PTACs with the highest Energy Efficiency Rating (EER) are not always the best option. In general, a PTAC with a higher EER will consume less energy during cooling operations. But, how do the PTACs achieve these higher EERs and how are they rated? As coils become “tighter” (deeper fin pack and higher fins per inch), it becomes easier for dirt to get trapped in the coil, resulting in loss of airflow through the coil and a drastic drop in capacity and efficiency. This means that to keep the PTAC operating at higher efficiencies, both the evaporator and the condenser coils will need to be cleaned more often to maintain the EER rating and capacity of the PTAC.
Ensure that your PTACs are properly sized. For example, oversized PTACs will not dehumidify well. Also, in general, PTACs with higher British Thermal Units per Hour (BTUH) capacities are less efficient than units with lower capacity. Larger units use compressors and fan motors that use more watts of electricity to produce the cooling BTUH. The same is also true for an electric heater. Larger heaters will spike your Kilowatt (KW) demand to the power company and could result in a much higher demand portion on your power bill.
Regardless of EER, you can minimize energy consumption by efficiently operating the unit. With the incorporation of microprocessors into the PTAC control, today’s models have many capabilities that were not possible just a few years ago. These capabilities include:
You can buy efficient PTACs and you can operate them efficiently; however, if you do not monitor the operation and regularly clean and maintain the PTACs, you still waste a lot of energy dollars. Here are a few tips that can save you money.
• Too Much Ventilation - Some properties use the PTAC for what is called “make-up air,” running the ventilation fans 24-hours-a-day and seven-days-a-week. This brings in unconditioned air and forces the PTAC to run much longer to condition the air and remove the humidity. In many instances, the PTAC is not able to remove the humidity that gets introduced into the room, and instead of helping, it actually causes potential mold and mildew issues. This ventilation air also uses more energy in trying to condition not only the air that is in the room, but also the outside air that is now entering.