I'm considering getting one of those Mitsubishi mini-split air conditioning systems as an alternative to central AC, with a single small external unit serving three units inside the apartment.
This is also a heat pump.
I've been told that these systems require a lot of maintenance.
I'd be grateful if anyone could provide experience with these systems. Thanks.
central ac will cost far less, and no individual units to service
If you are just cooling / heating the rooms you use instead of the entire house, then the savings in the electric bill would more than pay for any maintenance. Not to mention the savings you get from the higher efficiency of these units.
Something easier to understand is a refrigerator. New refrigerators are more efficient than older. I bought a new refrigerator for $800.00 seven years ago. It has saved me $15 a month on my electric bill (dropped that much as soon as I got it). So that refrigerator has saved me $180.00 a year on my electric bill. Or $1260.00 for 7 years.
It has not needed repair, but I don't care if it does! I'm money ahead even if I need to replace the whole thing.
Depends, if you live in a region (such as here) where hot water is commonly used as a medium for heating it is pretty spendy to retrofit duct work just to have central A/C.
Do you own this "apartment" ?
Are you allowed to place noisy equipment located outside which may impact the enjoyment of people in other apartments both inside their units and outside ?
Does your "apartment's" electrical service have enough extra capacity available to support adding such equipment ?
Before asking questions about how these units work and how much maintenance they require, why not let us all know the answers to the above questions first so we can be sure your project is even possible... Thanks...
Yes, from the limited info I got the impression that he doesn't already have a duct system. In which case the mini-splits could cost a lot less than installing a whole central AC system. There are mini-splits available that will run more than one evaporator/inside unit off of one outside compressor unit. Of course the downside is that you only are providing AC to certain rooms.
But I think it would be wise to consider both approaches before making a decision. There are also high velocity AC systems that are more like a central AC system. They use pipes that are maybe 2" to bring air to outlets that can be located in ceilings, etc. They force air at high speed through the smaller pipes. Used mostly in retrofit work because they are easier to install. The eqpt costs more, but eliminating the need for metal duct work can make up for it.
As for AC mini-splits needing a lot of maintenance, this is the first I've heard of that. I don't see why that would be as they are just very basic AC systems, nothing unusual.
I just walked in the door having just completed the wiring of 3 Mitsubishi (Mr. Slim) mini splits, each feeding multiple blowers. We set up a 4 ton unit with 4 line sets and blowers, a 2 ton with 3 sets and blowers and a 1.5 ton with 2 sets and blowers. I've been wiring these things (all brands) for years, and never heard of any maintenance problems. Unlike central systems, these mini splits are all heat pumps as well, they're very quiet and efficient. The running load on this 4 ton (48,000 BTU) unit is only 23 amps, which includes the 4 blowers it's servicing. The downside in my opinion, is the ugly line sets on the outside of the house, and a fairly large blower unit mounted on your wall. As far as the function, reliability, and economy, I think they're excellent.
Me too-- I cool 2 rooms about 10-20 days a year. The rooms are one above the other. Been using 5-10K BTU window bangers forever.
I looked at installing a unit on a pad and mounting an interior unit in each room.
Advantage- Rooms quieter; more attractive- doesn't plug a window; easier- no more taking them out in the fall; more efficient?? [I question that because I rarely run both rooms at once- so I'd be running an oversized compressor most of the time. Likely to be more efficient than central air-- but it seems like the window bangers are still cheaper to operate if only one is running.]
disadvantage-- *Way* more expensive. I can buy about 6 wallbangers for the price of a minisplit. And any service calls would cost as much as buying a replacement window A/C. [and I could replace the window unit in about an hour- and not wait for a service call, etc]
I could probably set up central air [I have hot air heat] for about what a mini-split and 2 wall units would cost--- but there is still that whole 'inefficiency thing.
Jim
Obama will still give you 30% back on a high efficiency mini I think. It was true when I got mine.
I think that you missed the entire point of my post:
Unless the OP is the owner of the building he doesn't have the right, legal or otherwise to install something outside on the ground outside of the boundaries of his "apartment" noise or otherwise...
So they may be quiet, and the ones that are maintained and properly sized usually are, but if it is running at full capacity and hasn't been kept clean they do get louder over time...
I had a Mitsubishi mini split system installed 2 years ago to replace a very noisy and much less effective window air conditioner. I have been extremely happy with the unit in nearly all respects, and have had no maintenance issues so far.
The 2 ton unit I bought runs very quietly, with varfiable speed fans on both in the indoor and outdoor units. The normal operation after the initial cool-down is amazingly quiet.
The window unit it replaced had one end of the area too cold and the other end too warm by many degrees difference. The split system is mounted on a wall in the central area, and spreads the cool area very uniformly both by using a sweeping motorized vane from left to right as well as a sweeping vertical vane to reduce stratification. The uniformity of the temperature is tremendously better.
The initial cost was close to $3500 versus $500 for an installed window unit. The conventional A/C option did not exist since I had no place to hide / place the ducts in this attic area. The mini was a very good solution and I would highly recommend it.
Only disappointments so far:
The remote control is pretty crummy with a marginal user interface for control.
The drain to the outside is hard to get to, and will eventually clog and cause serious problems within the wall unless I have a way to purge it.
The replaceable air filters are expensive, hard to find, and supposedly need to be changed often.
Of course, such absolutes are always wrong. ...but you're good at that.
Wow!
I'm 99% sure that tax credit expired over a year ago, Dec 31, 2010
Mini-split systems are extremely quiet. The 4ton Samsung unit I installed has two condenser fans and you can barely hear it running. The units were designed for living spaces in close quarters which is why very quiet operation is a basic characteristic of mini-splits. ^_^
TDD
Have you used the wire/line set duct system to cover the power and line sets on any of your installations? The stuff is like big Wiremold and makes for a much neater appearance since it can be painted to match the walls. ^_^
TDD
No, the airconditioning companies install the line sets and covers. I've heard of the covers you're talking about, and I'm always asking them, but all they ever use is crappy leader duct
He,he,he, I know what mean about the cheapest route. Me and JH do a lot of national contract work and one of the customers is an auto parts store. When we install phone and point of sale equipment in the stores, square PVC rain gutter drain pipe is often used in place of power poles for bringing power and data/phone lines from the ceiling to the counters. Heck, it works! ^_^
TDD
I'd just like to add another option to the discussion: PTAC (motel through = the wall units). They are closer to the price of the window units, but clos= er to the performance of the Mini-split. They don't marry you to a service = man, it it breaks, throw it away and get another, (I recently paid $700 to = get a central air compressor changed, under warranty, after shopping around= , the first guy wanted $1k). The downside is the original install requires = a sizable hole in the wall, plus a sleeve and grille, but only once, after= that you pop them in and out like toast in a toaster (150lb toast, but sti= ll..). They are also a bit ugly, to some, to me they are beautiful, they sa= ve me money and keep me comfortable year round. Just make sure to get the h= eatpump version, they always have a cheaper model with induction heat.
Thanks for the response. All of the questions you raise are either inapplicable or have been resolved in my favor.
Have you used the wire/line set duct system to cover the power and line sets on any of your installations? The stuff is like big Wiremold and makes for a much neater appearance since it can be painted to match the walls. ^_^
TDD
It may not be as simple as adding a unit above the furnace. In older homes the ductwork was designed for heating only. In such cases the returns are on lower floors and the ducts get smaller as you go up higher floors. So you may need to add a return at the top of the upper floor and have it come down through closets.
In my 1891 4-story rowhouse I put a packaged unit on the roof to handle the top two floors. I could have gone mini-split, but I was able to hide all the ductwork and I have ducts in every room irrespective of its size. With a mini-split one tends to skip the very small rooms.
To handle the bottom two efficiently I ran a return to high on the wall of the second floor.
And be sure to get variable speed. The added comfort of getting the humidity out is well worth the added cost.
Don.
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