Product Guide Multi-Split Systems Several ceiling-mounted air handlers in a Mitsubishi VRF multi-split system serve this exercise room. Photo: Mitsubishi Behind the recommendations Related articles Behind the recommendations Related articles Multi-Split Systems The highest-performing mini-split and multi-split systems on the market More about Multi-Split Systems 7 Tips to Get More from Mini-Split Heat Pumps in Colder Climates Air-to-air heat pumps are getting more popular as a primary heat source in colder climates. Here’s how to get the most from your system. Cold Weather Tests the Limits of Our Mini-Split Heat Pump Ductless Mini-Splits and Their Kin: The Revolution in Variable-Refrigerant-Flow Air Conditioning New Standard Showcases Efficiency of VRF Multi-Splits Electric Heat Comes of Age: Installing Our Mini-Split Heat Pump How Air-Source Heat Pumps Work Heating with cold air? Cooling off with hot air? Heat pumps performing these feats (especially mini-splits and VRF systems) have taken off, but how do they work? Top-10 Products for 2012: Our Picks for a Resilient Future