Boosting energy efficiency status of buildings to combat climate change - what does it take?

frozen_wastes · 19 May 2019 at 12:38PM

So, I was looking at what it would take to improve the energy efficiency of my house in order to make it carbon neutral.

It's a 1993 built scottish timber framed bungalow which originally had an EPC Energy efficiency rating of F when I moved into it 10 years ago.

That EPC report came up with a number of recommendations such as boosting loft insulation, replacing the boiler, energy efficient lights and so on. That would boost my house upto a rating of E.

Not very good is it? So the question I've asked myself is how to bring it up to a rating of A.

Now a bit about my house:
- Fibreglass insulation under the suspended floor
- Fibreglass insulation in the walls
- Triple glazed windows (original windows, so probably quite an old spec)
- 35cm insulation in the loft (upgraded from 15cm)
- A Rated LPG Boiler (upgraded from G Rated Boiler)
- Triple Glazed front door (upgraded from solid door)
- Newly fitted wood burner and chimney with sealed air supply

Reasonably modern don't you think? And yet it's far from good enough.

So my annual running costs are about £400/year firewood £700/year LPG and £400/year electricity. About £1500/year annually.

So to upgrade from that, to an A Rating would require my bills to be reduced close to zero. I'm guessing I need to do all of the following to achieve that:
- Replace fibreglass insulation in floors and walls with solid PIR board (stud depth is 80mm)
- Rotate outside wall studs 90 degrees in a staggered fashion to avoid cold bridging (building warrant required for that I think)
- Seal up all gaps that cause a draught
- Replace all windows with upgraded triple glazed windows, with extra attention to draught sealing
- Install MVHR system in the loft
- Replace LPG boiler with ground source heat pump
- Fit Solar Panels on the roof (replace every single tile, including shady roof side with solar, not just a "box ticking" exercise!)

It's sufficient to suggest that many of these activities will also be extremely disruptive to home living as well.

All eye wateringly expensive. I read somewhere that passiv haus retrofits are around £80-90k. All told it'll take in excess of 50 years to repay the investment.

Worse is the fact that if I sell my house, I'll need to write off that investment. The fact of the matter is that the housing market up where I live has barely any price distinction between F rated or C rated properties of similar size.

I've never seen any A rated properties for sale. Most new houses are C rated, and I've only ever seen one example of a B rated property (an upstairs flat). I've never a house that is higher than a C Rating, and most that do meet a C rating are brand new.

Now on a grander level, space heating is responsible for about 40% of the UK's final energy demand. But the depressing thing is that there's absolutely no incentive to refit existing housing stock to a level that is sufficient to meet carbon neutral targets.

In the current political environment we have something declared that's known as a "climate emergency". In my mind an "emergency" is something that requires hard, immediate action. I'm sure to a politician, it's just an empty soundbite that grabs attention without meaning anything more.

So I wrote to my MSP, as it is them that need to be held upto this statement. I suggested to him that in order to make all this happen, essentially inefficient properties need very heavy taxation, and efficient properties need to have tax discounts applied. Tax essentially becomes the tool needed to make EPC A ratings economically viable.

So what do others think on this forum? What does it take, economically speaking, to make building upgrades to EPC A ratings worthwhile and economic? Is taxation (specifically council tax and business rates) the only way of doing this, or are there other ways? Technical innovation seems to be something lacking when it comes to insulation, the builders merchants catalogues are much the same now as they were 10 years ago.

GreatApe · 21 May 2019 at 3:41PM

Taxes dont change economic reality they are accounting tricks not real productivity improvements so if as you suggest to go passive house costs 80-90 grand it will cost 80-90 grand irrespective of tax changes. Instead of trying to push accounting tricks to hide costs you should try to push for innovation in insulation methods to try and reduce this 80-90 grand cost you cite

Anyway you dont need houses to become passive you just need a green grid and a heat pump and regulations so you can buy non peak heating electricity for below 10p a unit and ideally just 6p a unit

Within five years the UK grid will be very green
We should have hopefully another 10GW of offshore wind and we are building 3.4GW interconnectors to france and 1.4GW to norway in that fiv eyear timeframe

So quite likely the UK grid of 2023 will be ~75% non fossil fuel ~25% fossil fuel with CO2/Kwh likely below 130grams

Therefore heating your home via a heat pump will be very green and will continue to get greeener as the grid becomes even less CO2 intensive

Also there is a plan to build an additional 2GW link to France (on top of the 3.4GW mentioned above) which would displace even more CO2 from the grid

GreatApe · 21 May 2019 at 3:51PM

The best method to green homes quickly is to regulate separate charges for electrical heating of less than 8p/kwh for non peak usage.

Smart resistance heating (only rapidly heating rooms when occupied for instance) will cut energy needs substantially perhaps by 50% or more. And direct heating of water at close to 100% efficiency eg an electric shower is much better than a typical boiler which might be 75% efficient but realistically pipe losses and tank losses will mean it is perhaps closer to 65% efficiency

A 10MWh gas fired demand might be supplanted by a 5MWh electricity demand

4p for the gas would cost £400 annual and 8p for the Electricity would cost only £400 for the electricity so no additional running costs for the electric version in fact it will be cheaper due to lower install costs and lower maintenance costs

Also going from 1.9 tons CO2 for the 10MWh of gas to 0.65 tons CO2 for the 5MWh of electricity (at 130grams assumed 2023 grid) therefore a 65% cut in CO2 too

Cost to the household, nothing. Compared to your quoted 80-90 grand to make homes excessively heat tight

frozen_wastes · 21 May 2019 at 7:10PM

Interesting thoughts.

I once considered heat pumps, and 10 years ago the price off the shelf for these things was about £8k for an Air Source and £15k for a ground source heat pump. Compared to £800 for an 18kW LPG boiler it was still a massive cost. We're not talking £80k, but we're still not talking economic sense.

That all assumed however that you could simply swap out your existing boiler and plumb these units into your existing central heating system. You could do this, but the coefficient of power was terrible. So you were faced with the prospect of ripping out the radiators, lifting up every floor and then retrofitting underfloor insulation. It was a massive cost, with lots of attention to detail required from potentially inexperienced plumbers in order to make it effective. This is where the concept of "insulate everything" becomes a much more attractive thought process.

Now running the numbers today, I come across this item:
https://les.mitsubishielectric.co.uk/products/heating/domestic/outdoor/ecodan-puhz-monobloc-air-source-heat-pump

Off the shelf cost is about £7900ish, SCOP (Seasonal Coefficient of Power?) is 3ish with 55 degree temperature.

I could run that off my existing radiators. But the installation cost is still 8x greater than a new LPG boiler.

GreatApe wrote: »

The best method to green homes quickly is to regulate separate charges for electrical heating of less than 8p/kwh for non peak usage.

Nice idea, but economic realities will confine such prices to the dead of night, or a mid summer noon, rather than when you actually want your home to be cosy in a mid winters early evening.

I'm paying 17p/kWH in the north of Scotland and with the CoP quoted, that leads to a running cost that's a bit cheaper than LPG, but a bit more expensive than mains gas.

Now in the future to add more [STRIKE]fuel [/STRIKE]water to the fire, we'll have time of day electric metering. I can't find it now, but there's a trial with my provider (Bulb) for willing volunteers. Price between 4pm and 7pm, is an eye watering 41p/kWH! That's precisely the time when you would otherwise want to run your heat pump.

Now might just get 30kWH batteries for our houses that don't cost £15k several years from now so we can take advantage of a suggested 8p/KWH night time rate. But for now, we really need to see heat pump prices dip at least 60-70% to make that a reality. The last 10 years certainly hasn't seen that happen.

This is why decarbonisation of our heating systems is going to take a while. Yes we do have an RHI, but as mentioned here, on a country scale that is just an accounting trick rather than a real cost reduction measure.

silverwhistle · 21 May 2019 at 10:36PM

Can't really help technically other than observe that here in Hampshire on the south coast my annual gas consumption is less than 1100 kWh, mainly for hot water when the solar panels aren't productive enough, the rest of my heat coming from scrounged wood. So a move from the frozen wastes might help!

On a more practical note, have you seen the Green Building Press website, which has a very helpful forum? The Navitron site also has lots of helpful people on their forum too, although I suspect you may already have come across it.

GreatApe · 21 May 2019 at 10:40PM

frozen_wastes wrote: »

Interesting thoughts.

I once considered heat pumps, and 10 years ago the price off the shelf for these things was about £8k for an Air Source and £15k for a ground source heat pump. Compared to £800 for an 18kW LPG boiler it was still a massive cost. We're not talking £80k, but we're still not talking economic sense.

That all assumed however that you could simply swap out your existing boiler and plumb these units into your existing central heating system. You could do this, but the coefficient of power was terrible. So you were faced with the prospect of ripping out the radiators, lifting up every floor and then retrofitting underfloor insulation. It was a massive cost, with lots of attention to detail required from potentially inexperienced plumbers in order to make it effective. This is where the concept of "insulate everything" becomes a much more attractive thought process.

Now running the numbers today, I come across this item:
https://les.mitsubishielectric.co.uk/products/heating/domestic/outdoor/ecodan-puhz-monobloc-air-source-heat-pump

Off the shelf cost is about £7900ish, SCOP (Seasonal Coefficient of Power?) is 3ish with 55 degree temperature.

I could run that off my existing radiators. But the installation cost is still 8x greater than a new LPG boiler.

Nice idea, but economic realities will confine such prices to the dead of night, or a mid summer noon, rather than when you actually want your home to be cosy in a mid winters early evening.

I'm paying 17p/kWH in the north of Scotland and with the CoP quoted, that leads to a running cost that's a bit cheaper than LPG, but a bit more expensive than mains gas.

Now in the future to add more [STRIKE]fuel [/STRIKE]water to the fire, we'll have time of day electric metering. I can't find it now, but there's a trial with my provider (Bulb) for willing volunteers. Price between 4pm and 7pm, is an eye watering 41p/kWH! That's precisely the time when you would otherwise want to run your heat pump.

Now might just get 30kWH batteries for our houses that don't cost £15k several years from now so we can take advantage of a suggested 8p/KWH night time rate. But for now, we really need to see heat pump prices dip at least 60-70% to make that a reality. The last 10 years certainly hasn't seen that happen.

This is why decarbonisation of our heating systems is going to take a while. Yes we do have an RHI, but as mentioned here, on a country scale that is just an accounting trick rather than a real cost reduction measure.

The cost of electricity is mostly the non electricity costs

A utility buys electricity for say 5p a unit and sells it retail for 15p a unit and say the average residential customer uses 3,000 units (just for arguments sake, the figures dont need to be exactly right)

What this means is the electricity costs £150 and everything else costs £300 and you pay a bill of £450

Lets say you instead use 8,000 units of electricity. Well the electricity cost is now £400 but the everything else cost is still only £300 (assuming the local and national grid does not need to be upgraded which is likely the case if you use outside of peak times) so the per unit cost is only now £700 for 8,000 units or just 8.75p a unit so you can be charged just 8.75p a unit and it all works

Or you can be charged 15p a unit for the first 3,000 units then just 5p a unit for the next 5,000 units as a 'heating tariff rate'

This is roughly what needs to happen
We need a normal rate for electricity and a much cheaper heating rate for electricity

The question is, do we have the spare grid capacity to move this additional power at 0 marginal cost. I would make the argument that in a lot of places the answer at least for now is YES by the fact that UK consumption was nearly 400TWh a year and now is 335 TWH a year so clearly there is capacity to move at least 65TWh more through the grid at near zero marginal additional cost

I think the above figures are maybe a bit optimistic as we will need some local grid expand hence why I say 8p a unit should be possible

With 8p a unit even if your heat pump gets 2 COP the price becomes affordable

And the grid will green over time anyway

Also I think just smart resistance heating will be very efficent
A resistance heater is really cheap and compact and very powerful
You might have for instance a 5KW resistance heater in a room and it turns on only when someone is in the room then it turns off when there is no one.
This way only the rooms with people in it are heated which should be a significant saving.

For instance my parents have a huge house they heat the whole thing because that is the way it is setup at the moment.

With smart electrical heaters operating just in the rooms in use it might save them 75% in KWH needed so there is a lot of efficiency gains that could be had with smart heaters

Certainly your first statement of spending 80-90 grand to insulate to the max the housing stock isnt going to fly. Doing that to 25 million uk homes would cost £2 trillion plus not gona happen

GreatApe · 21 May 2019 at 10:53PM

frozen_wastes wrote: »

Interesting thoughts.

I once considered heat pumps, and 10 years ago the price off the shelf for these things was about £8k for an Air Source and £15k for a ground source heat pump. Compared to £800 for an 18kW LPG boiler it was still a massive cost. We're not talking £80k, but we're still not talking economic sense.

That all assumed however that you could simply swap out your existing boiler and plumb these units into your existing central heating system. You could do this, but the coefficient of power was terrible. So you were faced with the prospect of ripping out the radiators, lifting up every floor and then retrofitting underfloor insulation. It was a massive cost, with lots of attention to detail required from potentially inexperienced plumbers in order to make it effective. This is where the concept of "insulate everything" becomes a much more attractive thought process.

Now running the numbers today, I come across this item:
https://les.mitsubishielectric.co.uk/products/heating/domestic/outdoor/ecodan-puhz-monobloc-air-source-heat-pump

Off the shelf cost is about £7900ish, SCOP (Seasonal Coefficient of Power?) is 3ish with 55 degree temperature.

I could run that off my existing radiators. But the installation cost is still 8x greater than a new LPG boiler.

Nice idea, but economic realities will confine such prices to the dead of night, or a mid summer noon, rather than when you actually want your home to be cosy in a mid winters early evening.

I'm paying 17p/kWH in the north of Scotland and with the CoP quoted, that leads to a running cost that's a bit cheaper than LPG, but a bit more expensive than mains gas.

Now in the future to add more [STRIKE]fuel [/STRIKE]water to the fire, we'll have time of day electric metering. I can't find it now, but there's a trial with my provider (Bulb) for willing volunteers. Price between 4pm and 7pm, is an eye watering 41p/kWH! That's precisely the time when you would otherwise want to run your heat pump.

Now might just get 30kWH batteries for our houses that don't cost £15k several years from now so we can take advantage of a suggested 8p/KWH night time rate. But for now, we really need to see heat pump prices dip at least 60-70% to make that a reality. The last 10 years certainly hasn't seen that happen.

This is why decarbonisation of our heating systems is going to take a while. Yes we do have an RHI, but as mentioned here, on a country scale that is just an accounting trick rather than a real cost reduction measure.

The solution is this

£50 smart heater per room (should be possible)

Your energy company charging you only 8p a unit and just limiting your usage to not be during 5-8 pm on winter evenings. You can probably get away with this with the thermal mass of the building. That is to say if you have 19 degrees set normally the home might heat to 24 centigrade for 5pm and might fall down to 18 centigrade by 8pm so you have this 6 degrees of thermal storage in the fabric of the building which will hopefully tide you over

If you currently use 10,000 units for gas or LPG you will likely only need 8,000 units of electricity as your boiler isn't fully efficient while electricity is 100%

If the smart heaters by virtue of only heating rooms in use save you another 25% that means you would only need 6,000 units of electricity

If your utility charged you even 10p a unit that cost is 'only' £600 a year
Bear in mind you do not have a boiler to replace every 10 years at a cost of £1000 and no annual service at £100 so effectively the replacement and maintenance cost is say £200 lower so the actual cost in this example is £600-£200=£400

Resistance heaters are very reliable and will outlast you unlike the gas boiler

Another option is instead of no heat during the winter peaks you might be allowed say 1KW if we convert 25 million homes to electric heating that would be 25GW additional demand which is significant but well within reasonable possibility of both the grid and additional CCGT powering it. Or that 1KW limit might be higher on the days the wind blows hard which might be for about 60% of the winter days plus the thermal mass and it would be fine

michaels · 21 May 2019 at 10:54PM

GreatApe wrote: »

The cost of electricity is mostly the non electricity costs

A utility buys electricity for say 5p a unit and sells it retail for 15p a unit and say the average residential customer uses 3,000 units (just for arguments sake, the figures dont need to be exactly right)

What this means is the electricity costs £150 and everything else costs £300 and you pay a bill of £450

Lets say you instead use 8,000 units of electricity. Well the electricity cost is now £400 but the everything else cost is still only £300 (assuming the local and national grid does not need to be upgraded which is likely the case if you use outside of peak times) so the per unit cost is only now £700 for 8,000 units or just 8.75p a unit so you can be charged just 8.75p a unit and it all works

Or you can be charged 15p a unit for the first 3,000 units then just 5p a unit for the next 5,000 units as a 'heating tariff rate'

This is roughly what needs to happen
We need a normal rate for electricity and a much cheaper heating rate for electricity

The question is, do we have the spare grid capacity to move this additional power at 0 marginal cost. I would make the argument that in a lot of places the answer at least for now is YES by the fact that UK consumption was nearly 400TWh a year and now is 335 TWH a year so clearly there is capacity to move at least 65TWh more through the grid at near zero marginal additional cost

I think the above figures are maybe a bit optimistic as we will need some local grid expand hence why I say 8p a unit should be possible

With 8p a unit even if your heat pump gets 2 COP the price becomes affordable

And the grid will green over time anyway

Also I think just smart resistance heating will be very efficent
A resistance heater is really cheap and compact and very powerful
You might have for instance a 5KW resistance heater in a room and it turns on only when someone is in the room then it turns off when there is no one.
This way only the rooms with people in it are heated which should be a significant saving.

For instance my parents have a huge house they heat the whole thing because that is the way it is setup at the moment.

With smart electrical heaters operating just in the rooms in use it might save them 75% in KWH needed so there is a lot of efficiency gains that could be had with smart heaters

Certainly your first statement of spending 80-90 grand to insulate to the max the housing stock isnt going to fly. Doing that to 25 million uk homes would cost £2 trillion plus not gona happen

There might still be a need to timeshift demand from the 4pm - 8pm peak so the grid could cope with both generation and distribution.

One way is obviously batteries but these still seem to be too expensive given their costs and life span.

I did suggest it might be possible to store heat as heat, either using storage heaters or perhaps using a large hot water tank as a thermal heat store - how much volume of water would it take to store 100kwh of heat?

GreatApe · 21 May 2019 at 11:06PM

Oh also a huge number of homes in the UK (and every developed country for that matter) are only lived in by 1 person. iirc the figure in the UK is something like 7 million homes where just one person lives

I would wager almost all those homes are heated fully and not room by room

Smart resistance heaters heating just the one room should see upto an 80% efficiency gain (heating 1 room rather than 5)

Why heat the kitchen the bathroom the living room the dining room and the two bedrooms the hallways and the two bedrooms when at most the one person living in that house is using just one room

In addition the resistance heaters could output a huge 5KW so even a cold room would heat up very quickly (unlike say a 1 KW wet radiator)

Plus the smart heaters can be fully automatic so when the person is out none of them are on
Plus the high wattage means people would not leave their homes heated 24/7 just to avoid the 30-60 mins heat time when they return from work to not have a cold house

Plus resistance heaters by virtue of cheaper to install and maintain would be lower embedded CO2 too.
A half dozen £30 smart fan heater with a mass of 10kg is a lot cheaper to manufacture maintain and install than a £3000+ wet system that has a mass probably 50 x as much in materials and transport costs

But it has to be a smart system
If you leave it to the individuals they wont know or bother
With the smart system it will all be automatic
Smart system might work with cameras or microphones and AI to determine if the room is occupied or not. If it gets it right 95% of the time it will be fine but it will probably grow to be 99.99% correct

Anyway heating is a problem that can be tackled with smart systems and can be converted relatively quickly but some regulations should be put in place to make this happen a little smoother and better

Such a system could be deployed in Norway and Sweden since they are more or less 100% resistance electrically heated already. Their electricity usage would go down so they could export that to the UK/Elsewhere

GreatApe · 21 May 2019 at 11:17PM

michaels wrote: »

There might still be a need to timeshift demand from the 4pm - 8pm peak so the grid could cope with both generation and distribution.

One way is obviously batteries but these still seem to be too expensive given their costs and life span.

I did suggest it might be possible to store heat as heat, either using storage heaters or perhaps using a large hot water tank as a thermal heat store - how much volume of water would it take to store 100kwh of heat?

That adds cost and complexity and wont really work. And we would only need to shift the hours where there is little to no wind. UK offshore capacity factor is roughly 30% summer 50% winter that means at least 50% of the winter days there will be the power to feed these electric homes even during the 4-8pm window

If the new wind turbines which promise 50% year round capacity are true they might be 40% summer 60% winter so 60% of winter days you can use your electric heaters at 4-8pm

I would be happy to accept electricity for <8p/KWh with the downside that I can not heat for 40% of the winter days during 4-8 PM which is not a huge issue I can still heat for 60% of those time/days

Plus we can allow some heating in the winter peaks if we build backup CCGTs or GTs
If you allow 1KW per home and say 70% of homes are full during those hours and we have 30 million homes that equates to 21GW of demand. So we would need 21GW more power stations than otherwise would be the case. That 1KW could keep one room toasty warm and remember something like 7 million UK homes only have 1 person living in them so its not an inconvenience for those people as they only need one room warm.

That is not a huge cost in the scheme of things to electrify all heating

Overall if you say 4 months are cold so 120 days
If wind covers 60% of those days
That is 48 days when you might be curtailed to heating just one room
Actually if offshore wind power capacity factor is 60% during the winter that does not mean 60% on 40% off that means some level of wind probably most the time so even less than 48 days when you are curtailed maybe only a third of that

not a huge problem

GreatApe · 21 May 2019 at 11:31PM

michaels wrote: »

There might still be a need to timeshift demand from the 4pm - 8pm peak so the grid could cope with both generation and distribution.

One way is obviously batteries but these still seem to be too expensive given their costs and life span.

I did suggest it might be possible to store heat as heat, either using storage heaters or perhaps using a large hot water tank as a thermal heat store - how much volume of water would it take to store 100kwh of heat?

You wouldn't do water heating but with mass EVs and higher offshore wind output in the winter (50%+) you would probably find that most the days the winter even during 4-8 pm you would be fine

Have the smart grid limit heating usage to just 1KW during winter 4-8 pm when the wind isn't blowing and you might add about 20GW to winter demand peaks and backup generation needs. This might be CCGTs GTs Batterieis VTG etc

Also you would start by electrifying the smallest most efficient homes often the ones with just 1 person in them and avoid the 100 year old 5 bed Victorian homes that need 30MWh of winter heat they can stay gas fired for 30 years until we figure something out or the AI gets here and figures it all out for us.

Boosting energy efficiency status of buildings to combat climate change - what does it take?

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