I purchased an entire whole house setup because the home I bought did not have AC. I live in New Hampshire. I purchased 10 tons of cooling – 2-36,000 units and the 48,000 unit. This was sold to me as 'this will heat your home, too'. Fast forward to two years of use, and I can tell you this: 1. The AC works well – be sure it's sized properly for your use. I have one section of the home where it's not sized properly and I'm having the contractor come in to add another head. 2. The heating piece is good down to 30 degrees outside, at the most; 20 degrees is worst case. Below that, it's a useless pig that will kill your electric bill. Let me be clear. If you expect these units to perform below 20 degrees you're kidding yourself. My experience showed these usages: October: approximately 2200 Kw for my home. November: approximately 3200 Kw for my home. December: approximately 6300 Kw for my home (and a whopping $1500 electric bill to boot). Now I shutdown the Mitsubishi's from Thanksgiving to April. I have oil heat, hot water baseboard. That's what I use in the winter and it is a superior heat as well as cheaper, even when oil was $3.75 per gallon. I laugh when I see these installers claim they work down to -5 degrees; they're either lying or don't have experience with these units. To prove this, ask your installer: do you have a backup heat source at your home? The 3 installers that worked at my house and installed my system all had backup heat systems. Do not buy these for full-time heat. They are efficient in my area from September to the middle of November, and then from April to the end of May for heat. But during the dead of winter these things are useless. I repeat, useless. Make sure you have backup heat.