Are the relative variation rates (RVRs) approximate in different cities for the same building with the same outer-window reform?

By analyzing and comparing hourly, monthly and classified cooling and heating energy consumption of Tampa and Guangzhou, it can be found that the reduction of heat transfer coefficient of outside window can obviously decrease annual heating need. Its effect is essentially similar to the reduction of outer-wall heat transfer coefficient. The reduction of outer-window heat transfer coefficient can significantly increase the heating or cooling RVRs of the hours without solar radiation (basic RVRs) and it can also increase the heating RVRs at the hours with solar radiation. However, it can just increase cooling RVRs at the hours with solar radiation limitedly. Only supplemented with restraining solar radiation effectively, it could raise the cooling RVRs significantly. Whatever any climatic conditions, the annual heating energy consumption is governed by the classification without solar radiation (>80%) and annual cooling energy consumption is governed by the classification with solar radiation (>90%). Therefore, in order to decrease heating energy consumption, the first choice is the improvement of envelope's thermal insulation performance while to decrease cooling need, the first measure is to restrain solar radiation and then supplemented with the improvement of envelope. It is shown by the research that under the same outer-window heat transfer coefficient (i.e., the same measure of outer-window thermal insulation is adopted for the same building), the heating RVRs are approximate and the cooling RVRs are also approximate in different cities. This paper proves at another angle the universalism of approximation of heating and cooling RVRs under different climatic conditions (or in different cities) for the same building with the same energy-efficient measure again.