The HVAC industry has adopted the SEER 2 standard, which is used to measure the energy efficiency of all cooling units, with the exception of portable and window air conditioners. This index, known as the Seasonal Energy Efficiency Index (SEER), is calculated by dividing the amount of energy a unit consumes in an hour by the number of BTUs (British thermal units) of heat it has removed from the air over the same period. Ductless heat pumps and minisplits have two different energy efficiency measures, as these units provide heating and cooling. The cooling efficiency of these units is still measured in the SEER, while the heating efficiency is measured as a function of the seasonal heating performance factor (HSPF).The new laws will change both the minimum SEER and the minimum HSPF, but for now we will focus on the SEER.
Before the SEER can be calculated, all new units first undergo rigorous testing to determine how much energy they consume under different conditions. Specifically, the units operate at various humidity levels and temperatures ranging from 60 to 100 degrees Fahrenheit. The new SEER2 system works exactly the same way as its predecessor, but with one major difference: it increases the amount of static pressure that units are tested at. Static pressure refers to resistance to airflow and is important because the higher the pressure, the harder the HVAC fan will have to work to circulate air throughout the duct system. This, in turn, means that air conditioners or other heating, ventilation and air conditioning units will need to work longer and consume more energy to completely cool a house. Under the old SEER system, units were tested with a static pressure of 0.1 inch, while under SEER2 this has been increased to 0.5 inches.
This is a major change as few HVAC systems have a static pressure as low as 0.1 inch. Problems such as dirty ducts, air leaks, clogged air filters and closed or clogged vents can contribute to increased static pressure. By testing units at a higher static pressure, SEER2 should be able to more accurately estimate energy efficiency and better reflect real-life operating conditions. With the new system, all refrigeration units in the northern part of the country must have 13.8 SEER2 (equivalent to 14 SEER). The new requirement in the southern half of the country is 14.3 SEER2 (equivalent to 15 SEER).
However, in Southeast and Southwest regions, this requirement only applies to split air conditioners and heat pumps of 45,000 BTU or more; for any unit under 45,000 BTU, the requirement is still 13.8 SEER2 or 14 SEER.
