Point of use home utilities are much more common in Asia.

[randomness]

For example, the standard home air conditioning solution is the mini-split, or ductless air conditioner, one to a room. This kind of air conditioner has an outdoor compressor and an indoor air-handling unit, with a thin tube for refrigerant connecting the two. In most of Asia from Beijing to Singapore and everywhere in between, this kind of air conditioner is the kind you encounter. There's always a remote control so you can adjust it from the comfort of your bed or your TV couch.

This appears to be the preferred way to do climate control, even in the most expensive of houses. Each room gets an air-handling unit. Multiple air-handlers can be attached to a single compressor, and the holes through the walls are quite small, so the system is quite flexible.

It is the height of extravagance to leave the thing on when you're not in the room. Even very rich people shut off the air-conditioning when they leave the room, and turn it back on when they come back, so they are only cooling the rooms they are in. The air conditioners are quite powerful and lower the temperature very quickly, even in places like Thailand or Singapore. This also means that the hallways between rooms can sometimes be quite warm.

As for water heating, the vast majority of water heaters in Asia are point-of-use. The modern ones come on automatically when you turn on the hot water, and there's a lag which is shorter than that one expects from a central water heater here in the States.

I've often thought about implementing this water heating solution here in the States, possibly combined with a central water heater somewhere to bring the water temperature from cold to warm before it reaches the point-of-use heaters, but not so hot as to lose significant heat along the way. digitalemur says that this idea would work best with a low-cost central heating system, like a solar water heater.

Comments

[docorion.livejournal.com]

Europe uses a similar water heating solution in some cases, but generally a more central one where the heating unit is central, and heats water for the entire house at time of use. (We called it a geyser, but I've seen them in the US as "tankless hot water heaters").

The point of use cooling idea is terrific; I wonder if there's a difference in installation price, though? Because it would be just like the US to skimp on initial cost and pass it down onto cheap utilities (since US utility cost is usually lower than comparable cost elsewhere). (Yeah, I know, it's the rational thing to do economically, but it ignores all the externalities I care about, without any countervailing virtues I don't (other than "cheap", which I value only if paired with "good").

[r-ness.livejournal.com]

Yeah, my parents actually have that solution you mention: a tankless water heater in their new house which heats the water centrally and sends it around the house. It's not bad but I wonder about heat losses in transit.

In Asia the point of use water heaters are also set higher. The ones in my friends' place were set at 58C, and you really needed to be careful when you turned on the hot water: hot water was hot. Because they were at the point of use there weren't any concerns about heat loss, but there can be a danger of scalding if the temperature is set too high.

(There was a nice guesthouse in Tokyo which carefully labeled each hot water tap with a sign that said, "Hot water is hot!" It seems redundant but if you're from the States and not expecting water hot enough to scald to come out of the tap, it's a useful warning.)

I think the point of use air conditioning wins in comparison to ducted central air, because you don't need to retrofit ductwork into your house if it's not already there. But even new construction seems to default to this cooling solution. puffydrake's house was built only a couple of years ago and uses this method of cooling, and it seems like it's just the way residential buildings are constructed. (Commercial buildings do often have central air.)

Finally, I forgot about my friends' spiffy new Siemens washer, which like most German front-loading washing machines has an in-washer water heater, rather than relying on an incoming hot water feed. The temperature setting on it goes up to 90 C, which I used on my white shirts. They got very clean.

[mamamoira.livejournal.com]

You can actually get tankless water heaters that are very localized; some friends of mine are getting their kitchen remodeled (courtesy of busted pipes upstairs in the winter), and are putting in a tankless unit behind the sink, but I believe the idea is to run it to the dishwasher as well.

So...how big is the inside air handler? Where does it sit? Equiv of a box fan, or mini fridge, or what?

A lot of houses at least in my part of the country built post-1970s assume central A/C ducted everywhere, and so the layout tends to be very open, not allowing for easy closing off of parts of the house. When you have one room that tends towards the warm (like, say the room housing all of the computers), you start thinking about window units. But those also are ugly and not always doable if the window isn't convenient.

[karakara98.livejournal.com]

Now we're talking my language. I have too much to say and too much to do to make comments in this post worthwhile. I'd love to discuss this further with you over a beverage or an ice cream!

[denyse.livejournal.com]

Yeah, coming from Singapore the idea that one would air condition one's entire house all the time still seems horribly extravagant. Esp when you're out of the house.

[totient]

I've seen a lot of point of use water heaters in Latin America, too. Perhaps the difference is that in the US, many hot water systems piggyback on the central heating system, whereas in warmer climates you probably don't have a central heating system.

Preheating hot water is by an enormous margin the best bang for the buck for solar energy systems. The equipment costs very little and the energy savings is quite significant.

[totient]

For that matter, central air piggybacks on the ductwork that's there for the central heating system, too.

[mangosteen]

You see occasional advertisements for mini-split systems in New England, where you have 100+ year old houses and no desire to retrofit ducting. I've actually thought about it a few times, since it would actually be pretty efficient and clever.

There's a chicken-and-egg problem, though. Since people don't typically have them, they stick out in a home environment, which means that it's a liability when trying to sell.

[nathanjw]

The air conditioning thing is interesting. I've been looking into retrofit AC options a bit lately, and aside from the ducting technology (high-velocity seems to be the way to go in retrofitting an old New England house), there's a lot of emphasis on getting the compressor sized correctly for the house size and heat load (sun exposure, number of windows, and so on play into this). It is frequently pointed out that getting too large/powerful of a compressor will only cool the house in short bursts, and that that's not good for getting rid of humidity - you end up with hot and humid alternating with cold and clammy. In fact, the theoretical ideally-sized system runs steadily, not in bursts at all. How was the humidity in these places?

[r-ness.livejournal.com]

Three feet wide, more or less, and about a foot or so high. It's mounted on a wall near the ceiling, because the air vents down and out. There's almost always a "swing" setting to get the vents to move up and down.

This video, How to Install a Mini-Split Air Conditioner from This Old House, might give some idea of scale.

The Department of Energy has this page on ductless, mini-split air conditioners: http://www.energysavers.gov/your_home/space_heating_cooling/index.cfm/mytopic=12430

This Google products result has a photo of the air handling unit and the condenser unit, but no real indication of scale.

[r-ness.livejournal.com]

That would be great, actually.

(I'm sorry I dropped the ball on getting together last time!)

[r-ness.livejournal.com]

Exactly.

[r-ness.livejournal.com]

Right. In the case of the Beijing apartment, the central heating had no ductwork, as it looked like it was steam radiators. (I say looked like because by the time I was there it was warm enough that it wasn't on. But those big metal objects with the valves sure looked like radiators.)

So there was no ductwork to be piggybacked onto even in the place that has serious winter weather.

[r-ness.livejournal.com]

How was the humidity in these places?

In Singapore, Malaysia, and Thailand, the humidity is high and constant. It's the tropics--Singapore is about a degree and a half off the equator--so the weather doesn't change much: it's hot, muggy, and damp 365 days of the year.

I suspect Boston never gets that muggy.

South China's weather approximates American Gulf Coast. Summers are hot and muggy. Winters are mild.

Beijing is dry. Very, very dry. My skin started cracking within days.

[denyse.livejournal.com]

It's extremely humid in Singapore - the climate is essentially tropical rainforest. But the point of use air conditioning seems to work pretty well.

[r-ness.livejournal.com]

Yeah. They're pretty much the standard in Asia, so that issue isn't relevant there.

BTW, remind me next time I see you as I have something to show you.

[(Anonymous)]

In the super-muggy places, do the AC'd rooms end up noticeably less muggy?
But it could easily be true that different rules apply in a completely different climate.

[nathanjw]

(Anon comment was me; wrong browser window).

How is the humidity in the AC'd spaces in the super-muggy areas? It seems possible that they're less sensitive to it, since it's much more normal there than it is here.

[r-ness.livejournal.com]

Oh, the humidity in the AC'd spaces is quite nice. Even to me. I hate humidity. The installed units have plenty of capacity, and appear to have been chosen so that they can really cool down a space quickly and keep it cold.

In general in Southeast Asia, and even South China, when there is air conditioning, it is aggressive air conditioning, so much so that some people keep a light jacket or sweater handy. (I don't, but that's because I am really trying to keep my core temperature low so that I can gain a few minutes respite when I venture out of air conditioning. This was particularly the case in Bangkok, which is noticeably hotter and nastier than Singapore.)

Some people think this is unhealthy, but not me (see earlier bit about keeping my core temperature down).

[whitebird.livejournal.com]

These air conditioner units are getting more prevalent in both residential and commercial usage in the US, or at least out here. I know a few people who have had them installed into room additions in their houses, and the air conditioning contractor for the college retrofit two small units for spaces where the regular A/C was sub-optimal, and then cut off the regular air flow.

[sarakate.livejournal.com]

Depending on the house, keeping it cool when there aren't people moving around and breathing in it may not take very much. One of the selling points for me when I bought my house was that it was only about 80 inside when opened up after sitting with the electricity off (so the AC had definitely NOT been running recently) during 95+ weather; my AC doesn't run much at all during the day when nobody's home.

[evilmagnus]

The point of use cooling idea is terrific; I wonder if there's a difference in installation price, though? Because it would be just like the US to skimp on initial cost and pass it down onto cheap utilities (since US utility cost is usually lower than comparable cost elsewhere). (Yeah, I know, it's the rational thing to do economically, but it ignores all the externalities I care about, without any countervailing virtues I don't (other than "cheap", which I value only if paired with "good").

late to the party here, but you can absolutely buy split-system AC in the US, and it's not that expensive ; cheaper than central (ducted) air for most houses, especially older ones. I've even seen some new builds here in Palo Alto that have split systems instead of ducted.

[evilmagnus]

Yah - a well insulated house can be cheaper to keep cool by constant A/C started early in the AM than to cool down after a full day's worth of heat load. But you'd really have to design for that.

[evilmagnus]

I dunno, I've had Boston get as muggy as Singapore. It's not something that I remember happening on a daily/weekly basis during the summer months, but I certainly recall a few days where it was *cooler*, and with a lower humidity, in Singapore that it was in Boston.