• Maximum Heat Load – the heat required to heat the house on the coldest day of the year. By minimizing the building’s heat load, we can eliminate furnaces and other expensive heating systems. Our low load residual heating systems are simpler and ensure higher thermal comfort. Heat Load is measured in Watts per square foot or Btu per square foot per hour.

• Annual Primary Energy Demand – the total amount of energy needed from a power plant (source energy) to meet on-site demand. Meeting the Annual Primary Energy Demand goal requires rigorous use of energy-efficient appliances, lighting and other power-using devices.

Annual Primary Energy Demand is measured in kilowatt hours per square foot per year (annum) or Btu per square foot per year (annum).

** Many variables including user behaviors, internal heat gains due to appliances and people make exact predictions of heat load and energy demand of the individual house impossible. However, calculations are accurate enough for all practical purposes and are confirmed by statistical averages over many buildings.