Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit https://heatinghelp.com/contact-us/.

New Hydro Air HVAC

cyates72cyates72 Posts: 1Member
edited September 18 in Gas Heating
I recently had a new Hydro air heating system installed:
2 - Bosch AHU50 Air Handlers (Zone 1 - main floor / Zone 2 - basement) 65K BTU 1000CFM
1 Bosch Greenstar 151 Combi boiler / hot water unit 97% AFU (Propane)


I live in New Hampshire where it gets really cold in the winter! I had a blower test and it was 1900 out of 4300. I have calculated needing: Zone 1 at 45 BTU per sq ft 90K BTU and 1732 CFM (15 vents) and Zone 2 77K at 45 BTU per sq ft and 1168 CFM (14 vents).

The House
Log home (Zone 1)
2000 Sq Ft with 19 foot ceiling in the main room and three bedrooms with 12ft ceilings
The log home is 9in Pine tongue and groove logs stacked with new caulking in between (R13).
Two nine foot sliders on the front of the house with two huge windows above

Basement Zone 2
10" concrete walls with 1in insulation on the outside, 2 in air gap in between 2x4 insulated walls, 9ft ceilings (R23)

The old system:
Zone 1 - Pellet furnace 112k BTU 100K BTU 1450 CFM (89%)
Zone 2 - Oil furnace 80K 1050CFM (86%)

There was some ducting issues that I have fixed and you can feel the air coming out of the vents. I had a 10x8 trunk that distributed to a 10x8 x24 distribution box with 4- 7" and 2 - 5" takeoffs via flex duct. I replaced with 10x8 r8 insulated ducts to the rooms and two 7" R8 insulated duct. I removed close to 220 feet of flex and replaced with 70 ft of metal duct.

My question is:
Based on the old system I feel that the new system for Zone 1 does not have enough CFM to properly distribute the air. Also, the system rates at 65K BTU but because it is a Hydro air solution it can go to 80K. Should I be concerned with the CFM? Would the system be more efficient going to the 90K BTU with 1400CM (Bosch AHU70)?

Thanks
Sign In or Register to comment.

Welcome

It looks like you're new here. If you want to get involved, click one of these buttons!