The ductless mini-split AC units are known as the most energy-efficient air conditioning type.
Energy efficiency is denoted by a SEER rating. The most energy-efficient mini-split air conditioners can have a SEER rating above 20. In short, they can produce an incredible amount of cooling power for a fraction of electricity costs (compared to other AC types).
The excellent energy cost – cooling power ratio is the No. 1 reason why the ductless mini split AC units are becoming increasingly more popular.
In recent years, the #1 unit type air conditioning engineers suggest when asked, “I want to cool down 1 or several rooms at a reasonable price, which AC should I get?” is the “Mini split air AC unit”.
We will look at the best mini split air conditioner system in 2021, based on specifications such as SEER rating. LearnMetrics recommends 7 mini-split systems:
But first, let’s learn a thing or two about what this AC unit actually is and the benefits of using it.
We’ll look at a speedy 3-key-factors-to-look-for ductless mini-split AC buyers guide to illustrate what makes the best mini-split systems, well, the best.
What Does Mini Split System Air Conditioner Consist Of?
The mini-split system keeps all the noise and the fuss outside the house. The unit inside the house is as quiet, comfortable, and energy-efficient as it gets.
The ductless mini-split AC is made out of 4 parts:
- Outdoor unit (see sketch below). The compressor enables the compression of the refrigerant. Usually attached to the outer wall.
- Indoor unit (see sketch below). Quiet and elegant part mounted on the inside wall (bedroom wall, bathroom wall, basement wall, etc.). It consists of cooling coils, an air filter, and a blower.
- Refrigerant lines (connection between outdoor and indoor unit). These lines enable the exchange of the refrigerant between the two units. To install it, you need to drill a hole in your wall. Hint: If you can do that yourself, there’s a good chance you can DIY mini split AC installation.
- Remote control or/and mobile app. You can lower or raise the temperature, set a programmable timer, and so on with remote control. With smart mini split ACs, you can connect your smartphone and control the whole AC with a simple app.
Here is what the insides of the indoor and outdoor unit consist of:
You always have 1 outdoor unit, but you can connect more than 1 indoor unit. The most powerful (and expensive) devices will be able to handle up to 5 indoor units.
Nonetheless, most people require a 1 zone mini split AC. That’s why the table of the best ductless units below consists solemnly of the 1 zone mini split AC systems.
What Are The Benefits Of Using A Ductless AC?
The benefits of using a ductless air conditioner instead of ducted one or room air conditioners are quite obvious:
- No ducts. That is as obvious as it gets; the ductless unit can help the central air conditioner or as a stand-alone AC.
- Zone cooling. You can actually pick the room you want to cool down. Do you want to cool down the bedroom? Just install the inside unit on your bedroom wall. You don’t even need a window – this makes a perfect air conditioner for basements. You just need to drill a hole in the wall.
- Quietness. The outdoor unit creates all the noise (because it contains the compressor). That means that the indoor mini split AC unit is quiet as a cat. The noise levels even go below 50 dB; this noise level window air conditioner or portable ones can’t match.
- Superb energy-efficiency. The big brands offer mini-split units with a SEER rating of 20 or more, which is incredible. With zone cooling, you don’t need to waste the cooling effect on parts of your house; you don’t need to be cooled.
- Heating. One of the best benefits of ductless AC units is that they often include a high-efficient heater for winter. You can basically use the air conditioner for heating as well.
3 Key Factors To Consider When Buying A Mini Split Unit
Some ductless AC units are obviously better than others.
Here are the 5 rules you have to follow if you want to pick the best ductless AC unit for your house:
1. Right Capacity In BTU (Be Aware Of The Voltage)
Knowing how powerful a mini-split AC you need is the first thing you need to figure out. Usually, we have a certain square footage of a room or rooms in mind. Those we want to cool down, of course.
The recommendation is to multiply the room size (in sq ft) by 20-30 to get a BTU value. 20 is the most eco-friendly; 30 basically guarantees you won’t buy a ductless mini-split AC that’s too weak.
Here are our recommendations for an average household based on available ductless AC sizes:
|Capacity (In BTU) Of Ductless AC||Room Size (In Sq Ft)|
|9,000||100-350 sq ft|
|12,000 (1 ton)||350-500 sq ft|
|18,000||500-700 sq ft|
|24,000 (2 ton)||700-900 sq ft|
|30,000||900-1,100 sq ft|
|36,000 (3 ton)||1,100+ sq ft|
The 12,000 BTU are the most commonly sold 1-zone mini-split ACs. That’s why we have based our comparison of the best mini-split ACs by comparing 12,000 BTU models.
In the end, you can also find a connection to 2, 3, 4, and 5 zone mini-split systems.
Note: With the high-capacity mini-split units, be aware of the voltage. The 15,000+ BTU devices usually need a higher voltage, 208/230V, instead of the standard 110/220V. The high-capacity units will almost always require you to install the 208/230V, which will add to the standard installation costs.
2. Which Are The Best Ductless AC Brands?
Taking the brand into account is very important. The reliability and the brand are very firmly connected in this industry.
The big brands have a good track record and can charge well over $1,000 for a ductless AC unit. The lesser-known brand, on the other hand, can be less trustworthy. The upside of this is that they price their units below $1,000; they are trying to build a good reputation.
Namely, there are bigger brands: MrCOOL, PIONEER, Bosch, GREE, LG, and Mitsubishi. They have been in this industry for decades and have a pristine reputation with the mini-split AC installers.
In fact, some installers will only be willing to install big brand ductless AC units because they’re aware of just how reliable they are. They are also more willing to give you a guarantee they’ll come back and fix a MrCOOL or GREE unit without charge. Because they pretty much know how unlikely big brand units are to break down.
Obviously, the lesser-known brands don’t have the length of experience in the engineering mini-split system that the big brands have. That doesn’t mean they aren’t any good; it just means they need to prove themselves.
Some smaller brands such as DELLA and Klimaire offer ductless systems that almost reach (but do not breach) SEER 20. They do offer reliable models at a reduced price compared to the big brand name models.
If you want to spend less than $1,000 for a SEER 19 12,000 BTU ductless mini-split air conditioner, these lesser-known brands can deliver. The big ones can too, but the price there can be up to 50% higher.
3. Energy-Efficiency And Price (Let’s Talk SEER And HSPF And Dollars)
Here at LearnMetrics, we especially love metrics. For mini-split units, the two energy-efficiency metrics are crucial to understanding:
- SEER (Seasonal Energy Efficiency Ratio). Measures how energy-efficient the cooling effect of the mini-split AC is. Simple rule: The bigger the SEER, the higher the energy efficiency.
- HSPF (Heating Seasonal Performance Factor). Same thing as SEER; it’s just for heating instead of cooling.
When determining energy efficiency, we really need to look at both the SEER and HSPF. That’s because we don’t use the mini-split AC just for cooling but also for heating.
SEER and HSPF affect the electricity bill. As an example, let’s say we use the cooling function 8 hours per day over 3-month summer, and the heating function 4 hours per day over 3-month heat. Also, let’s say that the watt-hour costs 13 cents.
What would be the yearly dollar difference between the #1 AC and the #7 AC on the list? Let’s calculate a bit:
|Metrics||#1 MrCOOL DIY 12k||#7 Klimaire KSIV 12k|
|Summer cooling cost:||$48.62||$66.07|
|Winter heating cost:||$42.87||$66.07|
The difference in yearly cost between a superb mini split AC and an above-average one is $40.45. In 20 years, the difference is $809.02.
The funny thing is the difference in cost between the #1 MrCOOL 22 SEER and #7 Klimaire KSIV 19 SEER is actually about $400.
Note: Over the years, the high SEER and HSPF ratings can save you a lot of electricity (compared with the average SEER, HSPF rating unit).
It’s no wonder that ductless ACs with extremely high SEER and HSPF cost more than $1,000. Big brands create those. On the other hand, the smaller brands assemble high SEER and HSPF units that cost less than $1,000.
Based on these three metrics (and a bunch of others such as dehumidification rates, airflow, noise levels), we’ve compared the best ductless ACs in the 2021 list:
Comparison Of The Best 12,000 BTU Ductless Mini Split AC Units
Let’s look at each of these mini-splits in depth. We’ll use specifications of 12,000 BTU units in order to compare them as objectively as possible. You will also see that most of the mini-splits can be found in 9,000 BTU, 18,000 BTU, 24,000 BTU, 30,000 BTU, and 36,000 BTU output cooling capacities:
#1 MRCOOL DIY DIY-12-HP-115B 3rd Gen (Best DIY Mini Split AC Unit)
|Available Capacities:||12,000, 18,000, 24,000, 36,000 BTU|
|SEER Rating:||22 SEER|
|HSPF Rating:||10 HSPF|
|Noise Levels (Indoor):||38/23.5 dB|
|Airflow:||Up to 533 CFM|
|Warranty:||5 Year Parts / 7 Year Compressor|
Just one look at the MRCOOL DIY DIY-12-HP-115B 3rd Gen model and you can immediately tell the specs are just incredible. I mean, some units do manage to create a ductless mini split AC with a SEER over 20. It is the highest seer mini split.
MRCOOL, with many decades of experience, has engineered the 3rd Gen DIY model with a SEER rating of 22. Every HVAC expert’s heart jumps when seeing such tremendous energy efficiency. This makes the MRCOOL the ductless mini split AC with one of the highest SEER ratings. And that’s just the cooling part.
The heating efficiency is top of the notch a well. The HSPF rating is 10. To put it into perspective: the MRCOOL’s best mini split is almost 15% more energy efficient than an average mini split AC unit. Just wow!
What is more, the incredible inverter compressor MRCOOL enables the production of the record-breaking 533 CFM (cubic feet per minute) airflow. The compressors – the heart of every ductless mini split system – and the thing responsive for incredible specs, in hidden in the outdoor unit you can install on your outer wall:
With such tremendous power, you would think that this thing will be loud as hell. Well, it’s not. All the noise levels are created by the outdoor unit (that contains the inverter compressors), and even this unit doesn’t breach the 50 dB. In fact, the maximum noise level of the MRCOOL’s outdoor unit is 49 dB.
The indoor unit (the one you will see more frequently) is connected with the outdoor unit via a refrigerant line. All the power of the MRCOOL compressor is transferred right into your home.
Additionally, the 3rd Gen MRCOOL has a built-in dehumidification function. It’s capable of removing up to 2.5 pints of moisture from your indoor air every hour.
The MRCOOL ductless mini split AC unit’s main drawback is the high electricity voltage – 220/240V. That means your mini split installer will probably have to upgrade your electricity grid. This is very reasonable. However, it’s impossible to deliver such power (with the 14,400 BTU heater, mind you) with a standard voltage.
Obviously, you also have to consider the price. MRCOOL has created the best ductless mini split system, and its cost reflects that. Nonetheless, having a superb and, above all else, reliable system with a 5/7 warranty is the wet dream of every HVAC engineer.
MRCOOL offers its 3rd Gen model in 4 sizes: 12,000, 18,000, 24,000 and 36,000 BTU. You can check an in-depth Mr COOL review here as well.
#2 GREE Vireo+ 22 SEER (Most Reliable Mini-Split Air Conditioner)
|Available Capacities:||9,000, 12,000, 18,000, 30,000 BTU|
|SEER Rating:||22 SEER|
|HSPF Rating:||11 HSPF|
|Noise Levels (Indoor):||45-29 dB|
|Warranty:||5 Year Manufacturer’s Warranty|
Nobody wants a power-hungry AC unit that frequently breaks down. GREE has developed its best mini split AC based on three distinct advantages:
- Superb energy efficiency (with 22 SEER rating)
- Wi-Fi connected mini-split for easy use.
- Tested reliability. GREE has been in the industry for 20+ years; they have a very good track record.
With that in mind, the Vireo+ Series – GREE’s best ductless mini-split ACs – were created. The GREE Vireo+ is the most reliable energy-efficient mini-split currently on the market.
The rotary compressor is capable of generating up to 400 CFM airflow. The bad side of that is that the GREE Vireo+ does produce up to 45 dB of noise levels due to above-average airflow.
Reliability and GREE go hand in hand. GREE is one of the biggest brands in the HVAC industry. They know how important it is to make a reliable device. It’s no wonder the GREE Vireo+ model is a unit that rarely needs additional fixes or maintenance.
All in all, the proficiency of GREE devices is reflected in the Vireo+ model, as is the price. This is one incredible ductless mini-split unit, to say the least. You can get it in 9,000 BTU, 12,000 BTU, 18,000 BTU and 30,000 BTU cooling capacities:
#3 COOPER AND HUNTER Sophia 21.5 SEER (Energy Star Quietest Mini-Split With DIY Installation)
|Available Capacities:||9,000, 12,000, 24,000, 30,000, 36,000 BTU|
|SEER Rating:||21.5 SEER|
|HSPF Rating:||9.8 HSPF|
|Noise Levels (Indoor):||36.5/30/25 dB|
|Warranty:||5 Year Parts / 7 Year Compressor|
Let’s first look at the COOPER AND HUNTER Sophia Series mini-split air conditioner specs because they are quite fantastic (especially for the price).
Every time we see a SEER rating above 20, we ask, “Wow, great, but what’s the price?” That’s because the super high SEER ductless mini split ACs cost $1,500 or more. Because, you know, in 10 years you are expected to get all this money back due to lower electricity bills.
Well, COOPER AND HUNTER have put together a unit with 21.5 SEER for (a bit) more than $1,000. That’s just something you don’t really see every day. The heating specs quite great as well; almost 10 HSPF rating.
So, this can’t be all gold for about $1,100, right? Well, it’s not. The Sophia Series has below-average dehumidification levels. Also, the airflow goes up to 306 CFM. But that does have one big advantage: silence.
Let’s listen to how quiet it is. Do you hear that? No? That’s the silent purr of the Sophia Series’s 36.5/30/25 dB indoor air handler. For comparison, 10 dB is the breathing noise, and 20 dB is the noise created by rustling leaves. Well, the most silent COOPER AND HUNTER Sophia Series mini-split is, on a low setting, almost as quiet at rustling leaves.
On top of that, besides the great specifications, the two main advantages of the COOPER AND HUNTER ductless unit are the WiFi connection and, above all else, the DIY installation process.
Yes, this is a mini-split system you can install yourself. The only thing you’ll need to do is to drill a hole in your wall. Everything else comes in a DIY installation kit:
The ductless mini-split AC installation manual will guide you through the installation process. To simplify, you have to connect the indoor unit with the outdoor condenser via insulted and pre-flared line set and communication wires.
That will require you to drill a hole in the wall and mount both the indoor and outdoor unit on your wall. The 12,000 BTU COOPER AND HUNTER unit can be powered by the standard 115V (you can also get a 12,000 BTU 230V unit). More powerful units, however, will need a 208/230V voltage.
Along with the purchase, you get the industry’s best warranty (5 years for parts, 7 years for the compressor). With Energy Star certificate, this is the quietest mini-split air conditioner and one that will save you about $100 on electricity bills every year:
#4 Bosch Quiet 20.7 SEER (Reliable Mini-Split With The Best Warranty)
|Available Capacities:||12,000 BTU|
|SEER Rating:||20.7 SEER|
|HSPF Rating:||9.6 HSPF|
|Noise Levels (Indoor):||39.5/35/28 dBA|
|Warranty:||5 Year Parts / 7 Year Compressor|
Bosch is one of the most popular big mini split AC brands. With their 12,000 BTU model, they put reliability first. It’s only sad to see that great specs were the cost of having great reliability.
Without a doubt, the Bosch 12,000 BTU mini-split air conditioner will serve you well. The energy-efficiency metrics (SEER = 20.7 and HSPF = 9.6) are above-average.
The indoor unit noise levels of 39.5/35/28 dBA are one of the quietest; it’s hard to find a mini-split air conditioner with below 40 dB noise levels. The 306/265/200 CFM airflow levels, however, are below to 400 CFM you can get if you check out #1 MrCOOL and #2 GREE units.
The best thing about the Bosch device is the reliability coupled with the ‘5 Year Parts / 7 Year Compressor’. That effectively means you will have to sweat less when thinking about AC breakdowns:
#5 PIONEER Diamante 20 SEER (Cheapest Mini-Split Air Conditioner With Superb Energy Efficiency)
|Available Capacities:||9,000, 12,000, 18,000, 24,000, 36,000 BTU|
|SEER Rating:||20 SEER|
|HSPF Rating:||10 HSPF|
|Noise Levels (Indoor):||40/37/34 dB|
|Airflow:||Up to 383 CFM|
|Warranty:||5 Year Parts / 5 Year Compressor|
PIONEER Diamante is, at first, a mystery. It’s a ductless mini-split AC with tremendous specs. However, it does cost less than $1,000. Obviously, the less-known brands such as PIONEER price their ductless AC lower, but the specs are usually lower.
How has PIONEER achieved to create a cheap mini-split AC with impressive big-brand big-buck specs? I mean, the PIONEER Diamante does have a very high SEER level of 20.
Well, the reason is quite simple—the heart of every mini-split system in the compressor. While the standard compressor is of the rotary type, the PIONEER decided to upgrade the inverter type. Did they develop it themselves? Not at all.
Here the simple and ingenious move explains the great specs: PIONEER decided to build in Toshiba’s ASN98D22UFZ compressor. That is how the WYS012GMFI17RL can achieve the SEER levels of 20, HSPF levels of 10 (for heating), and an above-average up to 383 CFM airflow.
Toshiba is one of the best compressor makers in the world. They add those big brand experiences in building compressors to a rigid and capable ductless mini-split shell of the PIONEER Diamante AC unit.
The noise levels are low as well (with 40/37/34 dB levels). Keeping the decibel levels below 40 dB is the point of all quiet mini-split air conditioners.
With the air conditioning, you also get an energy-efficient heater for winter as well as a dehumidifier (with 2.54 Pt/h levels).
PIONEER offers this model in many different capacities; 9,000, 12,000, 18,000, 24,000, or 36,000 BTU. The great thing about the 12,000 BTU is that you can choose to run on 110/120V or 208/230V. With the more powerful 15,000+ BTU units, you will need an upgrade to a 208/230V voltage.
All in all, PIONEER has created a low-priced ductless unit with superb specs thanks to Toshiba’s ASN98D22UFZ compressor:
#6 Della 12,000 BTU 20 SEER (Good Mini-Split For Less Than $1,000)
|Available Capacities:||9,000, 12,000 BTU|
|SEER Rating:||20 SEER|
|HSPF Rating:||8 HSPF|
|Noise Levels (Indoor):||34+ dB|
If you’re looking for the best cost-benefit mini-split unit, you need to look no further than the Della mini-split air conditioner. This is a 4-in-1 ductless air conditioner + heater + fan + dehumidifier for less than $1,000.
And if you really don’t like to spend money on AC installers, here’s a bonus: You can DIY the installation with the installation kit you get with the Della air conditioner.
With a great cooling-efficiency rating (SEER = 20), it’s not hard to see why the Della is a best-seller ductless mini-split AC unit.
To install the Della unit yourself, you will have to mount both of the units on your wall’s internal and external sides and drill a hole in between. The added 16 feet copper line set goes in that wall; just follow the included guide, and you should be fine.
The Della has a strong dehumidifier capabilities. Sadly, the airflow specs and noise levels specs are unknown.
The whole point of the Della unit is to decrease the cost as much as possible while still maintaining the great specs. The inverter compressor is powered by 110/120V, so you won’t have to upgrade your electricity grid, and you can even install the whole mini-split system yourself with a few technical skills.
#7 Klimaire KSIV 19 SEER (Up-And-Coming Inexpensive Mini-Split AC Brand)
|Available Capacities:||12,000, 18,000, 24,000, 30,000 BTU|
|SEER Rating:||19 SEER|
|HSPF Rating:||9.5 HSPF|
|Noise Levels (Indoor):||38/32/25 dB|
|Warranty:||5 Year Compressor|
Klimaire is a new brand in the HVAC world. Their flagship mini split AC is the Klimaire KSIV model that has reasonably high specifications. Nonetheless, Klimaire doesn’t have that great length of experience Mitsubishi and LG have in designing mini-split units.
What Klimaire has going for it is the below $1,000 price tag and the inclusion of the installation kit.
What is more, the 19 SEER rating and the 9.5 HSPF rating are quite decent. The noise levels of 38/32/25 dB for the indoor unit make the Klimaire one of the most silent mini split AC units (we’ll see how Klimaire engineers have achieved such low noise levels in a second).
Here’s how the whole installation kit with the indoor and outdoor unit looks like:
The ‘secret’ behind the low noise levels is the weaker-than-average KSIV012-H119-S(W) DC inverter compressor. It generates only 292 CFM of airflow. That means both the outdoor unit and the indoor unit are that much quieter. If the indoor blower doesn’t have to handle 500 CFM, it will obviously make less noise.
The KSIV012-H119-S(W) DC compressor is also cheaper than average, which explains the low price point. You can plug it in the standard 115V voltage if you go for a 1 ton (12,000 BTU) unit.
Like MrCOOL and PIONEER, Klimaire offers a wide range of capacities, from 12,000 BTU to 30,000 BTU.
All in all, the Klimaire KSIV model is a true cost saver and delivers a solid cooling and heating effect.
Help Us Upgrade And Improve List With Your Suggestions
We make this list to help people decide which ductless mini-split systems are best for them.
If you have a personal experience with a certain AC or are an AC installer, you are more than welcome to share your thoughts below.
We are always updating the 2021 list to get even the freshest models with the high specs in.
For everybody who’s looking to get a multi-zone mini split, you should check out:
- Best dual zone mini split systems.
- Best 3 zone mini split systems.
- Best 4 zone mini split systems.
- Best 5 zone mini split systems.
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