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Comment by leoedin | Hacker News Reader

This is interesting. We collectively spend _so much_ of our energy on heating and cooling buildings, and there's very little change happening.

The problems identified in the article are such low hanging fruit. Everywhere you look in residential housing there's huge efficieny gains to be made, but very little effort is going in to making them.

I'd love to find ways we can use technology to make housing more efficient. We need to - it's such a crucial pillar in dealing with climate change, and the vast majority of housing is so comically inefficient. The single tube air conditioners mentioned in the article are just the icing on the cake of all these massive energy wastes we accept because they're marginally more convenient. Does anyone know how to fix this?

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>and there's very little change happening.

There's honestly a lot happening and changing. Obviously you won't see it by buying "HVAC" junk from a box store. What this person should have done is paid an actual HVAC tech to install a ductless mini-split [0]. It would have been a heck of a lot more efficient. He states his one unit is drawing 10 amps (110 volt I assume). Whereas my american standard 4 ton (48,000 btu) unit draws 10 amps as well (240 volt) and cools a 2200 square ft house in 100+ degree texas weather with an electric bill usually not higher than $120 per month (1200 - 1400 kwh or so).

By comparison, at my old house (which was half the size, 1100 sq ft) with a much older 12 Seer unit, my electric bill was regularly over $200. I measured that unit at drawing 18 amps (at 240 volt) and it was only a 3 ton 36,000 btu out door unit. The latest and greatest 21/22 seer units are even more efficient than my current one mentioned above (which is probably only 17 seer).

[0]: https://www.americanstandardair.com/products/heating-and-coo...

> What this person should have done is

You can't say what somebody "should have done" without knowing a lot more details about their life.

Yeah, he should have just spend a few grand on a mini split system to stay cool for one summer at home. Makes sense.

Why do they cost so much in the US? I can buy a decent split unit for $400-$500 + around $150 for installation.

Installation will no doubt be more expensive in the US, but there is no reason for AC itself to be (if anything, most kinds of hardware seem to generally be cheaper in US than in Europe).

Largely because we have an HVAC cartel that charges insane hourly rates for even the simplest jobs. To be fair, a Mitsubishi mini split is going to run closer to $1200-$2000 for the unit itself, but you can expect to pay $2000+ to install on top of that, depending on how hard the job is.

I suppose it's hard to complain too much. HVAC installers need to have some decent technical background, troubleshooting skills, and their bodies tend to get injured/broken by the time they're in their late 40s like most manual labor trades. A HVAC installer/tech can make $80K or more a year, which makes it one of the few jobs still out there where you can make a decent middle class income without tons of schooling.

That's interesting, I see some lower-end Mitsubishi models for $600 here.

> you can expect to pay $2000+ to install on top of that, depending on how hard the job is.

Installing a mini split is nowhere the difficulty of an HVAC though, assuming your have the electrical circuit (which I'd guess would be an electrician's job not HVAC) it's a few hours' work, at least for a simple case and if the installer knows what they're doing: pierce the wall, mount the external unit, mount the internal unit, connect the two, charge[0], done.

By "simple" I mean a 1:1 setup with both units mounted on the same wall (and a wall-mounted indoor unit). Obviously a more complicated setup (multi-zone, slim duct, more distance between the two units) would take more time and be more expensive.

I can see $2000 for a non-trivial multi-zone setup.

[0] if you're handy there are mini-splits sold specifically for DIY installations which come pre-charged, though that means the pipes won't exactly fit the distance I guess

It's essentially the same (unless you use one of the DIY kits with pre-charged lines) as a full sized split system (traditional AC unit.) You (should) pressure test your lines and vacuum them out before releasing the charge. You also have to get a create a really good flare connection.

In addition, running the electrical is usually done by the HVAC company and setting up the mounting pad for the outdoor unit.

I completely agree that it isn't rocket science, and it's well within the realm of a skilled DIYer with about $250 in specialized tools. However, I can see why an HVAC company charges as much as they do. For an average install (not dead simple), it's probably 5-6 hours of labor, they have to pay for the company equipment, vehicles, health insurance, permits (my township requires one for a mini), taxes, etc.

Where? The prices for AC that I've seen in Germany were >1500 EUR, plus >1k for installation.

Croatia

Installing a mini-split would be a year-long project, including HOA negotiations, architectural design, electrical load calculations, city permits, and invasive construction. It's not the sort of thing you'd want to attempt at the beginning of a pandemic (or ever, for most people.)

Given the orders of magnitude less work required to find a product and click "Buy", it'd greatly benefit society for portable A/C manufacturers to compete on efficiency.

> a year-long project, including HOA negotiations, architectural design, electrical load calculations, city permits, and invasive construction

Obviously only you know your situation, but just in case any other readers are considering a mini-split: it doesn't have to be this way and it typically isn't.

From firsthand experience installing Mitsubishi mini-splits in multi-unit buildings in very regulated cities, a typical condo installation takes 2 days, including running power from an electrical panel that's not in the unit. A reasonable HOA can often answer in a week or two unless you're the first person to install a mini-split in the building. Larger buildings often recommend specific HVAC contractors. Your contractor will apply for HVAC and/or electrical permits online with very basic drawings; they're often issued immediately ("over-the-counter"), subject to field inspection. There's generally one inspection after it's installed. A good contractor will handle almost all of this.

Basically, it can be complicated but it doesn't need to take a ton of calendar time. Other than cost and needing outdoor space for the condenser, the hardest challenges you & your contractor will encounter are running new electrical circuits from the panel and draining condensate from the indoor head.

> are running new electrical circuits

Why is this needed? Is it because the electricity in the US is at 120V? Over here (Europe) you can just plug the cable from the indoor unit into the electrical outlet.

Depends, the lower btu units can plug in to any outlet, but even in Europe you can only get so much power.

Regardless, ac draws enough power that you want it on a dedicated circuit no matter where you are. Sharing that outlets with anything else is likely to result in annoying breaker trips when you overload the circuit.

bluGill answered this well. To add a little: the total load of all but the smallest systems (9/12k BTUs/hour) is too large for a typical 15A @ 120V circuit, so most outdoor units need 220V. That means a new circuit. Also, building code in the US typically requires a shut-off box right next to the outdoor unit.

At least in the US, many systems power the indoor unit(s) from the outdoor unit. My guess is that since a control wire is required anyway (for central control of fan speed and direction), the manufacturers think it’s easier to power everything from one run.

I learned recently that US housing generally gets 240V, but most circuits use neutral and a single hot to get 120V which is the standard mains in the country, and you'd run dedicated 240V for large appliances e.g. furnaces, dryers, electric oven, induction cooktop.

The AC would not have been planned for when designing the original circuits, so you would need to add a 240V circuit for it unless you put it in a room which already had one.

As the others have noted, since it's a high-power unit anyway you'd really want to have it on its own circuit to avoid adding too much load on the circuit. So even in europe you probably want a circuit exclusive to the AC, meaning you may have to run a new one unless an AC circuit had originally been run "just in case" (and even then it might not have been run to the room you wanted it in e.g. maybe the original builders put the circuit for an eventual AC in the living room but you want it in the bedroom you converted to a study).

A year long project to install a mini split? Wow.

Split systems are the norm on my continent, and most can be installed in well under a day. Many installers can do multiple per day into existing dwellings, code compliant, filled, sealed, and on a proper circuit. Units/Apartments are likely to take longer.

All depends on the locality, etc.

Many people don't understand the world of stupid they've joined when they buy an HOA property. Although I have to deal with the psychic trauma of a neighbor who doesn't mow often, living in a reasonable city on a normal block means that permitting nightmares and other bullshit don't really exist. :)

Lawns are really bad for the environment in many ways. A front yard that's all native plants both looks better and produces a healthier local ecosystem.

Hoa claims “we maximize the property value” which I don’t see how they say with a straight face.

At best they achieve a local maximum nowhere near the potential, while costing a mint in fees and preventing one from doing anything crazy like planting native plants in the front instead of grass or not painting your house the right shade of beige.

This is ridiculous nonsense. A mini split is basically the evaporation coils mounted on the wall and a hole cut to the outside for the refrigerant tubes to run. It would be nice to have it on its own circuit, though a 20 amp circuit might be able to just have it added on. That's pretty much it.

Mount it like a TV, cut a hole in the wall, hook up electricity. No architectural designs needed. I'm not sure who told you that, but there are dozens of DIY youtubers who must have gotten free split units, because there is a flood of videos of people installing a precharged version with only themselves and a helper.

The actual work of installing is a day labor. The pre work to get the paperwork in place so you are allowed to install it can be over a year.

I don't approve of the above, but that is how it is.

I don't think cutting a small hole in between studs requires "architectural design" and "electric load calculations" really means "it uses this many watts". There is nothing typical about someone needing a year to do something relatively simple. Most restrictions probably just say that the condenser coils can't be on the side that faces a street and maybe that it has to be on a dedicated circuit.

You would think, but California is a weird world where often it does take that long.

Both of your comments are basically saying 'this is true' and saying 'this is true' again. Do you have any sources or even reasons why installing a split unit air conditioner in all of california 'often' takes a year?

> including HOA negotiations

Yah done goofed.

HOAs are rather necessary for condos. When multiple people own a building, some entity needs to manage the common infrastructure.

Surely the US style HOA insanity is not necessary for condos, as demonstrated by the rest of the world.

If an HOA is being an obstacle to ordinary and customary improvements to the property you in theory own, you goofed.

In general if you bought a condo, you goofed.

The go by different names, strata, coop, HOA, condo, but they exist all over the world to manage the shared property.

It'd also greatly benefit society to make the more efficient solutions more accessible (e.g. by reducing permitting requirements, preventing HOAs from regulating them, ...)

Working with refrigerants is not that hard. A lot of sailors fix their own fridges in middle of nowhere.

Building code for electrics is probably your largest problem. But then some places you can't even change a damn light bulb.

Mini-split looks like a good design, but our landlord would not be happy about our leaving behind a 3" hole in an exterior wall.

If you have a good relationship with your landlord (and intend of staying some time), might be worth discussing collaboration and leaving the AC when you move? A unit with AC would command a higher rent for the next tentant.

Through wall designs, like you see in cheap motels, require an opening in the wall.

Mini-spits have an outdoor unit and an indoor unit connected by two hoses. The indoor unit basically screws to the wall. You do need a hole through the wall for the hoses but that's it. As a result they are cheap to and quick to install. They are also very efficient.

> You do need a hole through the wall for the hoses but that's it.

That's what they're pointing out. It's not a huge hole but it's still a hole going through the wall, and if they rent and buy the unit with their own money they'd be leaving with it, leaving that hole in the exterior wall. 3" is probably on the upper bound of what you need but it's not wrong. And it's not like the landlord would be much happier with a 2" hole.

One of the biggest reasons portable air conditioners exist is for apartments. It's something anyone can buy without having to get permission from their landlord to make modifications to the property. So I would not compare them directly to anything that cannot be installed by a tenant without additional permission.

And landlords have no incentives to install one for you. That's where regulation steps in (in normal countries)...

Fwiw I was told I needed to get a permit and have a 220 line ran to install a mini-split in my house. That hassle put it out of contention for me and my not be an option for people renting.

You'll need to run some kind of line for any kind of mini-split. Seems kinda moot point if it's 220 vs 110. Anything that isn't removed and evidence of install hidden within less than a day is probably not going to be doable with a rental.

> The single tube air conditioners mentioned in the article are just the icing on the cake of all these massive energy wastes we accept because they're marginally more convenient. Does anyone know how to fix this?

I'm using one of those portable units because I live in a rented apartment. There is nothing convenient about it compared to a much more efficient real (split) AC, but I have no other options.

Even if the landlord was OK with allowing it, "green" laws intentionally make it incredibly tedious and expensive to get the permits to install an AC, so people swarm to the option they can get without paperwork.

Regulation.

Builders spend money on things that make them profit and home buyers don't particularly evaluate efficiency.

After that you figure out how to spend public money on lower efficiency structures. Fraught, but spend money where it's likely to pay off and it probably works out okay.

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