Yesterday was the peak of our current heatwave, with air temperatures hitting 38-39ºC in the Madrid area, depending on which weather service you consulted and nighttime lows were a demoralizing 24ºC. Humidity was very low as usual, averaging below 20%. I'm here to share my particular experience of the day in the hope it will be interesting, informative and maybe helpful to others. I wish to preface though, that any positive tone I take in no way implies that heatwaves are no big deal. Our ability to personally cope has nothing to do with the increased risk of forest fires and the damage to agriculture.

Highlights:

1. I had to take around a 15 min walk round trip outside at close to 18:00. My personal cooling spray bottle failed me, everything was concrete and there was no particular shade on that walk. I joked that I could feel some of my proteins denaturing, but honestly it gets much worse than that. My bottle wasn't spraying well, but I dumped some of the water on my head and that was good enough. The shop I was going to not only was air conditioned, but as I've noted in other posts, it also had a couple big swamp coolers inside to supplement. I took in front of one for a few minutes and I was back to normal. I purchased another spray bottle for the walk back and sacrificed some drinking water for it. Totally worth it. The spray made the outside temperatures totally bearable long as the water supply held up.

2. I spent a short time in a non-air conditioned waiting area. All they had was a big fan. Spraying myself and standing in front of the fan was fine, but eventually I lost patience and went back to bring the car around to pick up the family at the door of the establishment (the swimming pool).

3. As long as the car was parked in the shade, I could dial the air conditioning down to 25ºC in eco mode and things were fine, for me at least. That was the waiting. When I had the rest of the family in the car and was one the move, I had to crank it up to 22º and dial the fans up to offer my wife relief from spending 45min in a non-AC space.

4. My daughter, who had just been at the pool, was very comfortable with her wet hair for about a 20min drive. We had to make a stop in a very reasonably cooled establishment. After that, she complained, in her 9-year-old way, that her hair was already dry and thus the cooling effect gone even though we were in the car.

5. Despite the high temperatures, I still got a chill after stepping out of the shower, indicating wet bulb temperature was still quite low.

6. The end of the day saw interior temperatures in the apartment at around 29.5ºC in the hottest rooms and around 28.5ºC in the coolest. I checked the output of my mother-in-law’s swamp cooler for safety and it was still managing to put out 24ºC air at around 9:00pm, which would improve as the night gradually cooled. I deemed normal operation safe. After filling all the swamp coolers for the night and having a shower, the kid and I flopped in the bedroom with swamp cooler blowing on us to talk before bed. No more comfortable place in the house, but notably we had to dial the fan to medium for best comfort while previous days it stayed on low.

All in all, this heatwave did not require anything particular of us beyond minding the savagery of being outside in the afternoon. It’s a testament Spanish building design and the incredible effectiveness of evaporative cooling when it’s dry. I understand not everyone has this option. Stay safe and cool out there.

I’m afraid of my HR rising outside in the summer, heat stroke, heat exhaustion. For my children I’m fearful of it being way too hot on them outside. Went outside for hours this week and it was nerve racking as hell but I did it. Really hot day but I did it!

I have heard that having a bowl of ice a fan can make a room colder but it would be difficult to do with a ceiling fan... any advice for how to make it cooler?

I live in the south of the U.S. if that helps to tell how cool it is...

i dont know if this question is serious enough for this subreddit sorry if not

i dont want to put my ac down further for environmental reasons

I've yaked on and on about my portable evaporative coolers here for a couple years now. In this year of multiple heatwaves all over the world, it seems appropriate to finally share some details of what happens to keep me and mine safe and comfortable. Not a good choice for folks in humid climes.

This is "Big Sister," as my kids dubbed her (the decorations are their work), a Mconfort brand (Spanish company out of Valencia) model Elite 28, which is no longer produced as it was kind of an oddball higher end consumer model. It was the first serious portable evap cooler I bought and while it's currently the weakest performing of my good units, it was the one that showed me how much was possible and it still has a place in my army. It is taller than my other units and thus the vents completely clear the top of the bed, which makes it ideally suited for use while sleeping.

The energy consumption officially peaks at 120w, it has four fan speeds, up to 8 hour timer, ionizer, a high humidity cutoff function, low water pump cutoff and dubious "anti-mosquito" feature. Officially, it can move up to 2400 cubic meters of air per hour or around 1412 CFM at max power. It has three filter pads for greater evaporative surface and better cooling performance. I get 4-6ºC of cooling versus ambient temperature under typical summer conditions.

Please excuse the ugliness of the water. While I've perfected keeping it free of bacteria between washes (mild hypochlorous acid) iron still builds up, giving that rusty tinge. The dark-colored rectangle is a plate of copper, which has its own antimicrobial properties to help keep the bacteria down.

Generally Big Sister is run on low or medium fan speed as a balance between volume of air and noise. On low, she's a perfectly viable companion for TV and she to this day remains designated night cooler for my wife and I.

This place is a textbook example of institutional failure. Banda has limited resources and unreliable infrastructure to the point where the people can't even depend on having electricity to run fans. This is where the government should be investing in some level of local solar installation so the people at least have semi-reliable power during daylight.

Also, I'm struck by the lack of some very low tech assistance when it comes to sleeping. The article details how many people in Banda go to the train station and just throw blankets on the ground to sleep because the open air is better than their homes, but those surfaces retain and reradiate a lot of heat. Just adding some kind of air spacing mat underneath would do a lot, and those things are cheap. The hotter parts of China have refined varies bamboo-based mats that provide spacing and airflow that are almost universaly used as bedding and seating covers on furniture and cars.

Known as "persianas" in Spain, these things are absolutely standard on every residential window in this country that matters (occasionally you get very small windows that don't have them) and a number of commercial properties as well.

The standard modern version is a roll of interlocking white plastic slats that are integrated into the outside of the window frame. As photographed, they are not all the way down, so there are holes to let light in while blocking the majority of the sunlight. If you bring them all the way down, the holes close up.

It's currently 7:18 pm in Spain and the sun is hammering the pictured west-facing windows. It is 34ºC outside. The shutters are 40ºC, but the glass of the window is only 33ºC. Interior temperature of the room is 28ºC.

Shade is best, but if that isn't possible, these are the next best thing to protect your windows from the heat of the sun.

Form versus function is an old problem, but it reaches new levels of importance when it comes to heat mitigation and cooling. Aesthetics and fashion have severely compromised some basic, cheap and effective heat mitigation options.

Awnings are extremely effective and cheap, but they fell out of favor on account of fashion, so millions of homes are baking worse than they need to because their owners are more concerned with changing style. My place hasn't got awnings and since it's an apartment, I can't just do it myself. They're actually reasonably popular here in residential and commercial properties, so score one for Spain. I just don't happen to live in a unit that has them.

White reflects heat. This is clearly understood physics. This is why historically, everything was white in places like the Mediterranean. Paint is cheap in the grand scheme of things and didn't demand constant energy input, yet we are not painting everything white even as we complain of being too hot. I wish I could just hit the roof of the apartment and paint it white, but home owners association.

Mini splits don't look pretty when strapped to the facade of a building, but it works. Northern Europe is in the throes of facing this issue as old regulations run into the reality of modern heat waves. Already got AC and it happens these regs aren't really an issue in Spain.

Of course, if Paris would say, get over preserving its look, paint its tin roofs white and install awnings, air conditioning would be become somewhat less critical.

The AEMET, the Spanish meteorological agency, has issued an official heatwave warning this week. Parts of Spain may hit 45ºC, but my part is most likely topping out closer to 38ºC.

While I am not pleased, I am not concerned for us. It's nothing we haven't dealt with many times. I've talked before in the past about separate measures, but here I'm going to try to give a more comprehensive picture of situation in the hope that's interesting and informative for your heat issues.

My Heat Defense Lineup

1. Thermal Mass. The walls, typical for this country, are thick masonry, which can absorb a considerable amount of heat. The consequence of this is that it takes sustained exposure to high temperatures to start heating the interior. This may sound bad, but thus far in the twelve years I've been here, even ten days of sustained 38-39ºC highs was not enough to start baking us. The walls got warm, but they did shed enough heat at night to remain protective during the day. The overall effect is a kind of smoothing off of internal temperature changes. The absorption and radiation of heat from the structure spreads out the transfer of heat over 24 hours so that while we don't cool wonderfully at night, we also don't bake so badly during the day.

2. Cross Ventilation. By design, the traditional Spanish apartment sacrifices some floor space in order to ensure each apartment has windows on at least two different sides. In my case, the apartment has windows on three sides. The vastly improves cross ventilation at night so you can maximize the free cooling once the outside temperature is low enough.

3. Rolling Shutters. One of the best inventions ever. Standard on pretty much every residential Spanish window and many commercial ones. Only takes seconds to block the sun from hitting your windowless, vastly reducing the radiate heat input from the sun. It's straight up cutting the local greenhouse effect.

4. Evaporative Coolers. AKA swamp coolers to Americans, the thing I won't shut up about here. It's bone dry here in central Spain, which makes it the ideal environment for this style of cooling. I now have four capable units that average around 100w max power draw each and under typical conditions, can easily achieve 4-7ºC drops compared to ambient. As I type, the sun has gone down but it's still 28ºC in my home office. My swamp cooler is putting out 22ºC air. The evap coolers have been the front line of my active cooling for around five years now. They do all that's needed and save enormous amounts of power.

5. Air Conditioning. While relegated to the reserves on account of the swamp coolers being able to handle our regular active cooling needs, this apartment is equipped with inverter mini splits. If necessary, we can leverage conventional vapor-compression cooling. I do not anticipate needing it though, as we've ridden out worse in recent times without it.

We had some friends over for dinner last night and, in standard practice in this household, I turned on the AC to cool off the living room and dining area to make our guests more comfortable. Normally I never turn it on now, but visitors are the time for it. I set the thermostat to 25ºC/77ºF, which may sound very stingy to Americans, but here in bone dry central Spain it's actually very comfortable a good balance between comfort and energy use.

And it was, for everybody except my mother-in-law.

Even before our guests arrived, my MiL was asking me if the AC was working right because it just wasn't cool enough for her. Mind you, this woman has been living without AC for the whole year other than occasions with visitors of her own accord as she's asked for, and gotten dedicated use of, one of my best portable swamp coolers.

This is actually is not too surprising, as it fits the science.

We focus a lot of air temperature and to a lesser extent humidity when talking about thermal comfort, but just as critical is exposure to radiate heat and whether or not there's any air movement.

My MiL has grown accustomed to having air movement from the swamp cooler, which is something a mini split simply doesn't provide unless you're directly in the path of the air and the fan is cranked up. She actually went right up to the swamp cooler I keep in the living room during the day (largely for her benefit) and turned it on herself. I figured that was the most efficient way to keep her happy and not freeze out everybody else, so dinner proceeded with the AC running and a swamp cooler blowing, mostly at my MiL.

Some on the internet would take major issue with this, claiming the two are battling because the AC is removing water from the air while the swamp cooler is adding it. It is technically true, but my experience both at home and observing the practices in businesses is that that fails to account for practical realities.

What started me on the entire evaporative cooling journey was when high energy prices in the wake of the Ukrainian War drove many businesses here to buy large, portable swamp coolers as supplemental spot cooling to backup their AC. This practice has continued and been expanded to this day. I see them all the time now, particular in mini markets. A trick the markets all seem to have picked up on is to point a swamp cooler down the produce aisle, providing those fruits and vegetables with a localized cooler environment than the rest of the store.

I don't do this often myself, as I don't run the AC normally, but this is not the first time it's come up. Back during my daughter's First Communion party, my MiL and one of her friends complained the same way that it was simply too warm for them (this is especially typical of my MiL's friend, who is perpetually too warm) when everybody else was fine. I pointed a swamp cooler at them and the problem was solved. While technically it was costing the AC some cooling capacity since it was increasing humidity, ultimately it was faster and I suspect cheaper overall to do this than to dial the thermostat on the AC down, wait for the whole place to cool down and risk freezing out other people.

Today it was 28c only but with 85% humidity it felt unbearable, there's no escape. Shade, swimming (sea is nearly 30c here), showers... Just unlivable, considering relocating.... How do you guys survive this?

Sun was beating down from the left while I was parked and listening to the podcast while waiting for my wife. Windshield brolly works pretty well on the side. It didn’t need to hold it in place.

We tend to focus on daytime highs when concerned about heat, but nighttime lows are also a critical concern that easily gets forgotten. There's been a greatly increased understanding in the medical community that while high temperatures are acutely dangerous, sleeping temperature is critical for both recovery from enduring daytime highs and long term health.

The precise definition of "tropical night" varies by country, but Austria, Belgium, Croatia, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Italy, Ireland, Latvia, Lithuania, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Spain, Sweden, Switzerland and the United Kingdom, agree that it is when nighttime lows do not fall below 20ºC/68ºF.

Spain has added additional levels:

Noche tórrida  (torrid night) -- 25ºC/77ºF

Noche infernal (infernal/hellish night) -- 30ºC/ 86ºC

If we're hammered by 40ºC/104ºF highs but nights drop to 18ºC/64ºF, then we can open up windows and crash out in peace because long as the bedroom cools to a similar temperature, our bodies are able to properly rest and recover.

However, if we pass one or more of the thresholds above, then night time cooling becomes something we shouldn't gloss over, especially considering that's just a measure of outside temperature and doesn't account for the individual circumstances of different houses and apartments, some of which might have bedrooms that do not efficiently cool off at night.

This is the case for me. During the summer here, 22ºC nights are typical and 25ºC nights happen. The forecast says I've got a noche tórrida coming next week. It's actually night time cooling that's driven much of my efforts as long as you're awake, you can take active steps to cool off, but not when you're asleep.

We used to run AC only at night to make sure we slept well. For the past few years, I've moved to portable evaporative coolers and I've finally got one powerful, reliable unit per bedroom that can drop the ambient temperature 4-7ºC depending on the exactly conditions. My MiL eventually may have to switch on the AC as her room is thermally hellish, but so far she's (by her own request) been cooled at night by a portable swamp cooler and been happy with it.

I found a surprising number of people on my thread about AC not being an all-in-one solution with some very optimistic ideas about the cost of operating AC, specifically in Europe, which is not the cheapest place around for electricity overall.

So, I'm going to break down some data and share some personal experience.

2025 data had Hungary as one of the cheapest markets with retail prices around 10 Euro cents per kilowatt hour and Germany on the high end of around 39 cents. Spain, where I am, is on the higher end as well, but less than Germany at around 24 cents, but not as high as France's 29 cents or Italy's 31 cents.

So, right up front, we can see how expensive it is to run AC is going to vary considerably by country.

My apartment is equipped with five Daikin inverter mini splits that have a peak draw of a bit over 1800w and a typical draw of around 1400w, according to the electrical data. As they are inverter units, they can ramp up and down as needed. Three of the units are in bedrooms while the two others are in the living room and dining room, which adjoin and do not have a door between them.

The master bedroom, dining room and living room all have western exposure to the sun and thus considerably greater heat load than the rest of the house.

Let's imagine that running one mini split consumes an average of 1 kWh to keep one room at a tolerable, but not frosty temperature. Running it for a whole day would be:

Spain

0,24€ x 24 hours x 1 kWh = 5,76€ / day

5,76€ x 30 days = 172,80€ / month

France

0,29€ x 24 hours x 1 kWh = 6,96€ / day

6,96€ x 30 days = 208€ / month

Italy

0,31€ x 24 hours x 1 kWh = 7,44€ / day

7,44€ / day x 30 days = 223,20€ / month

Germany

0,39€ x 24 hours x 1 kWh = 9,36€ / day

9,36€ x 30 days = 280,80 / month

Now, some might argue the cost is worth it. That's a personal issue, but I cannot countenance any argument these numbers don't represent a significant financial hit to ordinary households, especially since they're pretty conservative. If the heat load in the home was greater, insulation worse or the air sealing poor, the cost would go up and the effectiveness would go down. If a space larger than one room or multiple rooms needed cooling, then the cost would be multiplied.

I have a sister in Italy who straight up said this year she wasn't running AC more despite the heatwave because it was imply too expensive.

A few years ago, before I discovered embraced evaporative cooling, we ran the AC at night to be able to sleep comfortably but not during the day in order to save on costs. My MiL though, very reasonably, had to run the AC most of the day if she was home as her room is thermally the worst and she's elderly. The electrical bill was still an issue even with those limits, which was one of the reasons that drove me to look for alternative cooling options. The summer bill was over 300€ more than the cooler seasons and this was using inverter units.

So really, kindly no one tell me that running AC in Western Europe isn't costly.

I have a secondhand, but new-to-me Corolla. I really like my car, but it has a very large and very black dashboard and I haven't had time to get a new reflective screen for the windshield.

Yesterday, I couldn't find shady parking so the poor car was there in the sun for an hour. When I picked up my kid, who had been in dance class, I was a bit desperate so I started spraying the scorching dash with water.

I have to say, the science worked out.

It took around five applications at stoplights with the AC running, but within fifteen minutes the dash had cooled to merely being unpleasantly warm and the AC didn't have to fight against it keep the car comfortable.