently with the lower water temp. So it does work, but you are absolutely right in saying they are better with underfloor systems.
Cheers!
my dad, an engineer by trade, was looking into ASHP for his boiler upgrade recently. He was really sold on the technology, but the limiting factor for him was water temperatures running around the system, particularly for baths/showers. The nail in the coffin was the cost of replacing all the rads around the house. He went for a new boiler in the end.
If you go with a boiler, i’d recommend a Vailant. Expensive but very reliable. We have an outside thermometer/controller which is linked to the system so it regulates how aggressively the system fire ups – if it warms up outside, for example, then the boiler trims back on it’s heating temperatures. simple, but v effective in reducing bills.
Moreover, we have a digital time controller so we can regulate very frugally when our radiators heated day to day.
I chose a Vailant as it was “Which Magazine” best buy.
Hi LCIL,
Thanks for letting me know about what your Dad went for in a similar situation, that will come in very helpful when we make our final decision!
The Rads could well be the final nail as well for me. £6.5K didn’t seem “so bad” after you count in all the RHI payments, but when you get nearer £8K it’s starting to look a bit ridiculous!
Vaillant have been recommended by most of the quotes we have so far, but looking at comments before it looks like we’ve been overquoted even so.
Were the controllers you have all linked up that much extra to add into the system? Also would you mind letting me know how much it cost (and any idea on your Dads system as well while I am at it?) No worries if you’d rather not… bit of a personal question I know – “How much was ya Dad’s boiler then?!” 🙂
Hi. If your existing boiler still heats the house OK, then there’s no need to change it until it doesn’t. If it’s 30 years old, the boiler itself could be cast iron and may last for another 30 years. Modern condensing boilers don’t have much of a reputation for durability.
And I can’t believe your costs of boiler replacement – if you can’t get a new brand-name 12-15 kW gas boiler for way less than £1,500 fully-installed then you’re just not looking hard enough !
BTW, heat pump technology is not an ‘unknown quantity’. You’ve likely already heat pumps fitted in your house – they’re commonly called fridges and freezers….
Hi DM,
Well I’m glad I posted this now, as I clearly have two more options on the table that I didn’t really even consider:
4) Don’t bother replacing it till it conks out
5) Keep looking for a better boiler replacement quote
I’ll do a bit more research into my boiler make (It’s a Baxi, if anyone out there is a boiler expert and want’s to leave further comment on the prospects of this reaching OAP status?) and also into some more gas fitters to see if we can get any more quotes.
Cheers!
P.s. I did mention that the heat pump is basically a Fridge in reverse in the article, but I don’t blame you if you didn’t read the whole thing, I know I waffle on a bit 🙂 – I was more meaning that I don’t know anyone with a heatpump, so in that sense, it is unknown territory as I only have unverified internet articles (that usually are linking to sell me an ASHP) to go on, saying what benefits this technology will bring me.
As a landlord I buy a fair few boilers and even good ones like a Vaillant or a Worcester Bosch cost less than a grand – Google the model you need. A flue is another £60, plus fitting which is a day or so depending on the existing installation. I agree the whole deal should be around £1500. Most people pay FAR too much to cheeky plumbers who charge a grand for a day’s work. Or British Gas! Try and find a plumber who will let you supply the boiler, who works on an hourly rate. But… Jeff Howell, who writes about property maintenance for one of the papers, is forever telling people to keep old boilers. He says a lot are far better made than modern combi boilers which may be more efficient but have very short lives. Of course most plumbers will recommend a new one so they can screw you for a grand.
I’m quite stunned at how much our lowest quote, yes the one I quoted in the article was the lowest quote we received out of about 4-5, has come out to comparing to what yourself and DM have said.
I guess I didn’t do as much due diligence as I thought this time round, but thank god for the old blog again. This thing really has paid me back hundreds if not thousands of pounds already with great advice from readers!
I think perhaps the fact that I was trying to get quotes from Green Deal qualified installers, maybe they add an extra £1000 or so on because they know the government are giving people that off the price, so they know people will only consider the final cost and if they think it’s reasonable they’ll go for it? Not sure.
Anyway the lowest quote was actually from one of my Dads old school mates, so I thought it would be as honest a quote as I’d get, which is why I stopped looking (and it was £1000 lower than the next lowest… yep. £4300 was the next lowest quote we got. Ridiculous or what!)
That said, it’s not a 100% boiler only swap job, so I doubt we’ll get it for below £1500, the reasons being:
1) Boiler moving from downstairs cupboard (no ventilation… not safe to keep it there apparently*) to the upstairs airing cupboard. So extra pipes etc needed to get the gas supply up there.
2) New water tank needed, immersion heater, heating controls, etc etc. It all seems to add up and most of it does seem “needed”.
3) The old flue is asbestos which requires specialist care in removing.
That said, I still think we have been at least slightly over quoted 🙂 , so I’ll see if we can get a better quote from elsewhere and go from there.
*This is another reason why I think we need to replace the old one. But again is this just another case of the plumbers trying to scare us into buying the new one!?
I think you need to research exactly what it is you have installed at the moment – saying the boiler is a Baxi is a bit like saying your car’s a Ford ! What model, year, variant, flue arrangement etc do you have ?
Boilers don’t need ‘ventilation’ in the sense you may probably think – what they do need is sufficient combustion (or ‘charge’) air to burn the gas thoroughly, but in a typical ‘balanced flue’ installation this usually comes in directly from outside of the house. The flue pipe you see might not be a single pipe, it’s more likely to be a pipe-within-a-pipe, i.e. the hot burnt gases are carried outside the house up the central pipe and the fresh combustion air is simultaneously drawn in via the annulus between the two pipes.
Wherever the charge air comes in from, the installation will have met the Building Regulations at the time. Building Regs are not retrospective. You can repair / replace any and of all the components in the existing boiler to keep it running forever (even to the extent of Trigger’s Broom, where there’s nothing original left at all), but if you fit a brand new boiler then the installation MUST meet the Regs of today.
If you’re worried about ‘ventilation’, then buy some Carbon Monoxide (CO) detector patches for a few quid on eBay and stick them on the inside door of the boiler cupboard and around the room. They’ll change colour if the flue housing is leaking any dangerous unburnt gases.
If the flue arrangement is actually asbestos – have you had this confirmed by an asbestos specialist ? – then the boiler definitely pre-dates 1985 which is the time asbestos insulation was totally banned in the UK. However, all the boiler manufacturers knew many years before than this date that an asbestos ban was coming in, and so even much older boilers may have used alternative mineral insulation materials.
And if you’re re-siting the boiler to another location, then this doesn’t mean that you also have to rip the old one out at the same time. You can simply abandon it in-situ, at least until such time you want to spend the extra money getting asbestos specialists in to rip out the old flue….
Hi again DM,
You sir are a legend. Thanks for all the extra info!
I was actually thinking about getting the CO detectors, so I will get onto that right now! If like you say there are no naughty gases lurking about then it does make the case for replacing it pretty redundant, I agree.
The flue was highlighted as potentially asbestos in the house survey before we moved in, and most of the plumbers that came round also mentioned it looked like asbestos. I don’t know how you can tell that from just looking at it but I guessed they just all knew what they were talking about, as they all came to the same conclusion.
Anyway, I’ll get onto the CO thing now and update the post or comments when the results are in.
Cheers again
As per what others are saying, as long as your old boiler is still working and regularly maintained (for safety purposes), perhaps just keep it.
If you had to get a new one, I’d go for the boiler. Although you say they are minor, there are too many ‘unknowns’ with the ASHP, despite being more environmentally friendly and the water thing would just really pee me off!
You could always get the whole house properly insulated, eg loft and cavity walls, meaning that your house will keep the heat in and require less energy to heat up, be that gas or electricity. Since the government wants everyone to be energy efficient, insulation these days doesn’t cost half as much as it used to.
Sounds like you need to get a few more quotes!
Hi weenie.
Thanks as always for your thoughts.
I’d really like to chat with someone who has already got one to see what they are like with the water temperature etc!
We have good insulation already (Thanks, previous owners!) which I think was a pre-requisit of receiving payments for the solar panels. So I guess that is another argument to just stick with the current boiler if we aren’t actually burning through much gas, compared to other similar houses at least. It really is boiling down to my principals of trying to be “green” – is that worth nearly 8 grand. I’m not sure it is right now… principals schmincipals I guess. Hah. As I say we could hold out with the old boiler for another 5 years and then upgrade to a heat pump when they cost £1000 or whatever. Also there is something to be said for using a resource for as long as possible before sending it to the scrap yard, that is also green in it’s own way. I wonder what the embodied carbon is in a brand newly manufactured ASHP for example, I would be on quite a lot!
It is nigh on impossible to get ASHP quotes!!! Defo will be looking for a few more boiler quotes though.
Cheers again 🙂
Your costs for installing an ASHP are also totally excessive. Forget the green deal and any tariffs etc, you can buy a 22kW heat pump for around £2k.
Add in say £200 for an electrician to fit an additional 20A breaker to your main distribution board, plus a cable and fused spur to the unit’s location, and then do the rest of the job yourself, say a few hundred quid for pipe extensions and insulation. Then buy and fit the lower-temp radiators yourself, too.
The whole installed cost would be around £3.5k …
Interesting you mentioned that.
I did notice that there were some cheaper ASHP knocking around, but they are not RHI/Green deal qualified, so you wouldn’t get the RHI payments. But maybe that is just another scheme for manufacturers and installers to cream money off the government and I should ignore that and just go for the cheaper ones and install as much as I can myself.
I am definitely leaning massively towards keeping the gas boiler for a few more years if we can and it’s safe, then learning some basic plumbing then maybe installing most of it myself in a few years time. Thanks to yours and others comments.
I’m with DM – if it ain’t broke don’t fix it 😉
Your boiler has run for 30 years. Seems strange someone can qualify that it will die in the next year. What seems to kill old boilers is the unavailability of spares. When you reach that point, yes, let it go, and certainly save towards the capital cost of replacement. But don’t do it electively.
Assuming your table shows the capital costs there’s not much in it. However, the ASHP is a much more fundamentally expensive piece of kit, so spares will be dearer and less competition in servicing point to potential woe in that area. At least it’s electrical not gas, which should reduce some labour costs.
40C is fine. Have you tried a shower that hot? in hotels there’s often a stop at 38C so you don’t accidentally scald yourself.
If you are going to electively pay over the odds for all the green malarkey then you need to factor in the total lifecycle cost of the ASHP – how much carbon was used in mining, refining and manufacturing it. A car, for instance, damages the environment more in the process of being made that through its service life.
http://www.theguardian.com/environment/green-living-blog/2010/sep/23/carbon-footprint-new-car
re the future costs of electricity and gas take a look at the mix in use in the National Grid
http://www.gridwatch.templar.co.uk/
Most seems to be coal and CCGT. If they really are phasing out coal and we aren’t building much more nuclear then gas is the only game in town, renewables are < 10% of capacity it appears. If gas goes up your electricity is going up because that's largely what it's made from.
If you're rich enough to pay £8000 for the green badge then knock yourself out but as a way to get closer to being FI this looks nuts to me.
The difficulty you are having in getting comparative quotes for an ASHP indicates this is not a competitive market and if such a system is designed for a larger offered load it will run at less than optimal efficiency – most heating appliances work most efficiently at their design load.
Also I think elsewhere you say you are in a terraced house or a semi? In which case for the sake of your neighbours I beg of you not to put a 'king great big ventilation plant putting out 40-60 (presumably dBA @ 1m, 60 dBA@1m is the same volume as a conversation. ) as shown in
http://www.thegreenage.co.uk/tech/air-source-heat-pumps/
within 10m of their house – low frequency noise carries. Your green badge will come at the cost of their (and your) sleep, particularly if you are tempted by night rate electricity to run this at night.
On the efficiency front this looks iffy too. Never mind that the greenage site says "In fact, if you don’t have access to mains gas, heat pumps are definitely the way to go to fulfil your heating and hot water requirements"
and you do have access to mains gas, but gas is a lot cheaper per kWh than electricity – 4.3 versus 13.6p for me. The bungs and incentives sound fishy to me. Each 1kWh of useful heat costs you 13.6p/4=3.4p and you get a bung of 0.63*7.3=4.6p which gives you a net 1.2p per kWh used which sounds barmy, though it might swing the equation. Depends on your power usage – your power costs were lower than mine. My gas usage (semi) is 5528 kWh p.a. – half of the typical consumer usage it appears. That sets an upper bound as your usage is lower. For that usage so you'd get £66 in your back pocket as opposed to a cost of £300 (gas equivalent). Even at a £400 advantage accumulated over 10 years you'll only claw back half the cost of your green badge.
This seems to be in it's infancy, and the bungs and stuff seem to be distorting the picture. If you still have a serviceable boiler then run it for a few more years, hopefully the cost and competitiveness of ASHPs improves as technology usually does and maybe they will make them more suited to smaller houses. If it's not a fight you need to fight now then take it on a few years down the road. I guess decorating may shift the balance towards now, but it's a lot of money…
Hi ermine.
You are the voice of reason as always. Thanks!
I think I am pretty much set on the “do nothing” option now after yours and others comments, as long as the CO detector patch comes back with a clean analysis.
Quickly picking through some of your other points:
Lifecycle costs – Yes this was something I did consider, although I think I only mentioned it in the comments or footnotes, not in the main article. If you do consider this then I am certain that keeping on using an older slightly less efficient resource pretty much always wins doesn’t it.
Gridwatch – That is cool! Saved to favourites. Funny coincidence – I was looking at it last night and 5 minutes later we had a power-cut!
On the gas goes up / electricity goes up – The point was that RHI payments are index linked so if electricity goes up then your payments go up. But overall you will still be paying more, so point taken. And I haven’t run the figures on what you might be paying for boiler compared to ASHP plus RHI payments if it did, because I am no expert and it would be pure guesswork, so really I have no idea how better or worse either option would be. But it just seems like a mild hedge against rising prices.
Sound level – Yep good point again. The one we were looking at (Mitsubishi Ecodan 5kW) has 45dBA which seems reasonable to me. Yea we are terraced but it would have been hidden pretty well and enclosed in a fenced area, with neighbour windows far enough away (they checked for this in the survey).
Green badge – Yep agreed again I think on balance, specially when you combine this with the lifecycle costs argument. £8K is a lot of money for something that is arguably not going to save the earth single handedly anyway 🙂
Recommended solution – This was noted in the post but I kinda brushed over it. I guess I should listen to the experts and rational thinkers like yourself. I just get carried away with the green angle sometimes! I think maybe I feel bad for years of overconsuming and want to make amends. I think downshifting in general and consuming less in the future is probably a better way to do this tough isn’t it! (Which will save me money as well). Also I guess the consumer urge is still strong in me, so I am weirdly looking at ways to spend my money, even if it may not be totally necessary? Who knows. The human mind is a strange and beautiful thing, I certainly don’t understand mine fully that’s for sure.
Cheers again for bringing me back down to Earth in your inimitable way 😉
I have a mains powered CO meter next to my boiler to make a racket if the seal goes. It’s about £50 worth of peace of mind. So far the one time it’s gone off in ~10 years was when I burned the toast on the grill 😉
Another catch with ASHPs is that they are quite specialist and the number of suppliers that can service/fix is limited. A colleague of mine had one in a property he owned and it proved pretty unreliable and difficult to get anyone to repair it once the warranty ran out.
Hi SSMan,
Thanks for chipping in with the comment, that’s definitely something I need to bear in mind.
Thanks!
did you see the article in the telegraph on whether to replace old boilers – it says no! New ones have costly repairs (electronics etc) within 5 yrs. Also, the heat pump doesnt work when it is cold. Admittedly I live in midwest where it is much colder than you but friend needs to use those base board elec heaters around freezing temps. They are well pissed off.
Hi free by 50,
Thanks for the comment. I just checked it (or them, there are a few) out.
Very interesting stuff!
Here are a few links for anyone else interested:
http://www.telegraph.co.uk/lifestyle/interiors/jeffhowell/7129133/Jeff-Howells-DIY-advice-condensing-boilers.html
“Using an analogy from the world of motoring, a 50-year-old Rolls-Royce will probably last for another 50 years, while the latest Toyota Prius is unlikely to see a decade of use. If you take into account the manufacturing, scrappage and servicing costs, the Rolls will have a far lower “carbon footprint” year-on-year.”
Others:
http://www.telegraph.co.uk/lifestyle/interiors/renovating/9791140/Do-I-need-to-install-a-new-boiler.html
http://www.telegraph.co.uk/finance/property/advice/10138910/Jeff-Howell-should-I-get-a-combi-boiler.html
http://www.telegraph.co.uk/finance/property/advice/11365880/Do-I-need-to-replace-an-old-boiler.html
The evidence sure is mounting up for the cheapest option of doing nothing… which is music to my ears 🙂
Hi TFS, Is there any reason you wouldn’t consider getting a heat only unit like this: http://www.saturnsales.co.uk/Mitsubishi-SRKZM-S-Wall-Air-Conditioning-Heat-Pump.html?gclid=CL7hw8O8z8MCFQPHtAodm2IAxA
Hmmm…. Not 100% sure.
I think those are Air to air systems rather than air to water, which I haven’t investigated at all.
I guess the main point would be how would I get my hot water (obviously I could leave my existing boiler in place but then if that does go kaput within a few years I then have to pay out for that as well)
Anyway something to consider for sure so thanks for the suggestion.
Cheers!
Thank you for the in-depth breakdown of benefits and costs. These are the kinds of things I wanted to ask about, but the only source I could think of to ask was the companies that sell these systems, and I’m afraid I wouldn’t know enough to determine if I was being told the truth or being upsold to buy expensive equipment that surpasses my needs. Have you made the switch yet? And if so, what do you think?
I didn’t make the switch in the end!
The old boiler is still going strong and the carbon monoxide meter is saying we are safely in the “you are not going to die” section, so for now I think we are all set to continue with the gas heating for the forseeable.
Cheers!
Personally, I would buy the Air Source Heat Pump. I have one in my house right now, and it has served me faithfully for many years. Like you say, they run off electricity and because of the conversion process, they can generate up to 4 kWh of heat. That’s a lot of heat!
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