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Commercial · Laundromats & Dry CleanersLaundromat & Dry Cleaner HVAC — Dryer Make-Up Air
Laundromat and dry cleaner HVAC starts with dryer make-up air: every cubic metre a dryer bank exhausts has to be replaced, and the opening or make-up air unit is sized from the dryer manufacturer's airflow table multiplied by the number of dryers, not estimated from floor area. Gas dryers also need combustion air under CSA B149.1. A starved dryer room shows itself as longer dry times, burners cycling off on high limit, flame rolling out of the burner box and a front door that is hard to pull open.
A wall of stacked commercial tumble dryers moves more air than every other appliance in the plaza unit combined. Each dryer's installation manual lists its exhaust airflow and the free area of outdoor-air opening it needs, and those numbers add up across the bank. When the room cannot supply that air, the dryers pull it through the front door, down the water heater vent and through every gap in the building, and airflow through each drum drops. Less airflow means damp clothes at the end of a cycle, customers paying for a second cycle, and burners running hotter than they were designed to.
Passive louvres behind the dryers are the cheapest make-up air and the usual original install. They work until someone blocks them with a shelf, lint mats the screen, or January air freezes the pipes behind the machines and staff tape cardboard over the opening. A gas-fired make-up air unit interlocked to the dryers solves the cold but adds an appliance that needs annual service. Either way, the test is a pressure reading with every dryer running: the room should sit close to neutral against outdoors, and the water heater draft should hold.
Lint is the fire and maintenance problem. It passes the dryer screens, coats the inside of the exhaust duct, and what escapes into the room is drawn into the rooftop unit, where it blankets filters and the evaporator coil. Dryer exhaust belongs in smooth rigid metal duct, joined without screws protruding into the airstream, kept inside the manufacturer's maximum equivalent length, with clean-out access at changes of direction and a termination that has no screen to plug. A long shared duct that several dryers discharge into needs engineered sizing, and it is the first thing we open when a store reports slow dryers.
The other large gas load is hot water. Washers draw from high-input tank heaters or a boiler with storage, and hard water in Halton and Hamilton scales those heat exchangers fast enough that descaling is routine, as described under commercial water heater maintenance. Dry cleaners add two things a laundromat does not have: solvent vapour that needs exhaust at the machine as its manufacturer specifies, and steady heat from presses and the steam boiler feeding them. We handle the room ventilation, make-up air, gas piping and comfort cooling; see commercial HVAC for the wider scope, or describe your dryer bank to us to arrange a site visit.
Equipment we install and service
Fixed louvres or a gas-fired make-up air unit sized from the dryer nameplates and manuals. We verify free area, interlocks and room pressure with the full bank firing, and check combustion air for every gas appliance sharing the space.
Individual or manifolded rigid metal exhaust to the outdoors. Duct length, elbows, clean-outs, booster fans and the termination hood are inspected for lint build-up, and back-pressure is measured at the dryer collar against the manufacturer's limit.
High-input tank heaters, tankless banks or a boiler with storage tanks feeding the washers. Venting, gas pressure under full load, relief valves and scale are the service items; an undersized gas line shows up when dryers and heaters fire together.
Comfort cooling for the customer area, plus exhaust and spot cooling at dry cleaning presses. Lint-loaded filters and coils are the standing problem, so these units get a shorter filter interval and a yearly coil wash.
What goes wrong in these buildings
- Dryers that used to finish in thirty minutes now need forty-five and customers are complaining.
- The front door whistles and takes two hands to open when all the dryers are running.
- The water heater pilot keeps going out on busy Saturdays.
- It is sweltering at the folding tables in July with the air conditioning on.
- There is lint on top of everything, including the ceiling grilles.
- The pressers at the back of my dry cleaner are working in heat I would not stand in.
How it works
We list every dryer by model, total the exhaust airflow and required make-up from the manuals, and compare that with the openings you have. Room pressure and water heater draft are measured with the whole bank running.
Ducts are checked from dryer collar to termination for lint, crushed sections, screens and excess length. Where cleaning is needed we tell you, and where the duct layout is the fault we quote the sheet-metal correction.
Make-up air is corrected first, then gas pressure and water heating, then comfort cooling. A dated report records the readings so you can show an insurer or fire inspector what was found and fixed.
Common questions
How much make-up air does a laundromat need?
As much as the dryers exhaust. Take the exhaust airflow from each dryer's installation manual, multiply by the number of dryers that can run at once, and provide that through louvres or a make-up air unit, plus combustion air for the water heaters. Rules of thumb based on floor area undersize it. We calculate it from your equipment list and confirm with a pressure test.
Is flame roll-out on a gas dryer dangerous?
Yes. Flame leaving the burner box means the dryer is short of air or its exhaust is blocked, and it can ignite lint. Take that dryer out of service, do not keep resetting a tripped limit, and have the exhaust duct and make-up air checked before it runs again. If you smell gas, leave the building and call Enbridge Gas from outside.
Can I close the make-up air louvres in winter so the pipes do not freeze?
No. Blocking them starves the dryers and can pull exhaust gases back down the water heater vent, which is a carbon monoxide risk. The proper fixes are a tempered make-up air unit, a motorized damper that opens only when dryers run, or rerouting and insulating the water lines near the opening. Tell us which pipes freeze and we will price the options.
Do you service dry cleaning machines or press boilers?
We do not service solvent machines. Steam boilers that feed presses can fall under TSSA's boiler and pressure vessel rules, so tell us the make and rating and we will say plainly whether it is ours or a boiler specialist's. Our dry cleaner work is solvent-room and press-area exhaust, make-up air, gas piping and cooling for the front counter.
Related
Keep the building running.
One licensed team for installs, maintenance contracts and 2 AM calls.