Comment by ShinyLeftPad | Hacker News Reader

Comment by ShinyLeftPad | Hacker News Reader

You might be surprised how far you can get with a simple fan. What your body needs is to evaporate heat. You sweat, it evaporates, skin cools down. Airflow helps that process a whole bunch. It's physics. It may not make hot weather feel perfect but it will cover the necessity pretty much anywhere.

Same goes for tree shade and sensible city planning, also architecture (see all those textured dark grey or black condos currently in fashion and shudder). The other day I was biking along a road after dark and residual heat around it is so noticeable, biking 5 meters closer to the trees it felt so much colder.

I've spent some time in SE Asia. Many homes out there don't have an A/C. Apparently the real number is like 85%.

Should air conditioning maybe be less regulated in Europe? Sure. Do I enjoy A/C on occasion? Sure, guilty. Is climate change real? Sure. But A/C is a necessity like water/sewage/electricity? In Europe?? Idk.

Edit: I agree in advance with everyone saying it sucks without AC but just saying, a strategic fan (and opening windows if possible, closing curtains, etc) can be OP. It might sound stupid but for years I literally forgot fans existed because I was where everywhere is AC and often no fan. Just try it...

Edit 2: I think if you're in a hot AND especially humid place (probably not EU) I'm not sure if I'd take AC or dehumidifier

I think you're under-estimating how hot it gets inside well-insulated European homes. Your mileage may vary across European countries, but in the north where it gets cold in the winter our homes are built to trap heat. Opening windows won't get you very far as the temperature radiates through the windows and traps in the walls. Closing blinds will help, but not by much. It got over 40c in my office this summer. This is not livable conditions with a fan.

When it's around 20C, it's impossible for me to make my rooms colder than say 23C, because there is no way I can make so much of air exchange.

Even if I somehow manage to pull the air in, the moment I close it - the walls that have all that heat will start giving it back again, bringing the temperature back to where it was.

It's so funny, that when the winter starts, it's long into the winter before I have to turn on heating in my apartment.

You should come to Texas and tell me how well you get along with just a fan. We have had like over 40 days of 40-45 C in a row. The wind feels like a blast furnace and at night it can still be 38 C outside. Even the birds have fled to cooler locals. It is so intense that you can not walk barefoot outside around your home. If your car broke down on the side of a road, you would be dead in less than an hour, even in the shade. I like to tell people that Texas is the next stop after Hell and too be honest it is like living in the Arctic compared to Arizona where the temps are even worse.

I was in Vienna this summer and the inside of the apartment was over 40 for the entire week. Thank god, we were able to buy a portable AC unit from Mediamrkt before they ran out.

The problem is when humidity rises it makes it harder forbthe body to expel hear via evaporation. This is what is happening in places like UK this time around. An AC helps get rid of the humidity as it cools the air. I don't know about necessity now but 20 years down the line, who knows

Cooling the air by definition raises the humidity :-)

Dehumidifier mode in AC works by cooling the air below the dew point, removing the condensation, then warming the air up (either by itself or literally heating it up)

But for dehumidifier in AC, the heat is dispensed through the outdoor unit, so end result actually cools the house. I use our AC in dehumidifier mode, also, as I understand it has less power consumption (please correct me if I am wrong). In my experience, it cools down the room pretty well

It really depends on the type of ac unit and conditions. If for example it has to cool it first to condense the moisture out and then also reheat it back to avoid blowing back air that’s too cold, it may consume more power even.

I won't say "less power consumption". Definitely, not more consumption if efficient controls and motors are used (ECM motors for air handlers, VFD compressors).

The real problem is the repair costs of these advanced units in the developed countries. Carrier wanted $8k for a new control board for a residential unit in the US. Same thing for ECM/VFD.

There is nothing “advanced” about this. It is just cooling the air below the dew point.

Same water tray and a hose for water condensate.

"advanced" is about motors (blower motor and compressor) and their controls. The context is repairs: https://www.youtube.com/watch?v=iqzEIPEky1s

Suppose you have 27C with with 65% humidity.

Due point for that air is 19.8C. Meaning it reaches 100% relative humidity at this point. If cooled even more, water condensates from air into droplets.

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What this means: if you cool that air to 22 degrees (instead of 19.8) it will reach 87% humidity without loosing any water to the outside.

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That’s why we need humidifiers in winter as the opposite thing happens: if we heat cold air that has 80% relative humidity to room temperature it will drop its humidity to 20%

> Cooling the air by definition raises the humidity :-)

That’s a bit too nitpick-y. It raises the relative humidity by the condenser coil unit so it condenses and drips out, but air flowing back into the rooms will have less humidity.

Now my room is 26.5C and 40% relative humidity, it is really pleasant. There are days where it is 24C and relative humidity is showing 55%, that's when I turn on AC.

I know people who can't bear 40% and prefer 70%. Better for the skin.

I am from an SE-Asian country, AC usage has increased a lot, and, also we are hell bent on devastating every green that is available, as much as possible.

Dehumidifier works pretty well, provided it's built in to the AC unit, portable one's will increase the room temp: https://www.youtube.com/watch?v=j_QfX0SYCE8

Portable one's heat dispenser is inside your room, AC unit's outside. But the issue being, as it disperses the heat outside, it's probably still increasing the ambient heat?

People in Asia are in those conditions from the birth.

Like they literally put on the sweatshot/hoodie in the early mornings with effing 27 degrees Celsius

That’s not a normal temperature for Europeans.

Also I could not imagine doing some serious thought work in temps like this.

There are a lot of studies of how mental performance is correlated with temperatures with men needing couple degrees even lower than women (eg 22 vs 24)

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Airflow helps a lot, of course. But it must be in swinging motions / constantly changing direction — nervous system doesn’t like same constant stimulus to the point of neuralgia if prolonged.

During heatwaves the fan is no longer sufficient. It can improve ac cold air spreading though. A fan alone will not help you when your walls are warm and when even at night outside temp is above 20dg and humidity is high

It will. In SE Asia it was so hot even the water from the pipes is warm. Airflow does wonders regardless, as long as ambient temperature is lower than your body.

If humidity is high, you'll not cool down even if ambient temp is below body's. Needless to say, living with 30dg ambient temp inside the house is a misery

> If humidity is high, you'll not cool down even if ambient temp is below body's

No, it's about combination of humidity and temperature called wet bulb.

Highest wet bulb we can manage is 35 degrees. Below 35 wet bulb, a fan helps. And that's my point. For comparison the most extreme wet bulb temp that hit London in summer 2026 was 26 degrees according to met office. (I can't find other peak 2026 wet bulb temps in Europe)

Fans stop cooling you once air temps approach body temperature. The EU sees tens of thousands of excess deaths each summer, mostly among the elderly.

Fans stop cooling at 35 degrees wet bulb. For comparison the most extreme wet bulb temp that hit London in summer 2026 was 26 degrees according to met office. (I can't find other peak 2026 wet bulb temps in europe, feel free to contribute)

> But A/C it a necessity like water/sewage/electricity? In Europe, nah.

s/Europe/all parts of Europe/

I.e., Europe has a lot of different climate (sub)zones, and it heavily depends on where you actually live.

I'm fine with a fan in the Alps, where I sleep at 1,000 metres above sea level, and nights with the minimum temperature above 20°C are still very rare. I even don't bother turning the fan on most of the time, or just for an hour or so to clear the trapped heat in the bedroom at like 22:00 o'clock once outside cooled down enough.

OTOH I'm NOT fine in my Vienna flat with just a fan. There, this summer we got quite a few nights where the minimum temperature did not go below 25°C, even some with a minimum of 28°C and a maximum of 41°C. The flat is an old building and has only windows on one side facing a small curtilage without any trees or grass, so it traps heat, and I cannot even cool it well at night, even if the outside temperature goes a few degrees below the inside one, as the yard also traps heat.

Without an AC I could not sleep at all-even with a fan, it's very hard to sleep well above 25°, and frankly even above 23° for me. And I had to buy a much less efficient portable one (before the Midea Portasplit was a thing) because of braindead local regulations.

Ironically, in the winter the local gov suddenly starts calling those "bad ACs" again by their alternative "heat pumps" name, and they become the best thing ever for heating. I really cannot figure out how one can do that mental gymnastics without getting a headache.

Anyway, don't assume that your local conditions hold for all of Europe.

people in middle east literally use keffiyeh which is just a scarf in a head lmao

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