Home Office Projects Series: Air conditioner setup • Hacker News Board

Re: Home Office Projects Series: Air conditioner setup

#81

Post by thaumasiotes » Thu, Sep 03, 2020, 5:14 PM UTC

rsync wrote: post #24

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 even after all of these years I can't believe I continue to see shiny, brand new "high end" condo buildings in Hong Kong, Shanghai, Tokyo, Seoul, etc., with individual AC units hanging out the window. Contrast this with a condo in Minneapolis that I own wher…

> 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".

Re: Home Office Projects Series: Air conditioner setup

#82

Post by phantom784 » Thu, Sep 03, 2020, 5:17 PM UTC

I wish those holes for refrigerant lines in apartments were standard in the US. My apartment in the bay area has no AC and furthermore doesn't allow window units, so I'm stuck with inefficient portable units. I'd love to be able to just put some mini-splits in (and I'd probably still come out ahead over renting a place that comes with central AC).

Re: Home Office Projects Series: Air conditioner setup

#83

Post by esaym » Thu, Sep 03, 2020, 5:22 PM UTC

I find it odd that for heat he only mentions units external from the a/c. The 'cu-229cf' unit he bought seems to be capable of heatpump mode[0]. Nonetheless, I really hate mini-splits. They always have really thin intake air filters that really don't filter anything. Thus the insides of the indoor unit are always caked in layers of dust and mold.

[0]: https://panasonic.jp/aircon/housing/products/19f.html

Re: Home Office Projects Series: Air conditioner setup

#84

Post by bluGill » Thu, Sep 03, 2020, 5:26 PM UTC

gcds wrote: post #32

rsync wrote: post #24

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 even after all of these years I can't believe I continue to see shiny, brand new "high end" condo buildings in Hong Kong, Shanghai, Tokyo, Seoul, etc., with individual AC units hanging out the window. Contrast this with a condo in Minneapolis that I own wher…

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 h…

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.

Re: Home Office Projects Series: Air conditioner setup

#85

Post by bluGill » Thu, Sep 03, 2020, 5:33 PM UTC

marcinzm wrote: post #55

rsync wrote: post #24

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 even after all of these years I can't believe I continue to see shiny, brand new "high end" condo buildings in Hong Kong, Shanghai, Tokyo, Seoul, etc., with individual AC units hanging out the window. Contrast this with a condo in Minneapolis that I own wher…

>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 cas…

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)

Re: Home Office Projects Series: Air conditioner setup

#86

Post by reaperducer » Thu, Sep 03, 2020, 5:34 PM UTC

ClumsyPilot wrote: post #72

rsync wrote: post #24

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 even after all of these years I can't believe I continue to see shiny, brand new "high end" condo buildings in Hong Kong, Shanghai, Tokyo, Seoul, etc., with individual AC units hanging out the window. Contrast this with a condo in Minneapolis that I own wher…

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…

In Russia and Czech Republic we have district heating

This exists in some cities in the United States, but it's usually older cities like New York and Chicago.

The plus side, is that often if you have a building with district heating, you will also have district cooling.

On a somewhat related note, some of the buildings in Chicago heat and cool themselves with water pumped directly from the Chicago River. Lake Michigan acts as a giant thermal reservoir. ("Cooler by the lake," as the TV weathermen say.)

Re: Home Office Projects Series: Air conditioner setup

#87

Post by bluGill » Thu, Sep 03, 2020, 5:36 PM UTC

criddell wrote: post #80

L_Rahman wrote: post #63

Earlier quoted context omitted.

This examples fails to account for the fact that radiant floor heating is a default feature in all new Korean homes.

The examples seem to mostly be looking at cooling and dehumidifying. What do radian floors for heating have to do with that?

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)

Re: Home Office Projects Series: Air conditioner setup

#88

Post by fulafel » Thu, Sep 03, 2020, 5:39 PM UTC

rsync wrote: post #24

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 even after all of these years I can't believe I continue to see shiny, brand new "high end" condo buildings in Hong Kong, Shanghai, Tokyo, Seoul, etc., with individual AC units hanging out the window. Contrast this with a condo in Minneapolis that I own wher…

Insulation and ventilation cold/heat recovery is more important yhan central vs per room heat pumps.

Re: Home Office Projects Series: Air conditioner setup

#89

Post by jonpurdy » Thu, Sep 03, 2020, 5:47 PM UTC

rsync wrote: post #24

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 even after all of these years I can't believe I continue to see shiny, brand new "high end" condo buildings in Hong Kong, Shanghai, Tokyo, Seoul, etc., with individual AC units hanging out the window. Contrast this with a condo in Minneapolis that I own wher…

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.

Re: Home Office Projects Series: Air conditioner setup

#90

Post by jimbobimbo » Thu, Sep 03, 2020, 5:47 PM UTC

ClumsyPilot wrote: post #72

rsync wrote: post #24

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 even after all of these years I can't believe I continue to see shiny, brand new "high end" condo buildings in Hong Kong, Shanghai, Tokyo, Seoul, etc., with individual AC units hanging out the window. Contrast this with a condo in Minneapolis that I own wher…

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…

What's missing from the description of a district heating paradise in Russia (ex USSR really) are constant issues with hot water / heat availability throughout the year. It's not unheard of cities shutting down central hot water supply for months for maintenance, or breakdowns of central heating in the middle of the harsh winter. The further you go from regional centers, the worse situation gets. The temperature that you get in your apartment out of this system is also inconsistent, and depends on a variety of issues with aged infrastructure.

My family lives in a relatively small town in Ukraine, got fed up with that and installed a gas-powered heater that serves both heating and hot water. This setup is 15+ years old already, never looked back. When the rest of the building is freezing cold, it just works.