Frequently Asked Questions

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General Information

Unovent and DVS systems are low-flow systems, which cost little to run. However, when the supply air quality is bad these systems are programmed to switch off. Our systems operate in the same low-flow mode, but only when the supply air is too cold or hot.
Our advantage is that our systems also do higher airflows when the air is within the optimal range of 18-25°C to further improve the IAQ.

HRV and SmartVent use high-flow systems which only ventilate when the supply air quality is good. They use fans with a high energy demand which are noisy and expensive to run. When the supply air quality is less than ideal, the systems are turned off as they would otherwise affect the thermal comfort inside the home.
Our advantage is that our systems can similarly use high airflows when the supply air quality is good, but they are also able to do very low airflows when the air quality is less good, which helps to maintain the IAQ without affecting the thermal comfort or noise level within the house.

IAQ stands for Indoor Air Quality. The IAQ in a building is a measure of several factors, including temperature, humidity, and levels of harmful substances such as pollen, CO₂, and other VOCs.
The better the IAQ is inside your house, the better it is for your health.

VOC stands for Volatile Organic Compounds. It refers to organic chemicals that have a very low boiling point and are usually a gas at room temperature. This includes substances such as formaldehyde (caused by paint vapours) and car exhaust fumes. Most odours in your home are also caused by VOCs.

Not all VOCs are harmful to your health, but many can be. While they may not appear to have any immediate effects on your health, they can become very harmful to your long-term health if you are exposed to them over a long time. This is why it is important to continuously extract VOCs from your home.
Our VOC extraction fans can detect many of the more harmful VOCs within your home, including formaldehyde, benzene, carbon monoxide, ammonia, and cigarette smoke.

EC fans are Electronically Commutated fans, which means they use a brushless DC motor. Basic DC motors rely on carbon brushes and a commutation ring to switch the current direction as the motor turns, while EC motors use permanent magnets on the rotor and stationary coils that are electronically powered to control the rotor movement.
Using this "brushless commutation" means that these motors have a longer life as they undergo less wear during use, and they are more efficient and waste less power through the electronic motor controls. They are also very controllable with a speed range of 0-100%, as opposed to AC fans that often only have up to 3 speeds available.

For a more detailed explanation on the difference between AC, DC and EC motors, check out this webpage.

EVOAQ Ventilation
Our Ventilation Systems

The fan speed is determined only by the quality of the air available to be introduced into the home, which is measured via the fan sensors inside the ducting system. The closer the fresh air is to the ideal temperature of 22°C, the faster the fan will go.

The controller has several user selectable functions.
Low, Med and High ventilation rate adjust the desired amount of fresh, filtered air required to maintain high IAQ (Indoor Air Quality). The default setting is normally Low, until signs of condensation or stale air are detected.
Auto Mode is the only mode that uses the Set temperature (default 23°C). The controller will change between Low, Med and High ventilation rate depending on the difference between the Set temperature and Room temperature. The closer the Set and Room temperatures are, the higher the selected ventilation rate will be.
The selected ventilation rate is communicated to the fan, which will then determine the correct airflow at that rate, according to the quality of the incoming air.

The temperature sensor in the controller is used for Auto mode in ventilation systems, and for heat transfer mode in our Heat Transfer controllers.

Yes, the system defaults to High ventilation rate without a controller connected.

The system operates between 20dB and 33dB when installed correctly, following all provided installation guides and instructions.

Yes, our systems run 24/7 at an average minimum airflow of 10L/s per room. This meets the standard of ASHRAE 62.2 - based on “Build tight, ventilate right”.
Rather than turning off, our fans continue to run at a “trickle” rate, consuming as little as 3W while still maintaining the IAQ. As such, there is little difference in power usage of the system between running on trickle speed and turning the fan off.

As an example, the average running cost of a currently installed ventilation system in Auckland is about $0.13 per day, or less than $50 a year.

Our systems are designed according to the standards set by ASHRAE 62.2, which requires a minimum of 10L/s of ventilation per room to maintain IAQ inside your house. This is enough to replace the stale air inside the house with fresh air, while ensuring the system will not have any significant impact on the temperature inside your house.
However, if you do feel that the system is making your house colder, you could try changing the setting to a lower ventilation rate and lower the fan speed. If this does not fix the problem, it is also possible to turn the system off by manually switching off the wall controller, though this is not recommended.

The maximum house size for our ventilation systems depends on a number of factors, including house design and reason for ventilation. The more outlets you need per system, the smaller the recommended house size will be. And some houses require more ventilation to fight mould and condensation issues, which may require upgrading to a larger system.

This depends on the performance of the current system. If the system is currently running on Low ventilation rate without any issues, it may be possible to add more outlets without needing a second fan. It may also be possible to upgrade your current fan for a larger one under negotiation.

There is no need for manual operation, as the system will do this automatically. In summer, the roof space air will be between 16 - 25°C at night, which means the fan will run at higher speeds to bring in more of this air.

No. Our system automatically adjusts the airflow according to the quality of the available air – the better the air quality, the faster the fan will run. This makes set points irrelevant for the fan operation. We recommend a set temperature of 23°C at all times.

No. The system monitors the humidity of the air entering the house. If the moisture level is too high, for example when it is raining outside, the fan slows down automatically to avoid bringing in too much damp air.

Our ventilation systems only monitor the incoming air quality and do not react to higher moisture levels inside the house. In order to prevent condensation inside the house, e.g. from using the shower, it is most important to stop the moisture from wet zones entering the rest of the house. This is why bathrooms should have their own moisture management system.

We highly recommend combining our ventilation systems with our EVOAQ Extraction Systems to maintain maximum air quality throughout your home.

No. Using warmer air from your ceiling space in winter only has minimal impact on the indoor air temperature, due to thermal losses inside the ducting. However, this air can be slightly drier which may help prevent condensation inside the house.
As such, a ventilation system will help with condensation control and improve the IAQ, however it cannot heat your house without a separate heater or heat source such as a fireplace.

EVOAQ Extraction
Our Extraction Systems - bathroom extraction, garage extraction & kitchen extraction

Normally, our bathroom extraction systems do not require any backdraft shutters. However, if your house is built in a high-wind zone, it may become necessary to add a backdraft shutter to prevent bad (especially wet and humid) air from outside being blown into your bathroom on windy days.

EVOAQ Add-on Kits
Our kits for heat transfer and summer options

Yes. At EVOAQ we pride ourselves on ensuring all required components are included in our kits, excluding basic hand tools.

Our standard kits are designed to have only either one of two options (heat transfer or summer) added to the ventilation system. We recommend installing a standalone heat transfer system with your existing ventilation system with summer kit if you wish to have both.

However, we do have a custom system available that can do both heat transfer and ventilation (fresh air only) if you prefer this instead.
Contact us for more information if you are interested in this option.

Heat transfer systems are designed to transfer excess heat, regardless of the type of heat source. We only recommend adding heat transfer if you have an excess of 5 kW of heating available.

Heat transfer will only work for 6 outlets if the ducting runs are sufficiently short, and your heat source is a wood burner as this produces higher temperatures to over-come heat losses inside the ducting.

Yes. Since outside air is always suitable for ventilation, our summer kit takes air from both the ceiling space and from outside. In winter mode, most of the air is taken from the ceiling, whereas in summer mode the system shuts off the ceiling space, and only takes air from outside. This mode can be manually selected using our controller, so that the user themselves can choose the best air to use.

Installation Tips
Tips and tricks for installing our systems

Yes, the fan should always be installed away from bedrooms and living areas.
The ideal location for a ventilation fan is above a garage or service area, like bathrooms.
Extraction fans should be placed within 1.5m of the extraction vent to ensure optimal operation.
Heat transfer fans should be placed within 3-6m of the heat source, however care must be taken to not place the fan too close or directly above the heat source as this can damage the fan as well as affect the performance of the heat source.

A single experienced installer on a single storey house should be able to install a full system within 4 hours. While every house will have its own challenges, correct planning can reduce the installation time even further.

Insulated ducting is only required for heat transfer or heat exchange systems, but can also be used on our ventilation systems if needed.
Insulated ducting helps to prevent the ceiling cavity temperature from affecting the supply air temperature. This is particularly important for our add-on kits as these are used to supply warmer air in winter (heat transfer) or cooler air in summer (summer kit), when the ceiling temperature is significantly different from the supply air.

The maximum recommend length is 10 metres of trunk ducting (between the fan and furthest branch take-off) and 10 meters from branch take-off to diffuser, for a total of 20 metres from fan to diffuser.

For a standard ventilation system, the recommended maximum length between the fan and diffusers is 20m.
However, longer ducting means more heat loss. Especially for a controlled heat source like a gas fire, you may not get the desired results from your heat transfer system if the ducting is too long.
Our rule of thumb to calculate duct length is a 1.5°C decrease in air temperature per 3 meters of ducting @ ceiling temperature of 5 degrees.

Both having too little or too much insulation can indeed affect the system performance.
Incorrectly installed insulation – often retro-fitted or additional insulation added to the roof cavity – can cause the natural airflows into the house to become blocked, interfering with the airflow through the system.
On the other hand, having too little insulation inside the ceiling, e.g. iron roofs without building paper or insulation, can cause problems with condensation inside the ceiling space, which affects the quality of the air brought into the house.

Get in touch!

Ready for offers and cooperation

Phone: +64 9 558 5590
Email: sales@evoaq.co.nz
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