I should add another thought. Within reason, every house will have to have a heat pump in the next 15 years. People generally haven't realised yet that the question is not whether they should get a heat pump, it is just when will they do it! Even if the payback is relatively long it is still cheaper to run a heat pump than a gas boiler. Therefore the quicker you do it the faster you can start to benefit because you will have to do it in the end.
I'm not sure that is relevant. It's a bit like asking what's the payback on a new car.
The heat pump was installed as part of an entire sustainable energy system and therefore that's what I looked at in totality, but you can't arbitrarily just look at one element. The heat pump overall is about 4.5x more efficient than a gas boiler. That is the crucial part of this.
Due to the way electricy is currently priced in the UK (note the only major country to still rely on national not zonal pricing) heat pumps are articially made to appear expensive. This is entirely the government's fault and they should have started changing this!
The battery then allows me to store enough power to reduce the cost of my electricty to roughly 35% of the standard rate i.e. maximising my utilisation of off-peak pricing.
The solar then provides some free power in the winter and massively more than I need in the summer - my daily electricity charge (including the standing charge) has been a net credit every day since 23 April.
So each element of my system adds up to create the overal payback.
What needs to be decided by HMG is are they addressing climate change or the cost of energy. Miliband assumed the two naturally go hand in hand but they don't the reality is moving to a non fossil fuelled society will cost serious amounts of money and in the short to medium term, if not ever, will be more expensive. Thus the debate has to moved to this is a necessity trouble is on the face of it many big global emitters aren't bothering eg China. However, whats being missed is that Chinas energy demand/capita is still growing but that growth is now being met largely from renewables. Same in India. These countries being near the equator get better irradiance although your system is nevertheless impressive but expensive. The big problem in the UK demonstrated by your experience is whilst equipment costs have plunged installation costs haven't and nor will they given the labour mkt dynamics in this country. So for most people even with that grant is out of reach. Not sure how HMS is going resolve that one but moving the cost onto gas isn't the total answer.
Out of interest, you have quoted the total costs as being £36k. Does this include the cost of removing the chimney ? I'm hoping yes since the only reason to remove the chimney was for improved solar generation.
I also read in one of the other blogs that you had underfloor insulation installed. Is this cost included in the £36k ? It is also worth stating that having this additional insulation would have resulted in a reduction in your heating costs if you'd stuck with you gas boiler, therefore the direct comparison of running cost savings are not really correct.
It is worth keeping in mind that the economics of this type of setup are very dependent on there continuing to be good overnight electricity tariffs, and good electricity export tariffs - the current Octopus flat 15p/kWh export is unsustainable, and will likely be revised down significantly within the next 12 months.
All this said, I am very impressed with what you have done. Even without the solar and batteries you'd have improved heating with similar running costs to your existing gas boiler, and you are demonstrating perfectly that this type of house can work just fine with a heat pump without massive upgrades to anything existing. A very different message to that being run by the popular media.
I think the chimney was included. I'm being vague as I was having a bunch of other things done. Deciding which costs were in and what was out was tricky!
The current 15p export maybe unsustainable but the government still allowing electricity to be 4x the cost of gas is way more unsustainable. As that differential reduces as per the forecasts then my payback period will dramatically fall.
In the end I was broadly doing this for environmental reasons - it just needed to payback at some point. The big quotes we had were £60k+ to do external wall insulation. Even for me this was just way too much and couldn't be justified. We did have some underfloor insulation (not heating) in a couple of rooms, although I'm unconvinced that it made a material difference.
I still feel that just running the heating 24/7 was the key and using the solid brick walls as a heat store. We escaped the hot/cold cycles that most people run with gas.
I'm on a slightly different journey that will probably end with a very similar destination.
About one year ago we relocated to the far north of Scotland. A 1950's bungalow with multiple extensions at different eras, and varying levels of insulation to go with it. Heating is an oil boiler. The house had no renewables.
We now have 11kW of solar and 20kWh of batteries, since that is something we'd lived with for about 10 years at our previous house, and we understand how to maximise the benefits.
My original plan was to get a heat pump this year, but I am delaying that for at least one year while I continue to improve insulation. Oil use was better than I'd expected for the first 12 months (~18MWh), and radiators run at very low temperatures to hold a constant house temperature, so I know transition to heat pump will be relatively straightforward. But I need another year to assess the final benefits of insulation. Another consideration since we quite remote is power cuts. We've had more than I'd expected over the last 12 months, and while the batteries can easily power the electrical bits of the oil boiler heating for days, that clearly will not be the case for a heat pump.
When we do get a heat pump I'm planning to upgrade the batteries to at least 30kWh, hence we'll end up at a very similar destination!
Was there a particular reason you opted for octopu go rather than octopus intelligent go which would offer you a longer night time cheap rate period, windows of cheap period throughout the day depending on electricity generation, and a cheap rate of only 7.5p?
Also, with electricity costs due to decrease does that impact the payback period for the battery and solar or are you purely comparing it to gas prices alone? I wonder if just a heat pump would have a shorter payback period in a cheap electricity world.
I'm only looking at the total system payback. It's the first question everyone always asks so I thought I'd better address it! I'm not sure you can really separate the different elements
Possibly. I thought as long as octopus has a device it can interact with whether that be the car or the charger then you can opt for the tariff but I might be wrong on that.
Most of the modern decent EVs will work with Intelligent Go. I have a Tesla and a Zappi charger (both of which will work with Intelligent Go). I have been on Intelligent Go in the past, but this year I've switch back to straight Go - I'm charging the EV from excess solar at this point in the year, and Intelligent Go just adds another layer of "faff". 8.5p/kWh is cheap enough, so I'm happy with that.
The faff on Intelligent Go, sort of. When I previously used Intelligent Go, my EV was the component Octopus controlled. You then have to ensure you've set up the Tesla App and the Octopus App. It's usually the odd occasion when you need to charge to 100% overnight that you forget something and wake up with only 80%.
Also I have home batteries, sometime Octopus would start the car charging at 20:00 for a one hour slot which would take from the battery, and then I'd have no battery left for the last few hours of the evening, meaning I'm unexpectedly buying daytime electricity later in the evening.
Maybe if you just have an EV, no renewables it's a bit more predictable, but with my home batteries it just wasn't working how I wanted.
Yes, you get 6 hours of overnight for the whole house, but the EV has to remain in Octopus' control. If you try to work around what they are doing with the car (e.g. by setting your own overnight schedule on the car) you get annoying emails from Octopus, then ultimately they push you down to "Go". So to get 6 hours at 7p/kWh you have to play the game at put up with the negatives. For me it's much easier to get 5 hours at 8.5p and I can do what I want with the EV including daytime solar surplus charging (which I wouldn't be able to do on Intelligent Go).
If it helps, octopus only has control of my charger not my EV but that might be because of octopus having issues with the BMW api at the moment.
I can see the battery point would be really annoying. I suspect better battery management software would help here and it’s definitely possible to stop batteries from draining to charge cars but as I don’t yet have a home battery I can’t speak with any authority on how best to achieve that.
If the go tariff is working for you then stick with it. I’ve got to say I love the cheap energy slots for the whole house. Although it is impacting my assessment of the economics of getting battery and solar. A heat pump will probably change that as and I when I take the plunge.
I've looked at re-joining Intelligent Go with the Zappi charger as the smart device that Octopus would control. At least that would allow my daytime surplus solar charging to work, but the Zappi doesn't know the SoC of the car, so for overnight charging you have to set up to charge X kWh by a given time, and you have to determine X yourself. This is even more faff, so won't be going with that option.
So thats 18.5k for the heat pumps setup and alterations excl the BUS grant? What would the payback be if it was a heat pump only installation?
I should add another thought. Within reason, every house will have to have a heat pump in the next 15 years. People generally haven't realised yet that the question is not whether they should get a heat pump, it is just when will they do it! Even if the payback is relatively long it is still cheaper to run a heat pump than a gas boiler. Therefore the quicker you do it the faster you can start to benefit because you will have to do it in the end.
I'm not sure that is relevant. It's a bit like asking what's the payback on a new car.
The heat pump was installed as part of an entire sustainable energy system and therefore that's what I looked at in totality, but you can't arbitrarily just look at one element. The heat pump overall is about 4.5x more efficient than a gas boiler. That is the crucial part of this.
Due to the way electricy is currently priced in the UK (note the only major country to still rely on national not zonal pricing) heat pumps are articially made to appear expensive. This is entirely the government's fault and they should have started changing this!
The battery then allows me to store enough power to reduce the cost of my electricty to roughly 35% of the standard rate i.e. maximising my utilisation of off-peak pricing.
The solar then provides some free power in the winter and massively more than I need in the summer - my daily electricity charge (including the standing charge) has been a net credit every day since 23 April.
So each element of my system adds up to create the overal payback.
What needs to be decided by HMG is are they addressing climate change or the cost of energy. Miliband assumed the two naturally go hand in hand but they don't the reality is moving to a non fossil fuelled society will cost serious amounts of money and in the short to medium term, if not ever, will be more expensive. Thus the debate has to moved to this is a necessity trouble is on the face of it many big global emitters aren't bothering eg China. However, whats being missed is that Chinas energy demand/capita is still growing but that growth is now being met largely from renewables. Same in India. These countries being near the equator get better irradiance although your system is nevertheless impressive but expensive. The big problem in the UK demonstrated by your experience is whilst equipment costs have plunged installation costs haven't and nor will they given the labour mkt dynamics in this country. So for most people even with that grant is out of reach. Not sure how HMS is going resolve that one but moving the cost onto gas isn't the total answer.
Out of interest, you have quoted the total costs as being £36k. Does this include the cost of removing the chimney ? I'm hoping yes since the only reason to remove the chimney was for improved solar generation.
I also read in one of the other blogs that you had underfloor insulation installed. Is this cost included in the £36k ? It is also worth stating that having this additional insulation would have resulted in a reduction in your heating costs if you'd stuck with you gas boiler, therefore the direct comparison of running cost savings are not really correct.
It is worth keeping in mind that the economics of this type of setup are very dependent on there continuing to be good overnight electricity tariffs, and good electricity export tariffs - the current Octopus flat 15p/kWh export is unsustainable, and will likely be revised down significantly within the next 12 months.
All this said, I am very impressed with what you have done. Even without the solar and batteries you'd have improved heating with similar running costs to your existing gas boiler, and you are demonstrating perfectly that this type of house can work just fine with a heat pump without massive upgrades to anything existing. A very different message to that being run by the popular media.
Hi Mike
Thanks for your comments and support.
I think the chimney was included. I'm being vague as I was having a bunch of other things done. Deciding which costs were in and what was out was tricky!
The current 15p export maybe unsustainable but the government still allowing electricity to be 4x the cost of gas is way more unsustainable. As that differential reduces as per the forecasts then my payback period will dramatically fall.
In the end I was broadly doing this for environmental reasons - it just needed to payback at some point. The big quotes we had were £60k+ to do external wall insulation. Even for me this was just way too much and couldn't be justified. We did have some underfloor insulation (not heating) in a couple of rooms, although I'm unconvinced that it made a material difference.
I still feel that just running the heating 24/7 was the key and using the solid brick walls as a heat store. We escaped the hot/cold cycles that most people run with gas.
Thanks Dan.
I'm on a slightly different journey that will probably end with a very similar destination.
About one year ago we relocated to the far north of Scotland. A 1950's bungalow with multiple extensions at different eras, and varying levels of insulation to go with it. Heating is an oil boiler. The house had no renewables.
We now have 11kW of solar and 20kWh of batteries, since that is something we'd lived with for about 10 years at our previous house, and we understand how to maximise the benefits.
My original plan was to get a heat pump this year, but I am delaying that for at least one year while I continue to improve insulation. Oil use was better than I'd expected for the first 12 months (~18MWh), and radiators run at very low temperatures to hold a constant house temperature, so I know transition to heat pump will be relatively straightforward. But I need another year to assess the final benefits of insulation. Another consideration since we quite remote is power cuts. We've had more than I'd expected over the last 12 months, and while the batteries can easily power the electrical bits of the oil boiler heating for days, that clearly will not be the case for a heat pump.
When we do get a heat pump I'm planning to upgrade the batteries to at least 30kWh, hence we'll end up at a very similar destination!
Very best of luck!
Was there a particular reason you opted for octopu go rather than octopus intelligent go which would offer you a longer night time cheap rate period, windows of cheap period throughout the day depending on electricity generation, and a cheap rate of only 7.5p?
Also, with electricity costs due to decrease does that impact the payback period for the battery and solar or are you purely comparing it to gas prices alone? I wonder if just a heat pump would have a shorter payback period in a cheap electricity world.
I'm only looking at the total system payback. It's the first question everyone always asks so I thought I'd better address it! I'm not sure you can really separate the different elements
Makes sense. I might try to model it to see where the break points are
You need an intelligent EV charger I thought for this? We have an EV but with a very dumb charger unfortunately!
Possibly. I thought as long as octopus has a device it can interact with whether that be the car or the charger then you can opt for the tariff but I might be wrong on that.
Most of the modern decent EVs will work with Intelligent Go. I have a Tesla and a Zappi charger (both of which will work with Intelligent Go). I have been on Intelligent Go in the past, but this year I've switch back to straight Go - I'm charging the EV from excess solar at this point in the year, and Intelligent Go just adds another layer of "faff". 8.5p/kWh is cheap enough, so I'm happy with that.
Surely the faff on octopus go is entirely optional? The overnight period still exists and is cheaper.
The faff on Intelligent Go, sort of. When I previously used Intelligent Go, my EV was the component Octopus controlled. You then have to ensure you've set up the Tesla App and the Octopus App. It's usually the odd occasion when you need to charge to 100% overnight that you forget something and wake up with only 80%.
Also I have home batteries, sometime Octopus would start the car charging at 20:00 for a one hour slot which would take from the battery, and then I'd have no battery left for the last few hours of the evening, meaning I'm unexpectedly buying daytime electricity later in the evening.
Maybe if you just have an EV, no renewables it's a bit more predictable, but with my home batteries it just wasn't working how I wanted.
Yes, you get 6 hours of overnight for the whole house, but the EV has to remain in Octopus' control. If you try to work around what they are doing with the car (e.g. by setting your own overnight schedule on the car) you get annoying emails from Octopus, then ultimately they push you down to "Go". So to get 6 hours at 7p/kWh you have to play the game at put up with the negatives. For me it's much easier to get 5 hours at 8.5p and I can do what I want with the EV including daytime solar surplus charging (which I wouldn't be able to do on Intelligent Go).
If it helps, octopus only has control of my charger not my EV but that might be because of octopus having issues with the BMW api at the moment.
I can see the battery point would be really annoying. I suspect better battery management software would help here and it’s definitely possible to stop batteries from draining to charge cars but as I don’t yet have a home battery I can’t speak with any authority on how best to achieve that.
If the go tariff is working for you then stick with it. I’ve got to say I love the cheap energy slots for the whole house. Although it is impacting my assessment of the economics of getting battery and solar. A heat pump will probably change that as and I when I take the plunge.
I've looked at re-joining Intelligent Go with the Zappi charger as the smart device that Octopus would control. At least that would allow my daytime surplus solar charging to work, but the Zappi doesn't know the SoC of the car, so for overnight charging you have to set up to charge X kWh by a given time, and you have to determine X yourself. This is even more faff, so won't be going with that option.