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# Revision history [back]

### Window heat transfer

Hello all,

I already looked at previous questions but I still can not find an answer:

For a simple energy plus model, a room with one southside two pane glass window ( no frame, no divider, etc...)just glass:

(Surface Window Heat Loss Energy) is not equal to (Window Inside Face Net Surface Thermal Radiation Heat Gain Energy) and (Window Inside Face Convection Heat Gain Energy).

The calculation is for 1 am, so there is no solar radiation. There is no light and internal heat, so heat loss through inside window face should be only by convection and radiation. The difference is small but I wonder what cause this difference.

(Surface Window Heat Loss Energy) is a little higher than the sum of (Window Inside Face Net Surface Thermal Radiation Heat Gain Energy) and (Window Inside Face Convection Heat Gain Energy). This is also the same for single glass window, Why?

Thank you,

 2 retagged Aaron Boranian 12565 ●49 ●20 http://bigladdersoftware.com/

### Window heat transfer

Hello all,

I already looked at previous questions but I still can not find an answer:

For a simple energy plus model, a room with one southside two pane glass window ( no frame, no divider, etc...)just glass:

(Surface Window Heat Loss Energy) is not equal to (Window Inside Face Net Surface Thermal Radiation Heat Gain Energy) and (Window Inside Face Convection Heat Gain Energy).

The calculation is for 1 am, so there is no solar radiation. There is no light and internal heat, so heat loss through inside window face should be only by convection and radiation. The difference is small but I wonder what cause this difference.

(Surface Window Heat Loss Energy) is a little higher than the sum of (Window Inside Face Net Surface Thermal Radiation Heat Gain Energy) and (Window Inside Face Convection Heat Gain Energy). This is also the same for single glass window, Why?

Thank you,