Air Conditioning Guide for a 12×12′ Room (Size & Type)

A 12×12′ or 144 sqft room is a small room. What size of air conditioner is suitable for the room and which type you should use? This is a guide to air conditioning in a 12×12′ room.

First of all, what size do you need for a 12×12′ room? According to Energy Star, a 12×12′ or 144 sqft room requires 5,000 BTU of cooling capacity when occupied by two persons. If the room is heavily shaded, it only requires 4,500 BTU. If the room is very sunny, it requires 5,500 BTU. For each additional person, you need to add 600 BTU. In the case of a kitchen, an additional 4,000 BTU is required.

Knowing how much cooling capacity is the first step to buying an air conditioner for the room. Next, you’ll need to which type you should use, where you should position it and how much does it cost.

Before we get started, I’m obligated to highlight that the cooling capacity recommended in this post is only suitable for countries like United States where houses are insulated. If you are from countries like Malaysia and India where houses are not insulated, the recommended cooling capacity for a 12×12′ room is 7,200 BTU.

Mini split is a great heating and cooling system. However, there are many brands and models. So, I did some study to come out the 4 Best Mini Splits in 2023. I encourage you to check it out if you’re considering one now.

Which Type of Air Conditioner You Should Use?

A 12×12′ room is tiny. You probably already have a few types in mind such as the window AC, mini split and portable. So, which type is suitable for your application?

If you are buying an AC for a bedroom with windows, the most affordable one is the window air conditioner. Most window air conditioners cost around $150 to $400 only compared to mini split ACs at around $700 to $900.

However, they generate noise at around 50dBA. A noise level of 50dBA is like a conversation at home. I think most people have a hard time sleeping with that level of noise.

Alternatively, if you have the budget, I will recommend you go for a ductless mini split AC. Ductless mini splits are extremely quiet. They have better energy efficiency than window ACs and I think they are better looking than the window ACs.

However, the major downside of the mini splits is the higher cost at around $700-900. Personally, I think it is worth investing in them.

Relevant post: 5 Types of Mini Split Indoor Units (How to Choose).

On the other hand, if your bedroom is without windows, you don’t have much choice but to go for the mini split as well. However, if you are on a tight budget, I have a separate guide to air conditioning a windowless room where I outlined a few rare but possible cheap alternative solutions. Feel free to check it out.

In case you are wondering, don’t go for any air conditioner with a duct. It’s too much cost and trouble for just a small room. Then, portable ACs are as loud, if not, louder than the window air conditioners.

Portable ACs also have bad energy efficiency and they cost more than the window ACs. Thus, I will NOT recommend you use the portable air conditioner.

Portable ACs are generally more suitable for large houses where people can move the portable AC around so that those rarely used rooms no need to install an air conditioner.

Air Conditioner Types: What’s Their Pros and Cons?

In the following, I outlined the advantages and disadvantages of the three types of air conditioner I mentioned earlier. You can screen through them to get more information to help you decide which one to go for.

Window Air Conditioner

Window air conditioners are affordable. However, they are very noisy. So, they are usually not suitable for a bedroom. But, if you are buying one for the kitchen or other purposes, a window air conditioner has the best value for money.


  • Affordable – Most window air conditioners cost around $150 to $400 only compared to mini split ACs at around $700 to $900.
  • Easy to install– You can install a window AC by yourself. However, leveling and securing it is challenging.
  • Easy to maintain – Window air conditioners are installed at a lower level compared to the mini split ACs. So, they are easy to service as you don’t need to use a ladder like you do for the mini splits.
  • Flexible – You can move around the window ACs as long as there is a window fit for it.


  • Noisy – A typical window air conditioner generates noise at about 50dBA which is like a conversation at home. I don’t think it is a good idea to put it in a bedroom.
  • Low energy efficiency – Window air conditioners are not as efficient as ductless mini splits. According to Energy Star, a ductless mini split consumes 30% less power than window air conditioners.
  • Occupying windows – A window air conditioner takes up a portion of your window area. Thus, you’ll get lesser sunlight.
  • Risk of falling out of windows – If you are not installing the window AC properly, it may fall out of the windows.
  • Risk of getting stolen – If you live on the ground floor, you may want to cage the window AC.

Ductless Mini Split Air Conditioner

Ductless mini split or just split air conditioners are very popular in Europe and Asia. They have an indoor and outdoor unit which you need to connect both units with copper pipes. They are very quiet but cost more than window ACs.


  • Extremely quiet – A ductless mini split AC can go as low as 20dBA. It is barely audible.
  • High energy efficiency – Most ductless mini splits can regulate their cooling power with their inverter technology. Thus, they are more energy-efficient than window air conditioners.
  • Elegant – A ductless mini split AC installed up high on the wall. They don’t take up your living space and they usually look great along with your house interior.
  • Safe – Unlike a window AC which provides an easy entrance for intruders, a mini split only requires a 3-1/2″ small hole through the wall for its pipes.


  • More expensive – A mini split AC may cost as much as 3 times the price of a window AC. In addition, a typical professional installation (which a mini split AC most likely required) cost around $500.
  • Need a good installer – Mini split ACs have relatively complex copper pipes and cables. They must be installed properly or else, they can’t function. Also, repairing a mini split AC is expensive.
  • Risk of overcooling – The lowest cooling capacity of conventional mini split ACs is 9,000 BTU which is too much for a small room. However, modern inverter mini splits can operate anywhere between 4,000 BTU to 10,000 BTU.

Portable Air Conditioner

Portable air conditioners are a floor-standing type of air conditioner which you can move around as you like. However, they have a hose to discharge hot air outside of the house.


  • Cheaper than the mini split – A portable AC costs around $300 to $500 which stands between the mini split and the window AC.
  • Portable – As their name suggested, they can be moved around but limited by the length of their hot air discharge hose.
  • Easy to install – Unlike both the mini split and window AC, portable air conditioners are very easy to install. However, the installation of the discharge hose can be tricky.


  • Bad energy efficiency – Portable ACs consume the most power compared to both the mini splits and window ACs.
  • Noisy – Portable ACs are louder than window ACS. Many portable ACs generate noise at around 60dBA.
  • Drain water issue – The drain water of Portable ACs may overflow when the ambient air is very humid.
  • No heating – Unlike the window and mini split AC, portable ACs don’t have a heating function unless you opt for the expensive ones which can cost you around $700 to $800.

Where You Should Position the Air Conditioner?

Window air conditioners have not much choice when it comes to positioning them. However, ductless mini split ACs are installed up high on the wall and they can be cleverly positioned to improve comfort.

As a general rule, air conditioners should not blow directly onto your body. In a bedroom, the air conditioner should not blow cold air onto the bed which can cause you dry lips and headache.

Most of the time, the best place to put the mini split AC is on the wall above the head of your bed. Thus, cold air will not blow onto your body when you sleep. Don’t worry about the AC water leaking, the drain water is dirty but not harmful.

Ductless mini split ACs are installed up on the wall. It is recommended to install a split AC at around 7-8 feet above the floor. However, make sure the AC has a gap of about 100mm from the ceiling for good return air.

Be careful when you select a mini split AC with a motion detector. Do not put any object in front of the split AC because its motion sensor will not pick up any movement, thus it’ll assume there are no people in the room and starts to reduce its cooling power to conserve energy.

While I was researching, I found some great air conditioners which I think are good for your application. If you ask me, I will recommend you get a ductless mini split air conditioner for your 12×12′ room because it is quieter, more efficient and overall better than other types of air conditioner.

I wish to repeat myself here again because it is important. If you opt for the ductless mini split, you should use an inverter type or else, it’ll be too cold and uncomfortable. Inverter air conditioners can operate anywhere between 4,000 to 10,000 BTU. You may read more about Buying Air Conditioners: Is Inverter AC Worth the Price?

Here is a list of the best air conditioners for a 12×12′ room:

Best Ductless Mini Split Air Conditioners

Mini split is a great heating and cooling system. However, there are many brands and models. So, I did some study to come out the 4 Best Mini Splits in 2023. I encourage you to check it out if you’re considering one now.

Best Vented Portable Air Conditioners

Best Window Air Conditioners

Lastly, I would like to highlight particularly the safety of window air conditioners. Just google it and you’ll see window air conditioners do have the risk of falling out of windows. Furthermore, at ground level, they have the risk of getting stolen as well as providing an easy entrance for intruders.

If you want to learn more about the basics of HVAC system. Check out my HVAC Basics (eBook). It’ll give you the foundation you need to get started.

If you have anything to add (or ask) about this topic, leave a comment down below!

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