The total thermal resistance of the overall heat transfer through a single layer plane wall is given by the formula: R=(1)/(alpha _(1))+(delta )/(lambda )+(1)/(alpha _(2)) R=(1)/(frac (1)(alpha _{1))+(delta )/(lambda )+(1)/(alpha _(2))} R=(1)/(alpha _(1))+sum _(i=1)^n(delta _(1))/(lambda _(1))+frac (1){alpha _{2 R=(1)/(frac (1)(alpha _{1)d_(1))+(1)/(2lambda )ln(d_(2))/(d_(1))+ R=(1)/(alpha _(1)d_(1))+(1)/(2lambda )ln(d_(2))/(d_(1))+frac (1){

The total thermal resistance of the overall heat transfer through a single layer plane wall is given by the formula: where R is the thermal resistance, α1 and α2 are the thermal diffusivity of the two surfaces, δ is the thickness of the wall, and λ is the thermal conductivity of the wall material.