Ideally, yes - it allows for shortest, most direct ducting path outdoors (which is what we like!). But fans can be installed on any bathroom walls and ducted to ceiling vents or soffit vents. Extension ducting simply starts to reduce airflow. Our inline fan systems make up for this with brute strength and can be installed in various ways and yet still maintain great performance.
Nobody wakes up one day and says, "I need extra ventilation", without good reason. Ventilation systems are usually ordered to solve a problem, or to prevent a problem before it occurs. We can fix condensation throughout a property, poor ventilation and removing bad smells in kitchens and w/cs - we can't fix water ingress, leaks or rising damp with ventilation alone.
In a nutshell, we will recommend and install a system we have a warm fuzzy feeling will put a real noticeable dent in the sort of symptoms you're currently experiencing. The sorts of ventilation systems we fit certainly aren't cheap, but they do produce the results, as many of our past clients have come to find out!
