Like most other products for your home, the technology for air conditioning systems has vastly improved over the last 10 years. The efficiency of systems has improved, thermostats have become smarter, and even the refrigerant has been updated to be more environmentally friendly. One change having the biggest impact on overall performance is the shift from single stage cooling (On or Off) to multi-stage cooling (2-stage all the way to true variable speed). The benefits behind having multiple cooling stages are higher efficiencies, better comfort and indoor air quality, and quieter operation.
Multi-stage equipment is able to take advantage of lower cooling demands by operating at lower stages. The lower stages use less electricity which makes the system more efficient in the summer, and in the winter if you have a heat pump system. SEER (Seasonal Energy Efficiency Ratio) and HSPF (Heating Seasonal Performance Factor) ratings are like your car’s MPG – the higher the number the greater the potential for savings. For example, Carrier’s Infinity Series heat pumps offer a range of efficiencies that reach as high as 20.5 SEER and 13 HSPF. To put this into perspective a basic single stage heat pump starts at 14 SEER and 8 HSPF.
The real reason why you pay a premium for multi-stage equipment is for the better comfort and indoor air quality. Not only does this equipment control the temperature in the home, but it also has the capability to control humidity. As outdoor conditions and demands inside the home change, the equipment makes adjustments to maintain your comfort levels. This allows the system to operate longer and steadier throughout the day, and constantly remove moisture from the air. Also, since the system operates longer it is pulling more air through the filters thereby removing more dust and debris.
Most manufacturers only offer multi-stage systems in their higher tier offerings. For example, Carrier’s 5 stage and variable speed systems are only offered in their Infinity platform. Higher tier equipment comes with sound dampening features like a compressor enclosure, and when you couple this with the quiet operation of the lower stages the result is a more peaceful home.