Air Curtains 101: The Invisible Wall Saving Commercial Buildings Thousands in Energy Costs

Introduction: The “Invisible Wall” Most Contractors Walk Past Every Day

Every home service contractor has walked through one without thinking twice about it: that blast of air at the entrance of a Home Depot, a convenience store, or a walk-in cooler. Most people assume it’s just a rooftop unit blowing hard. It isn’t. It’s a purpose-built piece of equipment called an air curtain, and it’s quietly saving commercial buildings a significant amount of money on energy every single day.

Curtis Rosol from Mars Air joined the Service Business Mastery podcast to break down exactly what air curtains do, why they matter more than most contractors realize, and why this might be one of the easiest add-on offerings for anyone doing light commercial HVAC work.

This article covers what Rosol shared with hosts Tersh Blissett and Josh Crouch: how air curtains work, where the real ROI comes from, and what it takes to start offering them.

Why This Matters Right Now

Commercial buildings with high foot traffic, convenience stores, big box retailers, restaurants, cold storage rooms, lose a surprising amount of conditioned air simply because their doors stay open more than owners realize. That loss gets more expensive every year as electricity costs climb and more equipment shifts toward electrification instead of gas.

An air curtain solves a problem that’s often invisible until you know to look for it: an open doorway acting as a constant drain on heating and cooling. For contractors, that makes it a low-friction upsell. It’s inexpensive to run, straightforward to install, and solves a cost problem most commercial building owners are already frustrated by, even if they’ve never heard the term “air curtain” before.

Core Insight #1: The Real ROI Is Energy Savings, Not Just Comfort

Air curtains are often mistaken for a comfort feature. Rosol was clear that the primary financial case is energy savings, not the rush of air people feel walking in.

Bite-size takeaways:

• High-traffic commercial doors stay open a large portion of the day, and every minute they’re open, conditioned air escapes and outside air pours in.
• The energy lost through an open doorway ramps up utility bills significantly, especially in hot, humid climates or extreme cold.
• Electrification is compounding this problem. As more buildings and equipment shift away from gas, electricity demand and pricing are both expected to climb, which means the ROI on stopping energy loss gets stronger every year, not weaker.
• Standard commercial units draw roughly the same power as a single parking lot light bulb, and they only run when the door switch is triggered, not continuously. That’s a small power draw for a meaningful reduction in energy loss.
• Mars Air offers an ROI calculator on its site for contractors and building owners who want to model the specific savings for their location and door traffic.

Core Insight #2: Air Curtains Solve More Problems Than Temperature Control

The second major benefit, and the one most people don’t associate with air curtains at all, is pest and contamination control.

Real example from the episode: Rosol described a conversation with a restaurant owner who was visibly frustrated watching a delivery driver prop open the door to a cold storage room for an extended period while unloading. That propped-open door doesn’t just waste energy, it also causes coils to freeze, eventually leading to ice buildup that requires a service call to thaw and diagnose. An air curtain installed at that opening acts as a barrier that keeps the cold air in without requiring the door to stay closed.

Additional applications covered in the conversation:

• Flying insect control: the original use case for air curtains, sometimes still referred to informally as “fly fans.” The moving air stream intercepts flying insects at the doorway and pushes them back out rather than letting them ride the airflow into the building.
• Cold storage protection: an alternative to plastic strip curtains, which get dirty, get cut or torn by staff for visibility, and don’t hold up as well over time.
• Contamination and air quality control: some units integrate UV bulbs or HEPA filtration to help block dust, dirt, pathogens, and even wildfire smoke from entering a building through door openings.
• Safety: in industrial settings, condensation and ice buildup near open cold-storage doors has caused forklifts to lose traction, making the air curtain a safety investment as much as an efficiency one.
• Residential and light commercial use: less common but growing, particularly in higher-end backyard patio or pergola installations where owners want an open-air feel without inviting insects or losing climate control between indoor and outdoor spaces.

Core Insight #3: A Practical Playbook for Adding Air Curtains as a Service Offering

For contractors who do any light commercial work, Rosol laid out why this is an accessible add-on rather than a specialized, high-barrier product line.

1. Installation is simpler than most contractors assume. For the most common application, a unit mounted above a standard man door, installation is typically a back plate screwed into the wall above the doorway, with the unit clipping onto it. A door switch, if used, mounts to the door frame the same way. Rosol noted the first installation might take a couple of hours, but it becomes a fast, repeatable process after just one or two jobs.
2. Lead with the ROI conversation, not the technology. Rosol’s own 60-second pitch focuses on keeping “the bad stuff out and the good stuff in” using a controlled stream of air, then ties it directly to rising building costs and energy prices rather than technical specifications.
3. Identify the right buildings. High-traffic commercial entries, cold storage rooms, and loading areas where doors are frequently propped open are the clearest opportunities. Parking garages and similar spaces without a practical door option are also common applications, often running the unit continuously.
4. Know the purchasing path. Units are typically sold through local distributors or manufacturer reps rather than direct online purchase, so contractors interested in adding this to their offerings should expect to work through a regional contact.
5. Use manufacturer training resources. Mars Air runs recurring webinars covering a range of air curtain topics for contractors and customers who want a deeper understanding of applications and installation before pitching the product.

Conclusion

Air curtains are one of those categories that most contractors walk past daily without recognizing the business opportunity in front of them. The pitch is straightforward: low power draw, meaningful energy savings, added protection against insects and contamination, and an installation process that’s approachable even for contractors without prior commercial experience.

For any home service business already doing light commercial work, this is a low-cost, low-complexity way to add a genuinely useful line item to a proposal, one that solves a cost problem building owners already feel, even if they’ve never had a name for it.

FAQs

What is an air curtain? An air curtain is a device that creates a controlled, continuous stream of air across a doorway to separate two environments, helping maintain indoor temperature, block flying insects, and reduce contaminants entering a building.

Do air curtains actually save money on energy bills? Yes. By reducing the loss of conditioned air through frequently opened doors, air curtains lower the energy needed to maintain indoor temperature, with savings compounding further as electricity costs rise.

Can air curtains replace a door completely? Not entirely. Even a well-functioning air curtain is typically around 70 to 80 percent effective, compared to roughly 98 percent effectiveness for a closed door. However, many businesses use them in place of a door in high-traffic areas or spaces like parking garages where a true door isn’t practical.

Are air curtains hard to install? No. For standard applications above a man door, installation generally involves mounting a back plate and clipping the unit into place, along with a door switch if used. Most installers become efficient after their first one or two jobs.

Do air curtains stop insects and pests? Air curtains are effective against flying insects, using airflow to intercept and push them back outside. They are not rated for crawling insects or birds.

Can air curtains be used in residential settings? Yes, though it’s less common than commercial use. Residential applications are typically seen in higher-end installations, such as open kitchen-to-patio spaces or pergola setups, where homeowners want airflow and insect control without a physical door.