Jul 15 2021

What is a positive pressure home ventilation system?

Healthy home with a ventilation systemLiving in a warm, dry and safe home is vital for our day to day health and wellness. As New Zealander’s we spend on average 69.7% of each day at home indoors. That is roughly 16 hours a day, and slightly more if you work from home, are retired or have an infant at home. So making sure that your home is helping and not hindering your health is vital.

Lengthy exposure to indoor dampness can reduce healthy lung function and cause chronic health problems, such as asthma. Those who already suffer from asthma and allergies are more likely to have more severe symptoms when exposed. 


Two of the leading factors of an unhealthy home are dampness and moisture, which can be caused by water entering your house from the outside, or from moisture inside your home being unable to escape. Thankfully, there are ways to say goodbye to these unwelcome guests by ensuring your home is well ventilated.


Dampness or moisture buildup is not only found in older homes, in fact newer more modern homes are built to be more energy-efficient, meaning that they are better at retaining heat. They can also be better at keeping air, and the moisture it contains inside the home. Without proper ventilation and extraction moisture remains in the home and is confined to certain rooms. Because of this, it is even more important that new homes are well-ventilated. Without good airflow, moisture can build up, leading to condensation, dampness, and mould. This is where a home ventilation system comes in, as it can help circulate air around your home.


So what is a home ventilation system, what types of systems exist and how can it benefit your household and, more importantly, keep you and your family healthy? 


Where does moisture build-up come from?


According to Consumer New Zealand, the following home activities are the main sources for a lot of moisture buildup in the home:

  • Cooking - 3 litres per day

  • Washing clothes - 0.5 litres per day

  • Showering and taking a bath - 1.5 litres per person per day

  • Doing the dishes - 1 litre per day

  • Drying clothes indoors - 5 litres per day

  • Gas heater (unflued) - up to 1 litre per hour

  • Breathing while awake - 0.2 litres per hour per person

  • Breathing while asleep - 0.02 litres per hour per person

  • Perspiration - 0.03 litres per hour per person

So with so many potential moisture sources, what systems exist to help control moisture build-up and which ones can be installed in your home?

Open a window

The easiest way to dry out a home is to open the windows. By doing this, you remove moist air from your home. However, this can also let out warm air, especially in the winter and if it is more humid outside than it is inside you may be adding to the problem.

Portable Dehumidifier

A dehumidifier's only job is to remove excess moisture in the air. Which, as a result, will bring down the home's level of humidity. However, a dehumidifier can only reduce the moisture around the area that it is situated. While switched on it can only reduce humidity in a small area and not throughout your whole house.

Positive pressure ventilation system

This is one of the most effective ways to reduce water vapour throughout the entirety of your home without having to lift a finger. The fan in the space between your roof and ceiling area forces filtered dry fresh air down into the property through ceiling vents, pushing damp air out.

Heat transfer system

If your lounge is warm but the rest of the house is colder, then a heat transfer system helps transfer the heat from the warmer areas of your home to the colder parts. In many cases, a heat transfer system can be part of your ventilation system setup. But this will depend on the brand and model.

What is a positive pressure ventilation system, and how does it work?


The positive pressure home ventilation system draws dry and often warm air from your home’s roof cavity. It will then pass the air through a filter before distributing it throughout your house using a motorised fan. 


Because the fan is pushing newly filtered, dry air to the far corners of your home, the movement created means old, and stale air is forced out of your home to make space for the fresh stuff. 


Depending on the model installed, the cycle of replacing stagnant air with fresh air can happen up to three times per hour and results in a home that stays drier, with dampness reduced.

SmarVent positive pressure ventilation system

The benefits of a positive pressure ventilation system in your home

Positive pressure ventilation systems help provide several benefits, especially in New Zealand where our homes are subject to many different weather conditions and elements during the course of the year. The benefits can include:

Helps to reduce energy costs

This is due to having dryer air in the house, making it more efficient to heat. It takes more energy to heat humid air than it does to heat dry air because you’re heating more water. The more moisture in the air of your home, the longer your home will take to heat, and the more power it may use to do so. Plus, if you use gas heaters you’re actually adding moisture to the environment by using the heating system.

Prevents condensation from forming

Condensation is formed by water which collects as droplets on a cold surface when humid air is in contact with it. A ventilation system will remove the moisture from the air in your home, leaving your windows dry all year long. By reducing condensation, the chances of harmful mould forming in your home are significantly reduced, meaning a healthier home for you and your family.

Reduces black mould from forming

The main reason behind the formation of black mould is moisture/condensation. Without moisture, black mould can not grow. If someone in your household suffers from pre-existing asthma, has a weakened immune system, is an infant or elderly person, then they may be at the greatest risk of the effects of black mould. A ventilation system reduces black mould from growing, meaning a healthier home for everyone.

You don’t even know it’s there

Most ventilation systems are super quiet, meaning you are unable to hear them from inside your home, even when you're sleeping. 

Low maintenance

Annual maintenance costs can be less than $100 per year, and this is mainly due to the filter, which will need to be replaced. The actual service requirements and timing will depend on the model and brand of the ventilation system installed within your home. 

Low energy consumption 

The cost to run a ventilation system can be as little as eight cents a day. This means it can be a lot cheaper than repairing the damage done by excess moisture.

Heaters for winter or cooling options for summer

Some positive air pressure systems in New Zealand include the ability to add heaters to ducting, which can be useful if you’re concerned about cool air from the roof space reducing indoor temperatures. Summer cooling options, where the ventilation system introduces cooler air to the home, are also available.


As one of New Zealand’s leading prefab home companies, Manor Build is always seeking to improve its customers’ living standards.


That’s why Manor Build now provides the option to have a SmartVent ventilation system, supplied and installed during the build of your home, This ensures an even healthier, happier and drier home for all that choose to have this system installed. It’s just another way to help deliver the best quality homes to customers. 

If you’re interested in building a healthy new home, why not download our latest product catalogue!

Download our brochure

Tags: Transportable/Prefab home Design Options