# Direct Normal Irradiance boundary condition

Hello everybody,

I'm developing an energy model to describe the behaviour of two rooms and I'd like to impose a boundary condition on the external wall. In particular, I measured the direct normal irradiance with a pyranometer on the external wall and I'd like to use this data as boundary condition. I know that, using "SurfaceProperty:SolarIncidentInside", the incident solar radiation on the inside of the surface can be added as schedule, but I'd like to introduce the solar radiation inciedent on the outer surface. How can I do it?