The performance of three buildings heated with Weather Panels was modeled using Calpas3 software to determine what percentage of their space heat would be solar in four cities with cold and cloudy winters: Boston, Seattle, Munich, and Berlin. Tokyo and Paris have winters very similar to Boston and Seattle. The non-solar reference buildings from which the percentage of solar heating was calculated were insulated with R30 (or 5.25 sqM °C/Watt) walls and floor, and an R20 (or 3.5 sqM °C/Watt) ceiling. Because the reference building was so well insulated, each percentage of supplementary heat required by the solar buildings represents a small amount of fuel.

Buildings from Section
7 & 9
Solar Heating, %    
Boston 80% 100%
Seattle 76% 100%
Munich 77% 100%
Berlin 63% 100%
Super Insulated 79%  

A building with a roof made from heating and illuminating Weather Panels that is a solar and thermal model of the building shown in Section 7 was tested by the Belgian government's Building Research Institute in Brussels, which has a climate like Boston, Paris and Tokyo. BBRI coordinates passive solar test buildings and evaluations throughout Europe.. In their laboratory, BBRI measured the Weather Panels' thermal resistance and, as a function of temperature, their absorption and transmission of light. These were as predicted by Windows software. The Figure below shows the test results, which BBRI extrapolated with their elaborate modeling software to an annual solar heating of 85% in a climate where, they said, 50% had been tops. This performance, and the ability to heat with cloudlight, were predicted by Calpass3 software. The measured performance was achieved with cloudlight alone; the sun never came out during the test period.

By collecting heat and illumination from cloudy skies, and only when needed, Weather Panels make solar architecture free and simple, so it can fulfill its promise.