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Having individual heating and cooling units (per unit gas heaters!) is stupendously inefficient. I travel in Asia fairly regularly so this isn't new to me, but

• Scoundreller 6y ago
  Lately new condo builds in Toronto will have an in-unit heat pump that fails within 5 years (and May or may not sound like a spaceship), with a coolant line going to a central unit that’ll have a geothermal/auxiliary heating/cooling loop, that also tends to fail. All in all, a stupid system in practice. Only benefit of it all is that you don’t have to wait for the building to change between heating or cooling mode. At least we tend to still have central hot water and don’t meter water yet. Metering can make a lot of sense, but not when your account fee is $15-$20/month. Any reduction in use just means some rich dude goes on more jet vacations.
  • bkovacev 6y ago
    Why would it fail within 5 years? Isn't the usual lifespan of those pumps 10-15 years?
• gcds 6y ago
  I think it's more efficient to heat/cool single room than all house when for e.g. you spend most of the day in office/living room and then go to bed. That way you only have one AC running but of course if you have big family then it maybe makes sense but still... Those mini split AC efficiency is much higher than I have seen in US ducted systems (follow few channels) because mini splits uses inverter technology for higher efficiencies.
  • driverdan 6y ago
    With a central chiller you can still have each room on a separate zone.
  • bluGill 6y ago
    That depends on insulation. If your house is well insulated it doesn't make much difference as the cooling needed for when you are in the room (assuming you use all rooms every day) is most of the cooling needed for the entire day. Thus you may as well temperature control everything at once and call it good. The loss of energy is more than worth it considering the comfort. If you have poor insulation the above doesn't apply. In extreem climates there is another consideration:you need to keep the entire building warm enough to keep the pipes from freezing. Here you keep everything warm because if the heater fails in one room there is a risk you won't enter that room until it is too late and you have done major damage. By having one central unit it is much more likely someone will notice before there is a problem. Extreme climates also tend to have better insulation which makes the central system more convenient.
    • rietta 6y ago
      Or you have to keep it cooled to keep the relative humidity low enough that mold and mildew do not take over.
• edgarvaldes 6y ago
  >attitudes towards thrift that make it inconceivable/impossible to pay for AC that someone else might be using (or misusing) Sounds somewhat similar to the opinion some americans have against free healtcare
  • deleted 6y ago
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• asdfasgasdgasdg 6y ago
  I am not sure that it is true that split system ACs are substantially less efficient than central. And depending on the size of your unit and how much space you can leave unconditioned, it can save substantial energy to use a split solution. For example, we used space heaters during the winter in cali to save substantially on energy. This is because even with much less efficient electric heating, heating just two bedrooms at night is more efficient than heating the entire house. (We saved hundreds of dollars each winter despite that a btu from an electric heater costs two or three times as much as a btu of gas.)
  • EricE 6y ago
    Exactly - obviously the larger the home and more uneven the occupancy, the more the individual units make more sense. And you don’t have to have one indoor unit per outside unit. Systems that can have one outdoor unit with up to four inside units are readily available. What’s really wild is Mitsubishi’s City system - designed for commercial spaces (or really large homes) you can have dozens of internal units. And more impressively, it can move heat around inside the building. If you were having a party in the middle of winter and all the body heat was heating up the room where everyone was you could “AC” that room and then dump the heat elsewhere in the building. The key is the per-room zoning. Minisplits are by far the easiest and most efficient way to micro-zone. Also the elimination of loss from ductwork should not be discounted either; it’s often very significant. Especially if you can eliminate ductwork from unconditioned space!
• mattdoughty 6y ago
  I used to live in a flat (I guess you would call it a condo in the US) with heating provided by the building. My landlord who I lived with left the heating on 24/7 during the winter and the flat would get ridiculously hot. Even though he was the one paying for it indirectly through service charges. This arrangement is becoming quite common for new build flats in the UK but I would actively avoid if I was looking to buy.
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• falcolas 6y ago
  All of those images look more like heat pumps, which are actually ridiculously power efficient, especially if you're heating/cooling the rooms individually (since you're cooling only the hotspots, not the entire house to handle one hot room). EDIT: The unit installed by the article's writer is an AC only, which is probably because the AC is cheaper than a heat pump. But a heat pump can both heat and cool, and are quite efficient. The Google term of use is "Heat Pump Mini-Split"
  • gcds 6y ago
    It is heat pump it can cool/heat just in Japan they don't call them heat pump. Plus it is inverter based so super efficient.
    • falcolas 6y ago
      Interesting. Odd, but interesting. Thanks!
      • fomine3 6y ago
        Lower adoption rate of inverter air conditioner on other countries is odd for me. The only non-inverter mini split air conditioner in Japan is lowerst grade cooling-only model (and not so much cheap).
• Spivak 6y ago
  Whole building climate control isn't really the problem, it's that unlike electricity, there's not a good billing system attached to it like we have for eletric and gas. Other than "it doesn't exist yet" there's nothing fundamental about central air that precludes being able to bill individual units separately based on their usage. The fairest way for a group to pay for something isn't always diving the total cost equally among the group. Can you imagine if we did that for taxes?
  • tantalor 6y ago
    I doubt that. OP said "individual units can set their temperature to whatever they like" This implies they can turn on/off their usage. So you can install one electric meter per unit, which equally distribute the current load on the A/C, and turn the meters off (increasing load on other meters) when that unit is not consuming A/C.
    • Spivak 6y ago
      Whole building climate control doesn't mean all units are set to the same temperature! The discussion is specifically about a zoning hvac systems and billing for them. HVAC systems unfortunately don't work as nicely as you describe. You can't run the HVAC for just one unit, typically buildings are broken down into floors and either the system for the floor is on or off. This is how you see multi-tenant offices designed -- each floor is submetered and the cost is divided proportionally among the tenants on that floor based on square footage. The zoning works by controlling airflow in the ducts. So while your billing system is clever it would be absolute murder if you were the only one running AC/Heat and you would be much better off with a smaller individual unit.
• amluto 6y ago
  > Having individual heating and cooling units (per unit gas heaters!) is stupendously inefficient. > Contrast this with a condo in Minneapolis that I own wherein heat and AC are central in the building and individual units can set their temperature to whatever they like - all run with tremendously higher efficiency. This needs some real data. There are a few central technologies that might be used. A condensing gas-fired boiler might exceed 95% efficiency if you imagine that losses in the hydronic pipes are minimal. An evaporative cooling tower has awkward-to-define efficiency because it consumes water, but I doubt it works very well in Miami. A giant air-source central heat pump might be reasonably efficient (COP around 4?). But little modern heat pumps with variable-speed drives (often marketed as "inverters") can be very efficient indeed. Fujitsu will sell you a unit right here in the USA with SEER 29 or better, and the general trend is that the smaller units are more efficient than the larger units. (Yes, SEER uses ridiculous units.) Additionally, in most markets, a reasonably efficient heat pump is both less expensive to operate than even a 100% efficient boiler and has lower greenhouse gas emissions.
  • Melkman 6y ago
    I know it's only one datapoint but recently we had four indoor airco units installed in our house for the bedrooms and livingroom. I expected a single outdoor unit. However during talks with the installer he advised us to go for two outdoor units. This was cheaper in hardware, a bit more efficient and way cheaper to install by placing one outdoor unit on the front of the house and one on the back so all rooms could be reached within a meter or so from the outdoor units.
    • sgc 6y ago
      For heat pumps more outdoor units is definitely more efficient, since the outdoor unit needs to be big enough to accommodate all connected indoor units at once, and will be on even if only one is in use. Two per unit is my go to trade off on that one, with an attempt to group together units that are more likely to be used at the same time (so no bedroom / living room split, try to stick with bedroom/bedroom and living room/dining room etc). BTW they have low profile indoor units that can be embedded flush with the ceiling or wall, so the bulkiness indoors is not even required anymore.
• hinkley 6y ago
  I was a bit surprised he bought two condensers instead of one large one. I’m looking for a mini split currently and I found condensers with up to three separate coolant lines (although with the shape of my place. I might only be able to use 2 at once, and have to use a window unit on the other end). Unit size (especially width) goes up much slower than BTUs, so the main value of two seems to be cooling your house in installments, which he isn’t doing.
• smileysteve 6y ago
  This is not limited to Asian, single units are also common in European, and Central American cities; (likely buildings that existed prior to air conditioning ubiquity -- which also related to sealing of the home); Much of this is related to air conditioning attitudes as well; Do you need to have comfortable temperatures in the entire house or just a living room with comfort when working, watching tv, eating dinner. tldr; air conditiong views vary from necessary to an accessory; where they're an accessory, one of units are most common
• marcinzm 6y ago
  >Contrast this with a condo in Minneapolis that I own wherein heat and AC are central in the building and individual units can set their temperature to whatever they like - all run with tremendously higher efficiency. Is it more efficient? There is going to be loss as things get pumped across hundreds of feet even with insulation. The central system needs to run even if few units or not units are using it just in case. In Asia heating and cooling is done per room to the minimum as I understand it so "per unit temperature" wouldn't fly. And an in-room gas heater is going to be 100% efficient with no losses due to transmission.
  • quickthrowman 6y ago
    Generally (in a high-rise) the units are fed a steady stream of ‘supply air’ at 50 F or so, and heat pumps in the unit itself control the climate in the unit. HVAC needs to run constantly in these buildings as they’re sealed and need airflow for air exchange. Air isn’t heated and then sent thru the ducts in a high-rise building.
  • bluGill 6y ago
    Hard to say. Many central systems are old an inefficient. However modern high efficiency systems require a water drain which rooms often don't have available thus most room systems are not able to get the best modern efficiency. Most houses in Minneapolis I used to live there) have a single furnace in the basement which can achieve just as much efficiency as any other central system. There also indoor unvented space heaters. They work and are very efficient. However they put all the combustion byproducts into the air, and thus really only useful in rooms that have a lot natural ventilation (tents for example)
• L_Rahman 6y ago
  This examples fails to account for the fact that radiant floor heating is a default feature in all new Korean homes.
  • oehtXRwMkIs 6y ago
    You mean mainly apartment units right?
  • criddell 6y ago
    The examples seem to mostly be looking at cooling and dehumidifying. What do radian floors for heating have to do with that?
    • bluGill 6y ago
      Heating the air drys it out... The article is about Japan. I would expect Korea has a different climate which means different considerations. (but I'm not an expert in climate)
      • criddell 6y ago
        > Heating the air drys it out... I'm not sure that's true. Hot air can hold a lot of moisture, the extreme example being steam.
        • larrywright 6y ago
          I think what is more true is that typical furnace designs remove moisture from the air that they heat. Most comfortable place I ever lived in, heating wise, was an old house that had been converted into apartments. It still had steam heat. I loved that.
          • bluGill 6y ago
            A furnace doesn't remove moisture. Steam heat is radiant which feels very good. Nothing to do with moisture added, steam heat is almost always a closed loop so no water is put into the air.
• ClumsyPilot 6y ago
  When I moved to UK I was shocked that each house amd apartment (!) has a separate gas boiler, a device that need maintenance, takes up space, makes noise and regularly kills people with carbon monoxide. I then met a person who lost a loved one to that thing! In Russia and Czech Republic we have district heating, you just get billed for the amount of hot water consumed. Some of that heat comes from industrial sources or nuclear power-plants. Even where it's coming from a giant gas boiler, they can be efficient combined heat and power units. Ofcourse, some of that infrastructure is old, but a rich western country should be able to do even better. We'd only have a boiler in rural areas, to have them in apartments is just madness.
  • bserge 6y ago
    Yeah but there is no such infrastructure in most of the UK, so it would be a big and expensive undertaking to build it. Individual gas/electric boilers are a pretty good solution. Maintenance isn't that hard, though legally you need a Gas Safe certified technician to do everything, and they're smug, expensive, slow, and not all that smart tbh. But because there's no competition you have to put up with that :D That was the most frustrating thing for me - I could do everything myself, but wasn't allowed to.
    • ClumsyPilot 6y ago
      For apartment blocks it's particularly silly because you can install a single device in the basement at the time of construction. Some newer blocks have it. UK housing stock is in desperate need of upgrades, most houses are literally bleeding money through the walls because of poor insulation, and because heatpumps are much more efficient that boilers. Consider that they are more economical when supplying several houses, pay for themselves over time and that interest rates are zero. It becomes obvious that we need a large-scale program of energy efficiency upgrades, it would create jobs during a recession and help address climate change.
      • martinald 6y ago
        My new build flat in London has district heating like you describe. It's a complete nightmare and I wish I could get rid of it. Firstly, it's incredibly expensive. There's no regulation on the price you can charge for heat, and there's no competition for supply like gas and electric. So the apartment freehold owners charge eye watering fees for it. I could save probably 50-75% a month even paying for the cost on a new boiler, plus a service package. Secondly, there are a lot of outages. Much more than I've ever experienced with standard boilers. The outages are quite literally out of your control, unlike a gas/electric boiler where you can get someone to fix it out of hours. One particularly bad outage was nearly 48 hours in winter over a weekend, caused by incompetent building management and a seeming inability to get highly specialised parts from Germany to the UK to fix it on a weekend. I've obviously had normal boilers break down but usually they can be fixed in a couple of hours, at least temporarily enough to get a proper fix sorted.
• thaumasiotes 6y ago
  > It was explained to me once that there are Asian (specifically, Chinese) attitudes towards thrift that make it inconceivable/impossible to pay for AC that someone else might be using (or misusing). I don't know how true that is. I don't know how true it is either, but I can provide some mild support. Several years ago a vicious heat wave hit Shanghai, and the subway stations filled with people taking advantage of the air conditioning. I asked a friend about this -- I don't see the subway station as a particularly nice place to hang out, since it's loud -- and the response was "they all have air conditioning at home, but they don't want to pay for it".
  • bobthepanda 6y ago
    I've heard of people doing this in malls, but subway stations is a bit weird for sure. Movie theaters in the US were very popular prior to prevalent home AC for much the same reason.
    • thaumasiotes 6y ago
      Malls are far away. Your local subway station is necessarily nearby.
    • eunos 6y ago
      > but subway stations is a bit weird for sure Huge subway station e.g. A station with a lot of interchange might be huge enough with stores and food courts close to a mall.
• fulafel 6y ago
  Insulation and ventilation cold/heat recovery is more important yhan central vs per room heat pumps.
• jonpurdy 6y ago
  Others have mentioned the efficiency of cooling individual rooms instead of the entire home so I'll skip that. (Not to mention that in Korea and Japan, halls are considered "outdoors" and are not heated or cooled, which is a massive waste of energy for the few seconds that people spend in the hallways.) My issue is that any place I've lived with central AC (or a condo with a fan coil unit) is that when it's actually hot, the central units don't have enough capacity to cool my unit down enough and don't provide enough control. It's like the old cable modem congestion problem where the whole neighbourhood slows down during peak times. Heat is even worse; when buildings are heated centrally they're usually much too warm in the winter and I end up with my balcony door opened to let the heat escape. Vastly less efficient than letting me heat my own unit. By forcing people to heat and cool only their units as required, people either get the exact temperature they want, or will accept a non-ideal temperature and supplement with fans to save money.
  • larrywright 6y ago
    I’ve only been to one city in India (Chennai), but my experience there was that common areas are not air conditioned. Hotel and office hallways, public restrooms, etc.
  • fomine3 6y ago
    Now cold halls/hallways on winter considered to health risk in Japan, so some houses getting better insulation and whole air conditioning.
• jefftk 6y ago
  > tremendously higher efficiency For heat, yes, but not AC. For example, the Mitsubishi MY-GL12NA is a very efficient mini-split with an EER of 13, but a random modern window or through-wall unit (ex: https://amazon.com/dp/B07D8R2V8H/ https://amazon.com/dp/B07D8R2V8H/) will have an EER of ~12.
• novok 6y ago
  Wouldn't a shared system with individual metering, which is how electricity works for the most part, work then in that case?
• l3s2d 6y ago
  The bit about attitudes towards shared payments is fascinating. I wonder if this is truly attitude or just lack of choice. Are there any concrete examples of existing systems where people choose to pay more when the alternatives are significantly cheaper but pricing is shared? Hypothetical example scenario: Someone would choose to pay $10 for their own water instead of $2.50 (on average, with minor fluctuations), in order to avoid subsidizing other tenants' water usage. The difference in cost could be attributed to the maintenance burden of many monitoring devices. I have a hard time believing anyone would choose the more expensive option.
  • philwelch 6y ago
    Human intuitions about fairness are not always Pareto-optimal.
  • michaelt 6y ago
    > Are there any concrete examples of existing systems where people choose to pay more when the alternatives are significantly cheaper but pricing is shared? American healthcare? :-p
• shajznnckfke 6y ago
  Could this be a norm that developed when AC was less common in those countries and only became available as an upgrade in recent decades? Compared to western nations with a longer history of wealth and a reliable power grid, it’s probably a more recent phenomenon that installing AC during construction was practical.
• sfifs 6y ago
  New buildings built over the last couple of decades generally have provisions for keeping the outer unit of the air conditioners out of the way. We largely use ceiling fans in Singapore. The difference in electricity bill between the couple of months with horrific heat where we use a lot of air conditioning and the rest of the months where we don't is pretty steep. A few people may want to use air conditioning all the time - so it's fair to give others a choice. Heating on the other hand in cold countries is pretty non negotiable from what I've experienced - so centralized may work better.
• btgeekboy 6y ago
  I used to live in a building that had an electric furnace in each unit. The air conditioning coils were connected to a condenser shared with the building; the size of the piping led me to believe it might be pushing chilled water (vs. refrigerant) to each unit. No crappy boxes hanging outside, individual per-unit control inside.