Why we should ventilate our homes and how to do it (right)

Kiwis are notorious for two things, over ventilating and under ventilating. Getting it ‘just right’ is an essential part of a healthy home, let's take a look at why...and how.

Let’s start with over ventilating. 

This is when we leave our windows open all day in winter, to 'let the fresh air in'.  Hands up who does this?  My hand definitely went up...before I learnt leaving my windows open all day in winter not only achieved ventilation, but it also was fantastic at cooling the temperature in my home down so much it eventually matched the outdoor temperature  - or colder.  So by the time I'd get home from work my house would be freezing.  This also meant my heat source had to work that much harder to reach a healthy temperature (which wasn't always possible - and cost a lot). 

Over ventilating can definitely make a house 'feel fresh' and can get the moisture out (presuming it’s been a dry day), but the temperature in the house also becomes unnecessarily (and sometimes dangerously) low.  And if the day isn't dry, all that moisture from the rain will travel back into the house.

So what about under ventilating?

This is when we never open our windows and moisture from our everyday living stays trapped inside.  We know we need to minimise moisture at source such as using an extraction fan and practicing good bathroom behaviours (see my earlier blog) as well as using the rangehood and lids on pots in the kitchen (or opening a window), and never drying clothes inside the house (more on that in the next blog).  But even with the best practices, we'll still put moisture into the air during the evening while we are awake and at night while we are sleeping (active breathing can put up to 20 millilitres of moisture into the air per person). 

We need to get this moisture out of the house each day, otherwise it can cause us harm (think respiratory issues), and do damage to the house (think rotting).  Houses where no ventilation is practiced can often provide a breeding ground for mould, because mould will thrive in high humidity (moisture) and low temperatures.  Many houses in New Zealand have visible evidence of mould and this is not a healthy environment to be living in.

The ventilation 'sweet spot'!

We don't always need a fancy system to ventilate our houses, often all that's required is forming a new habit and using our windows. 

1. In the morning when we wake up, we need to open up all of the house, doors and windows (each end of the house and both sides).
2. Any condensation needs to be wiped away (if using a towel, make sure that towel goes outside to dry). 
3. Then, after 15 - 20mins, close everything up again.  Leave it closed.
NB: it's important to leave internal doors open when ventilating and during the day so air can move through your home, only close internal doors when heating if you don't need to heat that room (usually at night) 

This will get the moisture from the evening out, being replaced by dry (cold) air (cold air holds less moisture than warm air) without losing the temperature in your home. Remember if there is  frost on the ground, that's where all of the moisture is, so that dry, cold air is beautiful and will keep your house fresh.  If it’s raining outside, it’s still recommended to open everything up, as the overnight moisture still needs to migrate outside.

If you can repeat that exercise one more time during the day even better!

From a converted over ventilator to a pedantic 'just right' ventilator, this really makes a difference.  15 - 20mins is all it takes to ventilate and get that air change happening.  What we sometimes see when visiting homes is windows that won't open or, windows and doors that won't close and this is a problem that TradeBank wants to help with.  Are you a tradie that can fix aluminium and wooden joinery to ensure doors and windows open and close properly?  If so we'd love to hear from you, please contact Jo at jo.wills@so.org.nz or 021 2777 042