Home Ventilation and Why You Should Care

Poorly ventilated homes are a silent killer.

Nationwide, New Zealanders are suffering the effects of damp, germ breeding homes.

Asthma, allergens, colds and flus breed in homes that fail to breathe.

The solution?

Well, it’s home ventilation systems.


Home ventilation has been around in different forms since homes were first created. But sadly, home ventilation can be ignored at the expense of our comfort, health and power bills.

To understand what makes your home healthy we need to break down home ventilation systems.

The reward?

Every day and night you live in a home that smells clean, a home that feels fresh. The air is light and everything inside the home, including the people, are dry.

The power bill drops. And your wardrobe does not smell like your grandparents closet.

And because we spend so much time at home, keeping your home dry is fundamental to your health.

The need for home ventilation is serious. It has been recognised by the World Health Organisation (WHO):

WHO goes on to say:

The message is clear – but what remedial action should you take?

What makes a home ventilation system work and how should you choose a system?

There are many home ventilation systems out there.

Thankfully, in New Zealand we have developed some award winning home ventilation systems that will do the trick.



Home ventilation systems are great. However, when it comes to air quality, some systems are far superior than others.

Moving air around your home is a must. In particular, bringing outside air in. New Zealand even has a law to enforce air movement in buildings.

But there are more ways to move air than just open a window, which is what most of our homes do to be within the law.

Air circulation is how we minimise 'crying windows' and begin creating a healthy living environment. But that's just the beginning.


The building market responded to the NZS code by using our “warm, dry” roof space air and fanning it into our living and sleeping areas.

This is called a positive pressure system where no new air is introduced. Positive pressure systems takes air that is one area and moves it to the next. 

Roof spaces can be contaminated with dust, mould, insects and droppings. So a filter is included to keep the levels of some of these things down.

The cleanliness of the air that is fanned into the house depends on the type of filter and how often it is cleaned. 

Positive pressure systems companies are not required by law to prove the levels of air quality they move around. 


If you have one of these systems in your house you can have it retrofitted. While they provide a step up from an open window, they may not meet all your expectations of a ventilated home.

As the need grew, the industry has advanced to deliver so much more in a home ventilation system.



Despite living in pristine New Zealand, many of our homes are unhealthy, including brand new homes that don't breathe.

The statistics back this up:

The rates of asthma in New Zealand are staggering and are among the highest in the world. 1 in 6 adults and 1 in 4 children to be precise.

Asthma and other breathing difficulties alone is reason enough to consider properly ventilating your home.

But there are many other benefits and they can be placed into two main categories:

  1. Money
  2. Health

An Advanced Home Ventilation System can do things such as:

  • Reduce asthma due to improved air quality
  • Put fresh air into the home, not recycled (possibly contaminated) roof cavity air
  • Transfer unwanted smells to the outside (vent in the loo, perhaps?)
  • Bolster the overall room temperature across the home
  • Inhibit the multiplication of mould spores
  • Make the home easier and cheaper to heat
  • Protect clothes, drapes and soft furnishings from hitchhikers

Although there are long-term cost savings of properly ventilating your home, e.g your favourite curtains live longer, nobody likes to wait.

Thankfully, some of these savings can kick in nearly straight away.

Like the power bill.

Wet air takes huge amounts of energy to heat. A system that addresses the moisture problem is a must.

It is the 101 of warming a place up. Dry the air first. Check.


Not only is dry air the cheapest to warm up, it also has the ability to stay that way when inside a well insulated and ventilated house.

And a decent system can gently move air from the warmest parts of the house, say, right by the heat pump, to less cosy parts that the heat pump can’t reach. So places like bedrooms require less of the oil heater cranked up to full bore at night.

A further outcome of drying and moving the air is to have a funeral for all the nasty mould and mildew spores that have been breeding in your belongings.

Mould and mildew hate dry, moving air. It starves them to death. That is why there is no such thing as mould in the desert.


Let’s break down a superior home ventilation system to see what the best systems can achieve.



What sets a superior home ventilation system apart from other systems is the dehumidifier component.

Remember the 101 of ventilation? Dry the air first. Excellent!

Having the dehumidifier has a number of advantages:

  • It does not take up your floor space and it's not not clunking away in the spare room
  • It does not need to be emptied as it has a drain
  • All of the rooms in your home have the effect of the dehumidifier, continuously.
  • Dry air is cheap to heat. By drying the air first, your heating bill can decrease.

While you won't see the unit, your windows, blinds and shoes in the bottom of the wardrobe will thank you for it.


And so will your power bill. That's why the the EECA suggest running a dehumidifier with your conventional heater.

Plus your Doctor won’t be seeing as much of you as perhaps she’s been used to.

If you don't think you need a dehumidifier running year round you can always switch that component off.



A built in heat exchanger is efficiency and eco friendliness at its greatest.

The purpose of a heat exchanger is to, well, exchange heat.

Using your air that is already warm (refer to the heat transfer system below) the heat exchanger uses little aluminium fins to warm up the incoming fresh air. This technique has been used by the Europeans long before NZ picked up on it.



Quality filters are a key part of any home ventilation system.

Full Stop.  

It's the filter that protects your fans. It's filters that keeps the system efficient and it's filters that take nasty stuff from the air that goes in your home.

A gross fact is that dust is made up of about 70% dead skin. Other pollens, insects and chemicals are in there too, and stopping these nasties getting into your home is a good idea.

Filters are complex and come in many forms. 

When looking for a system, make sure the filters used capture unhealthy particles using 3 or more layers, ideally with a statically charged layer that attracts particles.

And don't forget to service your filter at least once a year.



This is where most home ventilation systems end.

But in the case of a comprehensive home ventilations system, it is just getting started. That’s why it gets mentioned last.

The cosy, pre-dried air from near the main source (roaring fire, gas fire or everybody’s friend, the trusty heat pump) is subtly and quietly dispersed to other more needy areas without incurring any extra costs.

Remember our new best buddy, the heat exchanger? He contributes to raising the temperature of this air too, with the obvious benefit of lower heating bills.


Let’s get technical.

Here are some technical facts that will satisfy any remaining curiosity you may have regarding the air movement in your home.

Get comfy.

Units like Dry Living can claim it meets the New Zealand Building Code G4 clause because they're designed and manufactured to do the following things:

1. Change your air.

For a normal dwelling, mechanical ventilation is required to change the air 0.35 times per hour and more for a kitchen and bathroom. Each home ventilation system needs to be customised to suit the correct volume of air in your home to achieve such changes.

Make sure your home ventilation system is quoted to your floor plans or by in-home appraisal to ensure sufficient air flow.



2. Be responsibly installed.

NZS 4303 has rules about seismic restraining and other safety issues that every trained home ventilation system installer must comply with.

No left over bolts or screws after it's installed.


3. Move fresh air.

To qualify as full ventilation, the air the system moves around must be fresh, funnily enough.

The recipe for fresh air is 20.94% oxygen, 79.03% nitrogen and other inert gasses and .03% carbon dioxide. As long as you don’t live next door to a chemical factory, this will be what your system will move throughout your home.

As the last take away from this guide, please understand that fresh air is the way forward. Ventilation is here to stay. And it's potentially compulsory for all new homes in NZ.

Our homes need to breathe. 



That brings us to the end of the Future of home ventilation systems and why you should care.

At Dry Living we are genuinely passionate about making homes as healthy as possible.

Did this article help in anyway? Please share this article with anyone you know who wants a healthy and economical home.

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