Manual J Load Calculator (Tampa Climate)
Estimates residential heating and cooling loads for Tampa, FL using ACCA Manual J simplified methodology. Tampa design conditions: 92°F dry-bulb / 77°F wet-bulb (cooling), 36°F (heating).
Building Envelope
Construction Details
Infiltration & Ventilation
Internal Gains & Occupancy
Orientation & Shading
Formulas Used
Conduction Heat Transfer (Cooling & Heating):
Qcond = U × A × ΔT × CLF
where U = 1/(R + Rfilm), A = area (ft²), ΔT = design temperature difference (°F),
CLF = Cooling Load Factor (accounts for thermal mass time lag)
Solar Heat Gain (Cooling):
Qsolar = Awindow × SHGC × Ipeak × OrientFactor × ShadingFactor
where Ipeak = 200 BTU/hr·ft² (Tampa peak solar intensity)
Infiltration – Sensible:
Qinf,s = 1.10 × CFM × ΔT
CFM = (ACH × Volume) / 60
Infiltration – Latent:
Qinf,l = 4,840 × CFM × ΔW
where ΔW = humidity ratio difference (lb/lb dry air)
Internal Gains:
Qlighting = W/ft² × Area × 3.412 BTU/W
Qoccupants,s = N × 250 BTU/hr (sensible)
Qoccupants,l = N × 200 BTU/hr (latent)
Tampa Design Conditions (ACCA Manual J / ASHRAE):
Cooling: 92°F DB / 77°F WB outdoor; 75°F / 50% RH indoor
Heating: 36°F outdoor; 70°F indoor