Author Topic: Individual Air Conditioners  (Read 6377 times)

ShanghaiStashing

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Individual Air Conditioners
« on: July 24, 2012, 01:06:28 AM »
I currently live in Shanghai and one of the nice features about our apartment is that it comes with individual air conditioners for each room in the place (5 built in AC units).

It has a high natural thermal mass (all marble floor / hardwood, granite counters) on a thick concrete pad which keeps the place cool. We wait until 9pm at night when the electricity becomes 1/2 price and only turn on the AC unit in our bedroom. Our electricity bill per month here is under $15 so far.

tooqk4u22

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Re: Individual Air Conditioners
« Reply #1 on: July 24, 2012, 08:23:21 AM »
Those seem to be more common in countries other than the US - probably because people don't like the way the look.

I have no idea about the efficiency of any particular individual unit but in general it would seem to me that if you are only cooling or eating the room that you are in then it would be more efficient then central air. 

Same goes for heating, my sisters place has baseboard heating that is controlled by a thermostat in each room. 

I wouldn't mind having either this kind of setup. 

militaryincome

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Re: Individual Air Conditioners
« Reply #2 on: July 24, 2012, 09:27:10 AM »
It's the same way here in Japan. People are much more conservative with energy.
Unfortunately Japanese houses are very poorly insulated.
My electric bill was about $85 last month, although we didn't use the AC nearly as much as this month.
When you think about it, central air is so inefficient. You really only need to heat/cool one or 2 rooms at a time.

kudy

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Re: Individual Air Conditioners
« Reply #3 on: July 24, 2012, 09:57:21 AM »
I've been looking at ductless mini A/C units for my house (I think that's what you're describing here) - they are used a lot in asia and europe; the total cost to have one installed is crazy: I got ballpark estimates from $4K-6K.  It would be nice to have, and it would work as a heater in parts of the winter as well, but I don't know about the up front cost!

tooqk4u22

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Re: Individual Air Conditioners
« Reply #4 on: July 24, 2012, 12:35:45 PM »
I've been looking at ductless mini A/C units for my house (I think that's what you're describing here) - they are used a lot in asia and europe; the total cost to have one installed is crazy: I got ballpark estimates from $4K-6K.  It would be nice to have, and it would work as a heater in parts of the winter as well, but I don't know about the up front cost!

After seeing this post I looked it up on the net and the ductless unit is it.  If it is $4-6k that would explain why they are not common in the US.  That is crazy and only makes sense if you want to cool one room and don't already have A/C.   Other than that it would be great to have them in each room. 

kudy

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Re: Individual Air Conditioners
« Reply #5 on: July 24, 2012, 08:20:42 PM »
if you want to cool one room and don't already have A/C

This is basically my position... I don't have A/C, and I don't like window unit coolers, because they take up the entire window, and it's not possible to put a big box fan in their place during cool nights.  The ductless system would be ideal because it'd cool the 2 bedrooms in my house where I actually need it, wouldn't take up a window, and work in my house that has no ducts.  I have baseboard electric heat, and I think the heater functionality on the ductless system would prove to be more cost efficient (even though it uses electricity as well) during some parts of the winter.

The real question is, do I put forward this large expense, as well as the increased cost of comfort into the future, or do I deal with the heat as I have for the past 4 years?  The cost would be potentially offset somewhat by the heating feature, but adding and regularly using the convenience of cooling would probably cancel out any heat savings.

ShanghaiStashing

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Re: Individual Air Conditioners
« Reply #6 on: July 24, 2012, 10:51:51 PM »
Crazy about the price! Next time I am in the hardware store I will look at how much they are here, but frankly, this being China I cannot imagine that the units cost 4-6K USD each here. this would be 30K USD for my condo alone which though expensive to rent, definitely does not have 30K USD of aircon in it.

The design of these units is built in in a central air fashion (with ducts) but the units are individually controlled and built into the wall. I will post a pic of what they look like later.

I agree, if you already have AC likely not worth it given the payback period (at that rate I would guess its somewhere around 20 years). However, if building a house from scratch these units are definitely something that I would look into.

Kibatsu

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Re: Individual Air Conditioners
« Reply #7 on: July 25, 2012, 08:09:45 AM »
I'm not sure about the quality of these things as I previously knew nothing about ductless AC, but I did a quick google search to see what they were and it came up with much cheaper units. For example:
http://www.goductless.com/
http://www.acdirect.com/ductless_cooling_heating_.php

Daley

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Re: Individual Air Conditioners
« Reply #8 on: July 25, 2012, 08:35:37 AM »
For all the talk of efficient cooling, I'm kind of surprised nobody's brought up swamp coolers yet. Granted, they're only practical in dry climates, but they're quite cheap to run and environmentally friendly.

kudy

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Re: Individual Air Conditioners
« Reply #9 on: July 25, 2012, 10:19:48 AM »
...I did a quick google search to see what they were and it came up with much cheaper units.

Yes, the units themselves are around $2K for a 2 room system, but I was factoring in installation cost because I am not comfortable installing a new circuit in my breaker box & wiring the electrical, and I have no expertise in charging the system with coolant and testing for leaks, proper pressure, etc. after installation.

For all the talk of efficient cooling, I'm kind of surprised nobody's brought up swamp coolers yet. Granted, they're only practical in dry climates, but they're quite cheap to run and environmentally friendly.

Yes, I have considered this option - I am in Colorado and they work well.  My stumbling block is where to install one, or whether to install more than one (1 for each bedroom?).  They also require a large hole to be cut into the side or roof of my house, and seem to take up a bit more space, which would be nice to avoid.  Of course, I imagine the swamp cooler route would end up being cheaper and cost less to run.

gooki

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Re: Individual Air Conditioners
« Reply #10 on: July 25, 2012, 02:55:44 PM »
Ductless Aircon is the standard here in NZ for both new homes and retrofitting existing homes. I looked at a ducted system, but it was 3 times the price of a non ducted for the same amount of output.

All up a good brand (Mitsubishi) unit cost us just under $3,000 USD including installation, and provides consistent 9kw of heating (30,000 Btu), and 8kw of cooling. This is sufficient to heat/cool our modest  3 bedroom home.

GP

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Re: Individual Air Conditioners
« Reply #11 on: August 01, 2012, 08:57:34 AM »
I am in Toronto and I use two of these units in a two story house (one on each floor).  They're the Mitsubishi Mr Slim version.  Cost was a little under $6k installed after some govt eco rebates. 

These things are fantastic. 

I've had them for three years and have had no issues with them at all.  They do all the AC for the house, although we don't use it too much, but when it was 38C and humid last week the house was lovely and cool with one of these two units running (the upstairs one). For heating I have baseboard heaters as a backup, but I only had to turn them on for four days last winter, the rest of the time the ductless units were more than enough to keep the house warm.

These things are also very very cheap to run, my hydro bill is roughly a bit less than half that of my next door neighbour who has the furnace/AC combo that is normal up here.

tooqk4u22

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Re: Individual Air Conditioners
« Reply #12 on: August 01, 2012, 09:10:47 AM »
This is definitely worth looking into if you are building a new place or need to replace the system, but the cost seems quite high and may not make much sense economically. 

My HVAC is old and will need replacement in the not to distant future and this would be a good option, but it based on the comments it seems like this option would be significantly more money to buy and have installed when compared to replacement of conventional system. The problem is that it is not like purchasing other things (cars/houses/ ipod) where there is a lot of information available about cost but that is not the case for replacing HVAC let alone for systems like this. 

BTW I have a 1700ish sf house (3beds upstairs and living room, family room, kitchen downstairs) - I suspect one would be needed for each bedroom, one for the living room and one for the family room (room is isolated).

Need to do more research but if traditional replacement is $8k and these would be $20k it is not even a discussion.

Also not sure how it would effect resale. 

mugwump

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Re: Individual Air Conditioners
« Reply #13 on: August 01, 2012, 09:27:56 AM »
We had a swamp cooler when we lived in Pueblo, CO. We had a small ranch, so we installed it on the north side of the house and cracked the windows where we wanted the cool air to go, and it cooled the whole house very well. I never noticed its impact on the electric bill.

Now we live in a ranch in North suburban Denver, and we haven't installed a swamp cooler yet.  We have a room air conditioner in the main room of the house (combined kitchen/living room).  My hyper-moustachian husband cut a hole in the house and installed the a/c unit permanently in the wall, then built an insulated fiberglass cover for the winter.

Our house gets a lot of shade in the summer, and no sunshine in the windows in the summer, because the windows are facing south or north.  We sleep in the finished basement during the summer and crack the windows at night and run an exhaust fan. We close the windows and the shades when it warms up during the day, and start running the a/c about 4:00 most days. We just got through the hottest July on record with electric usage of about 400 kWhrs, about 150 more than our base usage.

Both of us grew up without central air.  I definitely consider it optional in Colorado.  Oh, also, we avoid using the oven when it is hot.  We have a small toaster oven we put out on the patio.

GP

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Re: Individual Air Conditioners
« Reply #14 on: August 01, 2012, 10:10:40 AM »
BTW I have a 1700ish sf house (3beds upstairs and living room, family room, kitchen downstairs) - I suspect one would be needed for each bedroom, one for the living room and one for the family room (room is isolated).

Have you talked to an installer/dealer?  I have two for the whole 1500sq/ft house.  I think you may be considerably over-estimating your needs.

tooqk4u22

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Re: Individual Air Conditioners
« Reply #15 on: August 01, 2012, 10:17:51 AM »
BTW I have a 1700ish sf house (3beds upstairs and living room, family room, kitchen downstairs) - I suspect one would be needed for each bedroom, one for the living room and one for the family room (room is isolated).

Have you talked to an installer/dealer?  I have two for the whole 1500sq/ft house.  I think you may be considerably over-estimating your needs.

No, this post is what raised my interest so I haven't done anything more that look on the net.  You have one up and down but how does the air circulate between the different rooms - this is why I suspected I needed one for each room.