Mini Split Ductless Air Conditioner?

[inquisitive]

Not sure what the terminology is, but I'm thinking of getting 1 for my 3rd floor condominium. Last summer I was all about saving money but now I'm thinking the increased productivity I'll have from being able to think quickly and accurately due to the cool should more than make up for the installation and electricity costs, and I can keep it off when I am not at home.

Has anyone installed one of these? My plan would be to get 2 units for the 2 bedrooms on the main floor and 1 for the attic (which has been converted into a bedroom).

I would need to hire someone to do everything, how can I save on the costs? I have seen some selling on Ebay, is this an option?

Does anyone know what the electricity costs would be?

 

[inquisitive]

And should I consider other options? I don't want to use up all the windows for air conditioning units and they should be more expensive over the long run too.

I feel like with the cost of technology nowadays and all the advances that solar cells should be cheaper but they don't seem to be such a good deal, or at least the recovery time would be over years.

 

[billin]

The reliable ones work well. Be cautious and check out the brand before you buy. Are you in an area where a heat pump version would be of value to you?

 

[calmloki]

Know a person down in 29 Palms Ca who reported large savings on her electric after installing a mini-split. I looked into one, but wanted government assist on the cost and could only get gov assist for some of the rentals. While it would have been a nice upgrade for the places there is no way I would do it - way too many little fiddly breakable plastic bits and filters to replace and clean. I wonder at the longevity of the units - modern refrigerators don't seem to last as long, and if you needed a repair part for a unit that was six years old would it be available? I did like the heat/cool functionality - a certain lag time AIR during which it is blowing cold air before heat starts happening - maybe check that.

 

[kcowan]

I have 3 of them in my condo in Mexico. We only run them part time in May and October but they work well. We close the place up in June to September.

Pay atenntion to where you install the exchanger. For a little extra plumbing, you can save $$ on operation.

 

[inquisitive]

Already have high efficiency forced hot water heating, so don't see the need to combine this with heating.

How does the location of the exchanger save money?

 

[Lazarus]

These are used outside the US a lot. In Nigeria they just put in however many were necessary to cool the space. Common areas like halls were not cooled at all.

I like them but they are not as cheap in the US as the mass produced window units.

 

[calmloki]

Was just in Costco and saw a 14000BTU(?) / 4100Watt freestanding inside unit for $450. This is the type that has an in and out duct that fits in the bottom or side of a window. Not as fancy schmancy, but new and wheel it in and start it up and $450? Might be worth a look.

Think that Kcowan may have been suggesting that a heat exchanger placed in a shady spot has an easier thriftier time of it than in the direct sun, assuming you wish to cool.

Maybe I'm wrong, but my assumption was that it both heated and cooled - think i'm wrong, and that is a huge power load for a 120V circuit - needs further checking up on.

 

[kcowan]

....
Think that Kcowan may have been suggesting that a heat exchanger placed in a shady spot has an easier thriftier time of it than in the direct sun, assuming you wish to cool.

Yes if you want to cool then the unit (exchanger) should be in the shade. The difference between sun and shade can be 30 degrees in the afternoon when you need the AC the most.

 

[inquisitive]

Does anyone know how much it costs to operate these things? Naturally it will depend on my use and the temperature, but for a ballpark figure, per month? Am planning on installing 3 indoor units. Looked at one which is SEER 17 and has a power input of 1,090 Watts (250-1,090). Are they generally closer to the 250 or the 1000 so I can get an idea of how these compare to other household appliances?

Thanks for the tip about the shade. I'll determine a place that it could go.

Am also considering just installing ceiling fans in all the bedrooms and putting insulation in the roof (the attic has been converted into a bedroom and it gets really hot up there), but will insulation do anything without air conditioning?

 

[kcowan]

but will insulation do anything without air conditioning?

With or without AC, insulation is a useful step.

 

[travelover]

With or without AC, insulation is a useful step.

Right - insulation and proper attic ventilation go a long way toward keeping cooler.

 

[Telly]

Does anyone know how much it costs to operate these things? Naturally it will depend on my use and the temperature, but for a ballpark figure, per month? Am planning on installing 3 indoor units. Looked at one which is SEER 17 and has a power input of 1,090 Watts (250-1,090). Are they generally closer to the 250 or the 1000 so I can get an idea of how these compare to other household appliances?

Roughly speaking, SEER equals the unit's heat transfer in BTU per hour, divided by the power required in Watts. So the unit you are looking at, with SEER of 17 and max power of 1090 watts must be about a 18,000 BTU unit. Also called 1 1/2 Ton, as one Ton of ice = 12,000 BTU.

With "inverter" technology, basically a variable speed compressor, the control system will increase or decrease the compressor's speed to match the heat transfer required at the moment. So full speed, maximum power use, for initial cool-down or under heavy heat load. And slower speed, less power used, in low heat load conditions. I think the indoor evaporator blower changes speed on all of those high-SEER models too. The net effect is that the A/C system dynamically changes size, BTU and power-use wise. The rated BTU value (18,000?) will be at full output.

So whether its 250 watts, 1090 watts, or somewhere in between depends on the heat load it sees. Probably cranking at 5 PM, coasting at 3 AM.

 

[nphx]

I have done a few installs my self. I love the units because they are quite. The compressor unit which is pretty quite compared to window units is mounted somewhere nearby outside. The indoor unit of course doesent need a duct, it recycles room air. The indoor unit will need power and holes through the wall for two copper freon lines plus a drain hose for any condensate to drip outside. So - for a "mechanical install" the indoor unit will have about 2-3 feet of copper tubing that will need to be routed through the hole inthe wall you made. Also the drain tube would go through the wall. You would need 110v power to that wall mounted unit and 3 to 6 ligher gauge wires from the unit will need to get to the location of the compressor unit.

The compressor unit needs a pad or mounting ledge, plus power.

If you did the above yourself you would have done the mechanical/electrical portion of the install... but theres more.

You will now need to connect the correct diameter/pressure rating copper hoses from the lines poked through the wall to the compressor unit. Bending curves in the tubing benefits from a small tool that often comes in a kit that also allows you to cut and make flared ends - which you will need to connect the tubes at the compressor end. Assuming you are still thinking about the job.....

You now need to "evacuate" the lines of air. This concurrently will test out if you made all the line connections with integrity. After drawing a vacuum the negative pressure should maintain. You would need a vacuum pump plus a gauge set. gauge set and vacuum pumps often have specifc fittings that match the trype of freon in your system (i.e R22 R410 etc).

If youre still reading.... now you are in a position to "charge" the sytem with freon. Good news, nearly all splits have pre pressurized the compressor with enough freon for 50 feet of line. So with confidence you have no leaks you open a valve on the compressor and the lines are pressurized.

There is a need to use some insulation on the lines which can be exposed outside your home. I think one is more important (pressure side i think verses return line) but i insulate both.

Disclaimer - i am not an ac technician and i dont play one on tv. From my car hobby i had some experience with ac guages and vacuum pumps.

Harbor freight tools suffice for DIY work, when you buy mini splits on line they are small enough to come via UPS or if they are truck shipped you can sometimes save by agreeing to pickup up at the local freight depot verses home delivery.

 

[kcowan]

.... now you are in a position to "charge" the sytem with freon. ...

I think it is coolant. I believe "freon" is illegal in the US?

 

[ls99]

IIRC freon is a trademarked refrigerant (R12 ??) name owned by DuPont.

 

[ERD50]

I have done a few installs my self. I love the units because they are quiet. The compressor unit which is pretty quiet compared to window units is mounted somewhere nearby outside. The indoor unit of course doesn't need a duct, it recycles room air. The indoor unit will need power and holes through the wall for two copper freon lines plus a drain hose for any condensate to drip outside.

I'm surprised no one markets an 'easy-install' version of these. Seems to me, if you installed the fan and coils in the window, and plugged them into power inside (same as a standard window unit), you could extend that power and the coolant lines through that window unit to a small compressor that sits on a little stand on the ground outside the window. Advantage - small, light unit to mount in the window; quiet since the compressor is outside; no special power requirements or complex installation.

The 'trick' might be those coolant lines - I think they have something flexible for these for the ductless, and I thought I even read about some special fittings that can be connected and then open the valves (or a 'quick-disconnect' type with integral valve) so you can do an install w/o losing a significant amount of R134a (or whatever coolant they use in these).

-ERD50

 

[kcowan]

IIRC freon is a trademarked refrigerant (R12 ??) name owned by DuPont.

Right and its sale is banned in the US and Canada.

 

[samclem]

If you decide the cost of a mini-split system is more than you want to pay, you can still install a window unit, but without using a present window. Depending on your situation (type of siding, wall construction, etc), it can be a rather simple issue to frame a new opening in the wall at some convenient spot and install any standard window unit.
-- Disadvantages vs a mini-split:
--- The window unit will be louder (since the compressor and condenser fan are located near the living spaces). Also, if outside noise is an issue, the "window unit" will allow more of this noise inside than a mini-split would.
--- The mini-split may have slightly lower operating cost due to greater efficiency.
--- A mini-split will be less noticeable from the outside
-- Advantages vs a mini-split:
--- Less expensive installation
--- Less expensive equipment (window units are "commodity items" freely available directly to retail purchasers). When it dies you can easily replace it yourself-pull out the old one, put in the new one, plug it in. Done
It's not the "Cadillac" way to do things, but it can be very effective, cheap, and need not use up a present window. Put an insulated cover over the unit during the winter to reduce heat losses. Or, you can just remove the entire unit during the non-cooling months and install an insulated "plug" in the opening.