Can someone help me with the difference between the Lennox XP-15 and the XP-16.

I'm missing something.

The 15 is the Signature Collection but single stage.
The 16 is Elite Series, is a two-stage and is cheaper?

Thanks

XP15 is impressively quiet. Has a nicer case and generally depending on the match up about the same full capacity efficiency rating.

XP16 isn't as quiet. Has a cheaper case design (still not bad). But it has 2 stage operation which gets you some unrated savings (seer is _base_d on full capacity). 2 stage systems aren't available in 1/2 ton increments either not that it matters too much but sometimes it becomes a little annoying.

I prefer the XP16. Lennox is going to be changing a lot of this soon. I can see your confusion, why is a "better" unit in a lower category.