Composting, Recycling and Reusing: It's not Just a Kitchen Activity


Sponsored by Zehnder, the only company that helps professionals and owners do ventilation correctly over and over again.


Let’s take your basic 4 bedroom 3 bathroom house that is 1500 SQFT.


We will first calculate a hygienic 1/3 Air Changer Per Hour.


(((1500sqft * 8.2’) /3) /60) =68 CFM by average volume


As you see in table M1505.4.3(1) on this chart ventilation rate is only 60 CFM


Now let’s calculate ventilation by Bathroom & Kitchen Continuously because that’s how smells and humidity really work.


60 cfm for 3 Bathrooms and one kitchen give us 84 CFM and we can either supply OR exhaust a Laundry room with 12CFM. If it is condensing dryer no venting is required.


This gives us 96 Total CFM. Since this is the higher of the 3 numbers, we’ll use this number.


We’ll take 96 CFM and add 10% for duct/installer loss and that give us 106 CFM. We’ll double that number because we want our ERV/HRV to work in its center capacity where it’s most efficient, reserving higher speeds for BOOST MODE.


We’ll need an ERV/HRV that is rated at 220CFM minimum. 


See Zehnder Ventilation Options Here:


erv install1


erv install2


If you’re interested in more ways to be kind to the environment, breathe better, and save money, you can check out how we can apply passive house principles to your home, church, office, apartment, library, maintenance building, or upload your plan sets so that you can reduce your energy bills to nearly nothing per month! We provide passive house services for: passive house Colorado, passive house Wyoming, and passive house Nebraska. In addition, breathe clean and easy with Airtight and Ventilation solutions at we ship all over the place! We exist for the sole purpose of helping the world build healthier, wealthier, and wiser!