Long Island's weather swings—from humid summers to bitter winters—demand a reliable HVAC partner you can count on year-round. Denair HVAC brings over 19 years of expertise in heating, cooling, and emergency repairs across Nassau and surrounding areas. Licensed technicians, free estimates, and same-day service mean your home or business is never left uncomfortable.
Comprehensive heating, cooling, and ventilation solutions for Long Island homes and businesses—handled by certified technicians.
Expert repair and maintenance for all residential air conditioning and heating equipment. Licensed technicians service, maintain, install, and repair AC units, furnaces, water heaters, and ductwork to keep your system running optimally.
Round-the-clock emergency HVAC repairs with same-day response—usually within 4 hours. Certified technicians arrive fully equipped to diagnose and fix issues on all major brands from 1/2 to 100 tons of cooling capacity.
Proactive maintenance plans designed to extend system lifespan, reduce energy costs, and prevent surprise breakdowns. Free preventive maintenance for up to 18 months on all new installations, with annual contracts available.
Turnkey commercial and residential HVAC installation with end-to-end project management. Includes equipment, ductwork, piping, and controls—delivering projects on time, within budget, and saving clients up to 35% through value engineering.
Modernize outdated equipment with targeted retrofits and expert system tune-ups. Optimize performance, enhance comfort, and meet current energy standards without requiring a full system replacement.
Smart HVAC controls and automation solutions that significantly reduce energy costs and environmental impact—ideal for Long Island property owners seeking lower utility bills and greener operations.
Long Island's hot, humid summers and cold winters put serious demands on heating and cooling systems. Denair HVAC's licensed technicians bring over 19 years of hands-on experience servicing all makes and models across Nassau and the broader New York Metro Area. From emergency repairs completed within 4 hours to comprehensive preventive maintenance plans, we deliver upfront pricing, free estimates, and a quality guarantee—so your comfort is never compromised, no matter the season.
See how Long Island homeowners and businesses have benefited from Denair HVAC's expert service and repairs.
"Great reliable HVAC company, a very rare thing to say these days — the pricing is very competitive and the work is reliable. The staff is professional and courteous, they clean up after themselves and always answer. I would recommend them!"
"Impeccable install. You can tell they're pros the moment they walk in."
"Really great to work with, awesome staff, happy to work with them anytime again in the future! Highly recommend."
"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."
"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"
"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!"
"I am very pleased with the service and professionalism we receive from all the techs and staff at Denair."
"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..."
"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."
"Amazing HVAC vendor who is doing multiple accounts for my company."
"These guys are the best. Installed my central air condition. They are quick, thorough and honest! I definitely recommend them."
"Crew was respectful, fast, and left our place spotless. Five stars."
"excellent work and quality"
"Denair is the most dependable HVAC service company in New York!"
"Great reliable HVAC company, a very rare thing to say these days — the pricing is very competitive and the work is reliable. The staff is professional and courteous, they clean up after themselves and always answer. I would recommend them!"
"Impeccable install. You can tell they're pros the moment they walk in."
"Really great to work with, awesome staff, happy to work with them anytime again in the future! Highly recommend."
"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."
"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"
"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!"
"I am very pleased with the service and professionalism we receive from all the techs and staff at Denair."
"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..."
"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."
"Amazing HVAC vendor who is doing multiple accounts for my company."
"These guys are the best. Installed my central air condition. They are quick, thorough and honest! I definitely recommend them."
"Crew was respectful, fast, and left our place spotless. Five stars."
"excellent work and quality"
"Denair is the most dependable HVAC service company in New York!"
"Great reliable HVAC company, a very rare thing to say these days — the pricing is very competitive and the work is reliable. The staff is professional and courteous, they clean up after themselves and always answer. I would recommend them!"
"Impeccable install. You can tell they're pros the moment they walk in."
"Really great to work with, awesome staff, happy to work with them anytime again in the future! Highly recommend."
"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."
"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"
"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!"
"I am very pleased with the service and professionalism we receive from all the techs and staff at Denair."
"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..."
"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."
"Amazing HVAC vendor who is doing multiple accounts for my company."
"These guys are the best. Installed my central air condition. They are quick, thorough and honest! I definitely recommend them."
"Crew was respectful, fast, and left our place spotless. Five stars."
"excellent work and quality"
"Denair is the most dependable HVAC service company in New York!"
From Nassau to Brooklyn, here's what sets Denair HVAC apart from the competition on Long Island.
Our technicians respond to Long Island service calls usually within 4 hours, any day of the year.
OSHA-certified, manufacturer-trained technicians who meet New York's stringent HVAC licensing standards.
Free estimates with fixed proposal pricing—all unintended costs are absorbed at our expense, never yours.
Serving Nassau, Queens, Brooklyn, and greater Long Island with a dedicated team of 28 experienced professionals.
Experienced professionals dedicated to keeping Long Island comfortable year-round.
Founder & CEO
Dennis founded Denair HVAC in March 2007 with one man and a beat-up used truck right after being laid off from a 7-year career in the HVAC industry. Armed with over 17 years of hands-on HVAC expertise and deep knowledge of Brooklyn and NYC's commercial building landscape, he grew the company to $2 million in revenue within just five years. Under his strategic leadership, Denair earned recognition by Inc. 5000 as one of America's fastest-growing companies. Dennis oversees all aspects of the business—from rooftop unit replacement projects across Brooklyn's flat-roof commercial buildings to large-scale capital improvement contracts throughout the NYC metro area—ensuring every client receives honest, high-quality service.
Financial Manager
Tanya brings over 15 years of experience in finance, budgeting, and forecasting to the Denair HVAC team. She manages all aspects of accounting, financial planning, and insurance for the company—ensuring every rooftop unit replacement and installation project is backed by financial integrity and transparent cost management. Her meticulous approach to budgeting directly supports Denair's ability to offer fixed proposal pricing and value-engineered solutions that consistently save Brooklyn and NYC clients thousands of dollars. Tanya's financial stewardship has been a cornerstone of Denair's steady growth from a one-man operation to a recognized industry leader.
Lead Estimator
Farrukh has been with Denair HVAC since 2010, making him one of the company's longest-serving and most trusted team members. As Lead Estimator, he is responsible for preparing comprehensive and timely bid proposals for rooftop unit replacement and installation projects across Brooklyn and the wider NYC metro area. His expertise in tracking opportunities with vendors, subcontractors, and customers ensures every scope is accurately priced—with alternates and revisions provided for each bid. Farrukh's value engineering approach has helped Brooklyn property managers and business owners save significantly on their HVAC capital improvement budgets.
Service Manager
Thomas leads Denair HVAC's service operations, overseeing fast response times, efficient technician scheduling, and consistent service quality for rooftop unit projects throughout Brooklyn. He coordinates field technicians and customer communications to keep RTU systems running reliably—minimizing downtime for commercial tenants, property managers, and building operators. Thomas ensures that Denair's commitment to same-day service (usually within 4 hours for emergencies) is consistently met, and that every rooftop unit installation or repair is delivered with the smooth, professional experience Brooklyn clients expect from an Inc. 5000-recognized contractor.
Application Engineer
Ramil designs and supports HVAC systems tailored to the specific performance and efficiency needs of each Brooklyn building. Specializing in rooftop unit applications, he oversees equipment selection, technical planning, and engineering support to ensure every RTU installation delivers long-lasting reliability, meaningful energy savings, and full compliance with NYC building codes and LL97 sustainability mandates. Ramil's engineering expertise is particularly valuable for Brooklyn's dense stock of flat-roof commercial and mixed-use buildings, where precise load calculations and rooftop structural considerations are critical to a successful RTU replacement or new installation.
VP Business Development
Anastasiya leads Denair HVAC's business development and new client acquisition strategy, with a focus on building long-term partnerships with property management firms, general contractors, and building owners across Manhattan and the greater NYC metro area. In her role, she identifies market opportunities, develops strategic partnerships, and implements growth initiatives that have helped Denair expand its footprint across some of New York's most recognized property management companies—including AKAM, Douglas Elliman, Related, and Rose Associates. Anastasiya's client-first approach ensures that every new relationship is built on transparency, reliability, and measurable value.
Marketing Manager
Natalja oversees Denair HVAC's brand presence and client relationships, ensuring that building owners, property managers, and facility operators across Manhattan can easily discover and connect with the HVAC expertise they need. As Marketing Manager, she develops and executes strategies that communicate Denair's unique value—from 24/7 emergency availability to Inc. 5000 recognition—to the right audiences across New York City's competitive commercial real estate and residential markets. Her work building public relations and strategic outreach has played a significant role in Denair's growth and continued reputation as one of NYC's most trusted HVAC contractors.
A Reznor heater is a brand of commercial and industrial gas-fired unit heaters widely used in warehouses, garages, and large facilities. They are known for their durability and efficient forced-air heating output. Denair HVAC technicians are trained and certified by major manufacturers and can service, repair, or replace Reznor heating units across Long Island and the New York Metro Area.
Speak with a Long Island HVAC expert today—consultations and estimates are always free.
Denair HVAC proudly serves Long Island and the wider New York Metropolitan Area with fast, reliable HVAC service.
11+ Regions
Service Area
24/7 On Call
Emergency Availability
4.7★ Rated
Customer Rating
Contact us to confirm coverage in your area and get a free same-day estimate.
Named one of America's fastest-growing companies.
All technicians hold OSHA safety certification.
New York State licensed mechanical contractor.
Fill out the form below and a Denair HVAC specialist will reach out promptly to schedule your free estimate or same-day service call. No obligations, no hidden fees—just expert HVAC help when you need it most.
For immediate assistance, feel free to give us a direct call at 718-791-5074.
For immediate assistance, feel free to give us a direct call at 718-791-5074.