diff --git a/src/EnergyPlus/ConvectionCoefficients.cc b/src/EnergyPlus/ConvectionCoefficients.cc
index 0e138ec41c1..8524c1b5800 100644
--- a/src/EnergyPlus/ConvectionCoefficients.cc
+++ b/src/EnergyPlus/ConvectionCoefficients.cc
@@ -6301,7 +6301,7 @@ Real64 CalcClearRoof(EnergyPlusData &state,
 
     Real64 Rf = RoughnessMultiplier[(int)RoughnessIndex];
     if (Rex > 0.1) { // avoid zero and crazy small denominators
-        Real64 tmp = std::log(1.0 + GrLn / pow_2(Rex));
+        Real64 tmp = std::log1p(GrLn / pow_2(Rex));
         eta = tmp / (1.0 + tmp);
     } else {
         eta = 1.0; // forced convection gone because no wind