Ventilation vs draughts..what on earth is the difference?
The headlines
You may have seen my information about other blog articles on this subject. They will show how ventilation in a home is essential to properly deal with damp, condensation, and indoor pollution issues.
In fact a home cannot, and I really do mean CANNOT be healthy unless there is adequate ventilation, as this other article explains.
This article helps you understand the riddle: The difference between ventilation and draughts.
The differences are not well understood and aren't explained well online either!
In this article I'm going to attempt to explain the difference in a new way!
Draughts: The most common and important feature is that many draughts, and often bad ones, cause comfort problems for your feet. The sources of them are also usually out of your control.
Ventilation: These are sources of fresh air that you can usually CONTROL as much as you need to help with damp and indoor pollution. Ventilation solutions for homes are mostly at or above head height. This usually makes them pleasant from a comfort point of view.
Draughts vs ventilation - What on earth is the difference you say?
A completely understandable question. We've all seen messaging for years that draughts are a bad thing for heat loss.
Draughts - what are they?
Draughts are sources of air entering a home that either:
DIRECTLY make you feel colder. This is especially when draughts affect how warm your feet feel. For many people, feet are the most important part of the body to keep warm to 'FEEL warm'. If our feet are warm, we will be much more likely to feel warm.
Simply leak heat uncontrollably OUT of your home.
Create very cold zones that might attract damp air and condensation.
A few examples to explain what I mean
A draught from under the back door, or door into an integrated garage: Draughts from under doors into garages can let significant amounts of cold air into a home.
If this incoming air is near your kitchen or your dining area for example it will create a very cool layer at your feet.
Air leakage through holes in ceilings in cupboards: This is a common occurrence in cupboards that either are or were once used for a boiler or a hot water tank.
These are holes, gaps, and cracks, usually from historical plumbing or electrical work.
As hot air rises this warm air will constantly trickle away into the loft. This is one of the craziest types of uncontrolled draught or heat loss in a home. It is also one of the easiest to fix.
See my other article here with other examples of this problem and tips on how to fix them.
A draught behind kitchen base units or behind a bath: This is a very common problem and will mainly be felt at foot level, making your feet feel cold.
Draughts like these can also create cold zones for condensation and mould to form behind the kitchen cupboards or behind the bath.
A draught up into your loft from around a badly sealed loft hatch: You might not be aware of a draught from a loft hatch for most of the time. But as heat rises, a landing ceiling can actually get pretty warm.
A badly sealed loft hatch will mean warm air will continually leak away up into the loft. This can also cause problems of loft condensation and rotting roof timbers. While it DOES help ventilate air through the house, it can cause a lot of harm as well as loss of energy.
See my other article here on how to fix draughty loft hatches.
Draughts in downstairs rooms from the edges of the room. This is in homes that have suspended downstairs floors: If you have floors like these, the space underneath will be very cold. It will often be only a few degrees warmer than outside.
Draughts at the edges of the room will seep cold air in, making the air at foot level cool, affecting your comfort.
Even very narrow gaps will do this.
Draught from the patio doors into a lounge: If patio doors are not adjusted or sealed properly this creates unpleasant cold draughts at foot level.
See my other article here on how to accurately identify sources of draughts on windows and doors.
Ventilation - what is it that is different about them?
As I said earlier, ventilation is ESSENTIAL for a home to be healthy. Air pollution created inside a home from normal day to day activities CANNOT escape without it.
As you saw above, a common feature of draughts is that they cannot be controlled (although they can almost always be stopped). They also often affect our feet.
Ventilation is about creating CONTROLLED ways of ventilating a home. They put you much more in charge of how you get rid of polluted and damp air.
Ventilation solutions are also mostly aimed at providing fresh air into rooms in ways that try to keep it away from your feet. This is why trickle vents are at the top of windows and extractor fans are always high up, above face height. This is also why from June 2022 trickle vents are now a mandatory fitment on both new and replacement window frames (with a few exceptions).
Faces and comfort and why ventilation is good for comfort
Studies have shown that humans generally 'like' to have fresh slightly cooler air on their faces to feel comfortable. In a car for example, most people like to have a little fresh air on their face, even in cold weather. This is especially so for the driver.
Most ventilation solutions aim at providing ventilation either at head height or higher for this reason.
Ventilation solutions are therefore better for comfort.
For a thorough practical guide on different ways to ventilate your home and putting YOU in control of damp, condensation and indoor air pollution, see this other article.
Annoying exceptions
Unfortunately, ventilation can't always be high up or at head height. Here are a couple of exceptions.
The vent below is at my parents' house, near their gas fire.
They are common in homes with gas fires and log burners. They are very important for safety. They are always at a low level like this.
This is a pain of a location from a comfort point of view. Air from this vent can be felt a little at floor level. It very much depends on the outside wind conditions and direction though. When there is no wind, you actually feel very little cold coming in thankfully.
With low vents like this for fires they should never be blocked up unless the fire is removed. You cannot control them either. They remain fully open to meet safety regulations.
Similarly, if you have a low-level vent for an old chimney breast they should never be blocked. Chimneys need ventilation to avoid long term damp issues developing in the internally.
There may be situations where you believe a vent like these is unnecessarily large. Advice should be sought from an appropriate professional on whether this is the case.
Summary
Draughts: They are out of your control, and commonly cause problems for feet comfort.
Ventilation: These are sources of fresh air that you can CONTROL and are mostly at or above head height.
There is a garden comparison here that might help:
Some plants in the garden we like (ventilation)
Ones we don't we call weeds! (draughts)
Quick links to the other main articles on this subject.
Other supporting articles on damp:
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Thanks.
Mark Thompson
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