Important reading

The Moisture Cycle

The percentage of moisture in the air is considerably higher inside your home than outside. This moisture is produced from cooking, breathing, washing and showering and is absorbed into your soft furnishings and walls. During the heat of the day the moisture is evaporated into the air but when the house cools it often forms as condensation on colder surfaces like windows. This is a daily cycle and whilst this cannot be stopped it is able to be controlled by replacing the moist air with drier air – a moistureMASTER positive pressure system will remove the excess moisture from your home replacing the air with drier, filtered fresh air. The air in your home will be fresher and healthier, even if you have your windows closed.

One of the main components of air is water vapour. When air cools the amount of moisture it can hold is drastically reduced. If it cools too much the moisture will drop out of the air and form condensation on cold surfaces - like windows. The moisture that doesn't form as condensation is absorbed into your furniture and soft furnishings like carpets, bedding and drapes.

During the day the warmer air is able to hold more moisture so it draws the dampness out of the fabrics into the air. When the air cools again at night it will shed what it can't hold - onto windows and back into your soft furnishings. This daily moisture cycle happens in every home and can cause condensation and mould.

The moistureMASTER™ ventilation system is a controlled ventilation system that replaces the moist air with drier, warm, fresh air - the result is a drier, warmer and healthier home - guaranteed.

Humans generate high levels of water vapour from every day activities like showering, washing, cleaning, cooking and breathing (At least 10 mls of water liquid per hour per adult). This combines with the water that is naturally present in the air. The natural moisture content in air fluctuates with each passing 'weather system'. Weather systems in winter hold less moisture than in the heat of summer. Warmer air is able to hold very high levels of water vapour so our highest humidity occurs in late summer/autumn.

It is the combination of these two factors that is responsible for the total moisture content in the air in your home. The amount of moisture in the air is often a measure of the air quality in your home. A damp home is unhealthy and a breeding ground for mould and mildew.

moistureMASTER™ circulates fresh drier air sourced from either the roof cavity or from outside the home. This fresh 'external air' has less humidity so it is drier. The air is filtered then circulated through your home. There are options to improve the quality and temperature of the air. moistureMASTER™ systems offer a 'Pure Air Tube' and a 'Thermaflow Heater'.

The introduction of this fresh drier air creates a 'positive air pressure' that carries the moisture laden contaminated air out. moistureMASTER™ guarantees your home will be drier, and healthier. Another benefit is that drier air is cheaper and easier to heat.

The moistureMASTER™ HX is a 'balanced pressure system' which introduces fresh air by one fan and exhausts wet stale air with a second fan. This is a true Heat Recovery System utilising one of the worlds most efficient aluminium plate heat exchangers.

The moistureMASTER™ systems are the most advanced condensation control, ventilation solutions on the market, offering guaranteed results and a 5 year warranty. Because of the superior modular design we can offer a variety of solutions regardless of your homes layout, age, design or construction. The modular design also means that many of the benefits are unique to moistureMASTER™.

  • Control or eliminate condensation, control mould, mildew and odours
  • Enjoy a fresher, drier healthier home
  • Breathe easier with fresh filtered air
  • Heated systems to eliminate introducing cold air during winter
  • Systems suitable for almost every home
  • The best of European design and built specifically for New Zealand homes and climatic conditions.
  • The best of New Zealand innovation and covered by unique and proprietary patents.
  • Safe secure home because your windows can be kept closed

The Cold Hard Facts

A few home truths about fresh air ventilation for condensation control and insulation

  1. The serious downside of pushing COLD AIR into your home on a cold winter night cannot be ignored. There is no bank of ‘stored heat’ in the roof cavity at night during winter for a ventilation system to draw from. Some systems slow down or stop their fan when the air in the roof cavity gets too cold. This simply compromises good ventilation and condensation control.
  2. Heat Transfer Systems will not prevent condensation and are often very limited in their effectiveness. They also provide little comfort at 2am when the heat source has died down or been turned off and stale, cool, damp air is being transferred to the bedroom areas.
  3. Heat pumps, double glazing and increased insulation are not the answer to effective control of condensation.
  4. The current push for agencies, including Energy Efficient Conservation Authority (EECA) and the Department of Building and Housing, for improving insulation and sealing air gaps to create ‘healthier homes’ could be having a negative effect. By sealing homes they cannot ‘breathe’ and therefore dampness and condensation are trapped. Insulation is only part of the solution and on its own could make the dampness problem worse.
  5. Fresh Air remains our greatest asset and is the vital piece of the ‘healthy homes’ equation.
  6. The old saying ‘you get what you pay for’ does not seem to apply to the Home Ventilation Industry in New Zealand. Some companies systems are priced well over $3,000 and do little more than introduce cold unheated air all through the home and claim that it will make your home warmer. Whilst drier air doesn’t feel as cold as damp air and will make your home easier to heat, somewhere along the line, your home requires the positive input of heat. We at Condensation Control Ltd firmly believe sensible ventilation needs to prevent your home from becoming colder. We use a small heater to temper the air in our positive pressure system and a high efficiency heat exchanger in our Heat Recovery system. Both systems will truly enhance the heating of your home and deliver a healthier more efficient way of ventilating your home. Ventilation is a key component to preventing dampness and condensation but so is warmth. It is also interesting to note that generally fewer diffuser outlets are required in homes where the ventilation system includes a tempering or heating device.
  7. Research conclusively proves that excessive moisture levels in a home will make it harder to heat. It also lowers the performance and degrades the value of double glazing and insulation. Adequate ventilation will ensure that investment in energy efficient heat and better levels of insulation are fully realised. These are the cold hard facts.


Condensation Control Limited and moistureMASTER have developed one of the world’s most advanced ventilation and condensation control systems. The system can be set up automatically to take advantage of the FREE heat in the roof cavity or, when the heat is not there, provide electronically controlled background heat from a range of heater options.

Sealing up homes, better insulation and double glazing helps prevent the home from breathing. Without ventilation this encourages condensation, dampness and poor air quality. The three key factors for a ‘healthy home’ are ventilation, background heat and insulation. moistureMASTER supplies the first two components at very competitive prices with a solution for every home.

Getting the best from your moistureMASTER™ home ventilation system.

There are many things you can do to maximise the performance of your moistureMASTER™ Ventilation system. We hope you find the following information useful.


A positive pressure system lowers the moisture content of your home by replacing the moist air with drier air from outside. This is achieved by creating a ‘positive’ air pressure (fan) with the outside drier air, which drives the moist air out of your home. The less moist air - the less condensation.

Air Volume and Distribution

Positive pressure systems must be controlled. Too little air will compromise the performance and too much air decrease energy efficiency by forcing heat from your home. Establishing a balance can be achieved by monitoring the results. Additional diffuser outlets may be necessary if the original installation is not achieving the desired results. For a ventilation system to work efficiently the incoming air must not be allowed to escape too quickly. Unsealed down lights, permanently ventilating sky domes and louvered windows are just a few of the culprits. It seems ironic that while air tight homes seal in more of the contaminated air, they generally respond better to positive pressure systems.

Air Quality

To achieve the best performance from your moistureMASTERtm ventilation system the air being drawn into the home needs to be as dry as possible. The air outside is always significantly drier than the air inside your home. If the air is being sourced from the roof cavity space there must be enough air in the cavity to allow the ventilation system to work effectively. A badly ventilated or "air tight" roof cavity will reduce the effectiveness of the ventilation system. A badly ventilated roof cavity often has a musty smell or visible signs of condensation on the under side of the roof or on roof timbers. Another factor affecting the quality of the roof cavity air can be from too much ‘leakage’ from air within your home. Areas include badly fitting manhole covers and unsealed down lights. This leaking air carries with it the odours and moisture that is then recycled back into the house from the air in the roof cavity. In older brick bungalow homes the roof cavity air can be very damp as the air is drawn up from the ground in the cavity behind the bricks. If the roof cavity air quality is compromised a vent sourcing the air directly from outside may be necessary.


Once you have lowered the moisture content through ventilation, it is extremely important to maintain a level of ‘background’ heat throughout your home. This will prevent the temperature falling and allowing condensation to form. The problem period is between midnight and dawn. This is when the prime heating system is either reduced or turned off and the home is at its coldest. It is important that sufficient heat is maintained otherwise it will be extremely difficult to completely eliminate condensation. A moistureMASTERtm with a Thermaflow Heater will assist in maintaining a constant temperature. On severely cold nights you may want to increase the heat level on your Thermaflow heater. In colder parts of New Zealand or in larger homes with numerous diffuser outlets you may need to provide supplementary heat during extreme conditions. Even a couple of degrees will often make a huge difference. A good way of achieving this is an inexpensive low heat oil column heater running in close proximity to the colder windows.

Ventilation alone may not prevent condensation in the colder nights so maintaining sufficient heat during these times is critical. Maintaining the correct balance between heat and ventilation will control condensation.

Moisture Spikes

In extreme weather conditions it is possible that “Moisture Spike” may temporarily affect the performance of the ventilation system. This could last a few days but your home should re-adjust and the moistureMASTER™ will soon return your home to the normal level of condensation control you are accustomed to.


Climatic variations will affect the moisture content and temperature at which condensation will occur. In autumn and the early part of winter the day time temperatures may be warm but if the air is moist a sudden drop in temperature at night could cause a "moisture spike". To prevent this turn your moistureMASTERtm Thermaflow heater on before you go to bed.

Changes in Performance

A change in your moistureMASTERtm’s performance may be caused by one of the following. A "Moisture Spike", a dirty air filter, renovation changes in your home that may have altered the airflow characteristics, the installation of unsealed down lights, less heating being applied and a colder home due to a colder winter. Try to achieve a balance between heat and airflow. This is necessary for optimum performance. If you are unable to solve these issues then please call moistureMASTERtm 0800 866 855 for help.

Things to Avoid

  • Drying clothes
  • Running un-vented clothes driers
  • Operating un-flued gas heaters
  • A cold home - particularly between midnight and the dawn
  • Closing internal doors
  • Opening your windows on a cold winters night
  • Installing unsealed down lights
  • Extracting damp air into the roof space
  • A dirty clogged up air filter in your moistureMASTER™ system