Hi,
I just finish building 2 story ICF house in Connecticut. I had someone run Manual J for me with following results.
1st floor heating 14,583, cooling 7,098
2nd floor heating 16,024, cooling 8798
I also have done my own Manual J (CoolCalc) and BeOPT.
CoolCalc Manual J.
- Per room, 1st Floor heating 18,101
- Per room, 2nd floor heating 9,618
- Total Heating 33,509, Cooling 21,534
(I don’t understand why per room sum of outputs does not add up to final CoolCal output, is this bug in CoolCalc? (18,101 + 9,618= 27,719)
My 1st and 2nd floor dimensions are equal except I have more inner rooms with no outside wall exposure on the 2nd floor (laundry, walking closet, hallway, bathroom) these rooms have very small load which I think is throwing this imbalance between 1st and 2nd floor load. 1st floor more than half floor is 1 open space.
BeOPT
My own beopt calc,
House heating 28,900, cooling 18,000.
I’m planning on installing propane on demand boiler/water heater (Rinnai, Navien, Buderus, etc)
I have couple questions:
1. Which boiler would be good for family of 4 with occasional additional 2 to 4 occupants? BTW I’m on the well at 3.5 GPM.
2. I want to install underfloor in joist heating. How should I limit the output from PEX as at max rate 35 btu per foot I will be overheating my house. I need approximately 12 btu per foot.
3. Should I only have 1 run of ½ PEX per joist with heating shield to limit amount of PEX and control rest with water temp and flow?
4. Here is my main question. I’m not sure how I can calculate ratio of footage/temp/flow to get right output? Is there a formula that I can use for this?
BTW I’m working with heating/plumbing supply house to design my heating system but I’m not having full confidence that they are doing this correctly. I would like to educate myself so I can design or at least confirm someone else calculations.
Any help or direction to some source would be very much appreciated.
Thank you.
Jerry.