Compact HVAC Units

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Electric heating and BTU cooling PTAC units are just one of the variations found in the marketplace.

Packaged into one essential box, PTAC systems have been cooling/heating light commercial spaces for decades.

By Leah Den Hartogh

The term “Packaged Terminal Air Conditioner,” or PTAC for short, isn’t exactly new to the heating and air conditioning world, having been in the industry now for decades. Yet, the product that was introduced so many years ago is so different than what is found on the market today.

Available in gas, electric and heat pump options, energy efficiency has become top priority amongst manufacturers. “This type of product has had many iterations over the years. The technology is proven,” said Tom Hoefer, account executive—commercial HVAC for Napoleon. “It’s evolved a lot in terms of efficiency, reliability, and overall quality.”

This is evident in recent coil, motor, and compressor advances—“Each major component in the system has undergone a steady increase in performance to make modern PTACs much more efficient, quieter, and sleeker-looking, while advances in electronic controls have improved much of the overall functionality of the product category as well.”

In addition to gas, electric, and heat pump units, there are also hydronic PTACs in the market. Typically, those installs aren’t as common anymore and tend to be part of custom jobs.

Packaged terminal air conditioning units are typically installed beneath windows because they must have access to the outdoors.

PTAC units are most commonly found in apartments, condominiums, senior homes, and hotels, to name a few locations. “As long as there are hotels and people travelling, PTACs will have a place in the market for many years to come,” said Barry Bookout, director of sales—commercial and lodging divisions for Friedrich Air Conditioning Co.

The technology is largely going towards heat pump technology—“heat pumps use what is known as ‘reversing valve’ to put the traditional refrigeration cycle into ‘reverse.’ That is, instead of pumping warmer air from the inside of the space to the outside, a heat pump will pump the available heat from the outside air into each room,” explains Bookout. “This ‘free heating’ saves the end-user a measurable amount of operating cost each year. And the differential cost between a standard cooling only PTAC unit and a heat pump unit has come down in recent years, making heat pumps even more viable.”

Compared to ducted system installs, a PTAC installation has the benefit that it is a fairly simple process with shorter install times.

Typically installed underneath a window, a PTAC unit can fit in anywhere, even a closet, just as long as it has access to the outside. “You use the Delta T from the outdoor temperature to the indoor temperature and the air conditioning system can be leveraged to produce warm air,” said Brigitte Mader-Urschel, commercial director for GE Appliances. “Once you have all of your components set up, maybe you put a wall thermostat up, then you’re done. This baby will work.”

Compressor technology

The industry is slowly moving away from the standard compressor and moving towards inverter technology. “An inverter compressor is kind of like a ghost power, so it offers a soft start,” explains Al Myers, account manager for the B.C. interior at Carrier Enterprise Canada. “It’s kind of like your television. How your kind of always in ghost mode when you turn your television on. It’s still drawing a little bit of power all the time—so it’s not doing an additional hard start. This is what it’s like with a traditional compressor.”

Commonly found in hotels, apartments, senior homes, and low-income housing, PTAC units are becoming more and more efficient.

With a standard compressor, you could get a little dimming of the lights if there was a lot of power being drawn at the same time. Inverter technology gets a bit of a head start by constantly drawing power to the compressor. Electronic commutated motors (ECM) also goes hand-in-hand with inverter technology, which is increasing popularity in the market.

One big driver that is pushing the PTAC market forward is the increased motivation to reduce our environmental footprint. “The reduction of greenhouse gas emissions is really important. One major change that is coming down for the industry will be to change refrigerants,” said Mader-Urschel. That is to get rid of those refrigerants that have higher global warming potential.

Best practices

Overall, installs are fairly simple when it comes to PTAC units. “Installation instructions are generally well written and complete, as this is a product that has been on the market for many decades,” explains Bookout. PTAC units much be installed level but with a slight tilt to the outside. This is because PTACs remove moisture from the air as part of the air conditioning. As this moisture gathers in the base pan, that water is designed to exit to the outside. If the unit is installed with a tilt to the inside or level, there is a chance water could enter the occupied area.

Contractors need to carefully read the instructions regarding caulking, sealing, and insulating the unit in the wall sleeve. There is an increased chance of outside air infiltration into the room, if not done properly, says Bookout.

There are several other nuisances that contractors should keep in mind when installing a PTAC unit. Since these units produce condensate, it’s recommended to have a condensate drain kit. The drain kit is an accessory that can be installed within the PTAC wall sleeve to internally join right into plumbing, or externally to the outside, explains Myers. And make sure that the end-user or service contractors follow up with regular maintenance. It needs to be done to ensure a longer life for the unit.

Sizing plays a key role in the energy efficiency of the unit and the overall end user’s comfort. “If you put too big BTU unit, then you will cool that space up very quickly, but you don’t dehumidifier properly,” explains Mader-Urschel. “It’s really important to get the right size air conditioner for the space. If you go too big, you might have negative side effects.” Bigger doesn’t mean better in standard air conditioning terms. The lower BTU unit is actually less expensive and more efficient. “Usually what we recommend is go with what the original architects have specified for the building construction project.” It is the air conditioner’s job to both cool and dehumidify the space at the end of the day.

Compressor technology is moving away from standard compressors and looking at inverter technology.

The standard sizing of a PTAC unit is 16-inches by 42-inches. As mentioned prior, there are three common types of PTAC units: gas, electric, and heat pump. There are individual instances where each of these types of units makes sense for an install. One way to differentiate the different types is based on how much it will end up costing the homeowner in the long run. Gas is a bit more expensive. Electric a bit cheaper. Heat pump is the cheapest.

“For all electric units, you are near a one-to-one ratio for every dollar you pay for electricity, you get a dollar worth back of heat,” explains Myers. Gas units get around 70 to 78 per cent efficiency. Lastly, heat pumps can get twice the amount of heat for the dollar spent, he explains.

Within one unit there could be gas heat/electric cooling, electric heat/electric cooling, electric cooling with no heat, to name a few types of options.

Self-contained system

Since these units are packaged, there are no refrigerant lines to run. This means that there doesn’t have to be any brazing in the field. Nor do contractors have to add any refrigerant or fill and run a vacuum pump to clean the lines. Install times are a third compared to ducted systems, says Hoefer.

“PTACs offer a budget-friendly up-front cost, easy installation, relatively robust performance for the money, and ease of replacement,” said Bookout. Making PTAC retrofits easy for contractors. When a building is first constructed with PTACs units installed, usually they will stay this way for the remainder of the building’s lifetime. A metal frame is installed within the wall, which is where the air conditioner slides into. A grill is used to cover the unit up on the inside. Once the PTAC unit needs to be replaced, it can be taken out of the metal frame, where a new one can slide in. It’s a very easy replacement method,” says Mader-Urschel.

Contractors can find the assistance they need if they run into any issues by always asking for expert advice from any one of the manufacturers that make the units. All they have to do is reach out.

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