# Eplus Conduction Rate and Uvalue of the wall check

Dear all,

I am performing a simulation assuming the following parameters

- SurfaceConvectionAlgorithm:Inside,TARP
- SurfaceConvectionAlgorithm:Outside DOE 2 -Heat Balance algorithm: ConductionTransferFunction
- Zone air heat balance :AnalyticalSolution

Energy plus version 8.9

I have assessed the uvalue of a wall without surface thermal resistances because are both calculated by Eplus itself per each timestep.

Assuming that my wall has an U value of x W/m2K and i want to check if this value is the actual one calculated by the software, should I have to subtract from

Surface Avg Face Conduction Rate - Surf Outside HG Rate - Surface Inside HG Rate

and then divided it by the difference in temperature btw indoor and outdoor and the overall area? ( case without take into account conductive solar gain)

Following the previous for a wall of 0.98 W/m2K after the permutations i get a result that is almost two times. Why?

Furthermore If i divide the Surface Avg Face Conduction Rate by the difference in temperature btw indoor and outdoor and the overall area (without solar conductive gain) i don't get a result that is equal to the sum of the above mentioned uvalue plus the outside and inside convective coefficients .

Did I forget something?

I am very concerned because I want to check manually the reliability of the results and i still don't get any correct Uvalue, thus leading to higher thermal loads.

Thanks in advance