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 splits 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 consist 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 the 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 two big brands: MRCOOL, 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 MRCOOL 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 LG unit without charge. Because they pretty much know how unlikely a MRCOOL unit is 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 PIONEER, DAIKIN, 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 the 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-12-HP-115B||#7 DAIKIN RXB12AXVJU+ FTXB12AXVJU|
|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 DIY-12-HP-115B and #7 DAIKIN RXB12AXVJU+ FTXB12AXVJU is actually about $700 to $800.
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
#1 MRCOOL DIY DIY-12-HP-115B 3rd Gen (Best DIY Mini Split AC Unit)
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.
MRCOOL, with many decades of experience, has engineered the 3rd Gen DIY model with a SEER 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, a 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 COOPER AND HUNTER CH-12SPH-115VI/O-WK (WiFi Smart Mini Split With DIY Installation Kit)
Obviously, every ductless mini split AC unit you can install yourself is that much more valuable because you don’t have to pay the installer.
Nonetheless, let’s first look at the COOPER AND HUNTER CH-12SPH-115VI/O-WK 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 has put together a unit with 21.5 SEER for (a bit) less than $1,000. That’s just something you don’t really see every day. Add to that a superb 11.2 HSPF heaters; it’s just crazy how great these specs are.
So, this can’t be all gold for $1,000, right? Well, it’s not. The CH-12SPH-115VI/O-WK has a very low capacity as far as it’s dehumidification levels are concerned. Also, the airflow is rather weak. That’s because they used the cheaper (but still energy-efficient) rotary type compressor.
Nonetheless, 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). This is one of the quietest mini split systems with an indoor unit making low 36/32/23 dB noise levels.
The additional trick up the CH-12SPH-115VI/O-WK sleeve is the WiFi connection. When you’ve installed the AC unit, just plug in that USB key, and you’ll be able to control your ductless unit via WiFi.
#3 LG Inverter V LS120HSV5 (The Quietest Reliable Unit)
Nobody wants a loud and power-hungry AC unit that frequently breaks down. LG has developed it’s best mini split AC based on three distinct advantages:
- The quietest ductless unit.
- The most energy-efficient unit.
- The most reliable unit.
With that in mind, the LS120HSV5 – LG’s best ductless mini split AC – was created. In short, they’ve managed to score 2 out of 3. The LS120HSV5 is the quietest and most reliable, but, despite being incredibly energy-efficient, the 1st spot for energy-efficiency was taken by Mr COOL mini split unit (#1 pick in this 2021 list).
Let’s listen to how quiet it is. Do you hear that? No? That’s the silent purr of the LG’s 39/19 dB indoor blower. For comparison, 10 dB is the breathing noise, and 20 dB is the noise created by rustling leaves. Well, the most silent LG mini split is, on a low setting, quieter than rustling leaves.
The outside unit, on the other hand, is powered by the silent Inverter V compressor. The noise level on the wall-mounted outside unit is 48 dB or less:
Reliability and LG go hand in hand. LG 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 LS120HSV5 model is a unit that rarely needs additional fixes or maintenance.
One side effect of the upgraded reliability is the 2nd place for energy-efficiency. With the superb 22.7 SEER and 11.4 HSPF ratings, the LG’s ductless AC unit is incredibly energy-efficient. However, the #1 Mr COOL unit has the edge here, primarily because of LG priorities reliability above all else. This, in turn, meant they decided not to go to extremes with the energy-efficiency specs.
The LG’s Inverter V compressor runs on 220/240V, which is not ideal for people who don’t already have a 220/240V grid. The airflow of 459 CFM just shows you that the LG created a great specs unit while still prioritizing reliability.
All in all, the proficiency of LG HVAC devices is reflected in the LS120HSV5 model, as is the price. This is one incredible ductless mini split unit, to say the least.
#4 Senville SENA-12HF/Z (Cheapest Unit For Less Than $800)
If you’re looking for the best cost-benefit mini split unit, you need to look no further than the Senville SENA-12HF/Z. This is a 4-in-1 ductless air conditioner + heater + fan + dehumidifier for less than $800.
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 Senville SENA-12HF/Z air conditioner.
With a great cooling-efficiency rating (SEER = 19), it’s not hard to see why the SENA-12HF/Z is a best-seller ductless mini split AC unit.
Here are both the indoor and outdoor units with all you need to DIY the installation yourself:
To install the Senville unit yourself, you will have to mount both of the units on your wall’s internal and external side 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 SENA-12HF/Z has a strong dehumidifier capable of extracting 2.54 pints of water out of your air every hour. The strong 418 CFM enables all the great energy-efficiency, cooling, heating, and dehumidification metrics.
The Senville mini split AC unit’s bad parts are the higher-than-average noise levels (43/36/24 dB for the indoor unit), the average heating-efficiency with an HSPF rating of 8.5, and only a 2-year warranty on parts (instead of the standard 5-year).
The whole point of the Senville 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.
#5 PIONEER WYS012GMFI17R (Cheap Best-Seller With Toshiba ASN98D22UFZ Compressor)
PIONEER WYS012GMFI17RL 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 the impressive big-brand big-buck specs? I mean, the WYS012GMFI17RL does have a very high SEER level of 19.
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 the Toshiba’s ASN98D22UFZ compressor. That is how the WYS012GMFI17RL can achieve the SEER levels of 19, HSPF levels of 9.5 (for heater), and the incredible 500 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’s WYS012AMFI19RL AC unit.
The noise levels of the outside unit, however, are quite high – 54 dB. But what truly matters is how quiet the indoor unit is. With the 40.5/24 dB noise profile, it’s one of the quietest indoor mini split AC units.
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, 30,000 or 36,000 BTU. The great thing about the 12,000 BTU is that you can choose running 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 Klimaire B07TDR51BW (New Up-And-Coming Inexpensive Brand)
Klimaire is a new brand in the HVAC world. Their flagship mini split AC is the B07TDR51BW 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 38/30/28 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 294 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 Senville and PIONEER, Klimaire offers a wide range of capacities, from 9,000 BTU to 36,000 BTU.
All in all, the B07TDR51BW model is a true cost saver and delivers a solid cooling and heating effect.
#7 DAIKIN RXB12AXVJU+ FTXB12AXVJU (Reliable Unit With Best 10-Year Warranty)
DAIKIN is one of the most popular smaller mini split AC brands. With their RXB12AXVJU+ FTXB12AXVJU 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 DAIKIN RXB12AXVJU+ FTXB12AXVJU will serve you well. Nonetheless, the energy-efficiency metrics (SEER = 17 and HSPF = 8.5) are pretty in line with the industry’s average specs.
The whole installation kit you get can make for a cool DIY project:
The indoor unit noise levels of 41/34/30 dB are quite average. But it does need to be said that the airflow is only 358 CFM. It’s easier to design a silent mini split AC if you have a reduced airflow rate.
The best thing about the DAIKIN device is the reliability coupled with the 10-year warranty. That effectively means you will have to sweat less when thinking about AC breakdowns.
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.