Keeping people out of your building isn’t always as simple as locking the doors. When traditional break-in attempts are too risky or unsuccessful, intruders often look for unconventional access points—one of the most overlooked being your HVAC system. Whether it’s a professional burglar, a curious child, or an animal seeking shelter, HVAC ductwork can become an easy entry path if left unsecured.

This is where HVAC burglar bars become an important layer of protection.

Why Burglar Bars Matter
Burglars and other intruders will exploit any weak point—rooftop HVAC units included. Open ductwork can offer:

• Direct paths into corridors or open spaces
• Concealment during a break-in attempt
• Easy access when rooftop security is minimal

Beyond intentional intrusion, unprotected duct openings also attract:

• Children exploring rooftop areas
• Birds, raccoons, and other wildlife
• Vandals and trespassers

Burglar bars add a strong, physical barrier at a critical entry point the average security system overlooks.

Proper Location Is Critical
Installing burglar bars “deep” into the ductwork may seem like a good idea—but it can create serious risk, especially in emergencies.

When bars are installed far from the HVAC unit:

• Intruders or children may crawl far into the ductwork before discovering an obstruction
• Turning around or backing out becomes extremely difficult
• They can become trapped or disoriented within the sheet metal maze
• Emergency responders face a hazardous rescue scenario

Recommended placement:
Install burglar bars at the roof curb—right where ductwork transitions into the building.

This protects:

• Supply air openings
• Return air openings

And it ensures the barrier is as close to the rooftop access point as possible.
Typical Applications
Burglar bar systems are commonly installed in:

• Public schools
• Government buildings
• Facilities with elevated security needs
• Retail and commercial buildings
• Remote or isolated businesses

Anywhere break-ins or unauthorized access pose a risk, burglar bars should be considered.

Construction and Durability
Design varies by manufacturer. MicroMetl’s burglar bars are engineered for durability and long-term reliability:

• ½-inch steel round bars
• Welded at intersections
• Maximum 6-inch spacing
• Rigid, tamper-resistant framework
• Corrosion-resistant design for rooftop conditions

This robust construction stops intruders while withstanding years of HVAC vibration, weather exposure, and mechanical stress.

Factory vs. Field Installation
While burglar bars can be installed in the field, the best practice is to specify them at the time of curb order.

Here’s why:

• Factory-installed bars ensure exact fit and alignment
• They are welded securely during assembly
• Installation time is eliminated at the job site
• No risk of discovering incompatibility during install
• Once the rooftop unit is installed, burglar bars are permanently sealed in place

Field-installed inserts are available for many rooftop curb sizes, but ordering them integrated with your new curb guarantees perfect fit and long-term performance.

A Small Cost With Big Impact
Break-ins and theft can cause:

• Equipment damage
• Business interruption
• Inventory loss
• Insurance claims
• Safety incidents

Compared to the cost of repairs and disruption, burglar bars are an extremely affordable preventative measure.
Simply put:
If an HVAC system can be used as an entry point, it should be protected.