By Thad Warren
I went from knowing nothing about mini-splits to installing one on a whim. While it was a good learning experience, I wish I did more research.
I’ll share with you a few things I wish I knew before I jumped in headfirst.
Mini-splits are heating and cooling systems that allow you to control the temperatures in individual rooms or spaces. They are often called a “ductless mini split system” or “ductless air conditioner”.
Mini split systems have two main components. An outdoor compressor and an indoor air handling unit. Like a conventional AC unit, mini splits use copper tubing to carry the refrigerant from the outdoor unit to the indoor air handler.
But, with a mini-split, the cold hold blows directly out of the indoor handler. So ductwork is not needed with a mini-split.
A mini-split system can have several air handlers for various zones that use one outdoor condensing unit.
A zone is an area or room that will have its own temperature settings. Each zone has its own air handler.
Mini split air handlers are generally mounted on the wall, and look something like a long rectangular window unit.
The control mentioned above makes mini-splits more energy efficient in a lot of applications. You are only cooling zones you need. Not wasting electricity cooling empty rooms.
Mini-splits allow you to cool specific areas with the perfect-sized air handler. Have a small bedroom, and use a small air handler. Have a large living space. Use a larger air handler.
This also helps with energy efficiency. Oversized ACs are one of the biggest energy hogs. Mini-splits make sizing the perfect AC for a room simple.
Mini-splits don’t require ductwork. Many older homes and small spaces like workshops or tiny homes don’t have the space to run large ac ducts. Ductwork is also expensive to install.
Mini-splits allow you to set different settings for each zone. A traditional central AC unit does not.
With a mini-split, you can cool one bedroom in your home while leaving other zones off. With a traditional AC, each room receives airflow. That's a lot of wasted energy cooling empty rooms.
Mini split systems are not always cheaper than a central AC system. Especially if your home has existing ductwork. A full home system can easily fetch $8,000 or more depending on the number of zones.
Unlike window units or portable air conditioners, mini-splits are permanent. There is no uninstalling and moving it around in 30 minutes like a window unit.
Mini-splits take up wall space. You don’t notice a central AC vent in the ceiling. Mini-splits are the big plastic elephant in the room.
In extreme conditions (think Texas-sized heat) mini splits have been known to struggle. This issue will depend on your unit. Nonetheless, no one wants their AC to fail when they need it most.
Mini-splits are more expensive than window units. A good window unit is around $500. A good mini-split is several thousand dollars.
The extra cost buys you better performance and a quieter more comfortable experience.
Mini-splits are more capable than window units. While there are some large window units that have a high cooling capacity, mini splits are generally more powerful.
Mini-splits are more efficient than window units. Their design allows for more efficient performance.
However, there are energy-efficient window units. For smaller budgets or spaces they can be almost as efficient with a much lower cost.
Mini-splits are great, but there are times when a window AC makes more sense.
For most people, it’s in your best interest to get a professional to install your mini split system. It’s significantly more complicated than putting in a window unit. If you struggle with installing a light fixture, or other small DIY tasks, hire a professional.
If you’re a die-hard DIYer with a good amount of experience you can install it yourself. The one caveat is the electrical work.
Jump to the DIY install information.
If you choose to hire an installer there are a few things you need to think through.
Your installer can help you with the technical details like sizing your system, how many zones you need etc.
Ahoy brave DIYer!
There are a lot of people that have successfully installed their own mini-split. It can be done.
The actual installation of the air handler and condenser is pretty straightforward.
The air handler mounts to an inside wall via a bracket. You drill a few-inch diameter hole in the wall for the refrigerant, drain, and electric lines.
The condenser is mounted outside via a concrete pad or wall mount. The lines from the air handler connect o the condenser.
Here’s where it gets a little tricky. The electrical.
In the U.S you must install an AC disconnect switch that then gets wired into your circuit breaker box. Unless you have a good amount of electrical knowledge it’s in your best interest to get an electrician to handle this part of the job.
Even if you do have experience with electrical work, getting an electrician to inspect your work is recommended.
Bad electrical work could cause your system to work improperly or fail. Nothing would suck more than to short out your brand new $5,000 mini split system.
You have been warned.
This video gives a solid overview of a mini split install.
Energy Star ranks energy-efficient mini splits using the SEER rating system. Choosing the right mini split for your application can be challenging. There are a lot of variables for every application. A one size fits all solution is ideal.
But to help you get an idea of the most energy-efficient mini split ductless ACs we built this chart. It shows the most energy-efficient ductless mini split air conditioners per Energy Star at various cooling capacities.
Unit
SEER ▲
Cooling Capacity
Heating Capacity
Mitsubishi Electric - S-Series
15.6 - 21
36,000 - 60,000 BTUs (3.0 - 5.0 tons)
42,000 - 65,000 BTUs
American Standard / Mitsubishi Electric - S-Series
15.6 - 21
36,000 - 60,000 BTUs (3.0 - 5.0 tons)
42,000 - 65,000 BTUs
SAMSUNG - FJM Max Heat
18
21,000 BTUs ( 1.8 tons)
22,000 BTUs
SAMSUNG - FJM
18 - 19
25,000 - 28,400 BTUs (2.1 - 2.4 tons)
25,000 - 28,600 BTUs
See more Energy Star-rated ductless ac systems here.
A metric developed by the US Department of Energy to measure the efficiency of air conditioners. It’s defined as the ratio of measured cooling output (in BTU per hour) to measured average electrical energy input (in Watts) and measured standby/off-mode power consumption (in Watts.)
BTU stands for British Thermal Unit. One Btu is the amount of heat required to raise one pound of water by one degree Fahrenheit. BTU/hr is used as a benchmark for the capacity of an air conditioning system.
| Unit | SEER ▲ | Cooling Capacity | Heating Capacity |
|---|---|---|---|
| Mitsubishi Electric - S-Series | 15.6 - 21 | 36,000 - 60,000 BTUs (3.0 - 5.0 tons) | 42,000 - 65,000 BTUs |
| American Standard / Mitsubishi Electric - S-Series | 15.6 - 21 | 36,000 - 60,000 BTUs (3.0 - 5.0 tons) | 42,000 - 65,000 BTUs |
| SAMSUNG - FJM Max Heat | 18 | 21,000 BTUs ( 1.8 tons) | 22,000 BTUs |
| SAMSUNG - FJM | 18 - 19 | 25,000 - 28,400 BTUs (2.1 - 2.4 tons) | 25,000 - 28,600 BTUs |
