It matters if some of the delivered energy goes right back out the window.
Inside the room, heat the floor and you'll have convection and such pushing heat everywhere.
Inside a hot curtain even if it had 0 insulation value, half (ish) of the heat is going to head towards the room, and half (ish) is going to head back towards the window. The hotter the pocket between the window and the curtain, the more is going to head towards the room, the better the curtain is insulated, the more is trapped against the window to be transmitted back outside.
DogsSureAreSwell t1_iva0al9 wrote
Reply to comment by fml87 in Researchers designed a transparent window coating that could lower the temperature inside buildings, without expending a single watt of energy. This cooler may lead to an annual energy saving of up to 86.3 MJ/m² or 24 kWh/m² in hot climates by mossadnik
It matters if some of the delivered energy goes right back out the window.
Inside the room, heat the floor and you'll have convection and such pushing heat everywhere.
Inside a hot curtain even if it had 0 insulation value, half (ish) of the heat is going to head towards the room, and half (ish) is going to head back towards the window. The hotter the pocket between the window and the curtain, the more is going to head towards the room, the better the curtain is insulated, the more is trapped against the window to be transmitted back outside.