Heater Core Output Calculator

Calculate heater core heat output for cabin heating based on coolant temperature, flow rate, and air volume.

Input Parameters

Results

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Heat Output
BTU/hr
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Outlet Air Temp
°F
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Heat Output
kW
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Coolant Temp Drop
°F
Note: Typical heater core: 15,000-40,000 BTU/hr. Low heat output usually indicates clogged core, low coolant, or air pocket. Flush heater core separately if restricted.

Reference

ΔT_max = T_coolant − T_air_in Actual ΔT = ΔT_max × Efficiency Air Outlet Temp = T_air_in + Actual ΔT Coolant Temp Drop ≈ ΔT × 0.3 Heat = Flow × ρ × 60 × Cp × Coolant_drop