Comment I have an ancient heat pump (Score 1) 361
By these numbers in the article, my 70s built home is apparently a real rarity. I have no idea how old it is as the plate is beyond legibility, but my wife's HVAC-company-owning in-law just said "Man, I've only heard that brand name, never seen it. It's old!"
It is an interesting concept where it really does run backwards to generate heat. In the warmer months, it removes heat from inside the building and takes it outside to that hot exterior unit. In the cold months when the heat is on, it is doing the same thing, believe it or not. It's removing heat from the chilly cold air and making the interior unit hot. This means the exterior unit's coils are going to be colder than the outside air, so it may very well develop ice on the coils. That's where the disadvantage comes in to play for me. It obviously may be at more of a disadvantage in really cold areas needing to defrost more. How does it defrost? It has to run in AC mode... in the winter. So I'm up early in the morning getting a shower and all of a sudden, seems to happen when I'm getting out, cool air starts blasting out of the vent. Wakes me right up.
This defrost mode can also make a bit of racket as things change direction. The exterior unit is by our bedroom window and one of the first nights we slept here, the defrost kicked on and woke us up. Sounded like air brakes on a bus.