How is your house performing? Have you put in insulation into your home, but yet it is still cold and draughty in winter and too hot in summer? Do you know where the heat is escaping?
Draughts + air-leakage
Older style buildings commonly have draughts and air-leakages due to unsealed windows and doors, and unsealed vents and exhausted fans, therefore, heat and air can escape. It is difficult to control the air movement. Other sources for draughts are gaps within or around insulation, vented skylights, gaps between floorboards, open fire places, around air conditioners and heaters, gaps around other wall penetrations, such as down lights, pipes, cables etc. .
A thermal bridge is an element or part of a building, which allows heat to travel through it more quickly than through other parts and is therefore responsible for unwanted heat loss or gain. A thermal bridge arises for instance when poor insulative materials touch each other, when gaps occur between insulative materials and structural surfaces, and when materials with different R-values/U-values come in contact with each other. These thermal bridges allow heat transfer from a warmer to a cooler material. The main thermal bridges in a building are located at the junctions of floor to the wall, wall to the roof, balconies and window and door frames.
How to locate draughts?
– Are there any visible gaps? For example is light coming through gaps around windows and doors?
– Are blinds or curtains moving when the windows are closed?
A lit candle can be used to check air movement, such as around windows and doors, vents, floorboards, junctions of floor to wall and wall to roof connections
Obiously, when building a new home or when renovating your home you want to make sure that you don’t have any air-leakage or thermal bridges. Avoiding thermal bridges is extremly critical when you are aiming for a passive house standard.
A good way to access the air-tightness of a house is a blower door test.
A blower door is a powerful fan that is mounted into the frame of an exterior door. The fan pulls air out of the house, lowering the air pressure inside. The higher outside air pressure then flows in through all unsealed cracks and openings. This tests determine the air infiltration rate of a building and how much air can escape.