Restaurants call us about HVAC problems more than almost any other type of business, and the dining room thermostat is rarely the real issue. If your kitchen runs hot no matter how hard the air conditioning works, the cause is usually how the kitchen exhaust hood and commercial HVAC system interact, specifically a makeup air imbalance that no amount of extra cooling capacity will fix on its own.
Why Does a Restaurant Kitchen Get Hotter Than the Rest of the Building?
Cooking equipment generates heat, but that is only part of the problem. A Type I exhaust hood over a fryer, flat top or char broiler is designed to pull a large volume of air out of the kitchen continuously, sometimes several thousand cubic feet per minute from a single hood. Every bit of that air has to be replaced from somewhere. If the building's makeup air system is not sized to match what the hood exhausts, the kitchen pulls replacement air from the dining room, from gaps around doors, or simply runs under negative pressure and stays hot and sticky no matter how low the thermostat is set. We see this constantly in older strip retail buildouts in Carrollton and Richardson where a restaurant moved into a space that was never properly balanced for a commercial kitchen's exhaust load.
What Is Makeup Air and Why Does It Matter So Much?
Makeup air is outside air brought into the building specifically to replace what the exhaust hood removes. A correctly sized makeup air unit tempers that incoming air, so you are not just dumping raw 100-degree North Texas air straight into the kitchen in July or 35-degree air in a February cold snap. When the makeup air unit is undersized, missing a stage of heating or cooling, or simply not running because it failed and nobody noticed, the kitchen compensates by pulling air from everywhere else in the building. That is why a restaurant with a broken makeup air system often has a dining room that runs cold while the kitchen stays hot, even though both rooms are served by rooftop units that are working correctly on paper.
| Symptom | Likely cause | What we check |
|---|---|---|
| Kitchen hot, dining room fine | Makeup air undersized or down | Makeup air unit output vs. hood exhaust rate |
| Front door hard to open or whistles | Building running negative pressure | Makeup air balance, building envelope |
| Rooftop unit short cycling over the kitchen | Coil coated in grease | Condenser and evaporator coil condition |
| High humidity near the hood | Makeup air not dehumidifying incoming air | Makeup air unit's cooling and dehumidification stage |
| Rapid coil failure, more than other units on the roof | Grease-laden exhaust settling on nearby coils | Coil cleaning frequency, exhaust fan placement |
How Does Grease Buildup Make Kitchen HVAC Problems Worse?
Grease-laden exhaust does not stay contained to the hood and duct. Over time it settles on anything nearby, including the condenser coils of rooftop units mounted close to the kitchen exhaust fan. A coil coated in a thin film of grease and dust loses heat exchange capacity the same way a dirty residential coil does, except it happens faster and the unit is already working harder because of the makeup air imbalance underneath it. We have pulled coils on restaurant rooftop units that needed cleaning every quarter instead of the twice-a-year schedule that works fine for a retail store or office next door on the same roof.
How Does ERCOT Grid Stress Affect Restaurant HVAC in Summer?
A restaurant kitchen's HVAC load does not ease up during a DFW heat wave the way an office building's might. Cooking equipment keeps generating heat all afternoon, exhaust hoods keep pulling air out, and the rooftop units covering the kitchen and dining room are already running near their limit before the outdoor temperature even factors in. When ERCOT grid stress hits during a string of 100-degree days, a restaurant with marginal makeup air capacity or a dirty coil is one of the first commercial buildings to lose cooling entirely, usually during a dinner rush. We treat restaurant service calls with the same urgency as a residential emergency for exactly this reason.
What Should a Restaurant HVAC Inspection Actually Check?
A generic rooftop inspection checks filters, coils, refrigerant charge and electrical connections, and all of that still matters. A restaurant-specific inspection adds a makeup air balance check: measuring what the exhaust hood is pulling against what the makeup air unit is actually delivering, confirming the makeup air unit's heating and cooling stages both work, and checking how much grease has accumulated on any coil within range of the kitchen exhaust discharge. Skipping that balance check is how a building passes a standard rooftop inspection and still has a hot, uncomfortable kitchen every service.
Does Building Age Change What Goes Wrong?
Yes. A restaurant in an older building in Denton or a historic storefront downtown is more likely to have a makeup air system that was added or modified after the original HVAC design, sometimes more than once as the space changed tenants and kitchen layouts. Each change is a chance for the exhaust and makeup air balance to drift out of alignment without anyone catching it until the kitchen starts running hot. Newer buildouts in fast-growing retail corridors around Frisco and Plano usually start with a correctly sized system, but builder-grade equipment and tight commissioning schedules mean the balance can still be off from day one if nobody verified it against the actual hood installed.
Can a Restaurant Fix This Without Shutting Down?
Most of the diagnostic work, measuring exhaust and makeup air flow, inspecting coils, checking the makeup air unit's controls, happens on the roof and does not require closing the kitchen. Repairs that involve replacing a makeup air unit or rebalancing ductwork sometimes need a short window when the kitchen is not in full service, and we schedule that around your hours whenever possible rather than during a dinner rush. According to the EPA's guidance on indoor air quality in commercial kitchens, proper exhaust and makeup air balance is also a factor in keeping grease, smoke and combustion byproducts from building up indoors, not just a comfort issue.
What Should You Do Next?
If your kitchen runs hot no matter what the thermostat says, or the dining room and kitchen never seem to agree on temperature, the makeup air balance is the first thing worth checking before spending money on more cooling capacity you may not need. Ask about our commercial HVAC specials, including the $29 refrigerant check and $59 service call, when you book an inspection.
Call 940-208-5398 or request service online to get a restaurant HVAC and makeup air inspection scheduled. We are a licensed Texas contractor, TACLB20924E, with a 5.0 rating from 86 Google reviews, and we quote every repair in writing before work starts.