High Cfm Range Hood Make Up Air MUA
I WILL START OF BY SAYING I AM NOT A HVAC PROFESSIONAL THIS IS SIMPLY THE INFORMATION THAT I FOUND IN MY QUEST FOR A MAKE UP AIR SOLUTION IN WISCONSIN THAT MY INSPECTOR HAS APPROVED FOR MY NEW CONSTRUCTION HOME AND WANTED TO SHARE WITH THOSE OTHERS WHO ARE SEEKING A PATH THROUGH THE MAKE UP AIR DILEMMA
First you have to contact the health and safety official of your county and speak with with the inspectors, Do not go directly to HVAC contractor, there job is to sell you products to the best of their knowledge which may or may not satisfy the inspector, or may or not be needed. Sometimes they get it wrong and I am not willingly to give away money for what they think I need to pass code.
Read STATE code regard ventilation (Wisconsin was pretty simple to find) since this is easiet to find and the countys all follow state code, to prepare your self when talking with the inspector.
Simply tell the inspector you have a Xcfm range hood and wanted to figure out if make up air is required and how should I do it to get through inspection. Listen to there suggestions and compare it to the local codes you have read and work together, by asking questions
From the above process I found out the following for a 1266cfm blower in Wisconsin that my inspector said he is fine with passing.
When using passive MUA, WI codes states that only 40% of exhausting mechanical ventilation has to be made up from all sources that have interior intakes and air fultration is considered part of MUA, when house has no appliances that take combustion air from inside the house; ie fireplaces older water heaters and furnaces. All my appliances have air intakes on the exterior of the house
Blower door test should be done to determine air infiltration
Formula from working with inspector.
(Range Hood CFM * .4) - Air Infiltration - Range Hood CFM Allowance + Bath Fans = MUA requirement
In my case
1266 * .4 - 0(blower door test not done yet) - 300 + Bath Fans = 206.4 CFM + Bath Fans + Dryer
The most about of air that I would have to bring into my house would be 206.4 CFM + Bath Fans + dryer, which I can get with a 4" duct direct from outside with a damper and floor vent. I probably wont even need the intake duct, depending on the leakage that I find from blower door test. But will still do one. Inspector say I could introduce the amount using HRV also
***TIP = Keep bath exhaust fans small. Atleast for inspection calculation purposes. Chances are youll never have every single blower running in your house at the same time.
The catch - The inspector specified the air intake ducting must be insulated.
CONCLUSION MAKE UP AIR IS NOT THAT HARD, MAY NOT EVEN BE NEEDED TO RUN, EVEN THE HIGH CFM RESIDENTIAL KITCHEN RANGE HOODS.
On topic part of post.Anyone have recent review or stories about Proline Range Hoods