AIBU to think there is a green argument in favour of more aircon, because using it to heat in the winter pollutes less than gas boilers?

[ParentOfOne]

The cultural war on aircon beautifully illustrates modern stupidity and ignorance:

• climate change deniers and far right grifters don't want heat pumps for the winter but want aircon
• the econazis and far left grifters who think that suffering in the heat is virtuous want heatpumps in the winter but not aircon

However, both camps are too stupid, ignorant and dogmatic to understand that... aircons ARE heat pumps FFS!

Aircons are reversible air to air heat pumps, which is a kind of air source heat pump. Reversible means they can heat in the winter and cool in the summer.

If we use them to heat in the winter, we pollute much less than with gas boilers. The cost is about the same: they are about 4x more efficient than gas boilers, but electricity costs about 3.5x more, so it's a slight saving (look up their COP, coefficient of performance).

We are already expanding our grid capacity to cope with more heat pumps in the winter.

In the summer, the need for aircon will be directly linked to solar.

The only legitimate concern is that aircon may make the urban heat island effect worse. But it increases it by 0.5 to 2C, whereas things like more shading, more trees, reflective paints etc reduce it by much less.

Regardless, the environmental impact is not a valid reason not to heat our homes, so why should it be a valid reason not to cool them? The Econazis cannot explain this.

Imagine it the other way round: imagine forcing people to live in houses which remain freezing cold, and preventing them from installing any form of heating, because it would pollute, because it's not permitted development, because the council says no, etc. We would never accept this nonsense with heating, so why do we accept it when it comes to cooling???

None of this means that passive cooling and shading are not important. They are. Very much so. But, like the UK Climate Change Committee concluded, passive cooling alone is not always sufficient, and active cooling will become increasingly necessary.

PS For clarity, aircon became permitted development in May 2025. BUT it remains subject to very stringent noise limits (look up the MCS noise calculations) which are too strict and impossible to meet for many small terraced houses. For flats, only 1 external unit per block is allowed under permitted development but, regardless, freeholders almost never consent.

My parents have heat pump aircon/heating and solar panels, so on days like today it costs nothing to run.

They still won't turn the air-conditioning on, only used for heating in winter.

I think your title isn't helping here, because most people don't link air con to heat pumps. I had no idea heat pumps could work as air con. I use very little heat in the winter so would struggle to justify the switch over. I worry so much about climate change I hate using air con, despite struggling in the heat. Despite your slightly aggressive post, I will go and investigate this further. Perhaps change my plans regarding heat pumps, so thanks.

But most people won’t have an airpump as their sole system, they’ll have aircon be it portable or vented, and traditional gas central heating. Air pumps are only suitable for certain properties

Our entire system is a air pump, in our previous flat the entire building had central air, now that was absolutely terrible, it cost an absolute fortune to run. I also don’t agree the sound limits are too strict, the limit is actually quite noisy.

Using more energy than we currently do is not green, no matter how you dress it up.

@rattling I think your title isn't helping here, because most people don't link air con to heat pumps.

That's the point - ignorance.
That the general public doesn't know aircons are heat pumps is sad but understandable.
That people in position of power don't know, or pretend not to know, is inexcusable

@Simonjt But most people won’t have an airpump as their sole system
Even if you don't get rid of your gas boiler and use aircon for winter heating + gas boiler for hot water, you still pollute less than using a gas boiler for the whole house

@Ablondiebutagoody Using more energy than we currently do is not green, no matter how you dress it up.

Three arguments against this:

1. it all comes down to how that energy is produced. If it is produced burning fossil fuels > bad. If it is produced from a mostly decarbonised grid > not that bad. If you produce it from your own solar panel and your own battery --> neutral

2. Using aircon all year round, to heat in the winter and cool in the summer, will still pollute less than using gas boilers in the winter and no aircon in the summer. Eg Eurostat publishes data showing that even warmer countries use much more energy to heat than to cool. Is this not good enough for you?

3. Regardless, can you please explain why the environmental impact is not a valid reason no to heat our homes, but would be a valid reason not to cool them? Thank you! I mean, we'd pollute even less if we forced everyone to keep the heating off in the winter... Why are we not doing that?

This sounds like AI generated nonsense. I'm out.

We had something like this when we lived in New Zealand (but bear in mind this was 12 years ago), so I’m not sure it’s the same system you’re talking about. There were air conditioning units on the walls in each room which could double as heating in the winter. So in cold weather it blew out hot air. Lovely when it was on, but only when it was on. As soon as you switched it off the temperature plummeted within minutes. Having said that NZ homes are poorly insulated (it’s like they want to pretend they don’t have Winter!)

@Ablondiebutagoody This sounds like AI generated nonsense. I'm out.

So, let me get this straight: I demolish every single one of your arguments, you cannot reply, so you decide that you don't need to, because I am AI nonsense. How oddly convenient!

We had this in our old flat in London, we had the same issue, as soon as the heating was turned off it was back to being very cold within 10-15 minutes.

@Simonjt How insulated was the flat? I don't have an air to air heat pump in my house, but I have seen it in a few houses and flats, especially abroad, and it worked well. The rooms in question remained warm / cold for a while even after switching it off. By contrast, in the winter they became warm very quickly, whereas radiators may take a while

How good are modern reversible heat pumps?
Not in the UK, but we used to have central AC that also had a heating option. The AC was brilliant. The heating was pretty pathetic - and only needed to cope with single digit temperatures overnight - which might be why it was pathetic, as not needed in anger!

Oh, sorry, should have refreshed. I see im attempting to ssy the same as Simon and Missy

Quite well, before it was done we had very old heating, the radiators were those round tubes that went around the perimiter of the rooms. When we had that it was very easy to keep warm.

I dont care about green, I care about being alive

Access to aircon must be prioritised for tenants and homeowners

Tell Taylor Swift to hop on a Ryanair and stop using her jet. Can't even use a bloody straw in peace these days 🙄

You lost me at far right grifters and econazis far left grifters . Just have a conversation without throwing around insults in the first sentences .

@hattie43 You are welcome to disagree, but grifters is even too kind a word to describe:

• on one hand, those who have continuously denied or minimised the risk of climate change, and
• on the other hand, those who have banned aircon, hindered its installation, lied to us that it wasn't needed, etc.

Both camps literally have blood on their hands.

One of my friends drives a bus. Buying public transport buses without aircon is criminal.

France is even more bonkers. A minister said that she's horrified that people want aircon in a heatwave. They refurbished Nantes train station 6 years ago. It was supposed not to need aircon. The truth? it closes often, because it gets insanely hot and becomes dangerous. The architect said he has nothing to apologise for. And the same city is building a hospital where not all bedrooms will have aircon. Building a hospital without aircon is BLOODY CRIMINAL.
In Paris, zinc roofs are protected heritage. You cannot paint them white, you cannot install external shutters, let alone aircon. Basically the roofs get more protection than the humans baking underneath them. Oh, humans get less protection than animals, too, since it's illegal to transport live animals at more than 30C.
You don't want to call grifters and econazis those who protect zinc roofs and animals more than humans. What would you call them?

No, grifters and econazis are not inappropriate words - they are perfectly appropriate, even too kind and diplomatic, if anything

@ParentOfOne I don't know is the answer

Heat pumps would be perfectly fine for the small flats that really need it

If people in nice airy houses don't need it great, they don't have to have it

The rest of us need it

The green argument against it doesn't really stack up

If these people are willing to get rid of their heating, great. But I don't think they are.

and hospitals, and so on really need it

many shops already have it

I don't know what the objection is other than it seems to be fashionable to object. I've been saying this for about 20 years.

it's a bit like people who think electric cars are magic and don't lead to any kind of pollution at all. And then they say things like "I will use AI to investigate". Umm...

don't get me started on people who thinks that fires break out spontaneously with no human involvement! I can see that if you are a teenager or something and you keep seeing headlines saying "climate change causes fire" you might be confused

But a lot of of the threads on here go quiet when you mention arson, or nobody seems to care that there's a fuck ton of crazy people setting fire to things at the moment.

Are we on 150 arrests in France? That's really shocking.

I have been considering this but the important detail that isn't properly explained in the OP is that air-to-air heat pumps, which are reversible to aircon in summer, are a completely different thing to the air-to-water heat pumps that have become common, and which convert an existing radiator-based central heating and hot water system to run on a heat pump.

Air to air heat pumps only provide heating, so do not provide a full replacement, you still need a separate hot water system. Unless they are built into the walls of a new-build, the process to identify a combination of air-to-air heat pumps can be complex for many homes - the simple units are suitable for cooling a 1-bed or studio flat but as soon as you have multiple bedrooms, more than one floor and more than one reception room it can get very complex.

The OP is clearly very biased and use of terms like "econazi" demonstrate they aren't a rational person but air-to-air isn't a terrible idea if your home won't be too complex to install it in and especially if you combine it with also installing solar panels.

@KindlySurfiingPlatypus The OP is clearly very biased and use of terms like "econazi" demonstrate they aren't a rational person

Not rational? Sure...
I have explained my contempt for both types of extremism.

As for econazis, I stand by that word.

What do you call:

• those who go on British TV saying we don't have a right to be comfortable?
• the French who refurbished the Nantes train station saying aircon isn't needed, and who then refuse to admit their mistake even when the station closes so often because it gets too hot (see video above)?
• those who are building a hospital in the same city of Nantes without aircon in all bedrooms?
• local officials, in both UK and France, who keep ordering public transport buses without aircon? Some officials in France went on record saying that buses cannot have aircon otherwise people won't appreciate the extent of climate change if they are too comfortable. This sounds fanatic to me - to you?
• the Paris officials who protect zinc roofs more than the humans baking at 40C underneath them?
• those who cannot explain why the environmental impact is not a valid reason not to heat our homes but is a valid reason not to cool them?

@KindlySurfiingPlatypus Let me get this straight: I am biased and not rational for criticising these people. And what do you think these people are? Please, do tell.

Air to air heat pumps only provide heating, so do not provide a full replacement, you still need a separate hot water system

True. But electric water heaters exist. Regardless, even if you keep the boiler for hot water or for 1 room, and use air to air heat pumps for all other rooms, the net environmental impact remains positive.

as soon as you have multiple bedrooms, more than one floor and more than one reception room it can get very complex.

Not really. It is perfectly easy to connect 5 internal units to one external unit.
In fact. Mitsubishi Electric even makes an external unit that can connect up to 6 rooms, and its dimensions fall within the limits of permitted development.
I don't think most households in the country need to heat and cool more than 6 rooms

@DandelionClockSeeds , @Simonjt , @MissyB1
I think the problem is expecting air to air heat pumps to work the same way as boiler + radiators. They don't. They work differently - but this doesn't mean that they don't work.

Modern a2a heat pumps use inverters, i.e. they don't operate only in on or off mode, but, once they reach the target temperature, use much less energy to keep the temperature constant (both when heating and when cooling).

Eg with radiators it can take you one hour to warm up a room, but, once it's warm, it stays warm even when you switch them off.
So for the same room you may need to keep radiators on for, say, 2 hours, but a2a on for 4. However, during most of those 4 hours the a2a will operate at a very low setting, consuming very little energy.

So a2a can still end up costing you about the same, if not less, while lowering the environmental impact significantly.

This guy made a very detailed video explaining how and why a2a works well for heating his family home

"Does the room get cold the moment I switch a2a off?" is the wrong question.

The right question should be: "how much does it cost me, and what is the environmental impact, to warm my house with a2a to the same temperature as with radiators"?

I know how they work, I also know that it wasn’t sufficient to keep our flat warm at all, we had to supplement with multiple electric heaters and it cost an absolute fortune. It used to take about 9-11 hours to get any increase in temperature in our flat, not the desired temperature, but an increase of 1°c.

@Simonjt I'm sorry to hear that, but I wonder what the cause was, especially in a well-insulated flat. I don't have a2a at home but I was hosted in quite a few properties which had it and always found it good at winter heating.

Nope, ours ran 24-7. So not an expecting to retain heat like radiators issue. More an "pathetic heat output" issue.

But it’s not using more energy.

A reverse heat pump that keeps a dwelling at a year round semi-constant of +/- 5C from say 19C to 24C uses less energy than constantly letting a house cool down and then bunging heating on for a few hours a day in winter or letting a house heat up and turning on fans or coolant filled portable aircons to cool a house down.

Gas is burning a fossil fuel as well so not only is it more energy per joule it adds to the greenhouse effect. A heat pump run off green energy sourced electricity isn’t adding any emissions at all.