Type of room? living room bedroom hallway or kitchen bathroom What is below the room? heated room ground under wooden floor ground under concrete floor What is above the room? heated room a pitched uninsulated roof pitched roof insulated 50mm pitched roof insulated 100mm flat roof uninsulated flat roof insulated Type of outside walls? brick cavity insulated brick cavity 105mm solid brick 220mm solid brick wood frame insulated Type of windows? wood/plastic double glazed metal double glazed metal Single glazed wood Single glazed Number of outside walls? one two three Room height (metres)? Room width (metres)? Room length (metres)? Total sq metres of windows (h x w)? result Result (Watts) Result (BTUs)