Hello,

We bought a house a while back, and part of the deal was to fix the air
conditioning unit (heat pump), on the advice of our home inspector.

The outside unit was replaced, and it is physically quite a bit larger
than the previous heat pump. (I couldn't find any performance
information on the stickers, just part numbers, and I plan to look that
up tomorrow.)

Fast forward to now: Spring has arrived (Northern Kentucky), and the
house is in the low to mid-80's inside with the air conditioner on.

I've been doing some homework, and think I understand the components
better now (compared to when we bought the house.)

I took the panel off of the air handler unit (located in our basement),
in order to have a look at the evaporator coil. The coil has rust on
the copper tubing, and it looks like the fins are dirty on the inside
(it is hard to get a good look though.)

Notably, the air blows considerably harder through our vents with the
panel off of the air handler - I assume that this is a sign that the
evaporator coil is "dirty"?

I also wonder if there might be a refrigerant leak, as the big copper
intake tube does not feel very cold at all.

Having said that, I have one important question, as this pertains to
whether the people who installed the new heat pump did their job right:

1. Everything I've read in the last couple of days says that you should
replace the evaporator coil unit at the same time you replace the
outdoor condenser / heat pump. The installers did NOT do this - they
just replaced the heat pump. SHOULD they have replaced the evaporator
coil? Is there a strong enough reason to do this that I would be
justified in demanding that they replace it now?

2. I've also read that it is important that the evaporator coil must be
carefully matched in size to the condenser / heat pump. Unfortunately,
neither of my units have any performance information on them, but I do
have the model numbers, and so I will try to find that information out
soon. But, I can tell you that the new heat pump is considerably larger
(physically, at least) than the old one. Assuming that the new one is
(significantly?) larger (in capacity) than the old one, and that the
existing evaporator coil was in fact matched to the old, smaller, heat
pump - does this also justify me in demanding that they (the installers)
replace the evaporator coil with a new (matched) unit?

When we bought the house, I didn't understand how the whole
heating/cooling system really worked. They said they would replace the
heat pump, as the old one was making strange sounds. However, it would
seem to be a bit negligent to blindly hook up a larger heat pump to an
old (rusted & dirty) evaporator coil. If this is the case, I'm also
concerned that this may affect the life of the new heat pump (being
mismatched.)

Anyway, I would appreciate any comments on this, particularly on what
the installers _should_ have done (if different), as well as any
suggestions on what to do next.

Thanks for any help!

Mike