Demand for air conditioning is set to surge by 2050 | Hacker News Reader

Demand for air conditioning is set to surge by 2050

economist.com

Unfortunately American homes are designed with heating and cooling as an afterthought. Most of them are just designed with ducting and an HVAC to fill their needs, to keep design and building costs low. This naturally leads to terrible ventilation, a key ingredient of effective passive or low-energy heating and cooling. Without any active HVAC system, many of them hold in heat and don't cool down, or become much too cold because of how badly insulated they are. Modern code mandates better insulation and useful advancements like H/ERVs and heat pumps but American local governments do almost nothing to push their homeowners to update their homes to new code.

Tools like ceiling fans and attic fans are unheard of these days. Awnings to bring in winter sun and keep out the summer sun aren't considered. And despite a lot of the US being dry enough for evaporative cooling, they still mostly use AC. Most people have never heard of an H/ERV.

Hopefully as awareness of climate change increases, this changes. As for me, I live in a dry climate and through the summer our evaporative cooler is a mainstay. With the help of some ceiling fans, and well placed windows, we can go most of the year not using our AC at all, and having the evaporative cooler blowing cool, moist air on us feels fantastic on a dry summer day.

The cost of upgrades is prohibitive. It would probably cost us 20% of the home's value to really upgrade it to a reasonable place. Replacing our oil boiler with a heat pump based central air or mini-split system will cost us almost $40k -- 4x more than a simple oil boiler replacement.

Indeed. A lot of it is the failing of the government to offer meaty incentives/subsidies for these upgrades. Unfortunately the US still doesn't take climate change seriously or they'd do more than pay lip service to green initiatives. They'd actually incentive people to put in double pane windows or heat pumps or ceiling fans. I'm not even talking about urbanism and city design here, just help the existing renters and owners of SFHs in the US.

It's a lot of money but it's a matter of perspective and situation whether it's prohibitive. If energy/emissions are more expensive, the upgrade would pay for itself sooner rather than later; other countries have generous financing aids; you buy a house assuming that there'll be expenses like that in the upcoming decades (and planning the money correspondingly), ...

Yup, we need to be careful not to beggar current residents or create more resentment toward environmental initiatives. Offer subsidies in the beginning, and after a while, simply begin to tax electricity along with its pollution effects; price in the externalities. But we're a _long_ way from doing that in the US. We can't even get people to take the train from a park-and-ride to work and back!

Homes in general seem to be hodge podges of design with little optimization. Where is the Apple of homebuilding?

Frank Lloyd Wright died a long time ago. I think the incentives are misaligned and it is difficult to find out what's really wrong with a house until you live in it for a sustained period of time. Inspections and appraisals generally only yield surface details and obvious problems.

@coverbuild is literally attempting to be the Apple of homebuilding. They are making quick progress with modern prefab modular homes, starting in LA. I have no affiliation just an appreciation for efficiency and repairability/sustainability.

https://twitter.com/alexisxrivas/status/1423400137091518466

That’s awesome. Thank you.

Perhaps here? Article: Norway is pioneering energy-positive buildings https://www.theexplorer.no/stories/architecture-and-construc...

The difference in design between buildings in hot European countries, which almost universally have shutters and other forms of shading, and American ones which might have a porch if that, is striking. It's an extremely effective, cheap, and low carbon way of controlling temperatures which only requires small changes to design and behaviour.

Just window fans and shutters can go a long way to keeping houses cool. A tactic I like to use a lot in the wee months of the summer is to use a window fan to let cold air in at night, then put the shutters up during the morning to try and keep the night cold air inside as long as possible while still having some ventilation. Along with a ceiling fan this works very well, unless the night doesn't cool down enough.

The shutters you speak of are mostly for comfort because the sun is usually quite bright. You'll still see shutters + A/C units pretty much everywhere in Europe where you have 30+ degrees in the summer.

The significantly reduce heat from solar radiation - you might still need AC units, but they need to do less work and be on less often.

American houses used to be designed for the weather to some extent, eg having internal airflow to maintain cool cupboards in kitchens. Having worked in residential construction for a few years (only on the West coast) my feeling is that well-maintained older homes are often in better condition than newer ones.

2 years ago I bought AC for my bedroom. Before then, I didn't have AC in bedroom. It is now utterly impossible to live without it. Since beginning of July, we have a high of ~33c, low of ~25c, with ~75% humidity every single day until today. This is insane. It was never been like this

Might you share your (approximate) location, to give us some context?

Netanya, Israel

Have you considered using a fan instead? Nights of 25c are completely bearable with a fan.

I actually started with a fan for a while before I bought an AC. It gets to 25c only maybe at ~4am

A fan won't help you when outside air is 33°C, 75% humidity.

Also, AC units double as fans when the compressor is off.

I bought a portable AC this summer, and it's a night-and-day difference in quality of life (particularly for my pregnant wife and my 2yo daughter). Pre-AC, July was mostly unbearable, with temperatures around 34°C during the day, dropping below 30°C only around 20:00 or later.

Last week we had some cooler days (~24°C), so the compressor in the AC stays off most of the time - running the unit is just like running a fan, except I get to duct the exhaust and intake air with flexi-pipes, making it possible to create patterns of air flow that refresh the air in the whole apartment.

Fans cool humans by applying the evaporative cooling effect on the skin through sweat (and convection, in certain cases). At 75% humidity, the sweat will not evaporate. You need dehumidification in those conditions for a fan to have an effect. It would be interesting to see how much more energy efficient a dehumidifier and a fan can be than just an AC, but currently it makes more sense for most folks to just buy an AC. After all, a dehumidifier is very similar to an AC.

Someone else in this thread linked to https://www.nuscool.com/our-technologies/ which looks like a combination desiccant dehumidifier and an evaporative cooler. That may be a more efficient alternative, depending on the lifetime and maintenance of the desiccant.

I haven't looked into humidification space directly, but from what I understand, compressor humidifiers are more energy-efficient than desiccant ones. If so, that would make an AC unit more efficient than the dehumidifier/fan combo.

Plus, you'll eventually need cooling or heating; a heat pump is as efficient as you can get. Many AC designs control supply air humidity by dumping excess water with exhaust air (when cooling), or pulling it from intake air (when heating).

The more I look at it, the more I consider heat pump ACs to be a miracle in a box. They're a good default.

> The more I look at it, the more I consider heat pump ACs to be a miracle in a box. They're a good default.

They are! If you need heating and cooling, a heat pump AC is fantastic. We just need to make building design more efficient so you need to run it less frequently. But look, even switching most existing heating/cooling HVACs to heat pump units would be fantastic. There's a lot to do.

Northern Europe here. This summer I convinced my parents to get a portable AC (for health reasons). The first time the thought even crossed my mind was probably three summers ago.

If the summers continue like this, much less get warmer, the surge here will be before 2030.

We need a cooling technology that doesn’t emit hot air to the environment to prevent urban heat bubbles.

https://nuscool.com/our-technologies/ presents an interesting candidate: Membrane-based water capture followed by evaporative cooling. No chemicals, lower energy requirements and no emission of hot air. Produces potable water in the process.

Interesting, this is similar (and much more thoroughly researched lol) to an idea I've had myself. It runs a dessicant dehumidification process along with an evaporative cooler. I wanted to try a more DIY version of this by using a dehumidifier to pump water into an evaporative cooler. I live in a dry area though so I'm never in need of dehumidifcation myself shrug.

Doesn't work, all the evaporative cooler does is absorb the energy back that was released during dehumidification.

You would have to drain some of the water out. It's not as simple as directly pumping it. Ice might help as well.

Why the evaporative cooler if you want to drain water? Letting water condense and then evaporate is a zero sum operation.

Using ice is just moving your heat pump to another location. Maybe interesting if you can't install airco for some reason, but you're not improving the efficiency.

Correct me if I’m wrong, but membrane based air dehumidification seems to require a lot less energy than other approaches. https://www.researchgate.net/publication/270721905_A_review_...

I guess one might be able to make something that works somewhat better than a compressor, those don't use ideal Carnot cycles. Better than a Carnot machine isn't possible, you will always release heat when turning water vapor into liquid, so doing the evaporation afterwards and ending up with a cooler room is completely bollocks. You can't cool a room without discharging heat to the environment, the heat has to go somewhere.

My parents and grandparents have something ecological, made probably in 1950 or 1960 and in late 1990s https://en.wikipedia.org/wiki/Ground-coupled_heat_exchanger

It doesn't need plastic or electricity to work

> It doesn't need plastic or electricity to work

Not even fans to move the air around? That's neat, fully passive systems are awesome - though not always easy or possible.

In context of not blowing hot air out, the useful nugget here is heat exchange with the ground - which can also be used with a heat pump. Plenty of homes are built with such systems. But it's tricky to do in a multi-floor apartment complex, I haven't heard of any using ground-coupled heat exchangers. Perhaps some new constructions?

Of course, while the ground has amazing thermal capacity, it has rather poor thermal conductivity - for larger loads, your exchanger will need to be large and buried deep. This might be another factor limiting application in cities.

>Not even fans to move the air around?

Only in the hottest days when all room were occupied, as I no longer live there with my siblings, they no longer have fans there. There was one bath-vent-like-fan before.

>fully passive systems are awesome - though not always easy or possible.

I wouldn't install this in the UK as gardens are tiny, full of concrete and air humidity is high. Works well in central Poland.

>or larger loads, your exchanger will need to be large and buried deep. This might be another factor limiting application in cities.

yes, you need trees around, and grass not concrete or bricks.

Too bad the laws of thermodynamics forbid this kind of systems. Absorbing water from air and then evaporating it will result in nothing changed. Either you make a dehumidifier or you make a swamp cooler, combining them is pointless.

The idea is to remove moisture from the air using a membrane, not by way of condensation.

Doesn't matter, laws of thermodynamics still apply.

Green house gases -> global warming -> more extreme heat -> more air conditioning —> more energy used -> more green house gas emissions.

Also, people are becoming richer and can finally afford air conditioning.

Huh what? Source?

See: Singapore yesterday and India today.

Heating causes more green house gas emissions than air conditioning.

What causes emissions is deviation from optimal temperature. And with global warming there's more extreme deviations both ways.

Also - in my country recently the peak electricity usage moved from winter to summer because of AC. Nobody had AC 30 years ago, now it's common in offices and people start installing it in their homes. Heating still uses more energy overall, and in worse forms (burning coal and gas, mostly), but this slowly changes.

We need more efficient AC, no question about that. We also need to stop building glass buildings that can’t exist without AC. But there’s no way to live completely without AC, it’s likely going to get warmer even if we become carbon neutral now.

Most of those modern glass buildings are double glazed and fairly airtight which is probably better than the average house.

Houses-vs-glass-buildings is a tough comparison, as a lot of glass buildings are office buildings.

And (pre-pandemic, at least) office buildings often have far less floor space per occupant - especially meeting rooms.

So here in the UK, where only perhaps 1% of homes have air conditioning, it's not at all unusual for office buildings to have air conditioning.

I’ve been wondering if there’s a corollary to that with wildfires. It seems there could be a feedback loop, but wildfires happen naturally too and there’s also a fixed number of trees in the world to burn.

Renewable power -> use as much AC as you want; it's not a problem.

More power demand -> more renewable power because it's the cheapest way to get more power.

More renewable power -> all expensive/dirty forms of energy become less attractive.

That's a dynamic that's been playing out over the last few decades. Lots of coal plants are closing. Gas plants are getting a lot less attractive as well for the same reasons.

2050 is a year where lots of countries want to be carbon neutral; that's only 29 years from now. Once we are, you can install as much AC as you want/need without having to worry about adding CO2 to the atmosphere. If you have solar on your roof, you can chill your house guilt free right now.

AC is still a huge problem never mind the energy source: Hydrofluorocarbons, currently used as refrigerants, are 1000-9000 times stronger greenhouse gasses than CO2. They will eventually be phased out, but until then will leak into the atmosphere a lot.

https://drawdown.org/solutions/refrigerant-management

> Hydrofluorocarbons, currently used as refrigerants, are 1000-9000 times stronger greenhouse gasses than CO2.

There's also many more times less of them in circulation. Also, arguably, ACs are a drop in the bucket compared to refrigeration (which is roughly the same thing, but in a box).

There are options being explored, IIRC propane (aka. R290) turned out to be a great and environmentally-friendly alternative to hydrofluorocarbons.

They are a problem. But they also break down pretty quickly, just like methane. Unlike CO2, which can stay in the atmosphere for hundreds of years. That means they are much less of an issue than that number suggests unless we start mass dumping all of that into the air as opposed to recycling it. That is btw. happening with methane, which is leaking into the air from e.g. melting permafrost in Siberia, intensive farming and soil tilling, etc.

Also, some heat pumps use alternate fluids. So, we might clean that up further. But compared to the massive scale with which we are producing CO2 currently, that's a minor issue.

Yes, this is a subtle point that is often forgotten.

May think that "more energy use" = "bad", but's an oversimplification. It depends where your energy is coming from.

The traditional thinking was that baseload power came from coal and peaking power came from natural gas. This is true for many geographies but not all. There are other mixes. Texas, despite its reputation for fossil fuels, also produces a surprising amount of renewable energy and that has been mix has been growing over the past little while.

I completely agree with this. We need all this to run on renewables. Solar is a good fit because where it’s hot and people need AC there is usually plenty of sunshine as well.

I should have clarified that hot -> AC -> more hot dynamic holds until we have enough solar rolled out everywhere it is needed.

That's one of those feedback loops people keep talking about

Couldn't AC work as a heat pump in winter, saving energy and maybe emissions in the process?

So I suppose your solution is for people to just die of cold in the winter, and from the heat in summer?

It can get pretty hot in the summers, but I noticed that this is far less of a problem in brick buildings, and especially if they're built right.

I think far more emphasis can be put on which materials to use, strategic placement of windows, to make pretty energy-efficient buildings. In fact, some office buildings here in Norway, not far from where I live, are already energy positive.

On a slightly different tangent, I live in a really old building. This means it's pretty expensive to heat in the winter. On the other hand, there was a terrible water leak earlier this year, and it took days before the landlord finally checked in. In a new house that would instantly mean risk of mould. But due to the house being old and thus "very well ventilated" the moisture dried up pretty quickly. So there are pros and cons for everything, I guess. And there's more to the indoor climate than just temperature.

In the UK it's common to have brick/stone houses - the house I was living in before moving to Finland was built in around 1890. Leaky and hard to heat in the winter, but great in the summer where the solid mass took forever to heat up.

You could be indoors on a hot summer day and feel nice and cool, just due to the insulation from the stone/bricks. The only thing I'd do would be shut the blinds during the day, and keep the windows closed until evening-time.

I wonder how much of this demand is because people don't use fans anymore. I find many situations where people turn on the AC could easily be solved with a fan. But few people own fans anymore, and they're not sexy or profitable products to sell either.

Feature-wise, AC is a strict superset of fans - an air conditioner contains a fan. When there's no need to cool or heat the air, the compressor is kept off, making it no different than a fan.

Fans don't do anything to actually cool the air. They were primarily used in the past because nothing else was available, not because they were good.

When used properly, fans actually do quite a bit to cool an environment. Moving air can carry heat with it.

Let's say it's 33 outside and 28 Celsius indoors and you're running a fan. How exactly is it going to cool your room?

There are two common ways to use a fan to reduce heat in a room. One is that you use the fan at night when outdoor air is cooler, to pull in outdoor air and expell warmer indoor air. The other is you use a ceiling fan, spinnng counterclockwise so that it pushes air down in the center of the room that can cool your skin via moisture evaporation, and the cooler air on the floor will be drawn back up along the walls and recycled.

I personally use both. I've found that a fan makes temperatures feel like a few degrees lower. However, having a fan in my face all day dries my skin and often gives me a stuffed nose/stuffed throat. I only have a portable AC since in France AC for habitations is very rare.

Oh damn it. Now everyone knows, and my secret plan of getting rich from investing into AC / heat pump vendors is blasted.

More seriously, yes, demand for ACs will grow. My wife and I have long ago agreed that we'll be installing a proper AC system in the place we're planning to move to in the next year. This summer, we're on a rental, but after the first summer heat wave I decided to buy a portable unit[0]. It's been life saving.

AC is no longer a luxury item. Not with what's coming for us in the next years. Not by 2050 - by 2025. The summers won't get any easier. At this rate, by 2050, air conditioning will be a first-need survival item.

[0] - In particular, one of the few portable units that support multiple ducts, allowing it to be put on a balcony to reduce noise, and create separate supply/return and intake/exhaust air flows so that there's no pressure drop inside the apartment. Such unit is almost as efficient as a traditional, "fixed" air conditioner. Most portable units unfortunately suck (and not just air).

This won’t be good for emissions. Here’s an idea: limit the max installed AC power relative to the insulation standard of the home, or the renewable mix of the power used.

If the house uses nearly all renewable and has 1ft of insulation, great.

Melt the poor!

Anything is fixable in that regard e.g by having subsidies for adding insulation first, planting trees. The trees that give shade in 2050 should be planted now.

Can air-conditioners capture CO2, collect fuel while keeping you cool as the world heats up? [1,2,3]

Humans added fossile fuels into the atmosphere and oceans already. This won't disappear completely for a thousand years [4], so we need to find ways to remove it.

[1] https://www.fastcompany.com/90342957/what-if-every-air-condi...

[2] https://duanetilden.com/2019/05/18/using-building-air-condit...

[3] https://www.cbc.ca/radio/quirks/may-4-2019-brain-resuscitati...

[4] https://skepticalscience.com/why-global-warming-can-accelera...

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