Lesson Ten: Air Movement
Heading into warmer months, spring is here, and summer is coming (yay)! But what does this mean for how we feel in our homes? We have just spent the last six months warming up our home over winter, and it’s cosy – but potentially too warm now the seasons are changing. So, what now…?
What can we do to cool ourselves, and our home, in the warmer months?
Firstly, you shouldn’t need to hang out at home in your underwear to cool down – the trick is to get air movement happening inside the home, which will certainly make you feel cooler and allow you to keep your clothes on (reference to Peter’s ‘joke’ on the podcast)!
And why does air movement help?
- Air movement blows air across your skin, and if you are hot and have a bit of sweat on your skin the air will evaporate this and subsequently make you feel cooler
- The sun makes us feel hot, but the actual air temperature is cooler than what the sun makes us feel – so bringing the exterior air inside helps us feel cooler.
What do we need to cool down?
A balanced pressure ventilation system would be best. A what? Basically, a fancy box with a two fans and tubes that suck air inwards and blow air outwards. There’s also a filter in there to remove any particulates and pollutants (where are you Captain Planet?).
If you rent your property, you are probably somewhat restricted to what you can install – you can’t really go installing a full ventilation system. To substitute for this (number 8 wire approach), you could always get a large fan and place it in the doorway to either shift the air inwards or outwards. It works well enough, but you do need to think of where the air is coming from, so if you are blowing air outwards (remove kitchen / cooking smell etc) – you should have a window open elsewhere in the home so you are replacing the air that is being removed. Having this cross flow of air is really important – if you don’t have a cross flow, it won’t work as well, and the air that is being pushed outward could end up finding its way back in! And if the air is cool outside, turn the fan around so that it pulls air inward to cool your house.
Does a heat pump provide ventilation?
Ahhhh the old heat pump. Around 98% of the time heat pumps will not have ventilation. Only the really super fancy ones pull fresh air in from outside. Heat pumps work by sucking the air around it, warming it up (or cooling it if it has AC) and then blowing it back out into the home. It just circulates and recirculates the same air. Some heat pumps do have vents that take air outside, but yours very likely does not (sorry).
If you are trying to provide fresh air with oxygen – you won’t get this with a heat pump, or a table fan – these will simply recirculate the used air at varying temperatures. A ceiling fan will circulate the air at various levels, moving the air around to make you feel cooler, but remember – the air is not fresh – we are simply combining the various levels of air temperatures, and circulating it around the room.
So, how might I feel without a ventilation system?
Well firstly we need fresh air to breathe. You can keep breathing when oxygen decreases and CO2 increases, but only to a certain point (which is actually pretty hard to get to). However, we do feel the result of having too much CO2 and not enough oxygen – headaches, tired, confused etc. Why? Because having too much CO2 impairs your cognitive abilities (short term) i.e. You feel dumber than you should feel.
The threshold for a home or building to be healthy is CO2 measured under 1,000-1,500ppm, and in NZ we are failing. Take our schools for example, while some are adapting quickly, most schools don’t have a ventilation system in their classroom, so windows are the only option to ventilate air – which is great in theory, but what happens when it’s windy, cold, rainy or noisy outside? Windows stay shut.
A typical school classroom in NZ can measure up to 3,500 – 4,000ppm CO2 by the end of the day because they don’t have an adequate ventilation system – and how do you think the kids feel at the end of the day?? The Ministry of Education is starting to look at the performance of buildings and the effects on children – adding a proper ventilation system would certainly have positive effects on cognitive abilities, as opposed to relying on open windows. Why? BECAUSE, just opening a window doesn’t provide the air movement you need (unless the wind is the right temperature and blowing in the right direction). Quick solution – by a box fan and force that air in or out!
To conclude, let’s firstly get the kids of our nation learning in healthy environments (these stats blow my mind)! Then get to work on that air movement, whether through a mechanical ventilation system or a DIY box fan solution – you will feel better for it, and I’m sure will welcome the warmer months even more than before!
