Long Island's commercial facilities demand reliable, high-performance rooftop units year-round—from humid summers to harsh winter freezes. Denair HVAC's factory-trained technicians specialize in AAON RTU service, maintenance, and emergency support, keeping your systems running at peak efficiency. With same-day response and customized maintenance contracts, we minimize downtime and protect your HVAC investment.
Comprehensive AAON RTU solutions for Long Island commercial facilities, from routine maintenance to emergency repairs and system upgrades.
Proactive, scheduled maintenance plans tailored to your AAON RTU system. Reduces energy costs, prevents unexpected breakdowns, and extends equipment lifespan with customized annual contracts and free maintenance for up to 18 months on new installations.
Round-the-clock emergency response for AAON RTU failures. Factory-trained technicians arrive fully equipped, typically within 4 hours, to diagnose and restore your system with minimal operational disruption—any season, any time.
Modernize aging AAON RTU equipment with targeted retrofits, expert tune-ups, and mission-critical system enhancements. Optimize performance and energy efficiency without the cost of full system replacement.
Comprehensive service and repair for all AAON RTU components, from controls and refrigerant systems to coils and filters. Licensed technicians deliver lasting fixes backed by quality guarantees and up to 10-year warranties.
Integrate smart controls and automation with your AAON RTU to significantly reduce energy consumption and operating costs. Custom solutions designed for Long Island commercial buildings seeking measurable efficiency gains.
Certified air testing and balancing services to confirm your AAON RTU is operating at peak performance. Includes comprehensive reports ensuring proper airflow, temperature control, and system compliance after any service or installation.
Contact our Long Island service team to book a convenient appointment. We work around your facility's schedule, offering flexible weekday availability and 24/7 emergency dispatch for urgent AAON RTU issues that cannot wait.
See how Long Island and New York Metro facilities trust Denair HVAC to keep their AAON systems running flawlessly.
"I am very pleased with the service and professionalism we receive from all the techs and staff at Denair."
"Really great to work with, awesome staff, happy to work with them anytime again in the future! Highly recommend."
"They have the best Engineering Service I have ever seen; they are always available on request and perform the maintenance in the most efficient way. Great Service."
"Great company, our office was getting hotter by the minute. Denair had a tech on site with in the hour and the ac working perfect in two hours"
"I was able to upgrade my cooling towers through the help of Denair and I did love their Service rendered, Wonderful Experience."
"What a great service. I randomly called to get multiple system inspected in my building. They came on time, done a great job and provided a detailed report. I love their transparency."
"Dennis was always available when I called on him. Never was any additional work generated on any quote/contract awarded. Reliable, expert and a pleasure to work with. A real value!"
"Crew was respectful, fast, and left our place spotless. Five stars."
"excellent work and quality"
"Impeccable install. You can tell they're pros the moment they walk in."
"Denair is the most dependable HVAC service company in New York!"
"I didn't even know about their referral program sending DENAIR to one of my commercial tenants. It was a nice surprise to get paid for referral. Based on the tenant's feedback, the job was well-done. Now it's no brainer to recommend DENAIR to all my tenants"
"I recently used Denair for some repairs to my small two-story office building, and I have to say they are the most honest, hard-working and value focused HVAC provider I have ever experienced! Not only was the price competitive, but more importantly they helped reduce my energy costs from an..."
"These guys are the best. Installed my central air condition. They are quick, thorough and honest! I definitely recommend them."
"Denair is professional and courteous."
"I am very pleased with the service and professionalism we receive from all the techs and staff at Denair."
"Really great to work with, awesome staff, happy to work with them anytime again in the future! Highly recommend."
"They have the best Engineering Service I have ever seen; they are always available on request and perform the maintenance in the most efficient way. Great Service."
"Great company, our office was getting hotter by the minute. Denair had a tech on site with in the hour and the ac working perfect in two hours"
"I was able to upgrade my cooling towers through the help of Denair and I did love their Service rendered, Wonderful Experience."
"What a great service. I randomly called to get multiple system inspected in my building. They came on time, done a great job and provided a detailed report. I love their transparency."
"Dennis was always available when I called on him. Never was any additional work generated on any quote/contract awarded. Reliable, expert and a pleasure to work with. A real value!"
"Crew was respectful, fast, and left our place spotless. Five stars."
"excellent work and quality"
"Impeccable install. You can tell they're pros the moment they walk in."
"Denair is the most dependable HVAC service company in New York!"
"I didn't even know about their referral program sending DENAIR to one of my commercial tenants. It was a nice surprise to get paid for referral. Based on the tenant's feedback, the job was well-done. Now it's no brainer to recommend DENAIR to all my tenants"
"I recently used Denair for some repairs to my small two-story office building, and I have to say they are the most honest, hard-working and value focused HVAC provider I have ever experienced! Not only was the price competitive, but more importantly they helped reduce my energy costs from an..."
"These guys are the best. Installed my central air condition. They are quick, thorough and honest! I definitely recommend them."
"Denair is professional and courteous."
"I am very pleased with the service and professionalism we receive from all the techs and staff at Denair."
"Really great to work with, awesome staff, happy to work with them anytime again in the future! Highly recommend."
"They have the best Engineering Service I have ever seen; they are always available on request and perform the maintenance in the most efficient way. Great Service."
"Great company, our office was getting hotter by the minute. Denair had a tech on site with in the hour and the ac working perfect in two hours"
"I was able to upgrade my cooling towers through the help of Denair and I did love their Service rendered, Wonderful Experience."
"What a great service. I randomly called to get multiple system inspected in my building. They came on time, done a great job and provided a detailed report. I love their transparency."
"Dennis was always available when I called on him. Never was any additional work generated on any quote/contract awarded. Reliable, expert and a pleasure to work with. A real value!"
"Crew was respectful, fast, and left our place spotless. Five stars."
"excellent work and quality"
"Impeccable install. You can tell they're pros the moment they walk in."
"Denair is the most dependable HVAC service company in New York!"
"I didn't even know about their referral program sending DENAIR to one of my commercial tenants. It was a nice surprise to get paid for referral. Based on the tenant's feedback, the job was well-done. Now it's no brainer to recommend DENAIR to all my tenants"
"I recently used Denair for some repairs to my small two-story office building, and I have to say they are the most honest, hard-working and value focused HVAC provider I have ever experienced! Not only was the price competitive, but more importantly they helped reduce my energy costs from an..."
"These guys are the best. Installed my central air condition. They are quick, thorough and honest! I definitely recommend them."
"Denair is professional and courteous."
Denair HVAC brings nearly two decades of certified expertise and a proven track record to every AAON RTU service call across Long Island.
Our technicians are trained and certified by AAON and other major manufacturers, ensuring every RTU is serviced to factory standards—no guesswork, no shortcuts.
With 24/7 emergency availability and typical response times within 4 hours, Long Island facilities never face extended downtime waiting for a qualified AAON service team.
Every proposal comes with fixed pricing and a quality guarantee—if our service doesn't meet code requirements, we refund your money. No surprise invoices, ever.
Since 2007, Denair HVAC has served commercial facilities across the New York Metro Area including Nassau and Long Island, building a reputation on honesty and reliability.
Experienced professionals dedicated to keeping your AAON RTU systems running perfectly.
Founder & CEO
Dennis founded Denair HVAC in March 2007 with nothing more than a beat-up used truck and a deep expertise in the HVAC industry built over years of hands-on service work. Over the following 19 years, he grew the company from a one-man operation into a recognized Inc. 5000 fastest-growing business generating over $2 million in annual revenue. His strategic vision has shaped Denair into the New York Metro Area's go-to commercial HVAC contractor. For AAON RTU clients across Long Island, Dennis's leadership means a service company that understands mission-critical uptime, manufacturer standards, and the accountability that facility managers depend on every day.
Service Manager
Thomas leads Denair HVAC's service operations with a sharp focus on fast response times, efficient technician scheduling, and consistent service quality across every job site. For AAON RTU clients in Long Island, Thomas is the operational backbone ensuring that when a service call comes in—routine or emergency—the right certified technician is dispatched promptly with the right equipment. He coordinates all customer communication and technician workflows to minimize system downtime, reduce disruption to your facility's operations, and deliver a smooth, professional service experience from the initial call through to final sign-off and documentation.
Application Engineer
Ramil brings deep technical expertise in HVAC system design and application engineering, specializing in tailoring solutions to each building's unique performance and efficiency requirements. For Long Island facilities running AAON RTU systems, Ramil provides critical support at the technical planning stage—selecting the right equipment configurations, ensuring energy-efficient operation, and confirming code-compliant installations and upgrades. He oversees the technical aspects of every AAON service engagement, from diagnostic assessments and parts selection to system modifications that extend equipment lifespan, reduce utility costs, and keep facilities operating reliably through New York's demanding seasonal extremes.
AAON RTU systems are premium commercial units, typically ranging from $15,000 to $80,000+ depending on capacity, configuration, and options. Smaller packaged units (3–10 tons) fall on the lower end, while large custom rooftop units (25–100 tons) command higher prices. Installation, controls integration, and startup costs are additional. Contact Denair HVAC for a detailed quote tailored to your Long Island facility's specific requirements.
Speak with our Long Island AAON specialists for expert guidance and a free service consultation.
Denair HVAC provides certified AAON RTU service and support across Long Island and the entire New York Metro Area.
11+ Regions
Service Area
Within 4 Hours
Emergency Response
400+ Projects
Projects Completed
Contact us to confirm coverage and schedule your AAON RTU service appointment today.
Named one of America's fastest-growing companies by Inc. Magazine.
All technicians hold OSHA 40-hour safety certification for commercial job sites.
Fully licensed and registered HVAC mechanical contractor in New York State.
Fill out the form below and a Denair HVAC specialist will respond promptly to schedule your AAON RTU service, request a maintenance contract proposal, or dispatch emergency support to your Long Island facility.
For immediate assistance, feel free to give us a direct call at 718-791-5074 You can also send us a quick email at
For immediate assistance, feel free to give us a direct call at 718-791-5074 You can also send us a quick email at