Delta Air Systems Ltd.
“From the initial call, to arrival confirmation and the work that the techs did, the entire process was smooth and left us with a working AC!”
Best HVAC Contractors in Waterloo, ON
20 companies listed · all 20 in Waterloo · 5 open 24/7 · 11 open weekends · 17 rated 4.5+
Data verified October 21, 2026
Bast Home Comfort
“We own a rental that has had some issues with the furnace and a/c and Scott and the team at Bast have been so friendly and helpful.”
Afterglow Hvac
“They worked with me to figure out alternatives, how to work with the existing furnace fan to cool the place.”
Koebel Heating
“They give you the facts, not what you want to hear, recognizing it is about a long term relationship and not just an immediate sales.”
Cross Heating & Air Conditioning Ltd.
“They were punctual, respectful, accommodating and worked diligently for the entire day to ensure the job was properly completed and that the equipment was properly tested before they left.”
TRH Plumbing & Heating Inc
“I would definitely recommend over and over again to anyone needing a professional, courteous and prompt professional plumbing service for any job big or small!”
The 20 companies listed for Waterloo, ON handle furnaces and heat pumps in winter and the cooling side in summer. Profiles repeat what each firm publishes about hours, licensing and brands, with ratings and review quotes gathered from public reviews.
Area overview: Waterloo, ON
All 20 companies we list here are in Waterloo itself. The companies on this page are rated from 3.7 to 5.0 across 1,190 reviews; 5 have 50 or more reviews and 17 are rated 4.5 or higher. When customers rate these companies on specific qualities, they most often praise professionalism (95%), responsiveness (90%) and punctuality (82%). The topics that come up most in reviews of the companies on this page are "price", "efficient" and "cleanliness". 5 are open around the clock; 11 are open on Saturdays and 9 on Sundays. 3 show a licence on their websites. Domain records put 8 websites of the companies on this page at ten or more years old; the oldest dates from 1997. 6 offer emergency call-outs; 5 offer financing or payment plans; 4 give free estimates; 2 are family- or locally-owned and 4 list coupons or special offers. We have a website on file for 19 of the companies on this page; 16 publish a contact page; 13 list a public email and 1 takes bookings online. We count these figures across the companies on this page; hours and prices change, so confirm the details with the company before you book.
Do any heating firms listed for Waterloo work on Saturdays or Sundays?
Saturday or Sunday hours show up for 11 of the 20 companies on this page. Saturday is mostly repair work; installations land on weekdays, because supply houses and municipal inspectors keep weekday hours.
All Year Heating and Cooling Inc.
“From the initial consultation to the final installation, their team was professional, knowledgeable, and courteous.”
Cronin Verheul Heating & Air Conditioning Ltd
“We were able to have our furnace replaced on very short notice.”
Markle Heating & Cooling Inc
“They almost had my issue fixed before I even realized the service truck was in my driveway.”
SM Mechanical
“Scott MacDonald owner of SM Mechanical came to my rescue when our air conditioner didn't work at our office.”
ATN Mechanical Systems
“Genuine, honest, not looking to rip you off like the big HVAC service techs out there.”
Gastech Heating and Cooling
“Showed up very quickly, diagnosed the problem right away and fixed my ac immediately.”
Eastbridge Heating & Cooling
“Right from the start, they showed an impressive level of knowledge and expertise, offering valuable insights and personalized recommendations that perfectly suited my needs.”
K-W Fireplace Installations and Home Comfort
“We had KW Fireplace install our gas fireplace and we're very happy with their service!”
AAA Air Conditioning Inc.
VIP Energy Services Inc
Reitzel Heating & Air Conditioning
“They were efficient, friendly and today I picked up my new filter which a service person had exchanged as well as new insulation as both had been wet.”
Carter-Grant Mechanical
“Carter Grant has always provided us with great service, please keep up the great work!”
Elite Air Duct Inc
“We have been using Jim and Graham's services for decades to service our commercial properties.”
Jade Logic Building Technologies
“Everyone in the company goes above and beyond when it comes to service calls or preventive maintenance.”
Why these companies made our list
What customers say about companies in Waterloo
- “Excellent experience from start to finish. Installation of new heat pump was professionally done with a high attention to detail.” — customer of Cross Heating & Air Conditioning Ltd.
- “Loving our heat pump so much! Super professional, very knowledgeable, didn’t sell us on things we didn’t need.” — customer of Afterglow Hvac
- “We would highly recommend Delta and had a pleasant experience working with each of the team members.” — customer of Delta Air Systems Ltd.
- “We had a pleasant experience with everyone we dealt with, and we'd recommend Cross to anyone.” — customer of Cross Heating & Air Conditioning Ltd.
- “They were respectful of our home by using mats to walk on and always left things clean and tidy before leaving each day.” — customer of Delta Air Systems Ltd.
Excerpts from public reviews of the companies listed on this page.
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