Selecting mechanical equipment with low noise levels, specifically in the 60 Hz and 125 Hz octave-bands, will reduce the extent of noise mitigation and associated costs needed to reach the acceptable background noise levels.
Meeting the background noise level requirements typically will bring a minimal cost increase due to upgrades in mechanical equipment and calculations. There could be a substantial cost increase if a redesign with upgrades is necessary.
Many commercial toilets can be retrofitted with dual-flush flushometers, costing less than installing new dual-flush toilets. Check with manufacturers for retrofitting compatibility.
Aerators are very cost-effective, costing only a few dollars per fixture. Installing an aerator allows you to chose the sink fixtures that are desired and not have to worry if they are low–flow—simply purchase compatible aerators in addition to the fixtures. You can also easily retrofit existing faucets with low-flow aerators.
Plumbing piping must be doubled for interior water fixtures when graywater or rainwater is reused in addition to potable water. This is likely to add upfront costs, while potentially reducing water and sewer charges.
Meeting reverberation time requirements is usually a negligible or zero cost increase, as long as acoustics have been included in the design from the early stages and no redesign is necessary.
Hiring an acoustics consultant will add a cost, but can be a worthwhile investment in achieving this prerequisite. Hire a consultant as early as possible in order to incorporate recommendations cost-effectively.
Include acoustic performance goals early in the design process to help keep this prerequisite cost-effective.