I hear you...but depending how old your unit is, it may be cost efficient to replace it. We kept putting money into our old unit until five years ago when the guy said it's living on borrowed time anyway since heat pumps rarely last past 20 years are it was already that old. Yes, a new unit was $$$, but since then we've been much more efficient in both heating and cooling. One of these days, we'll have to replace our windows too, though, I think, to have it make more of a difference.
It's a tad bit over 8 years old. If it starts getting costly then I would replace it - but started with the cheapest option first!