R-22(Freon), which comprises of Hydro chlorofluorocarbons (HCFCs) has always been referred as an anti-environmental element. This is because these elements can make holes in the ozone layer which is also termed as ozone depletion. These holes in the ozone layer allow the harmful UV rays from the sun to penetrate into the earth’s atmosphere. These UV rays can then lead to an array of health hazards. Therefore the U.S. government has directed that all producers of air conditioning equipment phase out production of the refrigerant R-22 (Freon) or Hydro chlorofluorocarbons (HCFCs). The air conditioners have been using R-22 for many decades. The government has mandated that air conditioner should move to a more eco-friendly refrigerant technically called R410A.

Therefore since the beginning of this decade, the air conditioner manufacturers started making condensing units, without filling it with R-22. Thy fill it with an inert (nitrogen) holding charge and ship it to the outlets. Once these are purchased by the user, thy get it filled with R-22 by a local HVAC contractor. This is also called dry charging and these R-22 units are called “dry shipped” condensing units. The R-22 in the old system is captured. The nitrogen in dry-charged unit is emptied. Then the new unit is field-charged with R-22. R22 is still legal for HVAC contractors for a short time longer.

However it is worthwhile to note that that these units have a lower Energy Efficiency Ratings (EER), compared to new and advanced R-410A systems. But they are popular among homeowners because of their low prices. They go for it especially, if the air handler and indoor coil are working fine. Almost three-quarter of a million dry-charged units were installed in 2011.