New Heat Pump Technologies

Heat pumps provide both heating and cooling, so they are very practical for Tennessee’s climate. High-efficiency heat pumps also dehumidify better than standard central air conditioners, resulting in less energy usage and more cooling comfort in summer months. However, the efficiency of most heat pumps as a heat source drops dramatically at low temperatures, generally making them unsuitable for cold climates.

Technology Advances

The new crop of heat pumps offer technology advances that not only make heat pumps perform much better during extreme temperatures, but also double the efficiencies of 10 years ago. Indeed, the market has been heating up for heat pumps growing by double-digits in each of the last 2 years! Here are a few of the advanced features:

• Inverter Technology: varies the flow of refrigerant and adjusts the speed of the compressor according to the desired temperature and the current room temperature. By eliminating the cycling on and off of the compressor, efficiency is increased, and the temperature stays more steady.
• Two-Speed Compressors: save energy, reduce compressor wear, and allow zone control (keeping different rooms at different temperatures).
• Variable-Speed Blowers: allow the fans to keep the air moving, minimizing cold drafts, reducing noise from the blower, while also maximizing electrical savings.
• Scroll Compressor: consists of two spiral-shaped scrolls – one remains stationary, while the other compresses the refrigerant. Compared to the typical piston compressors, scroll compressors have a longer operating life, are quieter, and provide 10-15°F warmer air when in the heating mode.
• Back-up Burners: rather than using electric resistance heaters as a backup heat source during extreme cold weather, some manufacturers now use a combustion fuel source such as propane, natural gas, oil, coal, or wood, thus reducing the use of electricity.
• Refrigerants: the new crop of heat pumps use the more environmentally-friendly and less costly refrigerants, and new refrigerant formulations transfer, hold and deliver heat more effectively. Plus, the copper tubing through which the refrigerant travels has grooves on it to increase surface area, which also boosts efficiency.
• Computer-controlled motors and valves: consume less electricity and provide more precise control of the refrigerant flow.
• Electronic, programmable  thermostats: many of which are now wireless or Internet-capable, allow additional savings and conveniences. Check out our previous blogs on thermostats.

What to Look For

When shopping for a new heat pump system, check the Energy STAR® label and compare the HSPF rating (heating season performance factor) which is an indicator of the efficiency of the compressor and the electric-resistance elements and the SEER rating (seasonal energy efficiency rating), which rates a heat pump’s cooling capacity (see our post What’s Your SEER?).  HSPF should be between 8 and 10 and SEER should be greater than 14. In both cases, the higher the number, the more efficient the unit.