Draught Excluder Blog

Fitting a draft excluder or two is a fantastic way to save energy in the home. If you’ve not already fitted some to the windows and doors in your home, you could be wasting hundreds of pounds on your heating bills and pumping unnecessary into the atmosphere. Of all the energy efficiency improvements you can make, very few (if any) are as cheap and easy.

Draughts are caused when both two things happen: -
1 There are gaps in the walls, windows, doors, floor boards, etc
2 There is a pressure difference between inside and outside

Pressure differences in the home are caused by: -

a) Wind
Moving air creates a low pressure – the faster the movement, the lower the pressure. One of the best times to test your house for draughts is on a windy day.

b) Combustion
Burning wood in a fireplace causes the movement of air up the chimney. This is most obvious in the case of a wood burning with a glass window stove because as you adjust the ventilation you can see a the flames drawing air into the stove and up the chimney.

c) Extractor fans
Any air that is taken out of a bathroom or kitchen by an extractor fan will be balanced by air being drawn into to take its place.

d) The Stack Effect
Warm air is lighter than cold air so in winter and at night, when there is the biggest difference in temperature between inside and outside, this effect is most noticeable. The more stories a building has, the more this effect has. As a consequence, a draught excluder is most effective in basements or attics.

Other Handy Facts About Draught proofing:-
Draughts always take the easiest path – meaning the bigger gap, the more air will pass through. For example, an open chimney is one of the biggest problems for draught proofing.

Internal stud partitions can cause draughts as the link up the the space under the floors with the attic space.

You don’t always feel a draught. Warm air leaking out can’t easily be felt, but it will be balanced by cold air coming in somewhere in the house. That could be in a hidden spot like under the stairs or under the floorboards. One way to test your house is to walk around with some incense and watch where the smoke travels.

o Airflow will always take the path of least resistance. The greater the size of the opening, the more air will pass through. This only highlights the importance of ensuring that the largest voids are attended to first and that we discover where they are. Especially in older houses, air flow can occur through vertical channels up through the house interior. This is particularly true of wood-framed structures, but it can also occur in internal stud partitioning that connects top and bottom with the floor cavities. The same thing can apply to staircases and vertical service runs that are boxed in and allow large volumes of air to flow from floor to ceiling.

o Incoming cold air draughts arc balanced by outgoing warm air leaks. This is another obvious fact that we are often not aware of-simply because we don’t feel outgoing warm air leaks as we do incoming cold draughts. In two- or three-story buildings it is often noticeable that there are draughts at ground floor level, but these are not so apparent in the upper story or attic unless it is windy. We never go outside and up a ladder to the second floor windows on a cold day to check for hot air leaks!

Stay tuned! More draught excluder tips to come….