24/7 Emergency Service Available (631) 862-6016

Serving Nassau & Suffolk Counties Since 1983

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Count On Us For Sales, Service & Installation of:

  • Air Conditioning Systems
  • Ductless Air Conditioning
  • Heating Systems
  • Indoor Air Quality Products
  • Gas & Electric Water Heaters
  • Humidifiers
  • Ventilation
  • Thermostats

Quality Workmanship
at Affordable Prices!

Residential & Commercial

A/C & Heating Experts in Saint James, NY

DML & S Air Conditioning & Heating is a family owned and operated company established in 1983. We offer quality workmanship at affordable prices to our neighbors throughout Nassau and Suffolk counties, including Setauket, Miller Place, and Mount Sinai NY. We take pride in our work and go above and beyond to make sure our work is top notch. We use only top brand names that strive for innovation and excellence as we do. DML&S technicians are very professional, clean, and courteous. We are always honest and enjoy building a relationship with every one of our customers. We have many satisfied customers who have been using us for 30 years and we look forward to working with you!

Professional Affiliations


Air Conditioning Contractors Of America (ACCA)
ACCA is the largest association of HVACR contractors and the preferred service provider for members in all 50 states and worldwide.


Refrigeration Service Engineers Society (RSES)
Since 1933, Refrigeration Service Engineers Society (RSES) has been a leader in training and education for professional HVACR technicians and contractors.


Mitsubishi Electric Diamond Contractor
A Diamond Contractor has reached the highest level of accreditation from Mitsubishi Electric Cooling & Heating. Factory trained in the Mr. Slim product, they have hands-on expertise in sales, installation and service at one of Mitsubishi Electric's approved training centers.  When you work with a Diamond Contractor, you can be sure that you're getting the most professional, sure-handed installation and maintenance available.


York Liberties Dealer

As a York Liberties Dealer, DML & S offers a full spectrum of innovative residential and light-commercial products backed by excellent extended warranties and flexible financing options.


PSEGLI Cool Homes Contractor
A quality installation performed by a Cool Homes contractor will save you hundreds of dollars, provide maximum comfort, and qualify you for up to $1,400 in PSEGLI rebates. DML & S Air Conditioning & Heating is proud to be a participating Cool Homes Contractor.

Licensed & Insured

EPA Certified Technicians