Sizing HVAC for a laundromat is different from sizing HVAC for a normal retail space. A laundromat has people, glass, lighting, washers, moisture, outdoor air requirements, and—most importantly—dryers producing large amounts of heat and exhaust. If the dryer area is not designed correctly, the air conditioner may never catch up, no matter how many tons you install.

For Middle Tennessee, a good HVAC design should be based on local design weather, realistic customer occupancy, ventilation requirements, dryer heat gain, dryer make-up air, and humidity control. Nashville-area design references generally put summer design conditions around the low-to-mid 90s °F and winter design temperatures in the teens to around 20°F, depending on the exact county and data set used. ASHRAE publishes climatic design information for HVAC sizing, and local design references commonly use 1% cooling and 99% heating design temperatures for this type of work.

The examples below use 94°F outdoor summer design temperature, 75°F indoor cooling setpoint, and 70°F indoor winter heating setpoint. These are not a substitute for a stamped Manual N / commercial load calculation, but they show the process clearly enough for laundromat owners to understand the sizing logic.

---

The big mistake: sizing by square footage only

A normal light-commercial space might be estimated at something like “one ton per 300 to 500 square feet,” depending on construction, exposure, glass, occupancy, and ventilation. That shortcut does not work well in laundromats.

Why? Because dryers change everything.

A 30 lb commercial gas dryer can be around 90,000 BTU/hr input, and some models move hundreds of CFM of exhaust air per pocket. For example, Dexter specifications list a 30 lb dryer at 90,000 BTU/hr gas usage, and Dexter stack dryer specs list 600 CFM airflow per tumbler on a 30 lb stacked unit. Larger commercial dryers can be much higher; one 75 lb ADC model is listed with 175,000 BTU/hr heat input and 1,000 CFM airflow.

That does not mean all dryer BTUs become air-conditioning load. Most dryer heat should leave through the exhaust system. But if the dryer area is poorly designed, heat leaks into the customer area and the dryers may pull conditioned air out of the room, forcing hot, humid Tennessee air to enter the building. That is when laundromats become uncomfortable and expensive to operate.

A commercial laundry planning guide makes this point directly: dryers should not use conditioned room air for make-up air, and enclosing/separating the dryer area helps reduce operating expense because the dryer is not taking cool room air and heating it.

---

The sizing method

For these examples, we will estimate the cooling load in six parts:

1. Building shell, lighting, and miscellaneous sensible load
2. People load
3. Required outside air ventilation
4. Dryer heat leakage into the room
5. Humidity / latent load
6. Safety factor and equipment staging

One ton of cooling equals:

1 ton = 12,000 BTU/hr

So once we estimate BTU/hr, we divide by 12,000 to convert to tons.

---

Assumptions used in the examples

These assumptions are reasonable for a Middle Tennessee laundromat, but every actual project should be adjusted for the building.

The ventilation formula above follows the common ASHRAE 62.1-style method of adding a people component and an area component; one published retail example uses 7.5 CFM/person plus 0.12 CFM/sq. ft. People give off both sensible and latent heat, and published engineering tables show that human heat gain varies by activity level and indoor condition; for a laundromat, 450 BTU/hr per person is a practical combined sensible-plus-latent estimate.

---

Step 1: Estimate base building load

For a laundromat, the base load includes roof and wall heat gain, glass, lighting, small electrical loads, washer motors, controls, and general internal equipment heat.

For this simplified example:

Base load = square feet × 12.4 BTU/hr

2,000 sq. ft.

2,000 × 12.4 = 24,800 BTU/hr

24,800 ÷ 12,000 = 2.1 tons

3,500 sq. ft.

3,500 × 12.4 = 43,400 BTU/hr

43,400 ÷ 12,000 = 3.6 tons

5,000 sq. ft.

5,000 × 12.4 = 62,000 BTU/hr

62,000 ÷ 12,000 = 5.2 tons

This is why a simple square-foot estimate is incomplete. Before we even add dryers, customers, ventilation, and humidity, the building itself already needs several tons of cooling.

---

Step 2: Add customer heat load

Customers produce both sensible heat and moisture. A busy laundromat also has people opening doors, moving laundry, folding clothes, and waiting inside.

For this example:

People load = number of people × 450 BTU/hr

Assumed peak customer count:

2,000 sq. ft.

20 × 450 = 9,000 BTU/hr

9,000 ÷ 12,000 = 0.75 tons

3,500 sq. ft.

35 × 450 = 15,750 BTU/hr

15,750 ÷ 12,000 = 1.3 tons

5,000 sq. ft.

50 × 450 = 22,500 BTU/hr

22,500 ÷ 12,000 = 1.9 tons

---

Step 3: Add code-required outside air ventilation

Laundromats need fresh air for customers, odors, humidity, and general indoor air quality. The simplified ventilation formula used here is:

Outdoor air CFM = 7.5 × people + 0.12 × square feet

2,000 sq. ft.

7.5 × 20 = 150 CFM
0.12 × 2,000 = 240 CFM

Total outdoor air:

150 + 240 = 390 CFM

3,500 sq. ft.

7.5 × 35 = 262.5 CFM
0.12 × 3,500 = 420 CFM

Total outdoor air:

262.5 + 420 = 682.5 CFM, rounded to 683 CFM

5,000 sq. ft.

7.5 × 50 = 375 CFM
0.12 × 5,000 = 600 CFM

Total outdoor air:

375 + 600 = 975 CFM

Now convert that outdoor air into cooling load.

For sensible cooling:

Sensible BTU/hr = 1.08 × CFM × temperature difference

Using 94°F outside and 75°F inside:

Temperature difference = 19°F

For latent moisture load, this example uses a simplified Middle Tennessee summer humidity estimate:

Latent BTU/hr = 0.68 × CFM × grains difference

Using an estimated humidity difference of 38 grains between outdoor and indoor air:

2,000 sq. ft.

Sensible:

1.08 × 390 × 19 = 8,003 BTU/hr

Latent:

0.68 × 390 × 38 = 10,078 BTU/hr

Total ventilation load:

8,003 + 10,078 = 18,081 BTU/hr

18,081 ÷ 12,000 = 1.5 tons

3,500 sq. ft.

Sensible:

1.08 × 683 × 19 = 14,014 BTU/hr

Latent:

0.68 × 683 × 38 = 17,644 BTU/hr

Total ventilation load:

14,014 + 17,644 = 31,658 BTU/hr

31,658 ÷ 12,000 = 2.6 tons

5,000 sq. ft.

Sensible:

1.08 × 975 × 19 = 20,007 BTU/hr

Latent:

0.68 × 975 × 38 = 25,194 BTU/hr

Total ventilation load:

20,007 + 25,194 = 45,201 BTU/hr

45,201 ÷ 12,000 = 3.8 tons

Notice that ventilation alone can add several tons of load in a humid climate like Middle Tennessee.

---

Step 4: Add dryer heat gain

This is the most laundromat-specific part of the calculation.

For this comparison, assume the following dryer counts:

Not every dryer runs at full fire at the same time. A practical design diversity assumption is:

Peak active dryer input = total installed dryer input × 60%

Then estimate how much of that active dryer heat leaks into the customer space.

For a properly designed dryer area with separate make-up air and good enclosure:

Room heat pickup = active dryer input × 4%

For an open dryer bank with more heat spilling into the store:

Room heat pickup = active dryer input × 8%

---

2,000 sq. ft. laundromat dryer load

Installed dryer input:

12 × 90,000 = 1,080,000 BTU/hr

Peak active dryer input:

1,080,000 × 60% = 648,000 BTU/hr

Properly separated dryer area:

648,000 × 4% = 25,920 BTU/hr

25,920 ÷ 12,000 = 2.2 tons

Open dryer bank:

648,000 × 8% = 51,840 BTU/hr

51,840 ÷ 12,000 = 4.3 tons

---

3,500 sq. ft. laundromat dryer load

Installed dryer input:

20 × 90,000 = 1,800,000 BTU/hr

Peak active dryer input:

1,800,000 × 60% = 1,080,000 BTU/hr

Properly separated dryer area:

1,080,000 × 4% = 43,200 BTU/hr

43,200 ÷ 12,000 = 3.6 tons

Open dryer bank:

1,080,000 × 8% = 86,400 BTU/hr

86,400 ÷ 12,000 = 7.2 tons

---

5,000 sq. ft. laundromat dryer load

Installed dryer input:

30 × 90,000 = 2,700,000 BTU/hr

Peak active dryer input:

2,700,000 × 60% = 1,620,000 BTU/hr

Properly separated dryer area:

1,620,000 × 4% = 64,800 BTU/hr

64,800 ÷ 12,000 = 5.4 tons

Open dryer bank:

1,620,000 × 8% = 129,600 BTU/hr

129,600 ÷ 12,000 = 10.8 tons

This is where proper laundromat design pays for itself. The difference between a well-separated dryer area and an open hot dryer bank can be several tons of air conditioning.

---

Step 5: Compare the three store sizes

Recommended cooling load with proper dryer make-up air

This assumes the dryers have dedicated make-up air, the dryer bank is reasonably separated from the customer area, and the HVAC system is not expected to replace thousands of CFM of dryer exhaust.

These are good planning numbers for a Middle Tennessee laundromat that is designed correctly.

---

What happens with an open dryer bank?

If the dryer bank is open to the customer area and more heat spills into the store, the cooling requirement rises sharply.

The larger the laundromat, the more expensive this mistake becomes.

---

Step 6: The worst-case mistake—letting dryers pull conditioned air

If dryers pull air from the conditioned customer space, the HVAC system has to replace that air with hot, humid outdoor air. This is a major problem.

Using 600 CFM per active dryer pocket as an example, based on published 30 lb stacked dryer airflow data, the impact is enormous.

Assume 60% of dryer pockets are running:

Trying to air-condition replacement air for that much exhaust can add roughly:

That is not a recommendation to install 70 tons of air conditioning in a 5,000 sq. ft. laundromat. It is proof that the dryer make-up air design is wrong.

The answer is not simply “more HVAC.” The answer is to separate the dryer combustion / make-up air path from the conditioned customer area.

---

Recommended HVAC approach by laundromat size

2,000 sq. ft. laundromat

A properly designed 2,000 sq. ft. laundromat in Middle Tennessee will often need about 7.5 to 8 tons of cooling.

A good setup might be:

• Two 4-ton rooftop units, or
• One 3-ton and one 5-ton unit, depending on zoning and layout

The goal is not just total tonnage. The goal is staging. On a mild day, one unit can run efficiently. On a hot Saturday with all dryers active, both units can run.

3,500 sq. ft. laundromat

A properly designed 3,500 sq. ft. laundromat will often land around 12.5 to 15 tons.

A good setup might be:

• Three 5-ton units, or
• One 7.5-ton and one 7.5-ton unit, or
• A variable-capacity / staged system with dedicated outside air control

This size store needs careful attention to air distribution. The folding area, front seating area, and dryer aisle should not all be treated the same. The dryer aisle will usually need more return/exhaust strategy, while the customer seating and folding areas need steady comfort.

5,000 sq. ft. laundromat

A properly designed 5,000 sq. ft. laundromat will often need around 17.5 to 20 tons.

A good setup might be:

• Four 5-ton units,
• Two 10-ton units with good staging, or
• A larger staged system with dedicated ventilation and dehumidification strategy

At this size, humidity control becomes especially important. Oversized single-stage equipment may cool the space quickly but fail to run long enough to remove moisture. That leaves the laundromat cold, clammy, and uncomfortable. Staged or variable-capacity equipment is usually better.

---

Heating comparison for Middle Tennessee

Heating is usually less complicated than cooling in a laundromat because dryers contribute heat during busy periods. However, heating still matters early in the morning, overnight, on slow days, and when the store first opens.

Using a simplified heating estimate:

Heating load = UA-style building load + ventilation heating load

For a planning-level estimate, many laundromats in Middle Tennessee may fall roughly in these ranges:

But the heating system should be staged or zoned. A laundromat can need heat at 6:00 a.m. and then need cooling by mid-afternoon once the dryers, people, lighting, and sun load are active.

---

Design principles that keep customers comfortable

1. Separate dryer make-up air from conditioned air

This is the most important design principle. Dryers need a lot of air. Give them outside make-up air directly, preferably through a properly designed dryer enclosure or make-up air path, instead of letting them steal cooled air from the customer area.

2. Do not oversize one big unit

A single oversized unit may satisfy the thermostat quickly but leave humidity behind. In Middle Tennessee, humidity control is comfort control. Multiple staged units are usually better than one large unit.

3. Put supply air where customers actually stand and sit

Customers care about the folding tables, seating area, front counter, and walking aisles. The dryer aisle can be warmer, but the customer zone should feel controlled.

4. Use returns and air movement wisely

A laundromat can have hot pockets near dryers and cold pockets near supply diffusers. Good return placement helps pull heat away from problem areas without short-circuiting the supply air.

5. Plan for peak Saturday, not average Tuesday

The system should be sized for the busy period: multiple dryers running, customers folding, doors opening, humid outdoor air entering, and solar load on the glass.

---

Final sizing comparison

For a Middle Tennessee laundromat with good dryer make-up air and efficient HVAC design:

If the dryer area is poorly designed, those numbers can increase dramatically—but that is usually a design problem, not just an HVAC problem. The most efficient laundromats control the dryer air path first, then size the HVAC system for the remaining building, people, ventilation, humidity, and reasonable dryer heat pickup.

The best rule for owners is this:

Size the HVAC system after you design the dryer exhaust and make-up air system—not before.