#8. Noise Ratings

Sound power is measured in decibels, and an important thing to remember is that they are logarithmic, which means that they do not go up in a linear (straight-line) fashion, rather it is exponential. This means that a 3db increase is twice as loud. A 2-3 dB difference is considered to be a just noticeable. In duct fans (Weiss FV05) are usually quieter than wall or ceiling mounted fans, as the ceiling panel and insulation reduce the directly radiated noise, and the duct attenuates some of the noise (around 2dB per metre for typical household sizes). For this reason, if you use an in-duct fan, mount it towards the end of the duct, so it is far from the inlet over the shower to get the most effect. The fan should be no closer than 2 duct diameters from the end grille, in order to give the airflow a chance to straighten out and reduce turbulence losses. Fan noise is largely dependent on the air velocity through the grilles, so most solutions involve reducing the air speed, and larger ducting and grilles, or multiple inlets usually do this. Generally, the noise is also proportional to the amount of airflow and the fan speed, If you have problems with a noisy fan or are putting a system in: 1. Mount the fan towards the end of the duct 2. Use multiple intakes to reduce the air velocity through each grille 3. Consider speed control

1. Can the home handyman install the unit?
2. How much would a duct warmer unit cost to run?
3. Ducting Information.
4. Will the HVS System work the same with the internal doors closed?
5. What maintenance is required?
6. Is the Weiss HVS Expensive To Run?