Mini Split A/C Units??

[29aholic]

So my boss has a rental house that is probably not quite 800 sqft and is thinking about installing a mini split unit in it.


Thoughts?

 

[billwill]

They are great.

 

[Wee Hooker]

I have two (engineer) friends who have installed multiple split units in larger homes. Both chose Mitsubishi brand based on their research. One of the guys actually installed it himself. Both love them. The ability to make heat in the winter is icing on the cake.

 

[bigwheelzip]

Son-in-law replaced a 220v wall-mounted unit with a split. It's a much better system.

 

[Tex1001]

Split systems are extremely adaptable. They can solve a lot of weird cooling/heating situations. In my experience they are expensive. Maybe the prices will drop in the future as they become more popular.

 

[anoblefox]

Replaced conventional a/c system in our first house in the Calif desert. Just built a new home in the central valley foothills and specified Mitsubishi mini splits. No regrets, VERY efficient; no losses in ducts since there are none. The inverter technology means the fan AND compressor only run at the speed necessary. No all on, all off operations. Also very quiet inside. I will not have any other kind! Very easy to retrofit existing buildings. YMMV

 

[Onomea]

Yep. I am a believer, too.

 

[BAM-BAM]

After a lot of research and recommendations I"m putting one into my Carriage House at the lake .. about 800sq ft ..... for heat and AC.

high efficiency

IMO For such a 'small' space central separate air and heat don't make sense...

 

[Telecaster]

I have one for my 500 s.f. office, which has a front room (where the wall unit is located), a back room, and a bathroom. The one unit is sufficient to get cool air to all three rooms.

 

[29aholic]

Thanks guys, that's the way I was leaning.


I am thinking around 12000 BTU

 

[jeffrefrig]

Mini split systems

I work on many of these as there are scores of them installed all over the school district I work for. They are very good for what they are for, but they must be installed properly and by a reputable company. Make sure you get a good warranty. I have installed many in my days as a Steamfitter, and worked on plenty more. They are a nightmare to work on...they pack the controls into sardine-can size control compartments. Every manufacturer has different fault codes, and more often than not one fault code can mean many different problems. When they work right, they are great. It's mostly all in the proper installation. Almost all are heat pumps, whether you want that or not! Fujitsu is about the least expensive and they work pretty good. With the compressor inverter system you won't hear it running. Don't let Billy Bob install it, pay the extra cash for a proper install, and if they offer an extended warranty, get it. Good luck. I would never own one, but I have to work on them! We have them all over the PGH School District. I cringe when I see one going in some remodel on one of our 100 year old buildings (which is exactly what they are good for...or a man-cave/garage/shed, etc.!) Jeff T., PGH PA

 

[jeffrefrig]

Mitsubishi

The Mitsubishi units are about the most expensive, but they also are the ones I have to troubleshoot the most. Parts are not cheap, either. An old rule of thumb: 1 ton (12,000 BTUs) per every 5-600 square feet for general A/C. For small server rooms, electronic control rooms, etc., a good contractor will compute a proper heat load to size the unit.

 

[TTSH]

At what point in the size or style of a new construction house do "Mini-Splits" no longer make sense? Or do they always make sense regardless of house size or type?

I am struggling hard with that question right now.

 

[BAM-BAM]

The Mitsubishi units are about the most expensive, but they also are the ones I have to troubleshoot the most. Parts are not cheap, either. An old rule of thumb: 1 ton (12,000 BTUs) per every 5-600 square feet for general A/C. For small server rooms, electronic control rooms, etc., a good contractor will compute a proper heat load to size the unit.

What mini-splits do you feel/find to be the best?????

Any thoughts on the Fujitsu systems???

 

[Tex1001]

At what point in the size or style of a new construction house do "Mini-Splits" no longer make sense?

A single outdoor unit can support 2 or 3 indoor units. For an installation of more than about 600-800 cft multiple units can be installed. Unoccupied spaces can have their units turned off.
Hence the adaptability factor.

 

[TTSH]

A single outdoor unit can support 2 or 3 indoor units. For an installation of more than about 600-800 cft multiple units can be installed. Unoccupied spaces can have their units turned off.
Hence the adaptability factor.

Thank you. I'm probably not asking my question very clearly... or maybe there is no specific answer.

Let me try again: Up here in New England, prior to the sudden popularity of mini-split units, folks who wanted air conditioning of a medium to large sized house without a bunch of window units would do central air conditioning... either a whole separate ducted system or a system tied into their forced hot air heating system. In such cases, there was typically one (sometimes two) large condenser units (or heat pump units) mounted together on pads outside the house with air handling units placed inside the house feeding separate or combined heat/cool ductwork.

I guess my question is: For other than a retrofit job, what would be the advantage, if any, of going with multiple mini-split units instead of a traditional central air conditioning system?

 

[BAM-BAM]

IIRC..... central air units lose something like 25 or 30% of their cooling ... cooling the duct works. also you can zone easier; only 'fully" heating or cooling the spaces you are using......

need coffeeee.e.eeee.....

 

[jeffrefrig]

To BAM-BAM

What mini-splits do you feel/find to be the best?????

Any thoughts on the Fujitsu systems???

The Fujitsu systems we have used to replace the Mitsubishi, Airedale, EMI units seem to work very well. All the ones we replaced were single indoor unit types, but I do believe multiple rooms can be conditioned with one outdoor (condensing) unit. Some things to consider with all brands is where to run the piping, proper insulation because the piping will sweat, and the condensate drain. Also, location so the unit can be serviced and, as all man made products are, someday it will leak water due to plugged drain, pump failure, etc. Do not install it above your $2500 home theater system or above anything (GUNS?) you do not want to get wet.

 

[BAM-BAM]

jeffrefig I see you are in the Burgh......... we're building in the Laurel Highlands...

We were spec'ed with a 24K Fujitsu unit with 2 7K wall mounts in the BR's and a 9K in the Great Room (kitchen/living)... for the apt in the Carriage house... total space about 800 square ft.; extremely well insulated. Just 3 rooms and a bath.

Pocket doors between the rooms that will be open except at night. With ceiling fans in the BRs.......hoping for open windows at night for a little mountain air

Any thoughts?????

 

[jeffrefrig]

Thank you. I'm probably not asking my question very clearly... or maybe there is no specific answer.

Let me try again: Up here in New England, prior to the sudden popularity of mini-split units, folks who wanted air conditioning of a medium to large sized house without a bunch of window units would do central air conditioning... either a whole separate ducted system or a system tied into their forced hot air heating system. In such cases, there was typically one (sometimes two) large condenser units (or heat pump units) mounted together on pads outside the house with air handling units placed inside the house feeding separate or combined heat/cool ductwork.

I guess my question is: For other than a retrofit job, what would be the advantage, if any, of going with multiple mini-split units instead of a traditional central air conditioning system?

On new construction I would never even consider ductless splits. It would be very labor intensive to run all the refrigerant and drain lines, plus all the wiring. With one main system you can also add a duct to your return air to get a small amount of outdoor air if you desire. In very large houses people often have two systems and may use one for upstairs, one for down; or East side and West side, etc., of the building. As an HVAC service person, I would prefer everything in one place in the basement or utility room...everything is right there and right out the door to the condensing unit. (Another reason why I only do commercial/industrial A/C & Refrigeration!)