When claiming a residential energy credit for a heat pump, 1) how do i know my unit qualifies? 2) If it does, how do i know what to enter in for the kilowatt capacity?

Your heat pump must exceed the CEE highest rating tier for 2024 to claim the credit in 2024.  You can search here to find out if your model is on the list of qualifying models. 

For a unit installed in 2024, it must be in the top tier (not including an advanced Tier)  of CEE ratings that were in effect as of January 1, 2024. CEE ratings are equivalent to "Energy Star Most Efficient", which is a higher level than a general Energy Star rating. 

https://cee1.org/program-resources/tiers-and-energy-star/

For example, if the CEE has Heat Pumps listed in Tier 1, 2, 3 and Advanced, only a unit that is in Tier 3 or higher would be eligible, not Tier 1 or 2.  

You can search here.

https://www.ahridirectory.org/

Kilowatt capacity is only needed if you are claiming a credit for battery storage or a fuel cell device, it is not part of the credit for a heat pump.