Keith Alexander
@keithalexander.bsky.social
Interested in climate & the environment
Is this even possible? COP of 6? #heatpumps
December 3, 2025 at 12:37 PM
Is this even possible? COP of 6? #heatpumps
Unfortunately (we've still got lots of retrofitting to do) the heating just gobbles up energy, so the more I can get to run in the 15p/kWh periods, the better.
December 3, 2025 at 12:09 PM
Unfortunately (we've still got lots of retrofitting to do) the heating just gobbles up energy, so the more I can get to run in the 15p/kWh periods, the better.
Sealing up the escape at the end.
November 22, 2025 at 9:06 AM
Sealing up the escape at the end.
Spent way too long insulating this dormer cheek. The tiny crawl space and exit hatch made it time consuming, and important to sequence things in order to escape at the end!
The thermal image from the room shows 240mm woodfibre (red) 75mm shoved up blind, and no insulation (blue) #retrofit
The thermal image from the room shows 240mm woodfibre (red) 75mm shoved up blind, and no insulation (blue) #retrofit
November 22, 2025 at 9:04 AM
Spent way too long insulating this dormer cheek. The tiny crawl space and exit hatch made it time consuming, and important to sequence things in order to escape at the end!
The thermal image from the room shows 240mm woodfibre (red) 75mm shoved up blind, and no insulation (blue) #retrofit
The thermal image from the room shows 240mm woodfibre (red) 75mm shoved up blind, and no insulation (blue) #retrofit
A job ad to work on sodium (sulphur) batteries for “power without pollution” from September 18 1977
November 15, 2025 at 5:23 PM
A job ad to work on sodium (sulphur) batteries for “power without pollution” from September 18 1977
AEG’s website is shamelessly replete with AI slop 😳
November 7, 2025 at 11:35 PM
AEG’s website is shamelessly replete with AI slop 😳
If you’re going to do some insulating or air tightness/draught proofing, I recommend buying or borrowing a thermal image camera if you can.
It’s useful not just for identifying areas to insulate, but checking your work for defects that are often not obvious to the naked eye.
It’s useful not just for identifying areas to insulate, but checking your work for defects that are often not obvious to the naked eye.
October 30, 2025 at 1:26 PM
If you’re going to do some insulating or air tightness/draught proofing, I recommend buying or borrowing a thermal image camera if you can.
It’s useful not just for identifying areas to insulate, but checking your work for defects that are often not obvious to the naked eye.
It’s useful not just for identifying areas to insulate, but checking your work for defects that are often not obvious to the naked eye.
I was lime plastering yesterday and had ran out of corner bead to do this window, so somewhat inspired by @michaelburchert.bsky.social's beautiful photo, we decided a curved corner would look nicer anyway. It's woodfibre board underneath stuck with lime plaster onto a conventional brick cavity wall
October 28, 2025 at 11:34 AM
I was lime plastering yesterday and had ran out of corner bead to do this window, so somewhat inspired by @michaelburchert.bsky.social's beautiful photo, we decided a curved corner would look nicer anyway. It's woodfibre board underneath stuck with lime plaster onto a conventional brick cavity wall
Raggling/chasing rigid woodfibre. Palm router worked well for cutting a fixed depth, and creates loose insulation collected in the vacuum, which might come in handy elsewhere. #retrofit
October 22, 2025 at 4:59 PM
Raggling/chasing rigid woodfibre. Palm router worked well for cutting a fixed depth, and creates loose insulation collected in the vacuum, which might come in handy elsewhere. #retrofit
A #RetroFit #airtightness technique I’ve been using with areas that are awkwardly lumpy to tape, and with gaps too big to paint with liquid membrane, is to stuff the gaps with little clumps of woodfibre and then paint with liquid membrane.
October 19, 2025 at 11:10 AM
A #RetroFit #airtightness technique I’ve been using with areas that are awkwardly lumpy to tape, and with gaps too big to paint with liquid membrane, is to stuff the gaps with little clumps of woodfibre and then paint with liquid membrane.
I was told that EPCs had changed their methodology with regard to heat pumps, but while they recognise the environmental benefit, they're still giving a 450% efficient central heating system 3/5 for energy efficiency. 🤦♂️
October 14, 2025 at 10:10 AM
I was told that EPCs had changed their methodology with regard to heat pumps, but while they recognise the environmental benefit, they're still giving a 450% efficient central heating system 3/5 for energy efficiency. 🤦♂️
Siri, define hostages
October 13, 2025 at 9:47 AM
Siri, define hostages
One thing that gives me a bit of hope with regard to Reform’s prospects is that concern about immigration is not constantly high, and chances are that something else will displace it by the next election. yougov.co.uk/topics/socie...
October 13, 2025 at 8:05 AM
One thing that gives me a bit of hope with regard to Reform’s prospects is that concern about immigration is not constantly high, and chances are that something else will displace it by the next election. yougov.co.uk/topics/socie...
From the review paper reported on:
www.annualreviews.org/content/jour...
www.annualreviews.org/content/jour...
October 7, 2025 at 11:35 AM
From the review paper reported on:
www.annualreviews.org/content/jour...
www.annualreviews.org/content/jour...
At this rate my new solar panels will pay off their carbon debt in about 500 years....
Will they eventually save me money, but be bad for the climate? 🙃
Will they eventually save me money, but be bad for the climate? 🙃
September 29, 2025 at 11:20 AM
At this rate my new solar panels will pay off their carbon debt in about 500 years....
Will they eventually save me money, but be bad for the climate? 🙃
Will they eventually save me money, but be bad for the climate? 🙃
In my feed this morning:
- 3ºC possible by 2050, 1.5ºC probably already exceeded
- We can still keep "close to" 1.5ºC and get below it by 2100
- We can only reverse 0.7ºC at most.
- 3ºC possible by 2050, 1.5ºC probably already exceeded
- We can still keep "close to" 1.5ºC and get below it by 2100
- We can only reverse 0.7ºC at most.
September 26, 2025 at 8:39 AM
In my feed this morning:
- 3ºC possible by 2050, 1.5ºC probably already exceeded
- We can still keep "close to" 1.5ºC and get below it by 2100
- We can only reverse 0.7ºC at most.
- 3ºC possible by 2050, 1.5ºC probably already exceeded
- We can still keep "close to" 1.5ºC and get below it by 2100
- We can only reverse 0.7ºC at most.
This bit seems odd to me. Draughts of warm air to the head seem likely to be less comfortable than steady less draughty warmth!
September 24, 2025 at 1:50 PM
This bit seems odd to me. Draughts of warm air to the head seem likely to be less comfortable than steady less draughty warmth!
This is a bit hopeful
September 23, 2025 at 12:20 PM
This is a bit hopeful
Handy thing I found with the inditherm hemp product is that the fibres are strong and well-bound enough that you can staple the edges to timber to hold it in place. (Probably only necessary because these are only 50mm thick- 100mmx440mm would friction fit I think)
September 23, 2025 at 6:14 AM
Handy thing I found with the inditherm hemp product is that the fibres are strong and well-bound enough that you can staple the edges to timber to hold it in place. (Probably only necessary because these are only 50mm thick- 100mmx440mm would friction fit I think)
I’d like to reduce sound transfer from the kitchen to the floor above, and the ceiling is off atm. I’ve got some 50mm hemp and I was thinking I could maybe hold it in place with netting before putting plasterboard on.
September 15, 2025 at 8:33 PM
I’d like to reduce sound transfer from the kitchen to the floor above, and the ceiling is off atm. I’ve got some 50mm hemp and I was thinking I could maybe hold it in place with netting before putting plasterboard on.
The space comes up here under the bath on the floor above, which is also hard to make airtight at this point. (And the bath is currently leaking…)
September 13, 2025 at 3:57 PM
The space comes up here under the bath on the floor above, which is also hard to make airtight at this point. (And the bath is currently leaking…)
This is an awkward bit to retrofit. Cold air will come up through the solum, and it’s difficult to seal a membrane around all those pipes. And I need to preserve access, because that’s where the water main stop cock is. I’m also a bit nervous about preventing any leaks from draining into the solum.
September 13, 2025 at 3:55 PM
This is an awkward bit to retrofit. Cold air will come up through the solum, and it’s difficult to seal a membrane around all those pipes. And I need to preserve access, because that’s where the water main stop cock is. I’m also a bit nervous about preventing any leaks from draining into the solum.
I think maybe the black mould here was because those battens stopped the insulation sitting flush against the ceiling so moisture coming through the plasterboard from below would condense on the cold top of the ceiling.
September 1, 2025 at 9:07 AM
I think maybe the black mould here was because those battens stopped the insulation sitting flush against the ceiling so moisture coming through the plasterboard from below would condense on the cold top of the ceiling.
And I think the video is misleading in suggesting that a few mm of this insulation is going to have a dramatic effect on heat loss. If you take pretty much a worst case scenario (thin brick wall), then it could cut heatloss through the treated area by ~17%.
August 27, 2025 at 3:07 PM
And I think the video is misleading in suggesting that a few mm of this insulation is going to have a dramatic effect on heat loss. If you take pretty much a worst case scenario (thin brick wall), then it could cut heatloss through the treated area by ~17%.
For a start, he seems pretty confused about the difference between flammability and heat loss. "This is the heat inside your home - the heat is going to go straight through your wall" (burns polystyrene with blow torch).
That's not the same thing at all!
That's not the same thing at all!
August 27, 2025 at 2:18 PM
For a start, he seems pretty confused about the difference between flammability and heat loss. "This is the heat inside your home - the heat is going to go straight through your wall" (burns polystyrene with blow torch).
That's not the same thing at all!
That's not the same thing at all!