theoldwizard1
Well-known member
I will attempt to answer the question in the title, but I am not an expert on this topic so hopefully those who are will add mor and/or correct my mistakes !
What is a mini-split ?
A mini-split is a type of heat pump. It is called "mini" because they (originally) were fairly small capacity and would only heat/cool one room (more on this later).
A heat pump is just an air conditioner that can be run forward or backwards. By backwards I mean cooling the outside and heating the inside.
Why are they "suddenly" popular ?
The technology has been around for awhile, but because, until somewhat recently, they would only service 1 interior room. They are extremely efficient, so the cost of operation is low !
Why are they so efficient ?
There are a couple of reasons. (In the following, do not think of "heat" as how hot it feels to you. Instead think of "heat" more like water that can be moved from Point A to Point B.)
Heat pumps, in general, are fairly efficient because they do not "make" heat (burning a fuel or heating a wire with electricity). They simply move "heat" from one location to another. A standard A/C just moves heat outside. When running in "reverse", it moves heat inside.
Most heat pumps are capable of moving heat from outside to inside at 100% efficiency down to about 20-30F. The better min-splits will work to a much lower temperature (-10F with some loss in efficiency). Like any air conditioner, they start loosing efficiency around 95F.
Because a heat pump does not "make" heat, it only moves it, a heat pump USES MUCH LESS ENERGY (electricity) than almost all "heat sources* when the ambient temperature is between about 30F and 70F !
(* Coal and wood are excellent low cost sources of heat, especially if you can get the fuel cheap/free. Most people do not want the hassle of coal or wood)
Mini-splits typically use "inverter technolgy" compressors. The compressor is the component that uses most of the electricity. An inverter allows the controls to run the compressor at a variable speed, just enough to meet the load.
Another reason for their high efficiency is there is no ductwork. The air handler is mounted in the room to be heat/cooled typically on a wall and has its own fan and thermostat. Refrigerant lines are usually run directly through the wall from inside to outside and the straight to a outside compressor unit which is much smaller than a typical A/C compressor.
You said "one room". How big ? What if I have more than 1 room ?
This is where modern technology has really helped the popularity of the mini-split !
Large rooms, like a garage, are not a problem because all you have to do is add more inside unit that are plumbed back to the same outside unit, which now typically come with 4-6 sets of taps ! For one room, the interior units are "slaved" together to one wireless thermostat so they all run at the same time ! For really BIG rooms, you might have 3-4 units on one wall, plumbed to one compressor and 3-4 more units on an opposite wall, plumbed to a second compressor, but they all will run off of one thermostat !
Got multiple rooms ? Put one interior unit in each ! They are not cheap and plumbing interior rooms (especially of an existing building) is difficult. A typical 3 bedroom 1-1/2 bath house, might need 6 or more interior units (each with its own thermostat) for maximum comfort. Not very cost effective compared to central heat and A/C.
View media item 43976
What is a mini-split ?
A mini-split is a type of heat pump. It is called "mini" because they (originally) were fairly small capacity and would only heat/cool one room (more on this later).
A heat pump is just an air conditioner that can be run forward or backwards. By backwards I mean cooling the outside and heating the inside.
Why are they "suddenly" popular ?
The technology has been around for awhile, but because, until somewhat recently, they would only service 1 interior room. They are extremely efficient, so the cost of operation is low !
Why are they so efficient ?
There are a couple of reasons. (In the following, do not think of "heat" as how hot it feels to you. Instead think of "heat" more like water that can be moved from Point A to Point B.)
Heat pumps, in general, are fairly efficient because they do not "make" heat (burning a fuel or heating a wire with electricity). They simply move "heat" from one location to another. A standard A/C just moves heat outside. When running in "reverse", it moves heat inside.
Most heat pumps are capable of moving heat from outside to inside at 100% efficiency down to about 20-30F. The better min-splits will work to a much lower temperature (-10F with some loss in efficiency). Like any air conditioner, they start loosing efficiency around 95F.
Because a heat pump does not "make" heat, it only moves it, a heat pump USES MUCH LESS ENERGY (electricity) than almost all "heat sources* when the ambient temperature is between about 30F and 70F !
(* Coal and wood are excellent low cost sources of heat, especially if you can get the fuel cheap/free. Most people do not want the hassle of coal or wood)
Mini-splits typically use "inverter technolgy" compressors. The compressor is the component that uses most of the electricity. An inverter allows the controls to run the compressor at a variable speed, just enough to meet the load.
Another reason for their high efficiency is there is no ductwork. The air handler is mounted in the room to be heat/cooled typically on a wall and has its own fan and thermostat. Refrigerant lines are usually run directly through the wall from inside to outside and the straight to a outside compressor unit which is much smaller than a typical A/C compressor.
You said "one room". How big ? What if I have more than 1 room ?
This is where modern technology has really helped the popularity of the mini-split !
Large rooms, like a garage, are not a problem because all you have to do is add more inside unit that are plumbed back to the same outside unit, which now typically come with 4-6 sets of taps ! For one room, the interior units are "slaved" together to one wireless thermostat so they all run at the same time ! For really BIG rooms, you might have 3-4 units on one wall, plumbed to one compressor and 3-4 more units on an opposite wall, plumbed to a second compressor, but they all will run off of one thermostat !
Got multiple rooms ? Put one interior unit in each ! They are not cheap and plumbing interior rooms (especially of an existing building) is difficult. A typical 3 bedroom 1-1/2 bath house, might need 6 or more interior units (each with its own thermostat) for maximum comfort. Not very cost effective compared to central heat and A/C.
View media item 43976
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