diff --git a/src/emitters/sun.cpp b/src/emitters/sun.cpp
index 2f32a360..72a638f2 100644
--- a/src/emitters/sun.cpp
+++ b/src/emitters/sun.cpp
@@ -178,7 +178,7 @@ public:
 		Spectrum *target = (Spectrum *) bitmap->getFloatData();
 		Spectrum value = 
 			m_radiance * (2 * M_PI * (1-std::cos(m_theta))) *
-			(bitmap->getWidth() * bitmap->getHeight()) 
+			static_cast<Float>(bitmap->getWidth() * bitmap->getHeight()) 
 			/ (2 * M_PI * M_PI * nSamples);
 
 		for (size_t i=0; i<nSamples; ++i) {
diff --git a/src/emitters/sunsky.cpp b/src/emitters/sunsky.cpp
index c3e76f80..9e85692b 100644
--- a/src/emitters/sunsky.cpp
+++ b/src/emitters/sunsky.cpp
@@ -173,7 +173,7 @@ public:
 
 		Spectrum value = 
 			sunRadiance * (2 * M_PI * (1-std::cos(theta))) *
-			(bitmap->getWidth() * bitmap->getHeight()) 
+			static_cast<Float>(bitmap->getWidth() * bitmap->getHeight()) 
 			/ (2 * M_PI * M_PI * nSamples);
 
 		for (size_t i=0; i<nSamples; ++i) {