Home Ventilation System
- Fresh air ventilation
- Condensation Control
- Solar Heat Recovery
- Summer Cooling
- Air Transfer
WarmNdry can be supplied in kit form or fully designed and installed.
Operating Principles
The purpose of WarmNdry is to ventilate your home with introduced air that is fresher and drier than the air inside your home in a controlled manner. Air from the roof space replaces stale, humid air, which causes condensation and can lead to mould and damp problems, or at least reduce them to an acceptable level.
The diagram illustrates how the system works. Air is transferred from the roof space because it is always warmer than the outside air. During colder nights, the roof space cools down (though usually not as cold as the outside) and airflow into the home is reduced, but NOT completely stopped, to control condensation by providing adequate ventilation.
A continuous supply of fresh air into the home is essential to eliminate condensation during winter. The ventilation air supply positively pressurizes the home, causing stale air to be gently expelled through cracks under doors, floorboards, and so on. This method of positive pressure ventilation (PPV) is the most cost-effective approach to reduce moisture build up in the home.
Leaving outside doors and windows open can provide the necessary fresh air; however, there are several drawbacks to this method, including security concerns, difficulty in controlling the flow rate (too much or too little), and the increased heating costs needed to counteract these cold drafts in winter.
Heat pumps (reverse cycle air conditioners) do not dehumidify in heating mode and are only effective in cooling mode during summer. Room dehumidifier units can be costly to operate and, like moisture-absorbing crystals, have limited impact on moisture levels. None of these options offer the essential fresh air ventilation that your home needs.
Multifunction Smart Home Ventilation Controller
The WarmNdry Touch controller is a programmable smart device that manages filtered fresh air ventilation, solar heat recovery, and home air distribution automatically.
The amount of ventilation and air transfer is determined by the temperatures measured in the roof space and the living room.
The owner can define set points that the controller will use to calculate airflow algorithms and automatically control the amount of air movement needed to maintain air quality and comfort levels.
Fresh Air Ventilation
All houses need a small amount of air introduced from outside to keep us humans healthy. Houses that have good draft proofing and new homes are too airtight and suffer from insufficient fresh air ventilation. Indications of poor air quality and insufficient ventilation are:
- Condensation on windows
- Musty smells
- Damp and mildew
- Water stains on ceilings and walls
- Rotting timber work
- Cold in winter and hot in summer
- High energy bills
- Health issues especially asthma
The WarmNdry system is a mechanical ventilation system using a special EC fan which is economical and quiet with full speed control from 0 to 100%. Opening a window allows fresh air in however it is not controllable or secure. WarmNdry works 24/7 all year and is basically set and forget.
Condensation Control
Before WarmNdry
After WarmNdry
Condensation can be eliminated by introducing a small amount of fresh filtered air ventilation into the home. Air needs to be introduced even when the outside temperature is low. The amount of fresh air required depends on the size of the home, the number of occupants, and the severity of the problem. Too little fresh air will fail to manage the issue, while too much can make the home unnecessarily cold during winter or excessively warm in summer.
The WarmNdry smart controller is specifically designed to address this issue when the outside temperature is cold by minimizing airflow to an absolute minimum and then automatically increasing fresh air intake as the temperature rises.
What Is Condensation?
Condensation within the home results from excess moisture in the air. Indoor air consists of outside air plus whatever we contribute to it. The occupants of an average home can add up to 15 liters of water to the air daily through breathing, showering, cooking, drying clothes, and more.
When moist air cools down below its ‘dew point,’ such as when it comes into contact with a cold surface, the moisture condenses. This causes water to pool on surfaces and trickle down walls, etc. Glass windows typically show the first signs of condensation due to being the coldest surfaces. Condensation is a symptom; poor air quality is the underlying cause.
What Problems Can Condensation Cause?
Untreated condensation can promote mold and mildew growth, damaging woodwork, furnishings, and clothing. Mold spores are known triggers for asthma and allergies. Damp conditions lead to unpleasant odors, and damp homes require more energy to heat, feel unhealthy, and are uncomfortable to live in. Dust mites thrive in moist environments.
Heat Recovery
Heat recovery through the roof space is a cost-effective way to provide FREE heat in autumn, spring, and winter during the day. Sunlight hitting the roof warms the roof space significantly more than the outside air, and the WarmNdry system takes advantage of this by increasing airflow, which effectively ventilates the home, thus benefiting from the free heat and abundant fresh warm air.
The graph illustrates temperature changes in the roof space throughout a typical day. The sample was taken on 10/5/08 and shows a minimum temperature of 12 degrees and a maximum of 28 degrees. The actual outside minimum was just 10.8 degrees, with a maximum of only 17 degrees on that day. The difference between the roof and outside temperatures is significant, providing free heat by automatically transferring warmer roof air into the house as needed. During summer, the heating function is disabled when the roof becomes too hot.
The duration above the red line indicates the Heat Recovery period, which totaled 8 hours on this particular day. That means 8 hours with the fan operating at maximum capacity. During this time, warm air (19 to 28 degrees) is transferred into the home, reducing the need for other, more expensive heating methods, while also flooding the house with fresh air.
Summer Cooling
During summer, the system can increase ventilation when the roof is cooler than the house, helping to reduce indoor summer temperatures. Most of the benefits will be felt later at night, as the outside and roof cool faster than the inside of the home, making it more comfortable for sleeping.
Air Transfer
Warm or cool air generated in the living room can be distributed throughout the home, typically to the bedrooms. The WarmNdry controller can manage a separate air transfer fan that automatically operates at pre-set temperatures. Air transfer is completely independent of the fresh air ventilation fan and can therefore be operated independently or in combination, depending on the air ducting design and the mode set on the Touch Controller.
Ducting
Flexible ducting installed in the roof space is used to distribute air throughout the home. The duct design is determined by the location of inlets and outlets, as well as the aspects of the control system in use. If air transfer is needed in addition to fresh air ventilation, a second fan with its own ducting will be utilized. Customer service can assist with the duct design to meet individual requirements.
The number of ceiling outlets required will depend on the size of the house, its layout, and any barriers to airflow throughout the home. Typically, two to four outlets are sufficient; however, if internal doors are closed, additional outlets may be necessary.
Ducting design and layout
150mm (6 inch) flexible ducting is typically used to direct the fan output to desired locations throughout the home. Usually, the ducting is located in the roof space, providing easy access to all of the rooms on that level.
The two main types of ceiling outlets are:
- Cone – used to direct air across the top of the ceiling, suitable for all ventilation conditions. Also used as the inlet vent for heat transfer.
- Down Jet – used to direct airflow from the ceiling outlet to the floor, suitable for heat or warm air transfer.
The two types of ducting are:
- Nude ducting is used for ventilation designs; the air from the roof space is distributed to rooms via ceiling outlets, so there is no need for the more expensive insulated type.
- Insulated ducting is required for air transfer where warm or cool air is extracted from one room (main lounge where a heater or cooler is located) to another room via the roof space.
The two types of duct splitters that can be used to divide the ducting into two or more ducts, allowing branching to multiple outlets, are:
- Y splitters, which have a single inlet and two outlets that divide the air 50:50.
- Branch Take Offs (BTO), which have a single inlet, one 45-degree outlet, and a straight-through outlet, are more suited to a drop-off branch from a main trunk.
Fresh air ventilation that takes air from the roof space needs to be filtered to prevent any disturbed dust in the roof from entering the system. The filter supplied for WarmNdry is a 10-micron or G4 rated filter, which stops pollen and dust particles >10um. The filter will not stop smoke and is not designed to do so. Heat transfer does not require any filter, as it is simply moving house air from room to room.
EC fans connect to the Smart Controller to vary speed and airflow. EC (Electronically Commutated) fans are brushless, permanent magnet DC motors with onboard electronics available for controlling a fan rotor. EC fans achieve high-efficiency levels, reducing energy and heat loss and providing a longer service life. EC fan speeds are controllable between 0 and 100% without the humming noise associated with older AC fan types.
WarmNdry can be supplied in kit form or fully designed and installed
Installation
The type of system to be installed is determined in Setup Screen 3. The ducting is designed to accommodate the type and is based on home design.
Standard
Uses a single fan for fresh air ventilation only, with no air transfer. Distributes 50% of the airflow to the main living room where the controller is located, while the other 50% is split between the bedrooms. Ducting is suitable, as are cone vents in the ceiling.
Dual
Uses two fans for fresh air ventilation only, with no air transfer. Split 50% of the airflow to the main living space and the remainder to other rooms. Ducting without insulation is suitable, as are cone vents in the ceiling.
Combo
Utilizes two fans, one for fresh air ventilation and one for air transfer. Split the fresh air from the roof space to the main living room where the controller is located, with the other 50% directed to the passage.
The second fan extracts air from the main living room where the heater and/or cooler is situated and sends it to the bedrooms. The fresh air from the ventilation fan is distributed by the second heat transfer fan. Non-insulated ducting is suitable, as are cone vents in the ceiling for the first fresh air section; however, insulated ducting and down jets are necessary for the second heat transfer component. Use a cone for the inlet.
Heat Transfer
Uses one or two fans for heat transfer but lacks fresh air ventilation. Warm or cool air is extracted from the main living room and directed to the bedrooms. Insulated ducting and down jets are required for heat transfer. Use a cone for the inlet.
