$20k for a heat pump is sky high, you better have gotten a 24 SEER2 state of the art fully variable system for that.
If they sold you a 14 SEER1 for that then you got absolutely screwed.
If they sold you a 14 SEER1 for that then you got absolutely screwed.
Just as a data point, $20K is right in the ballpark for estimates you'll get for professional installation of a modern ≈3-ton forced-air 17SEER heatpump + air handler in the Seattle area.
People use the term "heat pump" to sometimes describe quite different things, so it's hard to know what's apples-to-apples.