"We Have worked with McCallum HVAC Design Inc on a wide range of custom residential projects over many years. Their team consistently provides thorough, well-coordinated HVAC designs and is responsive throughout both the design and permit processes.
We value their technical expertise, attention to detail, and ability to work collaboratively with our team and clients. Their reliable service has made them a trusted consultant on many of our projects."

"We've worked with McCallum HVAC Design Services on a wide range of projects over the years, and their team has consistently delivered high-quality, accurate HVAC designs that help our projects run smoothly from planning through construction.

What sets McCallum apart is their responsiveness, attention to detail, and practical understanding of real-world installation requirements. Their designs are thorough, well-coordinated, and developed with a clear understanding of both performance and constructability.

The confidence we have in working with their team comes from their professionalism, technical expertise, and consistent ability to support projects of varying size and complexity. We value our long-standing relationship with McCallum and look forward to continuing to work together on future projects."

"One of the key reasons I continue to enjoy working with McCallum HVAC Design Services is your team’s collaborative approach and ability to adapt to challenging timelines and evolving project requirements. Your team is always professional, proactive, and solution-oriented, which gives me confidence on every project we deliver together."

"Over the years we have retained McCallum HVAC Designs Inc. for HVAC designs of our custom homes and renovation projects. Doug and his team are always a pleasure to work with, knowledgeable and reliable. The final HVAC drawings are well presented and very organized."

"We’ve had the pleasure to work with McCallum on a number of projects, each with its own unique challenges. On all of them McCallum has always been willing to work with us collaboratively to find solutions that not only perform well, but stay true to our original design intent."

"McCallum HVAC have become our go-to solution for thoughtful, professional and responsive heating system design services. We’ve worked with many providers of these services over the years and struggled with poor quality work, slow turnaround, sloppy drafting, lack of knowledge and indifference to customer service. Working with McCallum’s team, we have none of these issues. Real pros, great communicators, and good people. We highly recommend them!"

"We have worked with McCallum HVAC Design Inc. since 2006 and during this time they have looked after all our HVAC design and consulting needs. As our building code changes along with the technology and building practices, McCallum HVAC continues to be on top and acquainted of code updates as well as new and improved equipment and systems. We rely on McCallum HVAC for our Heat Loss and Duct Design for both permit submittal and on site installation. Their staff and organization always make for an efficient and great turnaround."

"I have used Doug McCallum services for over 8 years and he is by far my first pick for planning and designing heat loss/heat gain and duct design drawings for all my projects. As an architectural home designer, I require good consultants that are professional, well informed in their trade as well as able to meet my deadlines and Doug has constantly met all my expectations. Doug has an amazing team that has the capabilities to work on a small residential project such as small renovation, additions, and minor interior alteration but he can also accommodate larger project such as sub-divisions and large custom house. I recommend McCallum HVAC Design to all my clients and anybody who require HVAC drawings."

"We are very pleased to provide a letter of recommendation for McCallum HVAC. We have worked with McCallum HVAC for over 7 years on projects of all sizes, from small addition/renovations to custom estate homes and commercial projects. Doug and his team are very professional and highly knowledgeable. They provide cost effective options for our clients and exceptional service in a timely manner. They are always very friendly and a pleasure to work with. We highly recommend them to anyone who is looking for HVAC design services and would be more than happy to discuss further. We can be reached at 905-825-0433."

"Tropical Heating & Air conditioning has had the great pleasure of working with Doug and his experienced team for over a decade now. Their HVAC, floor warming and snowmelt designs have been an important part of our Custom Home’s department. Their knowledge and experience has proven to be of great value. We look forward to working with Doug‘s team in this continuously evolving industry."

"We’ve had a great time working with McCallum on various projects, each presenting its own set of challenges. They’ve always been a pleasure to work with, happily adapting as needed to keep up with changing design needs and consistently delivering smart, high-performing solutions. Communication has always been excellent. We’d definitely recommend them."