Installing a Zehnder ComfoAir Q350 HRV System in Our Office Space

Installing a Zehnder ComfoAir Q350 HRV System in Our Office Space

Here at Fresh Ventilation, we're passionate about the benefits of clean, fresh air. We've witnessed firsthand how improved air quality can lead to increased productivity, improved concentration, and a healthier work environment. So, when it came time to upgrade the air quality in our own office space above our warehouse, we knew a high-quality HRV system was essential.

Why We Chose a Zehnder ComfoAir Q350 HRV System

Ventilation systems are pivotal in enhancing indoor air quality. They perform a crucial role by continuously introducing fresh air and filtering it in the process. This process significantly reduces the presence of pollutants, allergens, and stale air. We chose the Zehnder ComfoAir Q350 heat recovery ventilation system for several reasons.

1. HRV or ERV

When choosing an HRV system for our office, we carefully considered the pros and cons of both HRV and ERV systems. Ultimately, we decided that an HRV was the better choice for our specific needs. Here are the key factors that influenced our decision:

  • Climate: We're located in Mittagong, Australia, which experiences a cold, humid climate for half of the year. HRV systems excel in cold climates because they transfer heat from exhaust air to incoming fresh air, reducing heating costs and preventing drafts. ERV systems, on the other hand, retain some humidity from exhaust air, which can be beneficial in dry climates but can lead to condensation and mould growth in cold, humid climates like ours.
  • Indoor Air Quality: Our primary goal was to improve the indoor air quality in our office. Our HRV system effectively removes stale air and pollutants from the space, replacing them with fresh, filtered air. This helps to reduce CO2 levels, improve air circulation, and minimise the spread of airborne contaminants. While ERV systems also offer air filtration, they tend to retain more humidity, which can create a breeding ground for mould and bacteria.
  • Efficiency: We wanted an HRV system that offered excellent energy efficiency. The Zehnder ComfoAir Q350 boasts a heat recovery rate of up to 96%, whereas ERV systems typically have slightly lower heat recovery rates than HRV systems.
2. Energy Efficiency
  • Heat Recovery Efficiency: We wanted an HRV system that offered excellent energy efficiency. The Zehnder ComfoAir Q350 boasts a heat recovery rate of up to 96%, ensuring that precious heat is captured from exhaust air and transferred to incoming fresh air. This translates to significant energy savings and lower heating bills, especially in a cold climate like ours. ERV systems typically have slightly lower heat recovery rates than HRV systems, leading to higher energy consumption.
  • Energy Efficiency: The Zehnder ComfoAir Q350’s unmatched energy efficiency meant we could enjoy fresh air without worrying about skyrocketing energy bills. The Q350 houses a pair of energy efficient EC motors by ebm-papst which average a combined 37W consumption for our calibrated ventilation level of 200m3/h.
3. Smart Features and Control
  • App Control: With internet connectivity and an intuitive app for control, we can easily monitor and adjust ventilation settings remotely. The customisation and control offered within the app is so intuitive and bug free we haven't even installed a control on our wall.
  • Remote Access: The ease of remotely accessing the system is ideal for us to use when quoting and demonstrating the performance of the system, as we can access it remotely from site when out meeting with clients.
  • Humidity Protection: The humidity protection control can be used to automatically protect the office against high humidity by ventilating at a higher airflow level (up to 350m3/h as needed). The humidity protection control activates when the relative humidity of the extract air exceeds 75%. We have a shower in our office space, and we're yet to see it take longer than about 6 seconds to kick in when someone uses the shower.
  • Adaptive Temperature Control with Season Detection: The system features an intelligent bypass that can open (either in increments or all the way to 100%) and allow air to bypass the heat exchanger. This feature automatically adjusts the bypass based on outdoor temperature, preventing overcooling in winter and over-heating in summer. We're regularly seeing the bypass open and shut so that the system can bring warm air in when it's colder inside than we'd like it to be (and hotter outside) and can bring cold air in when it's hotter inside than we'd like it to be (and colder outside).
Fresh Ventilation Zehnder ComfoAir Q350
App Control Screenshots of Our Zehnder ComfoAir Q350
4. Indoor Air Quality
  • Improved Concentration and Reduced Fatigue: Of course, the most important reason for installing the Q350 was its ability to significantly improve the air quality in our office. With fresh, filtered air circulating throughout the space, we've seen a noticeable reduction in CO2 levels, leading to improved concentration and reduced fatigue for our team.

The Installation Process

As a ventilation company specialising in healthy indoor air, we've installed countless HRV systems from several manufactures, including many from Zehnder. When it came time to improve the air quality in our own office, we opted for the Q350, a powerful and efficient model that's perfect for medium-sized spaces.

Our office presented a unique challenge and we were keen to see how the system would perform in less than ideal circumstances. Unlike the modern high-performance homes that these systems are designed for, our office is far from airtight. While we were technically able to install the system within the thermal envelope, it wasn't much of a thermal envelope to work with:

  • Our warehouse is prefab concrete with single-glazed windows upstairs and a large roller-door downstairs.
  • Our office space, upstairs, is fitted out well above average, but still has an open stairwell to our warehouse downstairs and an uninsulated grid ceiling.
  • The cavity above our grid ceiling is about 1.2m high and the roof above is Klip-Lok with thermal blanket underneath.

Cameron installed the system over a weekend without any issues (it's only a small system with 6 supply grilles and 5 exhaust grilles). The unit itself is mounted on the wall near our kitchenette at one end of the space. This is ideal because it's near to the roof cowls we're having to use for both our outside air streams. All of the semi-rigid duct and both ComfoWell attenuators are located above the grid ceiling. Being a small office space, we needed to add a second exhaust grille in the bathroom to help with balancing the system and ensuring even pressures on both sides of the system (given our shower gets regular use after coming back from muddy subfloor installations, this isn't a bad thing).

Commissioning was a cinch with the included smartphone app. We booted up the system for the first time and the unit conducted about 15 minutes of diagnostic tests and measured the pressures on each side of the system at different airflow volumes. The system automatically balances itself, ensuring there are equal airflow volumes in both the supply and exhaust air streams. After this, we proceeded to measure and adjust the airflow volumes at each individual grille to our predetermined levels using our professional Testo measuring equipment.

Fresh Ventilation Office
Our Office Space
Installing the Attenuators and Semi-Rigid Duct Above the Grid Ceiling
Our Bathroom Exhaust Grilles
Two Exhaust Grilles in Our Bathroom Ceiling


Despite the less than ideal installation conditions in our office, we're happy to report that the Zehnder ComfoAir Q350 is performing exceptionally well. The air quality has improved significantly and we're all breathing easier (literally!). Even in our less-than-airtight office, the system has made a significant difference.

The air in our office is noticeably fresher and cleaner, and our team is experiencing improved concentration and energy levels. We're confident that this investment will benefit our health and productivity for years to come.

If you're considering improving the air quality in your own home or office space, reach out because we would love to chat about how we can help you and those lucky enough to be around you.

Reading next

Breathe Easy and Live Healthier: The Benefits of Positive Pressure Home Ventilation Systems
Home Ventilation and Subfloor Ventilation Services in Forster and the Mid North Coast

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