Air conditioning systems have two basic characteristics: Capacity and efficiency.
Residential HVAC system capacity is measured in tonnage, an archaic industry term which refers to the quantity of heat the system can remove in an hour. Typical Residential capacity ranges from 1.5 ton units which can remove 18,000 BTUs per hour to 5 ton units which can remove up to 60,000 BTUs in an hour. An Energy Vanguard article digs into the history of “tonnage” as a measurement unit.
Larger capacity is not inherently better. Large units are generally more expensive and, if used in smaller spaces, cool air too quickly to adequately remove humidity – providing less comfort than an appropriately sized unit. Undersized a/c systems may never be able to adequately cool a space. Stan’s Project Managers are expert at sizing units for a space. Your Stan’s Project Manager will make sure to recommend the right size unit(s) for your home.
Efficiency is expressed with Energy Efficiency Ratings and Seasonal Energy Efficiency Ratings. EER and SEER are related. EER is a direct measurement of a system’s cooling output compared with its energy input, using specific indoor and outdoor temperatures. The more cooling a unit produces from a single unit of energy, the better the EER. SEER applies this concept to approximate efficiency across a range of conditions, simulating an average year in a specific location. The Department of Energy mandates a minimum SEER in Texas of 14 SEER, as of 2015.