Common Air Conditioner Problems

Common central air conditioning problems occur when rooms are closed off and air flow through the home is disrupted.  On the other hand, if you have a room air conditioner, the opposite is true.  And are is improper operation. Be sure to close your home's windows and outside doors to isolate the room or a group of connected rooms as much as possible from the rest of your home. For a list of common air conditioner problems and what to look for, check out our Energy Saver 101 infographic on home cooling.

Other common problems with existing air conditioners result from faulty installation, poor service procedures, and inadequate maintenance. Improper installation of a central air conditioner can result in leaky ducts and low airflow. Many times, the refrigerant charge (the amount of refrigerant in the system) does not match the manufacturer's specifications. If proper refrigerant charging is not performed during installation, the performance and efficiency of the unit is impaired. Unqualified service technicians often fail to find refrigerant charging problems or even worsen existing problems by adding refrigerant to a system that is already full. Learn what to ask for when hiring a technician to maintain your air conditioner.

Air conditioner manufacturers generally make rugged, high quality products that last for years. If your air conditioner fails, begin by checking any fuses or circuit breakers. Let the unit cool down for about five minutes before resetting any breakers. If a central air conditioner's compressor stops on a hot day, the high-pressure limit switch may have tripped; you may be able to reset it by pushing the button, located in the compressor's access panel.

 A refrigerant leak is one common air conditioning problem

Refrigerant Leaks

If your air conditioner is low on refrigerant, either it was undercharged at installation or it leaks. If it leaks, simply adding refrigerant is not a solution. A trained technician should fix any leak, test the repair, and then charge the system with the correct amount of refrigerant. Remember that the performance and efficiency of your air conditioner is greatest when the refrigerant charge exactly matches the manufacturer's specification, and is neither undercharged nor overcharged. Refrigerant leaks can also be harmful to the environment.


Inadequate Maintenance

If you allow filters and air conditioning coils to become dirty, the air conditioner will not work properly, and the compressor or fans are likely to fail prematurely.

Before and After AC filters


Electric Control Failure

The compressor and fan controls can wear out, especially when the air conditioner turns on and off frequently, as is common when a system is oversized. Because corrosion of wire and terminals is also a problem in many systems, electrical connections and contacts should be checked during a professional service call.

Sensor Problems

Room air conditioners feature a thermostat sensor, located behind the control panel, which measures the temperature of air coming into the evaporative coil. If the sensor is knocked out of position, the air conditioner could cycle constantly or behave erratically. The sensor should be near the coil but not touching it; adjust its position by carefully bending the wire that holds it in place.

Drainage Problems

When it's humid outside, check the condensate drain to make sure it isn't clogged and is draining properly. Room air conditioners may not drain properly if not mounted level.


As deadly heat waves spread, access to air conditioning becomes a lifesaving question

The summer heat is most dangerous for low-income communities, where many lack air conditioning. Housing advocates want to change that.

The sun came blazing through the sliding glass door in Jollene Brown’s cramped studio apartment, a converted storage unit in southeast Portland, Oregon. As the heat started rising in late June — hotter than she could ever remember — her son, Shane Brown, hung a blanket over the glass to help block the rays, to little effect.

The $750-a-month apartment didn’t come with air conditioning, and the old floor unit that she and her son had scraped the money together to buy wasn’t working. When her son suggested getting a new one, she waved the idea away. “We’ll see,” she told him over the phone on June 27, the last time that they spoke.

“She didn’t want me to worry or feel like I was going to be burdened,” said Shane Brown, 35, who works as a packer at an Amazon warehouse. The next morning, he texted her a picture of the sunburn he had gotten on his shoulder that weekend, when the temperature hit 112 degrees. There was no response. He tried calling her, over and over. Eighteen calls — no response. In a panic, he jumped in his car.

“Please, God, let her be OK,” he thought as he drove to her home, worried that she was sick, as she suffered from cirrhosis and chronic leg swelling and needed supplemental oxygen around the clock. When he opened the door, he saw her slumped on the recliner in her pajamas, her head tilted to one side. He pulled the oxygen unit off her face and put his hand to her cheek, which felt strangely firm.

Hours later, when the medical examiner arrived, it was 100 degrees inside the apartment.

Jollene Brown, 67, was one of hundreds of people who died from this summer’s deadly heat waves in the Pacific Northwest. In Oregon, most of the 96 confirmed victims “lived alone in homes with no working air conditioning or fans,” according to a state report. (Stark Firs Management, which operates Jollene Brown’s building, didn’t respond to multiple requests for comment.)

 A collage made for Jollene Brown's funeral service.


An NBC News analysis of Oregon’s data, public records and obituaries found that many of those who died from hyperthermia in June were among the state’s most vulnerable residents: More than half were over age 65, and at least 13 lived in properties for older adults or in affordable housing serving low-income residents, homeless people or those with disabilities.

In both private housing and publicly subsidized properties where residents died, NBC News found landlords who didn’t provide air conditioning, which isn’t legally required. In some instances, landlords prohibited residents from having window air conditioners, concerned that the units would fall.

Extreme heat kills about 600 people in the U.S. every year — more than any other form of weather — and it will only become more common as the planet continues to warm. That makes access to air conditioning a lifesaving necessity, public health experts and advocates say.

“AC is a form of climate adaptation,” said Kelly Sanders, an associate engineering professor at the University of Southern California. “It’s critical to protecting people.”

But requirements for landlords to provide air conditioning or for new buildings to have cooling devices remain rare: In Oregon, as in most other states, there are no statewide or broad local mandates for cooling devices in housing, and the federal government similarly has no cooling requirements for publicly subsidized properties.

That leaves low-income people at the greatest risk, experts said, as they are more likely to live in aging properties without air conditioning or built-in fans, suffer from underlying medical conditions that leave them more susceptible to heat-related illness, and reside in urban areas where the concentration of buildings and paved roads drives temperatures up. During June’s heat wave, at least 21 people died in East Portland — an area of known “heat islands” — concentrated in three ZIP codes with higher poverty rates than average for the city, according to NBC News’ analysis.

A man is treated for a heat-related emergency call during a heat wave in Portland, Ore., on Aug, 12. 


Existing policies and programs to protect vulnerable people from preventable heat deaths lag far behind the growing need, officials and experts say. Federal funding that states could spend on cooling assistance has been dedicated mostly to heating assistance — and the demand for both has risen as climate change fuels extreme weather. In Washington, where 134 confirmed or suspected heat deaths have occurred this summer, the state had prohibited federal energy assistance funds from being spent on cooling assistance until early August, state officials said.

“One of the major problems with heat is that it doesn’t get the same attention as other disasters,” said Juanita Constible, a senior advocate at the Natural Resources Defense Council, an environmental advocacy group. “It’s not folded into the main thinking about how to keep people safe.”

Resources Stretched Thin


In the wake of June’s deaths, state and local officials in Oregon have focused on opening more cooling centers, expanding emergency heat alerts and outreach, and urging people to check on friends, neighbors and family members during heat emergencies.

But those steps won’t fully protect the most vulnerable residents during times of extreme heat, experts say: Some may have medical problems or disabilities that make it difficult for them to venture out to air-conditioned spaces, especially for long periods of time, or they may be reluctant to seek help. During heat emergencies, the risks can become even greater at night, because temperatures tend to remain high and most cooling centers are closed.

People rest at the Oregon Convention Center cooling station in Portland on June 28.


Low-income communities are less likely to have the resources to cope. Nearly 20 percent of people in the U.S. with annual incomes below $20,000 don’t use air conditioning at home, double the rate of those with incomes of $80,000 or above, according to a 2015 federal survey.

Complicating matters is the fact that air conditioning contributes to climate change through increased electricity use and hydrofluorocarbons, refrigerants that some states are phasing out for safer alternatives. Some cities are considering heat pumps, which combine air conditioning and heating to lower carbon emissions. But many environmentalists acknowledge that there is no total replacement for air conditioning.

While low-cost fans can help people stay cool during moderately hot weather, health authorities recommend against using them when the temperature is above 95 degrees, as they make it harder for the body to release heat through sweating — especially among older adults. And other strategies, like planting trees and painting roofs white, won’t be enough in isolation to keep vulnerable people safe, Constible said.

“Unfortunately, AC is going to be a major part of the solution going forward,” she said.

The federal Low Income Home Energy Assistance Program helps low-income families pay energy bills, weatherize their homes and fix or replace broken furnaces or air conditioners. Funding for the program, however, has dropped from $5.1 billion in 2009 to $3.7 billion in 2021.

State governments, which administer the program, have directed the vast majority of the funds toward heating bills and weatherization against the cold, not cooling bills and devices to cope with heat, said Mark Wolfe, executive director of the National Energy Assistance Directors Association, which represents state energy officials. Forty years ago, when the program began, the primary concern was protecting families during the winter.

Without heat, “pipes could freeze, and people could freeze to death,” Wolfe said. By contrast, “there was a perception that cooling was a luxury.”

The growing frequency of both extreme cold and extreme heat events has stretched limited resources even further, officials and advocates say.

In February, four months before June’s deadly heat wave, a severe ice storm caused more residents to lose power across Oregon than ever before.

“The reality is that if Oregon experiences a harsh winter, the resources will be limited to address the impacts of a harsh summer, and vice versa,” said Tim Zimmer, assistant director of energy services for Oregon’s housing department.

Other federal resources for cooling assistance haven’t been widely used in the region. Oregon’s state Medicaid plan allows some beneficiaries to receive free air conditioners if they have underlying medical conditions. But the application process can be long and complex, requiring a doctor’s note, said Marisa Espinoza, an advocate for Northwest Pilot Project, a social service organization for older, low-income adults. “It's not about whether or not people want them, but whether they can access them,” she said.

Last year, only 146 Oregonians got home devices like air conditioners and air purifiers through Medicaid, according to the state health department.

In this summer’s deadly heat, Multnomah County, Oregon, plans to ask for state approval to allow federal energy assistance funds to be used for cooling repairs and equipment, the county said. And Washington state lifted its prohibition on cooling assistance through the program this month because of the changing climate, a state spokesperson said.

On the federal level, Sen. Ron Wyden, D-Ore., is urging private insurers to cover air conditioners for chronically ill older adults enrolled in Medicare Advantage, calling it an “essential benefit.” Wyden helped change federal law in 2019 to allow air conditioners to be covered under the program, but insurers aren’t required to cover them, and it isn’t a broadly available benefit.

Oregon Gov. Kate Brown, a Democrat, has focused on raising public awareness about heat-related illness and access to cooling centers, but providing free or low-cost air conditioners to vulnerable residents “was an area identified for further study,” spokeswoman Liz Merah said. “All Oregonians should have access to measures that will help protect their health and their lives.”

 A homeless man who asked to not be named tries to stay cool near a misting station during a heat wave in Portland, Ore., on Aug. 13.


 Window Air Conditioners Banned

Cost isn’t the only obstacle: In Oregon, as in other parts of the country, many buildings prohibit tenants from installing window air conditioners, which are significantly cheaper than portable floor models, for fear that they could damage the properties, overload electrical grids or pose liability risks.

At Portland’s Fifth Avenue Court Apartments, residents are prohibited from installing window air conditioning units for safety reasons, said Hope Magee, an assistant building manager for the property.

“The windows aren’t built to take the weight, so jostling it even a little bit can cause it to fall out,” she said. “If you're on a tall floor and that window unit hits somebody, it can kill them."

But the heat itself proved deadly.

H Michael Monkman, 79, was an affable man from New York who introduced himself to everyone and was never the type to complain. “Every time he had an issue, he didn’t want to bring it up, because he didn’t want to be a bother,” Magee said.

The building did permit portable floor air conditioners. But Monkman didn’t have one in his unit, which was designated for low-income residents, and might not have realized that residents could take chairs down to the air-conditioned lobby, she said.

On the morning of July 1, Magee was horrified to find Monkman’s body in the apartment. “None of us even realized it was a heat issue until after things had calmed down a little bit,” she said.

Oregon state Rep. Khanh Pham, whose East Portland district includes the ZIP code identified as the hottest in the city, is examining ways to lift prohibitions on air conditioners through changes to the state housing code, most likely through legislation. Banning tenants from using certain types of air conditioners “is frankly a human rights violation in the midst of a deadly heat wave,” Pham said.

 'A Basic Human Right'

Elsewhere in the country, the growing risks from heat have prompted a handful of municipalities — including Dallas; Montgomery County, Maryland; and Tempe, Arizona — to require landlords to provide air conditioning or other cooling devices in all rental units. Phoenix requires ducted air conditioning in all newly constructed housing and helps provide tenants with portable units or temporary hotel stays if landlords need to fix or replace failing air conditioning systems, a city spokeswoman said.

“We've moved beyond the idea of AC being a comfort,” said Montgomery County Council President Tom Hucker, who spearheaded the push for the requirement last year. “In the era of climate change, it is just getting worse, and we have to protect our residents.”

In Nevada and Arizona, legal advocates have argued that landlords must provide air conditioning as a basic condition of livable housing under state law.

“When the weather is 110, it is about life and death — it’s not habitable, and it’s not safe,” said Pamela Bridge, a lawyer at Community Legal Services, a legal aid organization in Arizona.

People cool off with water mist in Phoenix on June 15.


Private landlords and affordable housing providers, however, warn that modifying all buildings to accommodate air conditioners could be extremely costly, threatening the already scarce supply of affordable housing.

After six of its residents died during June’s heat wave, Portland’s local housing authority, Home Forward, bought 60 more portable air conditioners for emergencies and expanded outreach to residents in public housing and other subsidized properties, spokeswoman Monica Foucher said. At least five of the six deaths occurred at homes without air conditioning.

But Michael Buonocore, Home Forward’s executive director, said the organization has no plans to install air conditioning in all residences, as the cost of installation, maintenance, repairs and increased energy bills would be prohibitive. Foucher said window units must be professionally installed and can’t be placed above the fifth floor because of safety concerns.

Public housing authorities aren’t required under federal law to provide air conditioning. They can use their own capital funds to install the devices, the federal Department of Housing and Urban Development said. But federal funding for capital investment has long been declining, creating a shortfall estimated at $70 billion.

Housing advocates urge local officials to look elsewhere for money. In 2018, Portland voters approved a ballot measure creating a clean energy fund that places a 1 percent surcharge on retail sales by large corporations, which is expected to generate up to $60 million a year. The fund — which has supported energy-efficient renovations and training for clean energy jobs — could also equip buildings with air conditioning and energy-efficient heat pumps and help residents pay their cooling bills, advocates say.

“Some people say that’s not environmentally friendly, but I would say saving people’s lives should be our first and foremost priority,” Multnomah County Chair Deborah Kafoury said.

In the wake of his mother’s death, Shane Brown believes air conditioning should be required in all rental housing, just like heating. Jollene Brown had been forced into early retirement after she was laid off from a telecom company, and she was relying on food stamps and Social Security to get by; a new air conditioner would have been a big-ticket purchase.

“Running water is a basic human right, but a livable temperature is also a basic human right,” he said.

Shane Brown, who visited his mother twice a week, had taken over a swamp cooler before her death.


Two days before his mother died, Brown took over a swamp cooler, which uses a fan and water to cool the air. But his mother, who relied on a walker, struggled with getting up to replace the water, she told him the day beforehand. Ultimately, the fan wasn’t enough.

“I don’t think her body could take it — it was just working too hard,” Brown said.

The extreme heat, meanwhile, hasn’t left the region: Oregon declared additional heat emergencies in July and August. Three more heat-related deaths in Multnomah County are under investigation.

“This is a solvable problem,” said Wolfe of the state energy directors group. “Most of climate change we can’t fix, but this is a problem we can address.”

CORRECTION (Aug. 20, 2021, 11:10 a.m. ET): A previous version of this article incorrectly identified an advocacy group. It is the Natural Resources Defense Council, not the National Resources Defense Council.