July 16, 2019
Written by Bob Nieman, CLA Member
The ABC’s of HVAC
How to Keep Your System Efficient – And Your Laundry Customers Comfortable
For today’s laundromat customers, comfort is a key. And store owners who provide temperature controlled interiors – especially during the brutal dog days of summer – have a definite leg up on the other laundries in their market.
“Everything we do in building, designing and managing laundromats is about making them as convenient as possible for customers to do their laundry,” said Karl Hinrichs of HK Laundry in Armonk, N.Y. “A huge convenience is personal comfort – so air conditioning is a must in today’s laundromats.”
Years ago, there were only a couple of stores in each market, Hinrichs noted. However, in today’s environment, there is competition everywhere. And every owner is trying to get an edge over the other stores in his or her neighborhood. Clearly, not having air conditioning can leave your business wide open to competitors.
“If customer comfort is important, a correctly sized and properly installed HVAC system is a necessity in any temperate climate,” explained Michigan laundry owner Larry Adamski.
Beyond that, a proper HVAC system is crucial to the drying process in a vended laundry. In fact, without proper consideration for the ventilation system, drying performance can easily be impacted, and serious issues can occur – including possible dryer fires.
“I like having the compressor units on the roof, to discourage any theft of the copper coils,” Adamski explained. “They also are out of the way up there. However, for obvious reasons, I try to avoid locating a unit near the dryer exhaust vents.”
“The biggest problem with AC coils is that they collect debris, get clogged and won’t work as efficiently when trying to cool your laundry,” Hinrichs concurred. “So, you need to keep the coils clean and free of debris. To that end, if the coils are placed far away from the dryer exhaust, you will have to clean them less often. If your dryers exhaust vents out onto the roof, consider placing your coil on the ground or have them hung on the wall. In other words, separate the lint from the coils.”
Interior vent placement is going to be somewhat limited, due to the need for proper rooftop placement, according to California-based industry consultant Larry Larsen. He added that one of the best locations for the placement of air conditioning in vended laundries is on the ground level, to avoid the drawing in of lint from rooftop locations; however, in higher crime areas, this may not be the best choice, since the theft of copper from your unit is then made easier.
“Intake for your cooling/heating units must be located away from the dryer exhaust vents to minimize lint being drawn into the filters of your unit,” he said. “The units must compete with the placement of air intake vents for the oxygen needed for heater and dryer combustion. Also, the best location for venting registers is above your folding tables. Customers spend more time standing and folding than at any other place during their visit to your laundromat.”
Air Flow and Ventilation
Ductwork design and implementation are critical to proper drying performance, as well as to a fully functioning HVAC system. Most installation manuals provide detailed plans and specifications, which must be followed for optimal drying performance. At the very least, drying can be adversely affected. At the extreme, an improper HVAC system will not allow proper airflow to exhaust the damp air, which can allow lint to accumulate.
As lint accumulates, the venting system is further compromised, which makes the situation worse. After time, an improper HVAC system can allow lint to build up within the ductwork. This lint buildup can achieve a snowball effect, which eventually can impact dryer performance.
“Ductwork efficiency can be measured by static pressure readings taken in your venting system by a qualified HVAC technician to ensure that excessive back pressure does not exist in the system,” said Alex Kane of Equipment Marketers, based in Cherry Hill, N.J. “This reading should match the values outlined in the installation manual for your dryer. If the venting system has numerous turns and/or a long length, this can contribute to a high static pressure. The exhaust run should be as short as possible with the least amount of turns. A larger diameter of venting pipe also can assist in reducing the static pressure in the system.
“Many stores are designed to vent the dryers into a common duct, also called a manifold. When this system exists, care must be taken to not have more than the allowable number of dryers connected to this main common duct. Optimally, the venting pipes should enter into a common duct at an angle to encourage airflow to the exhaust and prevent blowback. When venting joins together, care must be taken to ensure that the combining pipe has enough diameter to accept the total diameter of the supply pipes. In addition, backdraft dampers may be needed in commonly ducted systems.”
On the outside of the building, the vent pipe outlets should face downward, Kane noted. For roof-based outlets, it is important to have enough clear space below the outlet for proper ventilation.
“We always suggest that a venting professional be contracted to examine and modify your venting system and makeup air to ensure that the dryer requirements are satisfied,” Kane explained. “It’s very important that the dryers are operating under the requirements outlined in the installation manual.”
Getting the air into the store is one thing, but getting it back to the HVAC unit is just as important, according to Alabama multi-store owner Ken Barrett.
“Positioning the return ducts near the dryers pulls the warmer air directly into the AC,” he pointed out. “Ideally, the supply ducts are positioned to blow the cool air toward the seating and folding areas, as these are where people spend more time. “
Changing the filters often also will make a big difference in air flow. If you are installing a new system or building a new store, have the contractor install at least two filter locations, insist they use more than a normal installation, as you will have more dust than they would normally factor in. If your fan runs continuously, expect to change the filters at least once a week, but if the fan cycles only with the AC unit, you may get two or three weeks out of a filter.
“Be sure to monitor this and keep track of your filter changes. Filters are something that are easy to forget about, especially in an unattended laundry. There are some simple gauges available that can be installed to monitor your filters that work on the negative pressure created by the fan as the filters plug up; however, someone still needs to check the gauge regularly.”
HVAC in a Vended Laundry Setting
Of course, self-service laundries feature an extra heat component that is crucial to factor into your plans when considering the capacity of your store’s HVAC unit. Dryers kick off a tremendous about of heat in order to dry properly the clothes – and this added heat must be accounted for when designing an HVAC system for a laundromat.
“The additional heat load from all of the dryers is equal to 2 percent of the combined dryer gas BTU input,” Hinrichs explained. “For example, if you have 10 stack dryers with each stack requiring a 190,000 BTU gas input, the total bank of dryers would have an input of 1,900,000 BTUs and a heat load of approximately 38,000 BTUs.”
Also, as previously mentioned, it’s important to locate the compressors away from the dryer vents, as they pull in a lot of air through the condenser coils – and, if that air is full of lint, all or most of that lint will end up on your coils.
“All in all, a poorly designed HVAC system – including venting, distribution and returns – will not cool the entire store and will waste electricity,” Hinrichs warned. “This is not the area in which to try to save a couple of bucks. YouTube is good, but when it comes to your HVAC, you need an expert to design your system.”
Sizing Your System
A properly designed HVAC system will take into account such factors as windows, doors, dryers and other heat loads within the space. Clearly, the higher the heat load, the larger the capacity required to cool the laundromat.
“Laundromats are unlike most other commercial buildings when it comes to heating and cooling,” Adamski said. “Laundromats may be easier to heat, due to the heating effect the dryers put on the customer space. Conversely, laundries are harder to cool, because whenever a customer pulls a load of warm clothes out of a dryer, all of that heat goes directly into the customer space. That residual drying heat, combined with the normal solar heating of the building, puts an increased load on the air conditioning equipment. For this reason, laundromats typically require more tonnage of air conditioning than other businesses of similar size.
“HVAC dealers sometimes fail to understand the unique issues involved in air conditioning a laundromat and simply size the equipment as they would for a retail store of the same size,” he said, adding that laundry operators can expect to pay between $800 and $1,000 per rated ton for an HVAC system. “This is a mistake, and it will usually result in a poorly performing air conditioning system.”
“Air conditioning has a number of factors that can affect the sizing and operation,” Barrett said. “Ceiling height is one that can be incorporated into the design but also is limited by the building. A higher ceiling allows the heat from the dryers to move up and out of the main occupied area. For example, one of my stores has an eight-foot ceiling, and the air conditioner struggles to keep up on a hot, busy day. Then again, my newer store has 13-foot ceilings and doesn’t have those issues.
“Air movement makes a big difference as well,” he added. “The air conditioner needs to be sized correctly with the fan to exchange the volume of air in the store fast enough to reduce the temperature.”
The sizing of HVAC units is governed by the plumbing code, as well as local regulations. And, when faced with an option, always err on the side of including just a little more capacity.
“The size of the venting must be matched to the size of an air conditioning unit or back pressure will reduce efficiency and can lead to early unit failure,” Larsen explained. “To put it in laundromat terms, you need enough dryer capacity to handle your washer capacity, or you’ll have unhappy customers. The same is true with heating and cooling. You need enough capacity to generate an environment that will lead to happy customers.”
He added that HVAC pricing is subject to the size required, the time of year purchased, and the ability of the buyer to research various brands. “The summer months are not the best time to repair or replace air conditioning,” he said. “There’s too much demand, which means higher prices for installation and repair.”
For increased efficiency, Hinrichs suggested insulating the dryer walls and enclosures to separate the outside air from the inside air.
“Insulation is a key to good air conditioning operation and operating cost reduction,” Barrett explained. “Most of my stores have rolls of R-30 insulation on top of the ceiling tiles. This creates a better blanket of coverage than the normal batts of insulation. The insulation in unfaced to prevent any moisture/vapor barrier concerns. Additionally, any doors from the main area are exterior, insulated doors. I also have installed foam rolls – similar to pipe insulation – under the dryers to block the airflow around the base and leveling legs.”
Larsen noted that setting the temperature slightly higher (78 degrees) for air-conditioned stores will help reduce the costs of operation. Also, the shade of tall trees surrounding a laundromat can cool the interior and reduces stress on the cooling unit.
“It’s a great idea to plant a few trees to shade the air conditioner at your laundromat,” Larsen said. “To achieve energy savings, many owners are using white on their roofs, wind-driven turbine ventilators, ceiling insulation and careful isolation of the back of dryers to prevent mingling of cooler air with dryer intake air.”
Building direction is another factor with regard to efficiency. Which way does your building face? Do you have a large awning or overhang that blocks the sun?
“The amount of sun and the time of day will have a big impact on your unit’s ability to cool the store,” Barrett said. “You may need to add a clear film to the windows to reduce the heat from the sun. Fortunately, this can be added to any window at any time.”
“Most importantly, isolate the customer area from the dryer service areas,” Adamski said. “Dryers ingest a lot of makeup air, and it’s not a good idea to spend money cooling down the air for your customers’ comfort only to have that air drawn into the dryers, where it is heated up to dry clothes. Such a situation becomes the ultimate inefficiency, as far as a laundromat is concerned. Also, avoid under-sizing or over-sizing your system, by obtaining guidance from someone familiar with air conditioning laundromats.”
Maintaining Your System
Above all, it’s critical to keep the coils clean and free of debris, Hinrichs explained.
“If you have a rooftop unit, this also means free of lint,” he said. “The easiest way to clean the coils is to take a garden hose and spray from the inside out and remove the debris from the coil. If you spray from the outside going in, most likely you will just imbed the dirt and debris even deeper into the coils.”
Increased static pressure readings could indicate that the venting system has some accumulated lint built up in the system.
“It’s important that the venting system be periodically inspected and cleaned out to make sure that excessive lint has not accumulated in the system,” Kane said. “The frequency of these cleanings depends on the system design and dryer usage but we would recommend it be done at a minimum of once per year.”
A yearly visit to the roof of your building, where you observe roof conditions, should also include an inspection of your vents and HVAC units, Larsen agreed.
“Frayed belts, rust spots and clogged filters should be addressed,” he said. “Older units might have a grease or oil fitting. With air conditioning, check your Freon level before the summer heat arrives.”
“I only perform owner/operator maintenance, such as replacing filters, straightening fins and rinsing coils,” Adamski noted. “All major issues are handled by professional HVAC technicians.”
With regular preventive maintenance, compressor units and high-efficiency furnaces should last 12 to 18 years, according to Adamski.
“Of course, allowing dirt and/or lint to accumulate in the condenser and evaporator coils will shorten the life of your air conditioning units,” he added.
All in all, ignoring maintenance on HVAC units one is the most common mistakes made by laundry owners, according to Larsen.
“When the units are located on rooftops, it’s ‘out of sight, out of mind,’” he explained. “Maintenance should be done yearly, not when your units fail to operate. Ignoring a problem doesn’t make it go away. Customers deserve a clean and comfortable environment in which to wash, dry and fold their clothes.”