Commercial Make-Up Air & Exhaust Installation & Replacement in Southern California and Arizona

Why does make-up air matter as much as the rooftop units?

Every cubic foot an exhaust fan removes has to come back in somewhere. Make-up air units bring it back on purpose. Without them, the building pulls air through doors and gaps, and the rooftop units pay for it.

This page covers the ventilation and pressure-balance equipment around the main HVAC system: make-up air units, exhaust fans, air curtains, warehouse and loading-dock unit heaters, and air cleaners and scrubbers. Evaporative coolers have their own page. The principles behind pressure balance are in make-up air and exhaust balance in retail stores.

What are the signs exhaust and make-up air are out of balance?

Entry doors that are hard to open or will not latch, steady drafts at the front of the store, dust on the sales floor, and rooftop units running longer than the weather explains. Ventilation rarely fails in plain sight.

A building that runs negative pulls unconditioned air through every opening it has. Store teams notice the door long before anyone notices a fan. When those reports start, check the exhaust fans and make-up air units before the cooling equipment takes the blame.

When does a remodel need new ventilation equipment installed?

When it adds exhaust, people, or a process the original design never counted: new restrooms, a break room or food-service area, a stockroom turned into a work area, or an expansion. Added exhaust needs matching make-up air.

Installation work also covers buildings that have run negative for years and simply need make-up air added to match the exhaust already on the roof. Check local requirements for the ventilation a new use calls for, since codes set minimums by occupancy and use.

Should the fan, unit, or heater be repaired or replaced?

Repair a fan with a worn belt or a motor that is still made. Replace when housings are corroded through, parts are gone, heat sections are unreliable, or the equipment was sized for a use the space no longer has.

Equipment	Usually a repair	Usually a replacement
Exhaust fan	Belt, bearing, or a motor still in production	Corroded housing or repeat motor failures
Make-up air unit	Controls, ignition, or motor parts	Heat section or cabinet at end of life
Air curtain	Motor or door switch	Can no longer seal the opening it serves
Dock or warehouse unit heater	Ignition or thermostat	Fails at the start of every heating season

An air curtain sized or aimed wrong is an energy cost with no benefit, so replacement is also the time to check that the new one fits the opening.

What should a ventilation project plan for?

Measure what the building is doing now, size new equipment to the exhaust it must match, wire the interlocks, and time the work to the season. Pair it with other roof work where you can.

Exhaust and make-up air should be interlocked so they run together; a replacement that skips the interlock recreates the original problem. Roof penetrations, curbs, and duct runs get planned around trading hours, and anything that touches a fire or life-safety interface needs a check against current local code. Kelly Purcell, our Installation Director, carries the permit side, which in California means working city by city. Heater replacements belong before the heating season and cooling-side work before summer. If a rooftop unit replacement already has a crane and roof access booked, ventilation work can often share the day.

Does make-up air need to be heated or cooled?

Make-up air tempering depends on how much air comes in and where it lands. Small volumes into a back room can stay untempered. Large volumes into occupied space usually need heating or cooling, or the rooftop units do that work.

Tempering adds a heat section, sometimes a cooling section, and the gas, electrical, and controls work that comes with them. Getting this decision right at selection is cheaper than discovering in January that the stockroom is cold every morning.

Why does ventilation equipment go missing from site records?

Ventilation equipment is small, scattered, and rarely the cause of a dramatic failure, so inherited records often skip it. Equipment that is not on the list never enters the maintenance rotation and only turns up when it breaks.

Start any multi-site ventilation program with an inventory of every exhaust fan, make-up air unit, air curtain, and heater at each site, and flag the sites where store teams already report door or draft problems. New equipment belongs in the asset register from the day it starts up.

Who installs REE Mechanical’s ventilation equipment?

Our installation team under Install Foreman Anthony Renteria, made up of our own factory-trained technicians. REE Mechanical Inc. is licensed, bonded and insured, and we plan exhaust, make-up air, and the conditioned space as one system.

That means confirming the exhaust and make-up air interlock at start-up, not just a working fan.

Where does REE Mechanical install make-up air and exhaust?

In Ventura, Los Angeles, Orange, San Bernardino, Riverside, and San Diego counties, and in Arizona. See Orange County, Riverside County, or all service areas.

How do you get a ventilation problem assessed?

Call (800) 742-0910 and describe what the store team is seeing. For a failure that cannot wait, see unit heater and air curtain repair. For interlocks and fan scheduling, see HVAC controls repair and service.