When the Dining Room Overheats at Dinner
Of all the commercial rooftop units we install in Toronto, the 5-ton size is the most common over small restaurants and offices. The typical complaint sounds familiar: the dining room is comfortable at lunch and hits 28C by Friday dinner service, or a small office cannot hold setpoint on a hot afternoon.
A 5-ton RTU delivers about 60,000 BTU of cooling. Whether that is enough depends on more than floor area, especially in restaurants.
Restaurant Load and Make-Up Air Interaction
Restaurants have two loads offices do not: the kitchen heat load from cooking equipment, and the make-up air interaction between the RTU and the make-up air unit (MUA) that replaces air pulled out by the hood.
- If the MUA is off or undersized, the building goes negative. Doors get heavy, hoods backdraft, and hot outdoor air leaks in for the RTU to fight.
- If the MUA supplies untempered air in summer, the RTU has to cool that air too.
- Grease from the exhaust coats nearby condenser coils, cutting capacity.
That is why we size restaurant RTUs with the kitchen and MUA in the calculation, and why we often service both units together. See make-up air unit service.
Fit by Use
| Use | Why 5 tons often fits | Watch for |
|---|---|---|
| Small restaurant or cafe | Dining room + kitchen spillover | Hood exhaust, MUA balance |
| Small office | Several thousand sq ft, typical occupancy | Glazing, server closet |
| Retail with high traffic | Door openings, lighting | West-facing windows |
If the load is lighter, a 3-ton unit may fit. If it is heavier, see 10-ton rooftop units.
How Much Does a 5-Ton RTU Cost?
3-5 ton units run $9,500-$16K installed in 3-5 business days, including crane, curb check, connections and commissioning. Common models include the Carrier 50TC and 5-ton units from Lennox, York, Trane and Daikin. An economizer is worth adding for offices; restaurants benefit less because of kitchen loads.
Repair First, When It Makes Sense
Not every hot dining room needs a new unit. Our Liberty Village restaurant had a dead RTU and backdrafting hoods in July. A failed fan motor, a grease-coated coil and an MUA burner problem were fixed on one visit for $1,840. Restaurants get priority on our emergency service. We cover restaurant strips in Liberty Village, Etobicoke and across the GTA.
