Mini Split Ductless Air Conditioner

Some Good Info Here:
https://temperatureprocentralnj.com/everything-you-need-to-know-about-ductless-mini-splits/

These efficient units. which began appearing in the USA about 2015 
can quietly both heat and cool the inside of your house as needed. New homes seem to include these now, as opposed to a “central” air-ducted system.
You may already have seen some and not realised it as they are so unobtrusive

They come in three parts:

1) Outside Unit
A large weatherproof  outside metal box unit with a big but quiet  fan and compressor that dumps the heat out of your house
(or cold if used in reverse- More Later). It’s mounted on a solid slab or bracket. 
1300 sq ft area generally require a single 240v AC power supply “Fused” at 30A. USA homes have this at their power-panel but you will likely need an electrician to link things up properly.
Smaller units may only need 110v 20A.
A separate circuit should be provided in either case

2) Line Set:
A pair of copper pipes 25′ long on average called the “line set” with plastic insulation-

Outside  Diameters:  1/4″ high pressure (200 PSI) and one 1/2″ low pressure (50 PSI) Ave.
Plus- it is sold cleaned, purged and filled with dry nitrogen…

These pipes usually tuck into a 3″ duct between the Outside Unit
(Above) and the Inside Unit (next). to improve insulation and appearance.
Lengths can be changed but it’s simplest to use the default length.
There’s also 25″ of 5-conductor Power and Control cable, too,
as no separate ‘inside power’ is required.

3) Inside unit: (can be more than one)
This is the relatively small and quiet Business End of things that does the cooling with a long narrow “Squirrel cage” fan and evaporator coils rather than a bladed fan, and a very easy to clean filter.
This is what makes it so quiet!

It is generally fitted at least 6″ on all sides from obstructions,
high up on the wall in a central location, and not necessarily on an outside wall. A single hole 3″ in diameter is required to pass the “Line Set” through to outside,  to join all three parts, along with a simple 5-conductor control and power cable to get electrical power and controls from “Outside”.
The system is also called “Ductless” as no air ducts are involved. 

This is not a straightforward Plumbing Job as it might be with water or gas, be warned. I have done it myself but I advise you to get a licensed installer as its flared fittings must be correctly sealed & tightened, then ‘evacuated’ (vacuum pumped of air and moisture ), tested and filled with refrigerant that’s shipped inside the compressor.
I am also pretty sure the copper piping is specified in size and design for this and no other purpose.
Done right, 5 years is the usual warranty.

Mine has a remote control and you can set the temperature according to where you put the remote control rather than having it as traditionally, screwed to the wall where it measures the temperature there.
Lots more options are available, not least a simple default “Cool” one that maintains 73-77 degrees.

In winter they can switch to Heaters by REVERSING their function

It will more than gas but LESS than if you were using ’true’ Electrical Heaters. These devices are “Air to air heat pumps” being the reason- They move energy from outside to inside,
inherently more efficient than dumping electrical power straight to heat or cold.

Of Special Interest is the use of three “Inverter” motors in compressor, outside fan and inside fan.
More Info Here
Full torque is available at low speed s there are no start-up “surges”

My calculations  are for my  1300 sq feet with doors opened to other rooms so would need a “24,000BTU capacity unit” also mysteriously known as a “two ton unit”
(In fact the shipped weight of mine was 400 pounds, go figure)
Here is a calculator I used to figure the right size of machine
I went a bit ‘over’ as ‘under’ would disappoint on a hot day!

These start at $1500 from Amazon, Home Depot   etc.
Mine was less but be warned- an installer may not want to install something she did not order or is unfamiliar with.
This profession & business is known as: HVAC= “Heating Venting and Air Conditioning” and has various certifications.
Be Warned you will NOT get the warranty unless you use such a licensed installer! a “Handyman Install” such as I did, no matter how carefully or successfully  it is done, will allow the manufacturer or distributor to claim the warranty Void.

GOTCHAS:
These units can ONLY recirculate the air through filters and do not bring any new air in from outside.
This is Nice when its smokey or otherwise polluted outside but can make your home dry and stale
(They will naturally wring moisture out of the air)

I use mine in combination with a Whole House Fan- This is a huge extractor fan in the ceiling used to drag outside air inside via the House living space and push it out via the roof space, thus also purging hot air trapped under the roof area

I do this typically in the coolest part of the night around 4AM in the Summer- thus flushing the entire house of stale air in about 15 minutes.

One MUST leave some doors or windows open WITH SCREENS when doing this as the air must be sucked from somewhere, ideally bug-free
Certainly , leave things open at the furthest points in the house
and be warned unchocked doors can slam shut hard in the breeze!

This is all a certain amount of manual work but worth it-

No special arrangements needed for the air conditioner– In fact, most come with a WIFI Internet Connection and App. to maintain control remotely and pre set things more easily

That’s It in general. Comments are Welcome!

 

 

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