COMMERCIAL ROOFTOP HVAC

Yes, you usually need a permit to install rooftop HVAC units. This confirms everything meets Calgary’s safety and building codes so your system is installed properly and legally. This permit falls under the same mechanical permit as residential installs.

At One Stop HVAC, we handle the permits and paperwork so you don’t have to worry about what satisfies Calgary’s building regulations.

Most commercial buildings can have rooftop HVAC units installed. However, we always start with a thorough assessment of your building and rooftop to recommend the best, most efficient solution for your unique needs.

In general, you’ll want about 3 to 6 feet of open space around the unit. This gives it enough room to “breathe” properly and makes it easier (and safer) for us to do any maintenance or repairs down the line. Every building’s a little different, though, so when we come out for a site visit, we’ll take a good look at your setup and make sure everything’s spaced out just right and up to code.

Most installations take anywhere from a few days to a couple of weeks, depending on the size of the system and the complexity of the job. A straightforward replacement might only take 2 to 5 days, while larger projects that involve ductwork changes or crane lifts can take a bit longer.

Since we offer service 7 days a week, we’ll work around your schedule to minimize disruptions and keep your business running smoothly. After a site visit, we’ll provide a clear timeline so you know exactly what to expect.

Yes, RTUs can be installed during winter in Calgary (and we always do our best to accommodate you), but timing matters. We install year-round, even in cold weather, as long as conditions are safe.

That said, extreme cold, heavy snow, or high winds can cause delays. Spring and fall are ideal, but if an RTU fails in winter, waiting isn’t always an option. We plan winter installs carefully to minimize downtime and weather-related risks.

This comes down to proper setup and maintenance. We focus on:

• Correct airflow and damper operation
• Proper insulation and sealing
• Functional drain pans and heat trace where needed
• Low-ambient controls designed for cold climates

Ice buildup is usually a sign that something isn’t balanced properly, not just “because it’s cold.”

In Calgary, we commonly see:

• Failed heat exchangers
• Frozen or cracked drain pans
• Control board and sensor issues
• Burners and ignition problems
• Belt and motor wear from temperature extremes

Our climate is tough on equipment, especially without regular maintenance.

Big time. Calgary’s dry summers, wind, and construction dust clog filters and coat coils faster than people expect. Dirty coils reduce airflow and efficiency, which leads to higher heating costs in winter. We often recommend more frequent filter changes during summer and early fall to protect the unit long-term!

High heating bills usually come from a combination of:

• Older or inefficient RTUs
• Poor maintenance
• Air leaks or building heat loss
• Controls not optimized for Calgary’s climate

A well-maintained RTU shouldn’t struggle as much, even in cold weather.

With regular maintenance and proper care, a commercial rooftop HVAC unit typically lasts between 15 and 20 years, giving you long-term comfort and reliable performance.

We offer a 10-year limited product warranty on trusted brands so you can enjoy a great commercial HVAC unit for as long as possible.

Less disruptive than most people expect. We plan replacements to minimize downtime, often after hours or on weekends. Most swaps are completed in a single day, with heating restored quickly. Communication and planning make a big difference.

It depends on budget and unit condition. Replacing all at once can reduce labour costs and improve consistency, but phasing replacements can spread out costs.

We usually assess each unit and help owners prioritize based on age, efficiency, and risk of failure.

Winter rooftop work requires extra care:

• Fall protection and ice management
• Safe roof access and snow clearing
• Monitoring wind conditions
• Proper cold-weather PPE (Personal Protective Equipment) for technicians

Safety always comes first for our techs and your building!

First, call for service right away – don’t wait. Then:

• Check if other units can temporarily compensate
• Reduce unnecessary ventilation
• Protect plumbing from freezing if heat is lost

We treat winter RTU failures as priority calls because comfort and building safety are at risk.

We recommend keeping:

• Installation and warranty records
• Maintenance and inspection logs
• Repair history
• Gas and electrical inspection reports

Good records help with troubleshooting, budgeting, resale, and insurance claims.