For additional clarity, credit HC3 requires any type of ventilation system to be continuous and to be “whole-house”. In this context, “whole-house” means that continuous extract is required in wet rooms (bathrooms, kitchens, laundry etc) for both extract-only and balanced systems. Note that some balanced systems on the market cannot (or are recommended not to) extract from wet rooms because they cannot handle the extra moisture load. These types of system are not compliant with Homestar.

For a system to be classed as “balanced”, the total volume rates of supply and extract, and outdoor air and exhaust must be the same, with no other mechanical system installed that would unbalance the system (with the exception of kitchen range hoods). This means that separate intermittent bathroom fans are not permitted. 

It is recommended that project teams speak with their suppliers when discussing Homestar projects, to ensure that their design accounts for extract from wet rooms as required and includes the correct volumes of air.