Do You Need to Tilt or Level Air Conditioners When Install?


Many people are wondering if they should tilt their air conditioner to drain better. So, I went to find out if an air conditioner needs to be tilted.

It turns out that most air conditioners are designed to drain properly when leveled and thus, you don't need to tilt the air conditioner. Besides, a window air conditioner is already tilted when installed properly and so, you don't need to tilt the window air conditioner anymore.

Some people misunderstood that they need to tilt an air conditioner for it to drain water better. However, tilting an air conditioner can do more harm than good.

Why You Don't Need to Tilt a Window Air Conditioner?

Manufacturers design their window air conditioners to be tilted when installed properly. If you follow the clearance requirement and use the support bracket that comes with the window air conditioner, your window air conditioner is automatically tilted.

Basically, you don't need to add more plank on the window sill to tilt the window air conditioner. You just need to follow the installation manual when installing a window air conditioner and it will be tilted when done.

Follow the clearance stated in the instruction manual will ensure the window air conditioner is tilted when done

From LG LW6016R Window Air Conditioner Installation Manual

For example, the LG installation manual states that: “the top of the wood strip should be approximately 3/4″ higher than the storm window frame or wood strip (outdoors)”. By following the installation manual, the window air conditioner will be tilted at about 1/4″ when done.

Use the support bracket comes with the window air conditioner will ensure the window air conditioner is tilted when done

From Friedrich Kuhl Window Air Conditioner Installation and Operation Manual

Another example, the installation manual illustrated that when the support bracket is screwed properly, the window air conditioner will be tilted at about 3/8″ when done. Notice that the window sill is flat. Thus, the support bracket itself is already tilted and so, the window air conditioner will also be tilted.

From Frigidaire Window Air Conditioner Installation Manual

Similarly, if you check the installation manual, you can see that there is no need to add additional wood plank on the window sill. Just follow the installation instruction, the air conditioner will be tilted and working properly.

However, do read carefully the installation manual because some window air conditioners require you to adjust the bracket height in order to tilt the air conditioner.

Do You Need to Level the AC Outdoor Unit?

Source: Daikin RXL Series Installation Manual

In the installation manual of the Daikin RXL series outdoor unit, it stated that the outdoor unit must be leveled. Manufacturers may void the warranty if they find out that the air conditioner is not installed properly. For optimal performance and longevity, the outdoor unit must be leveled and not tilted.

Do You Need to Tilt a Wall Mounted Split Air Conditioner?

A wall mounted split air conditioner should not be tilted but be perfectly leveled. The wall mounted air conditioner already has a proper drainage system with sufficient gradient within itself. Thus, you do not need to tilt it anymore. Besides, a tilted wall mounted air conditioner looks funny on the wall.

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Do You Need to Tilt a Ducted Air Conditioner?

From Daikin Ceiling Concealed Installation Manual

A ducted air conditioner needs to be leveled and not tilted. Since the air conditioner is connected to a duct, tilting it will cause the entire ductwork to be tilted also. Furthermore, tilting a ducted air conditioner will cause imbalance force within the air conditioner since it has a blower fan spinning inside.

How about do you need to tilt the secondary drain pan of a ducted air conditioner? Usually, a good drain pan doesn't need you to tilt it because it already has slopes to channel drain water to the discharge outlet. However, if you notice that the drain pan is filling with water, try tilting it. Else, check the drain outlet if it is clogged.

Do You Need to Tilt a Ceiling Cassette Air Conditioner?

From Daikin Ceiling Cassette Installation Manual

A ceiling cassette air conditioner does not need to be tilted but must be leveled. It has a built-in drain pump to discharge the drain water. So, you don't have to worry about it. In addition, if a ceiling cassette unit is tilted, it'll not be flushing with the ceiling which looks very weird.

What Happen If You Tilt an Air Conditioner Too Much?

The compressor of the air conditioner needs lubricant or oil to run smoothly just like a car engine. When it is tilted and not leveled, part of the compressor is not getting the lubricant. Thus, the compressor keeps rubbing and eventually breaks. Such a breakdown mostly can't be repaired and it's very expensive to replace a new compressor.

Moreover, some outdoor units have an axial fan that discharges hot air vertically. If the outdoor unit is not leveled, it'll cause an imbalance of force acting on the fan. Over time, the fan may start to wobble, misalign and eventually fail.

Tiling a window air conditioner too much also makes it easier to slide off the window. So, just make sure it is slightly tilted as it is supposed to be and you'll be fine.

Why Your Air Conditioner is Leaking Water?

If your air conditioner is leaking water despite being properly installed, tilting it further will not solve the problem. Most of the time, a leaking air conditioner is due to the drain pipe is clogged. So, if your window air conditioner is leaking water, check if the drain hole located outside is clogged.

Besides, if your window air conditioner is dripping water from the supply air vent, check if the side panels are sealed properly because it may be letting the hot outside air coming in and in contact with the cold supply air, causing condensation.

How Much Should You Tilt a Window Air Conditioner?

Most of the window air conditioners tilt not more than 1 inch. Some only require 3/8″ and some window air conditioners need 7/8″. So, it is depending on the window air conditioner brand and model. Be sure to read the installation manual.

How to Measure the Tilt of Your Air Conditioner?

Using a basic level is the best way to know if your air conditioner is tilted. Because the tilt is just a little only, it may be difficult to eye it. Also, it doesn't matter if you tilt it slightly more, you don't have to measure and follow the number stated in the manual exactly. Just tilt the air conditioner reasonably and you'll be fine.

Some window air conditioners come with a complete set of accessories which makes the installation process much easier. Nevertheless, be sure to read the installation manual before you start to install the window air conditioner. If you can't find the installation manual in the box, you can always call the seller or search the model on the web to find it.


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Yu Chang Zhen

I enjoy working on air conditioners and ventilation fans because Malaysia is a very hot country.

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