In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
Looking for posts related to system I'm installing - pls direct if I've overlooked. I am installing an integrated HVAC system in my modest residence:
1. Install 95+ efficient tankless combined heating boiler (ModCon, sealed combustion) to supply DHW and hydro-coil (air handler unit or AHU) replacing 70AFUE FA (60k load), 0.55EF tank water heater, and 2.5T R22 AC w/ new type, retaining most piping and duct work.
2. Control flow from AHU, perhaps trimmed to supply pressure, to achieve variable flow (see #4) and to reduce fan energy.
3. Connect AHU to filtered outdoor air, controlled to limit interior
4. Zone dampers at air terminals to direct conditioned & fresh air supply only to occupied room(s).
5. AHU to accommodate AC coil, and zone control will be modified to maintain adequate air flow across coil.
Installers seem to have difficulty selecting an AHU w/ variable flow based on duct pressure, and accommodating a water/air heating coil.
I plan to install Navien CH unit to re-establish DHW (failed tank), though have not yet found AHU that will perform per above. Comments welcome. I can document system as it is installed.
I'm an energy auditor (finally making some change after 34 yrs) & intend this system to prototype what might be installed in any house having outdated FA, tank heater & AC, while working with existing piping & duct work.