Plus: Lego asks the London Conservatives to stop using yellow bricks to mock Sadiq Khan — and do you want to live in a former aircraft factory in Zone 3?
As someone who writes planning policy for new development, we wish to encourage developers to use “passive design” as much as possible, with “active cooling” (AC, forced air and other methods) as a last resort - basically encouraging good architecture and design first!
Passive design includes dual aspect for a cross breeze, shutters and canopies for windows, window size/openable area, minimising areas of unshaded concrete, building orientation and overshadowing etc.
No one wants to copy Phoenix and have buildings completely unsuited for the microclimate resulting in vast energy use for air conditioning. There will always be cases where AC is the best solution for a specific building, mind.
I love the idea of passive design but the lived reality for a lot of people in new build blocks is of unbearable heat in summer - and if electricity becomes cheap and green, it feels like some of the case against air con is obliterated.
As a survivor of the Guardian office at Kings Place, where the air con shuts down whenever it gets too hot, I’m aware of the challenges that something designed with best practice in mind even just two decades ago can face when confronted with ever hotter summers.
For sure - I also live in a new ish block that gets too hot… 🥵
I’d argue that the majority of the 2000/2010s new buildings did not consider those passive design principles properly, if at all. Think of the new build towers that are mostly glass… they’re basically a tall greenhouse!
Can you help me understand why the thousands of new flats in London, many with South and West-facing aspects, don't just have mechanical or electric window shutters fitted as standard? Something that is universal in most of Europe, that works well and costs very little? Is it a planning issue, or something else?
I see new flats being marketed with their vast glass panels shining in the sun and I genuinely pity the future buyers/tenants.
Requiring 'passive first' design in regulations is not the same thing as designing a building so it can benefit from passive cooling. Regulations interact with each other in costly and even impossible ways (eg dual aspect is much more difficult to achieve in dual staircase buildings, now required in buildings above 18m). Forcing developers to bad make trade-offs between onerous and expensive requirements results in worse and more expensive buildings, despite the good intentions of regulators.
London cannot end up like Phoneix because its built environment is already dense, it relies on public transport, and it's not in one of the hottest deserts on Earth.
However, London is already spending weeks at a time above 30°C. Unless you are a climate change denier, you have to accept that this will persist and intensify, and tiny dark windows and fans with ice are not going to be enough to keep Londoners comfortable and safe under such conditions.
The public is already leaving policy behind and buying mobile A/C units despite their inefficiency just to stay cool. If we want good design and high energy efficiency, we need to design new buildings to have A/C from the get-go, rather than forcing people to stick nozzles out of their windows for weeks at a time.
Has any modelling been done on how much this increases the cost and decreases the number of homes that gets built by limiting viability?
Or how much it increases demand for heating in the winter (when it's very hard to get reliable green energy) vs increases demand for cooling in the winter (when solar makes green energy easy, and if we're overbuilding solar for winter, we'll have plenty)?
Or how much it restricts other design?
This is the kind of policy that sounds good in a vacuum but:
- It can substantially add costs and restrict building when we're in a housing crisis
- It can only go so far.
I lived in some new build flats in London for 8 years, they had huge windows, thus tonnes of solar gain.
They were bloody hot in the summer.
But - I basically didn't use the heating ever, and it rarely went below 22. And large windows are nice, lots of natural light!
How much does attempts at passive cooling shift energy demands into the winter months, when the grid is at its dirtiest, because energy storage is hard.
Shifting the UK's energy use to be in the summer rather than the winter would help our carbon emissions massively, as you use AC when solar works well!
We need to get away from this idea that all energy use is bad. High carbon energy use is bad. Zero carbon energy use is good!
Do you think this policy has actually worked, and most new builds have functional passive cooling? The number which don't have external shutters makes me doubt it.
Having just installed air conditioning in my home this week, it feels like I’m living a life of luxury akin to have a Rolls Royce with a chauffeur. Finally getting eight hours of sleep again.
I'm surprised the list of reasons given here for the lack of air con doesn't mention its contribution to external heat, which is one of the reasons cited in the relevant London Plan policy. I've no idea how big an issue this is, but you can see how mass use of air conditioning could increase the urban heat island effect, causing more use of air conditioning, etc etc. Trying to reduce reduce that kind of negative cycle using simple technologies (shutters! recessed windows!) that are commonly used in other countries seems quite reasonable.
I am not an expert, but that seems negligible to me. UHI is real, cities have more stuff, which = more thermal mass! But I haven't found good evidence that AC shifts the needle, and I'd expect that other cities globally would have found it?
The corollary is that once we all switch to heat pumps, heat pumps will _take_ heat from the air, cooling it. Regardless of how much heat pumps affect outdoor air temperature, in London there'll be a larger cooling effect in winter than vice versa - we heat more than we cool!
But no one is worrying about heat pumps cooling the outside air causing a negative feedback loop, here or anywhere else, it just seems like policy experts focusing on direction rather than size.
Thanks Chris, that's really helpful. If that's the size of the effect, then (speaking also as a non-expert) it may well be acceptable. The study does have a couple of caveats - it seems to assume all buildings in the future will be insulated to post-1996 levels, which may be optimistic, and it also looks only at low-rise areas while noting that heat island effects are higher in denser neighbourhoods.
It's also difficult in leasehold blocks of flats because usually installing fixed AC means installing something externally, like a fan unit or vent, which will usually mean consent and a proper assessment including to make sure it doesn't increase fire risks. In the block I live in equipment externally is not allowed, so AC installations use a water based AC product so the excess heat goes down into the drain, but at a cost of water as well as electricity usage.
As well as noise - the thought of having to put up with a constant mechanical hum because someone’s installed air con badly is enough to put me right off the idea.
Wellll the impact of air conditioning isn’t just about electricity use, the refrigerants used - particularly historically - are HFCs. These are incredibly potent greenhouse gases. If they leak or are dumped at the end of their life, this is a huge problem. One tonne of HFC has the same global warming effect as 14,000 tonnes of carbon dioxide.
From what I understand the EU is trying to phase this out so it’s potentially less of a problem in newer air conditioners. But that’s the reason they have until now been discouraged in policy. It’s not really that much to do with the electricity usage of the appliance
I don't think this is true. The draft London plan explicitly cites active cooling as being something to avoid due to "energy use" and the "urban heat island":
You can assert that the real reason is HFCs, and that they're not stating that publicly, for some reason? But I think that's a much harder to prove claim.
When it's over 30 degrees outside, the best passive design in the world isn't going to bring your bedroom down to a comfortable temperature. And the UK is full of very old houses that just were not designed for modern summers - and it's only going to get hotter.
My bedroom is in the loft and my 16 month old daughter's bedroom faces west, so it is regularly nearly 30 degrees at bedtime, even with every window open and doing our best to block out the sunlight. Going to get AC installed as soon as we can afford it.
Fortunately the demand for AC coincides pretty neatly with the supply of solar power. As the article implies, given the global trends in solar power (and batteries), with renewable energy it's much easier to cool a hot country than warm a cold one.
Allowing air conditioning provides an additional incentive to replace gas boilers with much more efficient reversible heat pumps. It's incredible that this was against the regulations until recently!
External shutters are extremely effective at controlling indoors temperatures on sunny days, and are almost never seen in the UK. Is this a cultural thing or due to planning rules?
In addition, if I recall correctly , aside from planning permission, most if not all of the previous various Govt sponsored grant schemes allowed only for installation of heating only pumps not dual cooling/heating systems so you wouldn't get a subsidy for the latter.
Please do NOT rip your radiators out. Having moved away from the UK, I really miss them in the winter. An AC/heater that blows hot air in your face isn’t comparable
For anyone picking up a portable air-con unit, try to find a dual hose unit. They are significantly more efficient than the standard single hose units. Dual hose units are much less common in the UK unfortunately. Discourse online suggests it could be due to a lack of knowledge in the UK and a lack of willingness to spend money on devices that are not seen as an essential.
Single hose units pull air from indoors, warm it up and pump it outside. The air from indoors that the machine literally just cooled down. Dual hose units pull air from outside, warm it up and put it back outside.
Proper split outdoor units are better than both, but as others have said, are expensive and hard to install for many (like myself)
Looking at the weather for London right now — it’s 23 with an expected high of 27. In most of the world (e.g., the United States) is perfectly normal summer weather. Part of the problem is that Europeans and British people have been relentlessly propagandized about climate change to the point that normal weather is characterized as dangerously hot.
I’m curious to know if you have ever lived in London during the summer? As an Australian, 30°C did not automatically get classed as “heatwave” weather in my mind, but when I moved to London I grew to understand and appreciate that the city is not built for heat. There’s no cool breeze during these times, and the buildings have all been designed to keep warm. And as looking at the data even briefly will confirm, it is warmer than it has ever been. Climate change is not some propagandised boogieman, as much as some might like to pretend it is so.
Today we're all relishing the cooler temperatures, it was over 30C the past couple of days, and not much less before that. I haven't had a decent night sleep in weeks...
”There was a worry that if everyone gets air con the grid would collapse,” said Sissons. “[But] with more solar on hot days you’ve got quite a bit of extra capacity in the system.”
Data centres? Has their usage been figured in as well?
I think this website that the London Minute @thelondonminute shared on Friday has some really helpful suggestions to consider instead of or alongside AC.
But for renters and/or those of us in flats (that's a lot of us) most of these suggestions will be hard to implement because we need the landlord to do it for us or their permission.
I live in Australia. Reverse split system cycle air conditioning is bog standard here! Consists of an outside unit, some kind of magic gas which turns whatever from hot to cold or vice versa and pumps out either hot or cold air (your choice) via a filtered fan type unit mounted on your room’s wall or through ducting for whole house comfort. Solar power on the house roof makes it much cheaper to run, providing the sun shines of course! I live in a cool climate area and if I were to replace my gas central heating (not encouraged here by the way) my options would be new gas boiler or a split system which I probably would only use a maximum of 2 weeks in summer for cooling and maybe 4 to 6 months on heat mode between May and October. I’m not technical but reading the Times from afar I have conflated to understand that heat pumps which are promoted heavily for hot water systems in the uk are actually the same thing but they are only using the heating part of the system. Given the move to electrification I’m at a loss to understand why air conditioning is not encouraged especially if it’s connected to renewables.
Perhaps a limit on the kW per m2 (Aircon power, given the usable floor area)?
For new build, passive 'purge' design first, followed by mechanical nighttime ventilation, then by minimal cooling has to be the best approach. But as many commenters have pointed out, lots of existing new build has terrible shading, too much glazing and inadequate. So the problem is mostly bad design from developers/planning rules inadequate, rather than the lack of Aircon...
What I fear is if developers get the green light to throw in Aircon carte blanche, then all good design goes out the window and 1-sided concrete boxes with giant windows are in!
Existing dwellings are more complicated. For me, renting a Victorian converted flat, night time mechanical ventilation to cool the building would probably be adequate for all but the hottest great waves (and nights that are too warm). But in terms of passive solutions, external shading probably won't get past planning (even if I personally think Mediterranean style external shutters would look good).
As someone who writes planning policy for new development, we wish to encourage developers to use “passive design” as much as possible, with “active cooling” (AC, forced air and other methods) as a last resort - basically encouraging good architecture and design first!
Passive design includes dual aspect for a cross breeze, shutters and canopies for windows, window size/openable area, minimising areas of unshaded concrete, building orientation and overshadowing etc.
No one wants to copy Phoenix and have buildings completely unsuited for the microclimate resulting in vast energy use for air conditioning. There will always be cases where AC is the best solution for a specific building, mind.
I love the idea of passive design but the lived reality for a lot of people in new build blocks is of unbearable heat in summer - and if electricity becomes cheap and green, it feels like some of the case against air con is obliterated.
As a survivor of the Guardian office at Kings Place, where the air con shuts down whenever it gets too hot, I’m aware of the challenges that something designed with best practice in mind even just two decades ago can face when confronted with ever hotter summers.
For sure - I also live in a new ish block that gets too hot… 🥵
I’d argue that the majority of the 2000/2010s new buildings did not consider those passive design principles properly, if at all. Think of the new build towers that are mostly glass… they’re basically a tall greenhouse!
Well I guess I ought to link to my long history of investigating dangerously hot glass buildings in London… https://m.youtube.com/watch?v=hlRNO8xcrgU
Can you help me understand why the thousands of new flats in London, many with South and West-facing aspects, don't just have mechanical or electric window shutters fitted as standard? Something that is universal in most of Europe, that works well and costs very little? Is it a planning issue, or something else?
I see new flats being marketed with their vast glass panels shining in the sun and I genuinely pity the future buyers/tenants.
Requiring 'passive first' design in regulations is not the same thing as designing a building so it can benefit from passive cooling. Regulations interact with each other in costly and even impossible ways (eg dual aspect is much more difficult to achieve in dual staircase buildings, now required in buildings above 18m). Forcing developers to bad make trade-offs between onerous and expensive requirements results in worse and more expensive buildings, despite the good intentions of regulators.
London cannot end up like Phoneix because its built environment is already dense, it relies on public transport, and it's not in one of the hottest deserts on Earth.
However, London is already spending weeks at a time above 30°C. Unless you are a climate change denier, you have to accept that this will persist and intensify, and tiny dark windows and fans with ice are not going to be enough to keep Londoners comfortable and safe under such conditions.
The public is already leaving policy behind and buying mobile A/C units despite their inefficiency just to stay cool. If we want good design and high energy efficiency, we need to design new buildings to have A/C from the get-go, rather than forcing people to stick nozzles out of their windows for weeks at a time.
Has any modelling been done on how much this increases the cost and decreases the number of homes that gets built by limiting viability?
Or how much it increases demand for heating in the winter (when it's very hard to get reliable green energy) vs increases demand for cooling in the winter (when solar makes green energy easy, and if we're overbuilding solar for winter, we'll have plenty)?
Or how much it restricts other design?
This is the kind of policy that sounds good in a vacuum but:
- It can substantially add costs and restrict building when we're in a housing crisis
- It can only go so far.
I lived in some new build flats in London for 8 years, they had huge windows, thus tonnes of solar gain.
They were bloody hot in the summer.
But - I basically didn't use the heating ever, and it rarely went below 22. And large windows are nice, lots of natural light!
How much does attempts at passive cooling shift energy demands into the winter months, when the grid is at its dirtiest, because energy storage is hard.
Shifting the UK's energy use to be in the summer rather than the winter would help our carbon emissions massively, as you use AC when solar works well!
We need to get away from this idea that all energy use is bad. High carbon energy use is bad. Zero carbon energy use is good!
Do you think this policy has actually worked, and most new builds have functional passive cooling? The number which don't have external shutters makes me doubt it.
Having just installed air conditioning in my home this week, it feels like I’m living a life of luxury akin to have a Rolls Royce with a chauffeur. Finally getting eight hours of sleep again.
Was it a lot of work to get it in?
Not at all, but it’s a small new build
I'm surprised the list of reasons given here for the lack of air con doesn't mention its contribution to external heat, which is one of the reasons cited in the relevant London Plan policy. I've no idea how big an issue this is, but you can see how mass use of air conditioning could increase the urban heat island effect, causing more use of air conditioning, etc etc. Trying to reduce reduce that kind of negative cycle using simple technologies (shutters! recessed windows!) that are commonly used in other countries seems quite reasonable.
How much AC's contribution to UHI matters depends entirely on the magnitude of the effect.
If it increases external temperatures by a lot (3 or more degrees?) then we should probably be concerned.
If it's very small (0.2, 0.1, 0.05 degrees), then it doesn't matter that much compared to other factors like energy use.
This model implies to me that it's actually very small, 0.12 degrees. https://www.sciencedirect.com/science/article/pii/S2210670724006358?ref=pdf_download&fr=RR-2&rr=95d6b1c25e2b3784
I am not an expert, but that seems negligible to me. UHI is real, cities have more stuff, which = more thermal mass! But I haven't found good evidence that AC shifts the needle, and I'd expect that other cities globally would have found it?
The corollary is that once we all switch to heat pumps, heat pumps will _take_ heat from the air, cooling it. Regardless of how much heat pumps affect outdoor air temperature, in London there'll be a larger cooling effect in winter than vice versa - we heat more than we cool!
But no one is worrying about heat pumps cooling the outside air causing a negative feedback loop, here or anywhere else, it just seems like policy experts focusing on direction rather than size.
Thanks Chris, that's really helpful. If that's the size of the effect, then (speaking also as a non-expert) it may well be acceptable. The study does have a couple of caveats - it seems to assume all buildings in the future will be insulated to post-1996 levels, which may be optimistic, and it also looks only at low-rise areas while noting that heat island effects are higher in denser neighbourhoods.
My understanding is that urban heat islands are almost entirely the result of albedo (eg the roads are black tarmac instead of white). Energy use just isn't a significant contributor https://www.sciencedirect.com/science/article/abs/pii/S2210670723006492
It's also difficult in leasehold blocks of flats because usually installing fixed AC means installing something externally, like a fan unit or vent, which will usually mean consent and a proper assessment including to make sure it doesn't increase fire risks. In the block I live in equipment externally is not allowed, so AC installations use a water based AC product so the excess heat goes down into the drain, but at a cost of water as well as electricity usage.
As well as noise - the thought of having to put up with a constant mechanical hum because someone’s installed air con badly is enough to put me right off the idea.
Wellll the impact of air conditioning isn’t just about electricity use, the refrigerants used - particularly historically - are HFCs. These are incredibly potent greenhouse gases. If they leak or are dumped at the end of their life, this is a huge problem. One tonne of HFC has the same global warming effect as 14,000 tonnes of carbon dioxide.
From what I understand the EU is trying to phase this out so it’s potentially less of a problem in newer air conditioners. But that’s the reason they have until now been discouraged in policy. It’s not really that much to do with the electricity usage of the appliance
I don't think this is true. The draft London plan explicitly cites active cooling as being something to avoid due to "energy use" and the "urban heat island":
https://www.london.gov.uk/programmes-strategies/planning/planning-consultations/towards-new-london-plan#:~:text=This%20is%20because%20he%20use%20of%20active%20cooling%20(such%20as%20air%20conditioning)%20can%20increase%20energy%20use%20and%20contribute%20to%20the%20urban%20heat%20island%20(UHI).
You can assert that the real reason is HFCs, and that they're not stating that publicly, for some reason? But I think that's a much harder to prove claim.
Yeah maybe I over stated that every use isn’t an issue at all, but historically it is the refrigerants that have influenced policy and perceptions.
Here is an easy to understand guide to this issue from NZ https://www.epa.govt.nz/community-involvement/science-at-work/hfcs
When it's over 30 degrees outside, the best passive design in the world isn't going to bring your bedroom down to a comfortable temperature. And the UK is full of very old houses that just were not designed for modern summers - and it's only going to get hotter.
My bedroom is in the loft and my 16 month old daughter's bedroom faces west, so it is regularly nearly 30 degrees at bedtime, even with every window open and doing our best to block out the sunlight. Going to get AC installed as soon as we can afford it.
Fortunately the demand for AC coincides pretty neatly with the supply of solar power. As the article implies, given the global trends in solar power (and batteries), with renewable energy it's much easier to cool a hot country than warm a cold one.
Waiting for the next heatwave for a piece hoping to give me clarity about something I never understood: why the flipping buses don’t have AC? 🥵
Allowing air conditioning provides an additional incentive to replace gas boilers with much more efficient reversible heat pumps. It's incredible that this was against the regulations until recently!
External shutters are extremely effective at controlling indoors temperatures on sunny days, and are almost never seen in the UK. Is this a cultural thing or due to planning rules?
In addition, if I recall correctly , aside from planning permission, most if not all of the previous various Govt sponsored grant schemes allowed only for installation of heating only pumps not dual cooling/heating systems so you wouldn't get a subsidy for the latter.
Please do NOT rip your radiators out. Having moved away from the UK, I really miss them in the winter. An AC/heater that blows hot air in your face isn’t comparable
For anyone picking up a portable air-con unit, try to find a dual hose unit. They are significantly more efficient than the standard single hose units. Dual hose units are much less common in the UK unfortunately. Discourse online suggests it could be due to a lack of knowledge in the UK and a lack of willingness to spend money on devices that are not seen as an essential.
Single hose units pull air from indoors, warm it up and pump it outside. The air from indoors that the machine literally just cooled down. Dual hose units pull air from outside, warm it up and put it back outside.
Proper split outdoor units are better than both, but as others have said, are expensive and hard to install for many (like myself)
(Nerdy air con video for anyone interested in how air-con works & why single hose units are so bad https://www.youtube.com/watch?v=_-mBeYC2KGc)
Looking at the weather for London right now — it’s 23 with an expected high of 27. In most of the world (e.g., the United States) is perfectly normal summer weather. Part of the problem is that Europeans and British people have been relentlessly propagandized about climate change to the point that normal weather is characterized as dangerously hot.
I’m curious to know if you have ever lived in London during the summer? As an Australian, 30°C did not automatically get classed as “heatwave” weather in my mind, but when I moved to London I grew to understand and appreciate that the city is not built for heat. There’s no cool breeze during these times, and the buildings have all been designed to keep warm. And as looking at the data even briefly will confirm, it is warmer than it has ever been. Climate change is not some propagandised boogieman, as much as some might like to pretend it is so.
Today we're all relishing the cooler temperatures, it was over 30C the past couple of days, and not much less before that. I haven't had a decent night sleep in weeks...
”There was a worry that if everyone gets air con the grid would collapse,” said Sissons. “[But] with more solar on hot days you’ve got quite a bit of extra capacity in the system.”
Data centres? Has their usage been figured in as well?
I think this website that the London Minute @thelondonminute shared on Friday has some really helpful suggestions to consider instead of or alongside AC.
https://www.heatwavetoolkit.com/solutions
But for renters and/or those of us in flats (that's a lot of us) most of these suggestions will be hard to implement because we need the landlord to do it for us or their permission.
>Paint Yoghurt on Your Windows
Is this satire
I live in Australia. Reverse split system cycle air conditioning is bog standard here! Consists of an outside unit, some kind of magic gas which turns whatever from hot to cold or vice versa and pumps out either hot or cold air (your choice) via a filtered fan type unit mounted on your room’s wall or through ducting for whole house comfort. Solar power on the house roof makes it much cheaper to run, providing the sun shines of course! I live in a cool climate area and if I were to replace my gas central heating (not encouraged here by the way) my options would be new gas boiler or a split system which I probably would only use a maximum of 2 weeks in summer for cooling and maybe 4 to 6 months on heat mode between May and October. I’m not technical but reading the Times from afar I have conflated to understand that heat pumps which are promoted heavily for hot water systems in the uk are actually the same thing but they are only using the heating part of the system. Given the move to electrification I’m at a loss to understand why air conditioning is not encouraged especially if it’s connected to renewables.
Perhaps a limit on the kW per m2 (Aircon power, given the usable floor area)?
For new build, passive 'purge' design first, followed by mechanical nighttime ventilation, then by minimal cooling has to be the best approach. But as many commenters have pointed out, lots of existing new build has terrible shading, too much glazing and inadequate. So the problem is mostly bad design from developers/planning rules inadequate, rather than the lack of Aircon...
What I fear is if developers get the green light to throw in Aircon carte blanche, then all good design goes out the window and 1-sided concrete boxes with giant windows are in!
Existing dwellings are more complicated. For me, renting a Victorian converted flat, night time mechanical ventilation to cool the building would probably be adequate for all but the hottest great waves (and nights that are too warm). But in terms of passive solutions, external shading probably won't get past planning (even if I personally think Mediterranean style external shutters would look good).