I would appreciate any advice the knowledgeable folks on this board can spare the time to give me.

A little background: Our house is 13 years old. It was one of the builder's models before we bought it 10 years ago, so we're the first to live in it.

HVAC has always been a problem with this house. It's a two-story with 2600 sq ft on a slab, but it only has two returns, one directly into the unit in our attic from a 20x20 opening in the ceiling of the second floor, and the other a similar size in the wall downstairs that has very little draw. This was my first home, so I didn't know what I was doing. Apparently the builder has avoided lawsuits by "undercutting" the bedroom doors and claiming that takes the place of employing proper returns. Every contractor who has ever been in my attic has commented on the shoddy ductwork done by the builder.

The original coil busted a few years ago, and I replaced it with a heat pump, keeping the gas furnace for a dual fuel option. It seemed like a smart option at the time. However, the A/C has still struggled to keep up in the summer, and sometimes freezes. The company that installed the heat pump said at the time that we really should have them come in and redo the ductwork to improve the number of returns. Again, I was younger and dumber then, and couldn't justify the expense to myself.

Well, yesterday the A/C went out, and it's not an issue of just freezing over anymore. It appears our compressor died. Since I don't have adequate ductwork, any warranty repair would be unlikely.

I called in a competitor that tops Angie's List, and which once even got a recommendation from an employee of the company that installed the heat pump. They are recommending a complete system replacement. I wonder, though, if the sales guy felt sorry for us, and tried to recommend all bottom-of-the-line equipment to keep the total cost down. That's why I'm coming to you guys, to see if I need to ask for upgrades.

Here's the recommendation:

* Lennox ML180UH090E60C 80% furnace with direct current blower package

* Lennox HC10 air cleaner (I already asked to upgrade to HC16 because of allergy sufferers in the family)

* Lennox programmable thermostat

* Replace refrigeration lines (high diameter copper) to handle R410A

* Lennox 14ACX048 (4 ton) A/C

* Lennox C33 evaporator coil and r.f.c.

* Wet switch installed in drain pan

* Install ceiling returns in all 4 bedrooms (2nd floor)

* Install ceiling return in family room (other end of downstairs from current return)

* Combination of new returns should get the input and output (16 vents) of my system balanced at 1600

* Rework supply trunklines and reattach flex supplies to the new air distribution

Total cost: $9,900

I'm in Louisville, KY, if that matters.

So, do I need to ask them to upgrade anything?

This contractor says high-efficiency furnaces aren't a good idea in an attic. I can't remember if he said that local code actually disallows. But I have read comments both ways from folks on this board and others, so I may be okay with that aspect of his recommendation. However, should I insist on a variable speed blower?

I may have limitations based on the configuration of my attic. They used trusses, and the pitch of the roof makes it difficult to have a very tall vertical installation. In fact, the guys who installed the heat pump had to custom build a piece at the top to "bend" (my word, not theirs) the airflow before it hit the roof. So the new installer wants to use shorter equipment to take that quick bend out of the ductwork and improve airflow.

What do you think? Is my guy steering me the right way? Or should I make any upgrades?

Thanks in advance!