Sustainable Homes Scotland
1. Heating & Cooling
Principle: What is the more energy efficient way of keeping your coffee hot?
A: Constantly feeding energy into a heat leaking system (= active heat infusion)
B: Containing the heat in an insulated system (= passive heat containing)
The same principle applies for houses:
A: All houses loose heat through the walls, windows, roof and the floor. The heat loss of conventional buildings is substantial and to keep it warm inside almost constantly heat needs to be infused through a heating system. This is the active way of heating = through the burning of oil, gas and wood or through alternative means of heating.
B: With an optimised thermal envelope, which operates on the same principle as a thermos flask, 90% less input of heat is needed to keep it warm inside the house, compared to a good conventional build. This is the passive way of heating = through the construction of the building.
Dr. Feist, a German architect has formed this principle into an industry standard, which finds the optimum economical point of insulation. The standard is called “Passive House” or German: “Passivhaus” which is a voluntary industry standard.
No matter if you use conventional heating (oil, gas) or renewable means (solar thermal, ground source heat pump, pallet heating) the Passive House principle makes absolutely sense: Active heating costs money and the more heat is needed, the dearer it gets. Either more oil or gas is consumed or more solar panels have to be installed. Therefore a minimised heat energy demand minimises the costs of heating.
The same principle applies to the cooling of a house in warmer climates.
By the way, one nail protruding the insulation of the thermos flask reduces the heat retention drastically. That is why avoiding all thermal bridging in the construction of a house is very important.