Since 1976, MST has been a family business specializing in air conditioning and heating.

Who are we?

Based in Chateauguay, on the south shore of Montreal, MST is a reference and a leader in air conditioning and heating. Our goal is to redefine comfort at home.

A team of dedicated and professional experts

Our business philosophy is based on unparalleled service and continuous training for our employees to offer better support to our customers. In addition to possessing the required certifications in their trade, our technicians will take the time to advise and inform you about your new appliance, air conditioning, heating or ventilation system. Their advice will help you get the maximum benefit from your appliance and prolong its lifespan.

Thanks to our exceptional team, you are in good hands and benefit from professional support before, during and after your purchase. Peace of mind guaranteed!

Alexandre Tessier

President and Founder

Nathalie Blais

Customer Service Director

Myriam Champagne-Bolduc

Financial Controller

Nelson Palencia

Operations Manager

A family story

After having worked for more than 8 years as a refrigeration mechanic, Alexandre Tessier founded Entreprises MST in 2006 with his father, Jean-François Tessier, who at that time, already had 10 years experience in the field of ventilation and its maintenance.

The following year, with increased demand for their expertise, their unparalleled customer service, and the high quality products they offered, the small team grew.

In 2016, Entreprises MST expanded with the acquisition of G.P.Martel inc., which had been in business for over 40 years (2019 Service RG). This allowed them to improve their expertise and skills in electricity and other trades and to offer a centrally located showroom to their customers.

Today, MST has 30 employees forming several service teams, all highly motivated thanks to our stimulating work environment.

MST, success based on 3 major strengths.


Our advice serves to guide you in buying the air conditioning, heating or ventilation appliance or system that you need. We will never encourage you to spend money unnecessarily.


At MST, quality goes hand-in-hand with speed: speed in advising you, installing your new appliance or system, ensuring it functions properly, maintenance and repair as needed. We offer you the best products on the market and exemplary service.


Reassuring you, answering your questions and supporting you before, during and after your purchase. That’s how we thank you for your business.


Our customers are talking about us

Very professional.

“The service was very professional. After the installation, the place was spotless. The technicians were friendly and respectful. We love our appliance. It is high-performance and quiet.”

Jocelyne Blais

Excellent service.

“I had two heat pumps installed in my home, and I received excellent service. They did it quickly, and everything was clean. The technicians were very kind and professional.”

Michel Brisson

Our partners

Snap - Home Finance
Serenity Steffes