Central air conditioning units are commonly rated based upon their efficiency level. High, medium or middle and standard or low are the three categories.
Efficiency level is based upon the seasonal energy efficiency ratio of the unit. Central air conditioning units with a higher efficiency are typically more expensive to purchase but generate a less expensive electricity bill.
Likewise, those with a lower efficiency ratio are usually less expensive but use more energy when running.
High Efficiency Central Air
The Consumer Search website indicates a central air conditioner system with a 16 to 23 seasonal energy efficiency ratio is the number-one rated type of unit for those who are willing to pay a higher initial price in exchange for lower overall running costs. These units often have the most energy-saving features, resulting in the lowest energy bills.
The WebHVAC Top Rated Central Air Conditioners 2011 list rated Carrier Infinity Series Model 24ANA1 as the number-one high efficiency central air conditioning unit.
Mid-Efficiency Central Air
Consumers Search indicated that buyers seeking a "balance between ongoing energy costs and initial price" are best served by purchasing a midrange efficiency 145 to 17 seasonal energy efficiency ratio central air-conditioning unit. As a result of government mandates that require a new unit to have at least a 13 rating, consumers are often given local utility and government rebates when purchasing these efficient units.
In this category, the WebHVAC Top Rated Central Air Conditioners 2011 list rated the Heil QuietComfort Model Number DXT+ as number one.
Low-Efficiency Central Air
Although minimum-efficiency units typically cost much less their long-term operational costs are much greater. That said, Consumer Search rate this type of unit number-one for consumers who will either use it infrequently, plan on installing them in rental properties or are on tight budgets.
York Affinity Series Model CZE took top honors in this standard-efficiency category on the WebHVAC Top Rated Central Air Conditioners 2011 list.