An AED should be placed in a visible, central location where someone can retrieve it and return to a cardiac arrest victim within 3 to 5 minutes. Survival odds drop 7 to 10 percent for every minute without defibrillation, and after 10 minutes, resuscitation rarely succeeds. That tight window makes placement one of the most important decisions in any public access defibrillation program.
The 3-to-5-Minute Rule
OSHA recommends that AEDs be installed so that the total response time, including someone noticing the emergency, running to grab the device, and bringing it back, stays within 3 to 5 minutes. In practice, this means thinking about round-trip walking distance. A device mounted at the far end of a long hallway or on a different floor of a building may technically be “in the building” but functionally useless if retrieval takes too long.
For multi-story buildings, that typically means placing at least one AED on every other floor, and ideally on every floor in large facilities. Position them near elevators or stairwells so people moving between floors can reach one quickly. In sprawling single-story spaces like warehouses or convention centers, multiple units spaced throughout the floor plan are more effective than a single centrally located device.
Highest-Priority Locations
Not all spaces carry the same risk. A landmark study in Circulation identified ten location types with the highest rates of cardiac arrest per site: international airports, jails, large shopping malls, public sports venues, large industrial sites, golf courses, homeless shelters, ferry and train terminals, health clubs and gyms, and community or senior centers. Interestingly, high-rise office buildings had relatively low cardiac arrest rates compared to places like jails and airports.
Within a workplace, OSHA specifically flags these areas for AED placement:
- Assembly lines and open offices where many people work in close proximity
- Confined spaces where rescue response is already slower
- Areas with electric-powered equipment due to electrocution risk
- Outdoor worksites where lightning is a concern
- Company fitness rooms and cafeterias where physical exertion or stress may trigger events
- On-site health units where workers go with chest pain or other symptoms
- Remote sites like offshore rigs, construction projects, marine vessels, and pipeline corridors where emergency medical services are far away
Mounting Height and Accessibility
AED cabinets need to be reachable by everyone, including people in wheelchairs. Following ADA-aligned guidelines, the cabinet handle should be mounted no higher than 48 inches above the floor and no lower than 15 inches. These limits apply whether someone is approaching the cabinet head-on or from the side. Mounting the device at roughly chest height for a standing adult, around 42 to 48 inches, works well for most people and keeps the AED easy to spot.
Visibility and Signage
An AED that nobody can find in a crisis might as well not exist. Place the device along main corridors, near building entrances, or beside other emergency equipment like fire extinguishers, where people naturally look during emergencies. Avoid tucking it inside offices, behind reception desks, or in rooms that may be locked after hours.
Clear signage matters more than you might expect. An international survey published in Resuscitation Plus found that fewer than half of participants could correctly identify the standard green “safe condition” AED sign used in many countries. The sign rated most visible and easiest to recall was a yellow background with a red heart, blue “AED” text, and the phrase “NO TRAINING REQUIRED” in red. Whatever sign you use, it should be visible from a distance and from multiple angles, not just when standing directly in front of the cabinet.
Unlocked Cabinets Are Safer
A common concern is theft, but the evidence strongly favors leaving AED cabinets unlocked. The International Liaison Committee on Resuscitation reviewed the data and issued a clear recommendation against locked cabinets. Theft and vandalism rates across multiple studies were consistently below 2 percent, even for devices with 24-hour public access. In the one study that directly compared locked and unlocked cabinets, theft rates were 0.1 percent for locked and 0.3 percent for unlocked, a negligible difference.
Locked cabinets, on the other hand, cause real problems. Two simulation studies found significantly slower AED retrieval when locks or other security measures were in place. In one survey of first responders, half reported injuries while trying to access a locked AED, with most of those injuries caused by breaking glass to reach a key. If a lock is used for some reason, the code should be available by calling emergency services, and instructions must be printed clearly on the cabinet itself.
Cabinets with audible alarms that sound when the door opens are a good compromise. They deter casual tampering without slowing down a rescuer by even a second.
Temperature and Environmental Limits
Most AEDs are rated for an operating range of 32 to 122°F. Temperatures outside that window can drain batteries and degrade the adhesive gel on the electrode pads, potentially making the device unreliable when you need it most.
For indoor placement, this is rarely an issue. Outdoor and vehicle placement requires more thought. If an AED lives in a car, keep it in the climate-controlled cabin rather than the trunk, and bring it inside overnight during extreme weather. For outdoor installations at pools, sports fields, or worksites, invest in an insulated, weather-rated cabinet. Place it in a shaded spot out of direct sunlight, and check the device’s self-test indicators regularly to confirm it’s still functioning.
Making Placement Work Around the Clock
The American Heart Association recommends 24/7 accessibility for public AEDs. A device mounted inside a lobby that locks at 6 p.m. is unavailable for roughly half the day. When choosing placement, consider whether the location stays accessible after business hours, on weekends, and on holidays. For buildings that do lock, placing the AED in an exterior-facing cabinet or in a vestibule that remains open can maintain access without compromising building security.
Registering your AED’s location with local emergency services or a public AED registry is equally important. Many 911 dispatchers can direct callers to the nearest AED if the devices are mapped in their system, turning a frantic search into a direct set of instructions.