Window Air Conditioners Wiki

It’s this time of year again! Heat waves and suffocating temperatures will hit us in a matter of months, and it’s the right time to be thinking about installing a window air conditioner in your home.

Well, this is all nice and all, but from theory to practice, buying and installing a window air conditioning device brings a lot of questions to mind. Fear not, you will not have to bore a hole in your wall (yup, we’ve got this question a lot – it makes sense by the way!). Let’s do this!

Your questions, our answers!

So with no further ado, let’s dive into your questions!

ℹ️ It goes without saying, but let’s say it: we are not doctors or lawyers, and the following does not constitute legal or medical advice. When in doubt, please always stay on the safe side!

The basics

How does a window air conditioner work?

Short version: For the indoor air to stay at the desired equilibrium, warm or cold air has to be expelled. Through a network of various components, a window air conditioner is able to provide a blissful experience while making sure the air is clean and free of pathogens.

Just as your home refrigerator, albeit a giant one, a window air conditioner works using the same principle. This means all components, including the refrigerant gases, also apply in an air conditioner.

Window air conditioner.

As determined by the thermostat, air passes through the fins connected to tubes. These tubes carry a refrigerant that changes from liquid to gas as it transfers heat from one place to another. A blower is then used to push the chilled air across the room. The appliance uses the principle of convection currents to keep the air at the desired level with the help of a thermostat.

Numerous studies suggest that air conditioners might not be leaving soon. More and more homes are using air conditioners now more than ever, and rate keep rising.

Wealthy families are opting for central air conditioning solutions. The ‘not so wealthy’ families are going for the much smaller, room-based conditioners that they fit on windows and other places. This helps cut on bills and the cost of installing the more expensive central heating system. Window conditioners are meant for single rooms only and cannot be used to cool the entire house.

Since the window is the most convenient hole in the house, a window air conditioner has to be installed in a window for it to work as expected. This is because they are specifically designed to work on windows. However, if you have another temporary place to put, you can use it.

Alternatively, you can opt for a portable version if, for some reason, you are not able to install your unit on the window.

Different air conditioners have different efficiency ratings. This rating is measured using the energy efficiency rating(EER). Be sure to look out for the Energy Star Label on your unit. This figure comes from getting the ratio of the unit’s cooling capacity (BTU per hour) to energy used in Watts.

Window air conditioners are only able to regulate the air in one room only. If you are looking for a whole house solution, you will need to go for the central air conditioner that is designed to cover entire houses.

Since space heaters run on electricity, the bills may escalate if run continuously for a long time. That’s where a thermostat comes in handy. With digital controls, it lets you set your desired room temperature. The unit will continue to run until that equilibrium temperature is reached.

Nest smart thermostat

Some units ship with a timer function, to help you determine the duration the unit will run.

While blowing in the air, window air conditioners may blow in dust particles, bacteria, and smoke. This would make the indoor air potentially unhealthy and may lead to discomfort and diseases. However, most units come with a filter that helps traps those particles. If well maintained, it may ensure dirt doesn’t clog and get its way into the coil because it would chock it.

See our selection of best window air conditioners β†’ xxx

Are window air conditioners safe?

Short Version: Yes, most of these are perfectly safe. However, for them to continue being safe for the long term, a couple of things have to be right first. Cleaning filters is one of these.

While installation and removal are worries for the majority, safety has given window air conditioners a bad rap. The low entry barrier makes some people question the quality of air emitted by these appliances. Myths even fly around that these appliances emit carbon monoxide gases.

While you can’t possibly get CO-poisoned by air conditioners, these freakouts are warranted, and it is good we demystify most of these theories as much as we can.

There is no internal combustion that happens in any window air conditioner. If your detectors are registering carbon monoxide, it is good you check your other sources of heat.

Viral posts have been circulating on the internet claiming that some window air conditioner exposes occupants to the risk of getting cancer. However, we can firmly confirm from multiple sources such as the American Cancer Society, American Chemical Society, and the National Library of Medicine that window air conditioners do not cause cancer.

Ensure you install your air conditioner the right way as this will ensure it doesn’t fall off and cause injury to passersby, especially during fire outbreaks. Be sure to read the installation manual carefully or call an expert if you don’t feel confident doing it yourself. Loosely hanging units could be potentially dangerous if they fall on someone from a multi-story building.

Your air conditioning could be the cause of more sick days you are reporting at work. While air conditioners are designed to get rid sickness-causing pathogens, the filter may not be working correctly anymore. This means the unit is just recirculating dirty air around the room, and this could create perfect breeding grounds for these pathogens.

Unmaintained air conditioners could be dangerous exposes occupants to molds and bacteria which can cause serious health problems.

The age of your window air conditioner may sometimes render it unsafe for the environment. Outdated air conditioners using chlorofluorocarbons may contribute to the depletion of the ozone layer if they leak and get their way into the atmospheres. Some countries have very punitive punishments for their uses, and fines could go up to $25,000.

Replacing your window AC not only saves on operation costs but also conserves the environment

Be sure to check with your local authorities on regulations relating to refrigerants, and disposal facilities for leaking units.

See our selection of best window air conditioners : XXX

Running a window air conditioner: Is it expensive?

Short version: Window air conditioners are relatively cheaper when compared to central heating systems both in price and the cost of operating them.

Most window air conditioners range from 500 Watts to 1400 Watts. This makes them great options for budget-minded people. Compared to the central heating units, window air conditioners do not use a lot of electricity. If the goal is to heat the entire room, however, you’ll need more than one unit to achieve this feat.

Most household appliances stores will spoil you with choices if you are looking to purchase the unit. Numerous of these companies are coming up with innovative ways by the day to ensure your experience with their appliances leaves lasting positive effects on their consumers.

These appliances are designed to be smart enough in terms of energy conservations. However, you will need to ensure you also engage in best practices.

Keep the doors and windows shut

These air conditioners work best when the indoor air is circulating in a closed loop. If air keeps seeping in the room through shades or blinds, your unit will have to work more to ensure it changes the incoming air to the desired temperature.

Most air conditioners will automatically shut off if the desired temperature is reached. Air coming in from outside means that an equilibrium will never be reached, and the unit will keep running until it is switched off. This might make them very expensive to operate and may also make the unit to be worn out faster.

Make sure the filters are working properly

HEPA ac filter

If the filters are damaged, the filtering system may keep the AC running for long periods as it tries to purify the air, which may lead to increased costs. Filters need to be checked every now and then to make sure they are running as desired.

Turn the thermostat up a bit

During summer, we expect to come home to a chill house after a long day at work. However, you can tone down the efficiency especially if you are not in the house so you can ensure you save on electricity. Turning the thermostat to run on full blast increases efficiency, but at the same time, it hogs down on power.

Ensure you carry out maintenance regularly

Making regular maintenance checks ensures the appliance is always running at optimum conditions. Check on the filter and the coils to ensure no molds and dust have accumulated. Also, check for leakages on the ductwork. If your heater stops working properly, the refrigerator section could be low on fuel. It’s time you called on an expert to have a look at it.

For our budget picks, click here : XXX

Choosing the right product

Window AC, portable AC or dehumidifier?

Short Version: There isn’t much difference between the two since they both require either a window or a large ‘opening’ on the wall to draw air for cooling from the outside. A dehumidifier only gets rid of excess humidity, but do not change the temperature.

For window and portable air conditioners, they both consists of a condenser, evaporators, and fans. Some of them even have a thermostat onboard to ease the temperature setting.


A portable air conditioner uses a large exhaust pipe that connects to the window. The window AC is already outside, and it solely effaces hot air from there. Both use a similar type of refrigerant that regularly changes from gas to liquid as conditions in the house changes.

Some window units require prior experience some installation manual and kits to mount them on the window. In other cases, the windows don’t permit placement of window ACs as they end up hanging on the outside. Some homeowners won’t even allow their installation.

On the other hand, portable ACs don’t require any complex installation. You only need to place the exhaust on the window.

Knowing which AC is best for you

Two things you need to consider while shopping for an AC;

The nature of your space. Some spaces won’t permit the placement of large appliances due to their sizes. If your space is small, a portable AC is probably not a good idea as it will eat up the much-needed space in your room. In such cases, a window AC is probably a better option than its portable counterpart.

A portable air conditioner is best if you need to use it in multiple rooms.

Whether you need to move it to other rooms. Window units are fixed on walls outside the window, this means they cannot be moved elsewhere without uninstalling them. If you are looking to use the appliance on multiple units, a window AC is not the best option.

Portable ACs, while not portable per se, do permit movement from one place to another.

You will want to be careful with your carpet as the 80-pound unit’s (sometimes even more) caster wheel may damage it. The unit might also require you to seek help especially if there is a raised threshold between rooms.

EER ratings. Window air conditioners are known to be more efficient this means you should get more cooling power per British Thermal Units (BTU). They also come with cool features such as thermostats, remotes controls, and digital timers.

These features give you complete control of the appliances and allow you to customize it. EER ratings on your device may also help you decide which unit will help you save on energy.

Should you shop for a separate dehumidifier? No, you don’t need to. There is a condenser in the unit that does dehumidifying functions though it’s weaker as compared to commercial ones. As warm humid air blows over the coils in the AC, the moisture it contains is cooled and condenses on the coils and thus the resulting air is drier and cooler.

If you are looking for a whole-house solution, a separate dehumidifier, though an added investment, would be good for you.

Check our selection of dehumidifiers and portable air conditioners: XXX

What window air conditioner is the best/the quietest/the best brand?

Short Version: There is an AC for everyone. It all depends on your preference and needs. Lucky you, we’ve done all the dirty work for you.

There is a huge revolution in consumer electronics. Air conditioning has not been left behind. From the noisy rattling models to remote and app-controlled ones, different firms are squaring it off to get a share of the market.

This is all good news for consumers as they get top notch appliances with top notch features, quality, while at the same time saving on energy.

Others go further to offer voice controls and are smart enough synthesize sound and help cozy up rooms without having to move them over. This is all but making life easier for consumers.

What to look for before purchasing a window unit

Ensure your appliance can cover room size.

ACs are more than just the aesthetic looks. They are required to keep out the warm humid air out of the house in the summer and spring. Choosing the correct appliance for your room is important as different models are made for different purposes. Some of the best brands include Kenmore, Haire, and Frigidaire.

  • The space to be covered. Ensure you look out for the BTU rating of the appliance. Generally, as a rule of thumb, 20 BTU per hour covers an area of square feet.
  • The number of people that use the room. The more the number of people using the room, the more hot air they emit through perspiration. This means the more people need a higher capacity unit.
  • Room ventilation. A room with many doors and windows means that heat is lost to the outside and therefore it would need to work more to keep the room chill.
  • The efficiency of the AC. This is calculated by dividing its capacity in BTU/hr by the energy it uses in Watts. The result is a ratio commonly known as Energy Efficiency Ratio(EER). Higher values mean the appliance is more efficient.
  • Noise level. Ensure you can tolerate the noise level of the appliance you are looking to buy. Enquire about your desired unit’s dB values before going ahead and purchasing the item. Some of the quietest models currently in the market include the Frigidaire 15,000 BTU window air conditioner.

The size of your window.

Some appliances are either too big for your window, or they may not even fit. There exist small versions specifically meant for small windows.

This will greatly help you save on space as opposed to purchasing a portable version that can eat the much needed real estate in the room. Kenmore Elite Smart (8000 BTU model) and Haier HWR0XCR are some of the smallest window air conditioners in the market.

Check our pick for quietest air conditioner as well our best dehumidifier: XXX

Installing and optimizing

How to install a window air conditioner?

Short Version: Most window air conditioners are easy to install. Most are fairly DIY and one doesn’t necessarily need an expert to mount the appliance on to the window.

Make sure your unit fits the opening

One of the common mistake people make is not first making sure their unit fits the size of their window. Some windows are not made in the recommended size and some won’t even open. Double-hung windows are best as they also ensure the window does not block egress in the event of a fire.
Ensure the unit is installed on the bottom sill of the window though there models that are manufactured to work with casement type of windows.

Prepare the window and set up the kit

Installation kit.

Slide open the window and set up the weather strip if your unit came with one.
A couple of things you’ll need:

  1. A screwdriver, and screws
  2. A pair of scissors
  3. Measuring tape.

Measure the complete length of the window and cut the foam strip provided with the installation kit to fit the length. Attach the side panels to the unit and makes sure they are well secured with screws. Some units also come with some additional padding that you can fit with some L brackets.

If yours doesn’t come with some padding, just extend the side panel to the window. You can put some brackets if your air conditioner isn’t wide enough to make sure it is sealed.

Expansion pieces can create leakages in the window. You should make sure you examine each one of them and seal them appropriately to ensure no air enters the room from the outside.

Secure your unit

Poorly installed units can easily fall off and may injure pedestrians. If your AC comes with an installation manual, you are better off following it to the latter other than using your experience with other models.

How to conceal your ugly window AC

Perfectly concealed window AC.

Unlike other ACs, most window units are not easily concealed from the inside view since they have to be on the window to work properly.

Ugly window ACs may become eyesores as they may not blend well with your interior designs or gardens. If you feel they disrupting your pleasant indoor patio, there are some clever hacks you can implement to deal with this unsightly experience.

Create a patio area. Drawing visitor’s attention away from the units is one way you can achieve this feat. This involves creating a landscape distraction that makes the AC less easily noticeable. An eye-catching structure like a fountain or a fire pit works perfectly.

Use a trellis system. Climbing plants on a trellis system could do wonders to help mask the posterior side of your AC appliance. Honeysuckle and Trumpet vine are very suitable for this purpose. However, on a multi-storied building, this might not be achievable. You would have to ask an expert to build a structure around it.

Use wall art. Custom wall art can do wonders in helping you camouflage those eyesore window units. You can achieve this by creating a decorative metallic panel. This provides both the space for proper airflow while concealing it.

Make sure the appliance is level

Most people believe that a window unit has to be installed at an angle for it to drain properly. Tilt angles are usually well stipulated by manufacturers manuals. In most cases, the drip direction is usually taken care of during manufacturing.

You don’t have to tilt the appliance for it to drain properly. You can’t also mount the window AC vertically, or sideways, it won’t work. Make sure the appliance is always level if the tilt angle is not strictly stipulated in the manual.

If the unit is not properly leveled, the condensed moisture might collect inside of the appliance. This will provide a rich environment for mold and bacteria to grow. The pores from the mold could be blown into the house and cause all sorts of health problems.

Also, fasten the brackets firmly to ensure the there is no movement that could lead to tilt over time.

Read more in our blog about installing window air conditioners: XXX

What is recharge, and how to recharge a window air conditioner?

Short Version: It’s not a good idea to recharge the window air conditioner yourself especially if you have never handled any HVAC system before. Study the basics before you attempt to handle anything on the unit because the refrigerant is very destructive to the ozone layer.
Some of the tools needed to recharge a window AC.

If you think your unit is spitting less cold air than it used to, it could be time you thought of recharging your AC. Most of the time, this does not need to happen unless there is a leak in the system that could be letting out the refrigerant.

Recharging a window AC could subject you to huge fines if you don’t have a certification to do so.

It is very unlikely for the unit to lose the refrigerant in less than 2 years, which is in most cases the time covered by most warranties. In that case, you can have the manufacturers replace that for you. Besides, some window air conditioners are sealed and do not have a place to add a refrigerant.

Clean the unit thoroughly

Your appliance may not be working properly, not because of the refrigerant, but because it has become dirty and dust has clogged the filters. All cooling fins and fans should be free of dust and dust particles.

Find and fix leaks first

Before you even think of refilling your appliance, it is best you find leaks and refill them first. One of the most common methods of finding a leakage in the refrigerant container is to first fill it with nitrogen and use some soap to find the place where the leak is located.
Using a solder fix the affected joint and ensure the leak is perfectly sealed.

Refill with the correct refrigerant

Most appliances do not come with a service port to change the refrigerant. More so, you need to be EPA certified to work with refrigerants like freon. Exercise extreme caution as this immediately voids warrants and could lead to huge fines if caught.

The DIY service ports and self-piercing valves you’ve installed should be of good quality. Failure to do this could lead to the price of repairing exceeding that of replacing the entire unit.

Majority of the units will have a serve-tag that shows the type of refrigerant that works best in that unit. These can easily be bought at Amazon or other online and supply stores.

Different window air conditioners use different refrigerants but most do need freon to work properly.

Make sure you don’t overfill your unit. Use an HVAC gauge to measure the pressure and make sure it is at the required level.

See our selection of best window air conditioners : XXX

Fixing Issues

Rain and ice: are window air conditioners waterproof?

Short Version: Window air conditioners are designed to work with all weather conditions, including rain, snowstorms, hail, extreme wind conditions. The compressor system, which is the part of the A/C that is most exposed to the outside air is made of waterproof material to ensure no water or contaminant can enter the appliance.

Preparing for heavy rains

A cover can help stop water leakages on window ACs.

While rainwater may not do anything serious to the AC, it might destroy the house walling structure if the unit is improperly installed. Annoying ‘ping’ sounds of dripping water will be heard if the window air conditioner is leaking water and this could turn your cozy afternoon into a crazy experience.

Some people, however, usually do not have a problem with the sound and it can serve as a white background pleasant noise for them.
Leaks should be inspected carefully from all angles and sealed appropriately.

Places such as the contact points between the window frames and the ACs should be inspected as they are prone to leaks due to seals coming out. This could lead to water leaking its way into the house and causing molds and fungus to grow.

Window air conditioners are not 100 percent waterproof. If they are not set up properly during rains, they could get wet inside and may become a breeding ground for molds or not work as intended.

If there are power fluctuations, which are common during heavy rains, be sure to switch the appliance off until at least the power becomes stable again. Doing this will shield your unit from blowing internal fuses or damaging the internal electrical components.

Safeguarding against snow and ice

During the winter, ice can form on the unit and prevent it from functioning properly. If not acted upon, running it while it’s frozen could damage the fans as they may not be spinning freely.

  • Inspect the unit thoroughly and note areas of concern and act upon them accordingly.
  • Use a moderate-pressure hose and some warm water to help the ice thaw quickly and while at the same time clearing all debris and dust particles that may have been trapped inside by the ice.
  • Wipe off the water and dirt off the appliance with a towel and wrap another towel beneath to help thaw the frozen fins and coils.
  • Remove and clean the filter with warm water and laundry detergent and then rinse it with clean water. This will help get rid of debris that could be blocking the flow of air. Only replace it after it has completely dried off.
A moderate pressure hose could do the job.

Defrosting freezers

So, what causes window air conditioners to freeze up? Insufficient airflow over the compression chamber could cause the window air conditioner to freeze up which could lead to start up problems and cause the moisture surrounding the appliance to become ice and accumulate.

These build-ups could permanently damage the appliance if not addressed immediately. Most of these problems could be addressed by simply changing your filter, or clearing the air passages off dirt and dust.

See our selection of best window air conditioners : XXX

Common issues: mold, musty smell… What to do?

Short Version: Faulty window units are known to become a breeding ground for mold and mildew which can be transferred to other places in the house. This could be the cause of that foul, dank smell you experience every time you AC is on.

Musty smells should be the first indicator of serious water problems that need to be tackled immediately. If you own a window AC, you should check it first, before anything else. Your window conditioner could be having water or ice inside.

Getting rid of the smell

The first step you need to take is to identify where in the appliance the smell is coming from. This involves turning off the appliance by unplugging from the power source and removing the outer casing such that the coils, the fans, and the compressor are exposed.

In most cases, water and dust may have accumulated over time in the appliance. This is mostly caused by small amounts of water leaking into the unit’s compartment which traps dust.

This might lead to accumulation of mold in the air conditioner.

Remove the filter on the front body grille and clean the filter and wipe any visible mold thoroughly. Use a brush to scrub off any hard-to-come out material. Flush out the drip tray off muck and debris with moderately pressurized water for several minutes. This should at least freshen up window air conditioners that have the musty dank smell

Also, if you own a spray bottle, fill it with 1 part of bleach and 3 parts of water and spray the blower fan and the vents.

Let it dry out completely before reassembling the unit.

Protect yourself from molds

Black molds are known to be very toxigenic.

Some molds, especially black molds, are very toxigenic and could pose a health risk to the household occupants. This is because they produce mycotoxins that are dangerous to the body and have sometimes been linked with conditions such as pulmonary hemorrhage or memory loss.

If inhaled, especially by young ones an elderly, it could seriously have a detrimental effect on their health.

It has also been proven to aggravate asthmatic conditions, or lead to coughing and wheezing in previously healthy people. Contrary to popular belief though, there is no evidence that black mold will cause cancer.

However, people already having cancer and similar conditions could see their situations get worse if exposed to mold and associated bacteria.

Ensure you regularly do some maintenance on your appliance. Molds are everywhere and small amounts do not pose any danger. But when they settle on damp surfaces for enough time, they quickly grow and spread. Huge amounts of them will start to produce foul smells and can be easily seen.

Before this happens, ensure you clean the unit at least every month and change the filter every 3 months. Ensure water does not settle inside the appliance as this will provide a perfect place for the molds to thrive. This will greatly reduce the mold spores in the air along with the dust that comes out of a poorly maintained unit.

Read more in our blog about common issues with window air conditioners : XXX

Fixing your window air conditioner: how to fix, clean and service your window AC?

Short version: Window air conditioners, like any other appliances, are not fail-proof. They will sometimes fail when we direly need them. This can greatly affect our comfort. We can, however, ensure they are in peak conditions and this will reduce the probability of failing.
Trouble-shoting window wall & AC unit.

When the AC won’t turn on.

Sometimes, the AC won’t turn on. Sometimes, the problem is usually just a minor fix though there some cases you’ll need to replace the entire unit. Most common places that could be causing the problem are more likely to be:

The circuit breaker

Most of the time, if the current being drawn from an outlet is large enough, it might trip the breaker, cutting off the power to the unit. This is mainly caused by sharing the socket with other appliances leading to large currents being drawn from the outlet.

Appliances like window air conditioners are better off using a single outlet for every unit since their current requirements are much larger as compared to other smaller appliances.

Faulty motors

If the motor becomes faulty, the appliance will shut down entirely. You will need to call a professional to check the viability of replacing the unit vs repairing the motors. Motors are commonly destroyed by a power surge in the lines and using surge protectors might help prevent such problems.

Power cables

If your window unit can’t start, maybe the power cord is no longer able to provide power to the appliance. To test whether it could be the cause, use it with another appliance that is working properly.

If the test appliance also won’t start, that power cord is defective and requires replacement. Do not try to repair it but replace it with a similar type.

Outdated appliances

Sometimes, your appliance is just but worn out. While service life might vary depending on the type and how the appliance has been maintained, some appliances reach a point where they can’t give any more service.

These units start to have all sorts of problems like failing to start due to internal circuit problems. Things might even get their way into the appliance and wreak havoc by blocking the air flow or producing crackling noises that are very annoying. The cost of repairing such units start to become too big such that the only solution is to replace the entire unit with a new one.

Window air conditioner

Maintenance and regular servicing

If you want your appliance to always be in peak performance, you’ll need to commit yourself to set aside time to tend to the appliance. This means thoroughly inspecting the appliance.

This should be a simple process that will ensure the unit is always performing optimally.

  1. Unplug the unit from the wall.
  2. Remove the outdoor cover.
  3. Remove the filter and clean it. Replace it if necessary. Vacuum the condenser and hose off the coils clean.
  4. Check the fins for bents and straighten them, and
  5. Put the unit back to its frame, put back the cover and plug it back to the electrical outlet.

These maintenance steps, if done periodically, will keep your appliance always on top conditions and you won’t have to call a professional to fix it for you.

See our selection of best window air conditioners : XXX