We have a mixed project with residential and office units. Residential area has apartments and few (12) duplex units. As per LEED requirement for Prerequisite 1- Minimum IA performance, CO sensors have to be provided for all residential units even if the cooking or any associated combusion are electric based.

As the project has 12 duplexes do we need to provide 12 CO sensor units or more. As per the credit language, "CO monitors must be installed on each floor of each unit", does that make 12X2 CO sensors for the 12 duplexes? 

As the duplexes will have kitchens in the zero floor while the upper floor will have bed rooms only, providing CO sensor for the upper floor may not be needed. Kindly advise. 

Thanks in advance.