I am building a 2 story custom home in the Los Angeles inland valley area.  I already have a 7KW solar PV system in operation.
In looking for a solar domestic water system I received this proposal for a hydronic forced air system. (much consideration has lead me to use forced air for the system due to the A/C)  

I am not familiar with a hydronic forced air system(?) Any experience? 

The proposal is to not try to use solar to heat the house but size it for just the DHW. (this was discussed elsewhere in this forum related to a radiant system) But in this combo system I am thinking that during our 'winters' (not freezing, but heavy, gray overcast) it will be functiong as a 100% boiler system. (for the DHW and heating)

Also how reliable are the proposed components and will there be service available for a European design in 10+ years?
Maybe a using a solar DHW system and a high efficiency furnace separately would be better?
The proposal aint cheap, but if it will be best in the long run that is what I am seeking.


Description of Work: A Complete 4 Zone HVAC system Approximately 4,300 sq. ft. conditioned space
More specifically as follows:
1) Generate heat loss and heat gain report for residence. Custom design installation for building parameters. Detailed heat gain / loss and boiler load data are now available on the home.
2) Supply and Install Thermostats w/night setback for each radiant and HVAC zone.
3) Supply and Install Viessmann Vitodens 200 6-24 95% AFUE Modulating / Condensing Boiler
4) Supply and Install Viessmann Vitocell 300 119Gl indirect WH Tank w/ LIFETIME Warranty
5) Supply and Install 2) ESP HE-140H DX cooling / hot water fancoil heating Air Handlers
6) Supply and Install 1) Ruud 16 SEER / 2 Stage / 5 ton and 1) 4 ton 410a condenser units.
7) Supply and Install Flex ductwork, standard white supply and return frills
8) Supply and Install Arzel zone damper system and controller to create 4 discrete zones.
9) Pipe Fancoi Loads from Boiler. Pipe boiler to Indirect Water Heater for DHW production ProgramViessmann Comfortrol boiler control module
10) Purge, Test, and Commission systems.

Option 1 – *Solar Thermal Option. Supply and Install 2) Schuco Slim “V” solar collectors. Upgrade tank from 119 Gl single coil to 119 Gl dual coil. Provide mounting system insulated lines to roof, pump and sensor to provide solar hot water with boiler back-up.

Option 1 – Supply and Install SunPure SP-200 MERV 11 air cleaner w/ UV light sterilization