Comment by bradlys | Hacker News Reader

Comment by bradlys | Hacker News Reader

Someone said Japan used to be in the title - and now that it isn't - I think it should go back. HN is mostly a US based website (with an emphasis on Silicon Valley). This methodology is wildly uncommon in the US. There's very little likelihood this kind of thing would happen in well over 90%+ of the USA.

First off - if you're renting - you're not putting holes in the walls that go to the exterior and there certainly aren't any already existing. I've never seen or heard of that in the USA - particularly for apartments. Secondly - you're not hanging air conditioning units off the exterior walls of the apartment (rental or owned - you don't own/rent the exterior and ain't no residential building consenting to that shit). If you had a balcony, that's where it'd go, at best. Thirdly - where's your power coming from!? Most of these units are 220V and usually there is only one or two 220V power outlets in American homes these days and they're always dedicated to the washer+dryer. Maybe you have a third for an electric oven/stove. (Or an electric water heater) You'd have to run new power lines and that involves tearing up the walls. You could try to find 110V mini-split AC units but they're pretty uncommon in the USA (and much less powerful). As well, not having that AC on a dedicated breaker means you'll be giving up all other outlets on that breaker whenever the AC is on, which could be a lot of essential outlets in esoteric places.

Great insight for someone who lives in Japan and someone who wants to see what it looks like to install AC in Japan. Put it back in the title!

> Most of these units are 220V and usually there is only one or two 220V power outlets in American homes these days and they're always dedicated to the washer+dryer.

Meh. Only relevant if you need to pull more than 15A or so. There are plenty of portable air conditioners for sale in the US and most are happy with 110V and less than 15A.

> HN is mostly a US based website

This sounds like gatekeeping. There are lots of readers from all around the world.

> Secondly - you're not hanging air conditioning units off the exterior walls of the apartment

In the US. This is not particular to Japan. In fact, I'd argue that this is the most common air-conditioner setup worldwide, with building in many countries providing supports for either split systems or, more commonly, 'window' units.

These minisplit units are typically, at least 9k to 12k BTUs, and if it a multi-zone unit it can be 24k or more.

I have yet to see a portable AC in the US that is more than 12k btus and as quiet as a mini-split.

Mini-splits are more popular now in the US, but, for whatever reason, the US is really into ducted systems.

I never understood why putting an air duct in a hot attic and an air handler in a hot garage made any sense.

You do have me curious on traffic stats for HN by country, though.

A lot of central AC installations in the USA were added to the house some time after it was built, and the heating ducts were already there, so now they are used as the AC ducts too.

Do you have any more info about this?

I am curious about the history of residential HVAC in the US.

I only really know about it in the area where I live. AC was not generally included in new construction in the San Francisco Bay Area until the 1980s or 1990s. I wouldn't be surprised if a majority of apartments in the area still didn't have AC, based on the amount of window AC units I see.

However, most homes built in this area were built central ducted heating systems since the 1950s-1960s, when there was a massive building boom. Most older homes have had central heating added as a retrofit decades ago -- even old Victorian homes. So when people upgrade to AC today, it's very common to just use the same ducts.

It's not easy to find a house with a ductless mini split AC system around here. Most homes have a single-zone central system that cools the entire house.

> Meh. Only relevant if you need to pull more than 15A or so. There are plenty of portable air conditioners for sale in the US and most are happy with 110V and less than 15A.

You don't really know if people are happy with what they have. They just get what they get because that's all they can do. If your building outlaws window units, just because they have portable units - does that mean they're happy with a portable unit?

> This sounds like gatekeeping. There are lots of readers from all around the world.

American readership dwarfs every other country and region. It doesn't matter if there are "lots" of others when it's a US based website. YCombinator itself is mostly about investing in US based companies. Just look at the number it invests in in the US vs every other place. https://www.ycombinator.com/companies/ It isn't gatekeeping - I'm asking for someone to put in a more accurate title. After all - if I put "Rules of the road" up and it was Japan's rules of the road on an American website, it would be misleading. One would be expecting something relevant to the website they're reading it on (an American one!) while reading it but - instead - it isn't. Thus, bad title! It would be better to say, "Rules of the road in Japan".

> In the US.

How many times did I reference the USA in my comment? Five times. Guess I should have done six so that people wouldn't get confused about where I was talking about!

> many countries providing supports for either split systems or, more commonly, 'window' units.

I think that's what GP was saying about the US -- while window units are very common, split systems are relatively rare. But anyway I think most of the article wasn't specific to a split system A/C unit, or even air conditioners in general.

I have had a mini split system in my basement for 5 years and I am the only one I know who has one. They are around enough that Home Depot carries them and yet rare enough that many HVAC contractors do not have experience with them. It was a great retrofit for my basement office. However, my system is oversized. It is in the 90s F and high humidity outside and when I have the system set to 72, it makes the basement 64 degrees F and I have a space heater on under my desk since my computers don't put off nearly enough heat.

The relative humidity in my basement is 48% which is AMAZING for Georgia. That thing plus the dehumidifier makes it the perfect home office and pantry storage.

>> HN is mostly a US based website

> This sounds like gatekeeping. There are lots of readers from all around the world.

As a non-American reader of HN, I assume things posted are about the US (or even SV specifically) unless the location is specifically mentioned.

Also, I believe it is illegal to install a mini split yourself in the U.S. unless you are licensed to work with freon.

Most of the blog post was about reverse engineering the control protocol and automating the unit. The same principles could be applied to other A/C units, like window units that are ubiquitous in many parts of the US. It is not specific to split system, they didn't even install it themselves, that was a minor part of the blog post. Also, their methodology of writing their own software is uncommon anywhere, even in Japan; but that's true of many things that get posted here, that's what makes them interesting.

Most of your points are very good ones, but one thing jumped out at me - in my experience, 12000 BTU 110v mini-splits aren't that hard to source, nor crazy-expensive, in the US. Super worth it, too, if you can manage it.

> First off - if you're renting - you're not putting holes in the walls that go to the exterior and there certainly aren't any already existing. I've never seen or heard of that in the USA - particularly for apartments.

This is allowed in my apartment. My closest neighbor cut a hole in the door leading outside and affixed an air conditioner to it, then made a setup of plastic bagging to make it lead all the way to their bedroom across the living space. In fact multiple other renters on the first floor did exactly the same thing.

It's a relatively expensive place in Washington at around $2,200/mo market price.

Or maybe I'm misunderstanding and the hole in the door existed before. I'll have to ask the next time I see them.

Did their front door have a pet door? I can imagine venting hot air through that. Or maybe taking the original door off the hinges and putting it back when you move out, though landlords get cranky about not having working keys.

No, it was an actual hole sized to fit the nozzle of the A/C.

Portable air conditioners with a hot air vent to the outside are common, but a mini-split like in the post needs a licensed installer or you can face EPA fines.

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