How to Repair Your Window Unit Air Conditioner

Window air conditioners are a fast and affordable way to cool certain rooms in your home. Ideal for renters or people living in mild climates, a window air conditioner uses a minimal amount of energy to maintain optimum comfort levels in your home. As with any appliance, your air conditioner can’t run properly without regular care and maintenance. Get to know your window air conditioner so you’ll understand what’s happening as it runs and why your annual tune-up is so important.

If you detect a problem, begin troubleshooting immediately. Calling in a licensed professional to service your unit when it’s having serious problems will help you save money in the long run by squeezing a few extra years of service out of your appliance.

Getting to Know Your Window Unit Air Conditioner

Before you can troubleshoot or repair your window unit air conditioner, you must understand all the parts that make up this system. Window units feature both interior and exterior parts separated by a center panel.

Interior parts include:

• Front panel or grill: This is the only visible part of the interior half of the window air conditioner. The front panel includes the controls you use to adjust settings on the device as well as the return air grills that pump out cool air. Adjustable louvers in the air grills let you adjust the air’s direction.

• Evaporator coil: Cold refrigerant runs through the evaporator coil. When air passes over the chilled coil, it becomes colder.

• Fan or blower: The fan or blower pulls warm air into the unit, then pushes it past the evaporator coil and through the filter to cool and clean it, respectively.

• Fan motor: Located between the evaporator coil and condenser in a window AC unit, the fan motor enjoys a very compact location. It is fitted to both these components via small shafts. An AC blower motor replacement costs between $100 – $300.

• Thermostat: The thermostat is responsible for measuring and maintaining the temperature inside your unit.

• Filter: The filter is the part of your unit that you will have the most contact with. It’s typically found just inside the front panel, making it easily accessible. You should change or clean the filter regularly.

Exterior parts include:

• Compressor: The compressor pressurizes gas inside the condenser coils. The pressurized gas turns to liquid refrigerant.

• Condenser or condensing coil: The condenser coil releases heat from the refrigerant, allowing it to escape into the surrounding air.

• Condenser fan: The condenser fan blows air over the surface of the condenser coil. This helps release the heat from the refrigerant back into the air.

• Drain pan: Condensate builds up on the cooling coil. This will drip down onto the drain pan.

• Condensate drain tube: Water from the drain pan exits the unit through an exterior condensate drain tube. Not all units have this tube. Instead, some simply have a hole that water can drain through.

A basic understanding of how your window air conditioning unit works will make it easier for you to understand the potential problems you might experience. All air conditioners use refrigerant to cool air, so if you’re familiar with how standard HVAC units operate, then you have a basic understanding of window air conditioners. Window units are simply smaller.

In the compressor, the hot gas is pressurized until it reaches the chilled liquid state. The liquid refrigerant then passes into the evaporator coil. The system’s fan pulls warm air through the filter and into the unit. Here, the air passes over the cold evaporator coil and becomes chilled. The cool air blows back into the room where it mixes with the warmer air in the environment, creating a cooler and more comfortable space.

Troubleshooting Simple Problems

You can easily fix many common issues with your window unit air conditioner. Troubleshoot the unit for these simple problems before calling in professional help.

Water Dripping From the Unit

It’s alarming to see water dripping off your window unit air conditioner or to find a puddle growing beneath it. Fortunately, this issue isn’t as serious as it seems. A water leak simply means that the pan beneath the unit slopes toward the front of the unit and not the back. Readjust your unit so it slopes backward to instantly correct the problem. When the pan slopes toward the exterior of the home as it should, condensate from the evaporator coil will gather in the pan and drip outside.

Unit Cycling On and Off Frequently

If you feel like you’re constantly hearing your unit cycle on and off, there’s probably a problem with the thermostat or temperature sensor. You might be able to fix this issue yourself. Before calling a professional, adjust your drapes so they don’t obstruct the thermostat or front panel, and clear leaves away from the condenser. If this doesn’t solve the problem, keep reading to learn about problems best serviced by a professional.

Unit Cools Inefficiently

If you’re fighting a constant battle to keep your home cool, there’s probably something preventing your air conditioning unit from operating at peak efficiency. The most common diagnosis – and easiest solution – is a dirty filter.

You should change your window AC filter regularly. Aim to change it at least once every three months and as often as once a month if you have children, pets or a lot of dust in the home. Changing the filter is quick, simple and affordable. Simply open the unit, remove the old filter and replace it with a new one.

AC Unit Won’t Turn On

If your unit won’t turn on, there are a few simple problems you can troubleshoot before calling a professional. First, check to make sure the unit is plugged in. This might seem fairly obvious, but it’s easy to overlook, particularly if the unit plugs into an outlet hidden behind a piece of furniture. If the unit is plugged in, check to make sure you haven’t blown a fuse. If resetting the circuit breaker doesn’t work, it’s time to move on to professional solutions.

When to Hire a Professional Contractor

There are many instances where simple at-home solutions won’t work. It’s important to turn to a professional for all serious problems with your window air conditioner unit. Below are some common problems that a professional contractor can help you with. If you’re experiencing other less common problems with your unit, your contractor can help you diagnose and solve those, as well.

Unit Cycling On and Off Frequently

A unit that cycles on and off too often typically has a problem with the thermostat or temperature sensor. A professional will check the unit to make sure the thermostat sensor is positioned correctly. This might include delicately adjusting the wire and moving the thermostat sensor so it doesn’t touch the evaporator coil.

Your unit might also suffer from a small refrigerant leak. Any standard service visit will catch this problem. Have your contractor tune up the unit and check for anything out-of-place. He might perform a variety of helpful tasks including straightening the fins with a fin comb, charging the refrigerant and repairing leaks.

Blown Fuses From the Window Unit Air Conditioner

If your unit blows fuses or pops the circuit breaker when it turns on, you’re probably running it on an inadequately sized circuit. The typical unit can run off a 15 amp circuit, but larger window air conditioners need a dedicated circuit. Contact an electrician to run a dedicated 20 amp circuit directly to the window air conditioner. This will put an end to blown fuses and eliminate the need to strategically reposition electrical devices throughout the home in an attempt to avoid the problem.

Unit Cools Inefficiently

If changing the filter doesn’t improve your unit’s performance notably, it probably needs a full servicing. Ideally, you will schedule a tune-up with your HVAC contractor once a year before you begin operating your air conditioning unit for the season. During this appointment, your contractor will:

• Check the thermostat to make sure it’s operating correctly

• Inspect the air filter and change it if needed

• Inspect the condensate drain for buildup or blockages and clear as needed

• Check the evaporator coil for dust and dirt buildup and clean when necessary

• Check the evaporator fan and motor for proper function

• Lubricate bearings

• Clear dust and debris from fan

• Adjust fan as needed for proper rotation

• Inspect refrigerant lines for leaks or kinks and repair when necessary

• Inspect and clean the condenser coil

• Check coil fins and straighten as needed

• Lubricate the condenser fan

• Ensure condenser fan has proper rotation and connection

• Check refrigerant levels and charge as needed

Dust and debris will build up naturally inside your air conditioner. A dirty fan or coils will decrease system performance. Low refrigerant levels might also be to blame. A simple tune-up will address all these issues and might even alert you to problems you weren’t aware of. It’s important to work with a reliable contractor and schedule this visit yearly.

AC Unit Won’t Turn On

If your unit fails to turn on while it’s plugged into a working outlet, the problem is likely in the power cord. A professional can test the power cord using a volt-ohm-milliammeter (VOM) to RX1 scale attached to the prongs. If the power cord is indeed the problem, your AC contractor can replace this part entirely, instantly restoring your system to proper operation.

Repair or Replace: Asking the Essential Question

There comes a time in the life of any appliance where you must decide whether it’s more cost-effective to continue repairing the unit or to invest in a replacement. The average cost to repair a window air conditioner is $213, but this can vary from just $50 for minor repairs to $700 for major problems. The first thing you can do when you’re considering the value of a repair is to compare your contractor’s estimate with the cost of a new unit.

Window air conditioner units can vary in price from less than $150 to more than $500 per unit to purchase. Here are some examples of window AC units and what they cost.

British thermal units, or BTUs, are the deciding factors that will help you choose the best appliance for your needs. If you’ve been struggling to adequately cool your home, consider your current unit’s BTU before investing in extensive repairs. Even the best-maintained unit can’t combat full sunlight, kitchen heat, or a large room if it lacks the proper BTU. Check this chart to see if your unit is the proper size. If not, it’s time for a replacement.

If a room regularly has more than two people in it, you’ll want more than the recommended BTU. Add 600 BTUs per person to maintain adequate home comfort.

Your appliance’s age also plays an important role in your decision to either repair or replace the unit. Most AC units have a lifespan of about 10 years. If you’re diligent about your annual maintenance, filter changes and safe storage of the unit when it’s not in use, you might add a few years to the lifespan. If your air conditioner is older than 10 years, you’re probably better served buying a replacement than investing in more repairs. Today’s newer systems offer energy-efficient benefits that can reduce your energy expenses, helping you recoup some of the initial cost of the investment.

Window Units vs. Central Air Conditioning

If you’ve decided that it’s time to invest in a new air conditioner, you have one final decision to make. Do you want to stick with a window air conditioning unit or upgrade to a central air conditioning system? There are drawbacks and benefits on both sides of the argument.

Benefits of Window Air Conditioning Units

• Easy installation – Plugs into a standard outlet with no additional wiring

• Affordable

• Designed for one room at a time – Ideal for climates where you don’t need to cool the entire home

Drawbacks of Window Air Conditioning Units

• Inefficient at managing high humidity levels

• Difficult to properly seal in the window, so air might escape

• Low efficiency with typical energy efficiency ratings (EER) of 10 or 11

Benefits of Central Air Conditioning

• Cools the entire home

• Manages humidity effectively

• High efficiency with typical EER ratings of 14 or 15

Drawbacks of Central Air Conditioning

• New units are expensive

• Installing a new central air conditioning system is complex and time-consuming

• Might provide unnecessary cooling to unused rooms

If you live in a relatively cool climate and only need air conditioning for a few rooms in your home, window units are an efficient answer. By turning these air conditioners on and off when using the rooms, you’ll avoid the cost of cooling your entire home when you spend the day in only a fraction of the house.

If you live in a hot and humid climate, however, you will probably find that you’re better served by central air conditioning. This is a significant expense and something you’ll probably need to save up for. Installing central air conditioning typically costs between $3,681 and $7,173, and repairs to upkeep the unit typically run homeowners between $150 to $500.