Final answer:
Residential air-conditioning systems have efficiency ratings such as EER and SEER, which are essential for energy-saving and cost-effective operation. These ratings depend on the installed coil type and are impacted by the difference in indoor and outdoor temperatures.
Step-by-step explanation:
The temperature settings (t-stats) on most residential air-conditioning systems are crucial for maintaining the system's efficiency ratings. These ratings, such as the Energy Efficiency Rating (EER) and the Seasonal Energy Efficiency Ratio (SEER), help determine how cost-effectively these systems operate.
Notably, efficiencies are higher when there is a small difference between the indoor temperature (T₁) and the outdoor temperature (To), as this impacts the coefficient of performance (COP). Additionally, when choosing an air-conditioning system, the installed coil type can affect the system's heating efficiency, which can vary slightly by geographic region.
Air-conditioning systems are most cost-effective when they operate in climates that require less energy to maintain the desired indoor climate, which is why the SEER is averaged over the cooling season, and the Heating Seasonal Performance Factor (HSPF) over the heating season. For consumers, the EER and the Energy Star Rating provide a quick reference to assess energy efficiency. Remember that while a higher EER can mean lower operational costs, it might also mean a higher initial purchase price for the air-conditioning unit.