PTAC Selection Wizard

Now that you’ve used the PTAC Cooling Calculator to calculate your maximum cooling BTU/HR., use this simple wizard to refine your search:




 

PTAC Selection Wizard Help Topics:

 

1. Select the PTAC size that is close but LESS than your calculated maximum cooling BTU/HR:

We know how tempting it is, the next size up is only $50 more….please don’t do it! It’s important to never oversize any air conditioning product. A byproduct of the cooling mode is dehumidification. The right balance of temperature and humidity creates the most comfortable environment. If you oversize your PTAC unit, it will quickly match your temperature set point, but will not run long enough to dehumidify. The result is a cool, damp environment, similar to a basement. Under sizing your PTAC will allow it to run longer and dehumidify more. This will result in a more comfortable environment.
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2. Select an air conditioner with electric heat or a heat pump air conditioner with back-up electric heat:

Heat pump air conditioners have become the norm. Improvements in technology allow heat pump air conditioners to operate longer in colder climates, they are as reliable as air conditioner units and the additional cost can be justified. Heat pump is a term used to describe a PTAC air conditioner that offers a reverse cycle heating mode. By reversing the air conditioning mode, heat pumps can generate heat that is 3 times more efficient than electric strip heat. Even though electric heat strips are 100% efficient, heat pumps can be up to 300% efficient! This means that for every BTU of energy you put into a heat pump unit, you receive 3 BTU’s in the form of heat. There are limitations to the heat pump mode. When outdoor temperatures drop below 35F, the heat pump mode can no longer generate sufficient heat, and electric strip heaters are energized. The heat pump vs. non-heat pump debate can be endless and it usually involves critics that experienced the pitfalls of early heat pump unit designs from 40 years ago. Here’s a simple way to decide: The additional cost of a heat pump unit is about $60. If you won’t use your PTAC unit for heating, don’t spend the extra money on a heat pump unit. If you will use your PTAC unit for heating, it will take about 240 hours of operation in the heat pump mode (when it’s 35F-60F outdoors) to pay for the $60 premium. In the Northeast, a heat pump would pay for itself in 1-2 years. The cooling mode is identical with both types of units.
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3. Select your voltage:

A higher voltage does NOT mean more cooling and heating capacity. Residential voltage is almost always 220 volts, which falls between the ranges of a standard PTAC unit designed for use with 208-240 Volt power. Occasionally old industrial spaces are wired with 265 Volt power.
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4. Select your electric heater capacity:

THE ELECTRIC HEATER SIZE DETERMINES WHAT SIZE ELECTRICAL FEED IS REQUIRED. Normally a heating calculation is performed when sizing any heater. PTAC units are different. Since PTAC units are primarily used for cooling, it’s important to size them for cooling. Choosing the electric heater size is simply a selection of the best available options. Often times your electrical capacity will dictate which heater to select. For example, if your circuit breaker panel can only handle a 20 Amp circuit, the maximum heater size you can select is 3.5 KW. If you’re replacing an existing PTAC, it’s important to match the electric heater size to the existing electrical circuit; otherwise, you’ll be calling an electrician for an expensive upgrade. If Amperage is not a concern, there are still only 3 choices: If you will never use the PTAC for heating (hot climates or you already have a primary source of heat) choose the 2.5 KW electric heater. This will allow your PTAC unit to be wired on the smallest 15 Amp electrical circuit. If your PTAC is the primary source of heat, use the map below to determine your zone and pick your heater size:

PTAC Climate Map

Shades of blue - pick the largest heater available.
Shades of green - pick the middle heater available.
Shades of red - pick the smallest heater available.
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