Bathroom extraction is simple in theory: remove warm, moist air from the room and push it outside. But in practice, the ducting you use can make a big difference to how well the system performs. This is especially true in New Zealand homes, where bathrooms often extract through cold roof spaces. When warm, moisture-laden air travels through uninsulated ducting, the duct wall can become cold enough for condensation to form inside the duct. Just like what happens to your windows if you don't have a SmartVent system installed. Once this happens, water can collect in low points, run back towards the fan, drip onto the ceiling and roof space, generally causing damage and mould growth. Uninsulated ducting can turn a good bathroom fan into a moisture problem. Why insulated ducting? Insulated ducting helps keep the air inside the duct warmer as it travels from the bathroom to the outside. By reducing the temperature difference between the moist air and the duct wall, it helps minimise condensation forming inside the duct. This is less of an issue with our continuous extraction range, as the constant airflow helps manage moisture, but large enough temperature differences between the air and ducting may still see moisture forming. You should be thinking about using insulated ducting whenever you run ducting through any space outside the building’s thermal envelope (un-insulated spaces). This typically includes areas like roof cavities, garages, subfloors, or anywhere the ducting is exposed to cold air. Ducting can also be acoustically insulated as well. This won’t make the fan silent (particularly if it’s a centrifugal or through-wall fan), but it will help reduce the noise of the air through the duct. Acoustic insulation can make a surprisingly large difference, particularly in regions with low background noise. For the best result, insulated ductingshould be installed with short, direct duct runs where possible. Avoid unnecessary bends, sagging, or crushed ducting, as these all reduce the amount of airflow the system can push through and creates locations for moisture to pool. And if you want to be extra safe, ducting can be hung so it falls slightly towards the external outlet, so any moisture that does form is directed outside, not back into the home. A better system Bathroom ventilation is not just about choosing a good fan (although that is a big part of it!). The ducting, airflow path, and installation quality all make a significant difference on the systems performance. For NZ bathrooms, especially in colder regions or where ducting passes through an uninsulated roof space, insulated ducting should be the standard choice. It is a small upgrade that helps protect the building and keeps the system running smoothly.