Know your Sone – Whole House ventilation

In Washington State it has been required for new construction to have a whole house ventilation system since 1991 as prescribed by the Washington Ventilation and Indoor Air Quality code.

These systems can be achieved in various forms as long as they meet the requirements.  
The most common approaches I see are; Intermittent Whole House Ventilation Using Exhaust Fans & Fresh Air Inlets. (IRC M1508.4) and Intermittent Whole House Ventilation Integrated with a Forced Air System. (IRC M1508.5) Link-Washington State Code

                                           
One important issue is that these fans need to meet a noise standard. The level of loudness is known as “SONE” (HVI  (Home Ventilating Institute) has rated products in sones, based on one-third octave measurements in a diffuse reverberant chamber, using the comparison method in strict accordance with ANSI consensus standards.).

IRC code - M1508.4.2 Fan Noise.
Whole house fans located 4 feet or less from the interior grille shall have a sone rating of 1.0 or less measured at 0.1 inches water gauge. Manufacturer's noise ratings shall be determined as per HVI 915 (October 1995). Remotely mounted fans shall be acoustically isolated from the structural elements of the building and from attached ductwork using insulated flexible duct or other approved material.

Okay you say all well and good but why does this matter? It matters because we are humans and if our fans are too noisy what is the most likely outcome? We do not use them as intended.
In modern construction as we develop tighter building envelope to control energy loss we need a way create better air quality, we need to ventilate the home. Exhaust fans are very important in this equation.

So when looking at replacing and or repairing any exhaust fans in the home you should be evaluating the noise level of that fan. All fans will have a “Sone” rating on them.

As a home inspector I will note if a fan is noisy for two reasons. One a noisy fan is most likely not to be used and two it could be an indication of the fan has a problem and needs repair or replacement.

Ancora Imparo

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