Manual J calculator?

[PCustoms]

Is there a good manual J spreadsheet out there?

Trying to confirm what we need for some family, old quote was for 18k btu which seems undersized.

• 1k sqft over walkout basement
• 10' ceilings in 50%, balance is cathedral to 20'
• 500sqft loft
• NW gable end has over 75sqft of windows (low e) and a glass patio door
• 2nd entry door on W side
• Another 40sqft windows spread around
• R30 walls, ceilings are 50+

House kicks up a lot of heat from the afternoon sun.

 

[American Locomotive]

18k doesn't sound too out of line for that house, especially considering the decent insulation. We have 20,000 BTU worth of window air conditioners for our 1800 sq ft 1700s home with some exterior walls still uninsulated and almost no insulation in the ceilings. It keeps up just fine in RI. House gets baked by the sun, too.

The reality is most homes have grossly oversized heating AND air conditioning systems.

 

[ericm]

HVAC Load Calculation - Maunualj - Whole House Loadcalc

ManualJ load calculator, HVAC calculation, Whole house, - www.loadcalc.net

www.loadcalc.net

 

[PCustoms]

HVAC Load Calculation - Maunualj - Whole House Loadcalc

ManualJ load calculator, HVAC calculation, Whole house, - www.loadcalc.net

www.loadcalc.net

Yeah I get 7k btu

Using it wrong or it's broken

 

[ericm]

It's kinda tricky. I kept getting low sounding numbers and then going over it and finding I missed an entry.

 

[PCustoms]

Bumping soni can find this later.

Time to do my house this summer.