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Comment by jedberg | Hacker News Reader

It's a lot easier to add heat to survive in a cold place than take away heat in a hot place.

Kinda like how people complain in an office "Can we turn down the thermostat? You can put on a coat but I can't take my skin off".

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I think the point GP was making was that hot daytime temperatures in desert climates tend to coincide with peak renewable energy generation, while at higher latitudes in cloudier places the the source of energy is more likely to be from combustion.

If we're only worried about temperature, sure

But fresh water is a pretty huge concern as well and moving/producing large amounts of that in extremely hot areas is going to more than offset the difference in heating costs

Additionally, when you add new construction to a hot place, the additional sidewalk and asphalt makes it hotter. Adding new construction to a cold place doesn't make it colder.

Given the heat pump technology that we have these days, moving heat from A to B is roughly the same as moving it from B to A.

Wet bulb events aren't that simple to deal with. Grid stability doesn't exist in any of the poor and hot equatorial countries. Many people don't even have airtight housing which rules out aircon. If it was too cold instead they could just add clothing and blankets and survive.

Grid stability isn't necessary. It's OK to only run air conditioning when the sun is shining.

There are often blackouts while the sun is shining in lower income countries.

Yes, local solar panels are needed too.

It's cost prohibitive, a small hybrid system costs $4000usd which exceeds the average annual income of many equatorial countries. But you are right that if somehow everyone could install this system (along with an AC and the construction of an airtight room) then wet bulb events would be manageable.

The solar panels to run an air conditioner are a similar cost as the air conditioner.

What difference does it make if heat leaks out or in? The transfer rate is roughly the same.

You can't install aircon into a shack. The cold air will escape.

What happens to heat in a shack?

Its easier, but it isn't more energy efficient, at least not for winters. Average deltaT is smaller when cooling 35 to 25, compared to heating -10 to 20, say.

A problem in cities is that aircos increase outdoor temps, on top of heat from pavement, cars, etc.

There is no way heating isn't more energy efficient than cooling

Heat is even a side effect of cooling, heat is a side effect of basically everything

You’re correct that it is more energy efficient to heat, but the US spends much more energy heating buildings compared to cooling them. As the person you’re responding to pointed out, the difference between cold days and comfortable temperatures is usually much, much higher than the difference between hot days and comfortable temperatures for most people.

That's reasonable

Then again the difference between lethal cold temperatures and comfortable temperatures is also much much bigger than lethal hot temperatures and comfortable temperatures too. EG humans can be pretty comfortable between 32F and 80-90F. The upper limit is pretty much 110F, so only a 20F difference. There's not really any sort of clothing short of some kind of spacesuit with a personal cooling device that can make those temperatures survivable.

Humans can tolerate ridiculously cold temperatures with adequate clothing layers. With clothing you can buy at Walmart you can be pretty comfortable at -40F. With specialized equipment there's basically no limit to how cold the surroundings can be

Not so much with ridiculously hot. Being too hot is just a more complex problem to solve

> the US spends much more energy heating buildings compared to cooling them

I was curious about the stats here:

The latest numbers I can find indicate that the annual US 50-state heating-to-comfort requirement is about 2.5x the cooling-to-comfort requirement. Measured in BTUs.

However: a) These numbers do not account for HVAC energy efficiency (much higher for heating than cooling -- maybe ~90% heat, ~50% cool, so that 2.5x would be closer to 1.5x today) b) Due to warming trends, these numbers have been changing. Was ~3x in 1990, trendlines look like they might converge by the end of the century. With efficiency considered, convergence in about 25 years.

Some obvious unaccounted factors: a) Changes in HVAC fuel or efficiency mix, e.g. heat pumps b) Changes in climate trends c) Migration patterns (more people headed to TX/AZ than AK)

Have a look at how heat pumps work. The difference between cooling and heating is just which end you point inside or outside.

For efficiency it only matter what the delta-T with the outside environment is. Since that is typically lower when cooling than when heating, it is therefore cheaper. Just look at your power bill.

> Have a look at how heat pumps work

Most buildings where I live don't have heat pumps

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