I am putting a new HVAC system into a house from 1865...about 3,000 sq ft - basement and 2 stories...no duct work and not many places to put duct work. It currently has an oil boiler with the big old radiators - pretty cool IMO, and at some point I will put in a pellet boiler and zones for a supplemental system...

For the main system, I have checked out the Carrier Performance series heat pumps - we would have to do 2 units - one in the attic and one in the basement...Not a lot of room for ducts, and limited access to put the unit into the attic... Positive side is that dual controls would be pretty efficient I would think....

Just found out about the Unico systems today...one handler unit in the basement with an 8" or 9" trunk to the attic, and 2" offshoots...high pressure... Positives are that it really helps with install... I am not sure how the heat side works - the installer quoting is going to bring out a few more guys to have a look at the install for a better idea on the quote - but he mentioned that someone was using a Renai hot water coil for the heat? Never heard of that..

Not sure these systems can be zoned however? Another negative is that the Unico warranty is weak compared to most other systems.

Anyway - what are anyone's thoughts - dual or single? Is it a wash? Anyone familiar w/ Unico systems?

Thanks!