Block Wildfire Smoke Entry: Pressurize Your Home’s Breathing Zone with Highly Filtered Outdoor Air 

Here are the steps you need to follow to keep your home free of wildfire smoke:

  1. Make your home as airtight as possible by sealing all openings and cracks in the  home’s exterior. Yes, we know that this is exactly the opposite of the way western USA homes have been built for years. Your building code needs to be changed to keep wildfire smoke out of the homes and to increase energy efficiency.
  2. Filter all air entering your home through a smoke-removing filter.
  3. Use this highly filtered fresh air to pressurize your home to force (gently blow) wildfire smoke AWAY from cracks instead of sucking it IN through cracks. The old California theory was that if you suck outdoor air in through cracks, the cracks would filter the smoke and pollutants out. Doesn’t work well, never did. A first class filter MERV 13 or better, filters out smoke far better than the cracks in your home.
  4. Use caulk to seal all cracks and apply weather stripping to all doors and windows.
  5. Once your home is sealed, supply ALL fresh air into the home through a filtered ventilation system using a filter of MERV 13 or better. 
  6. Install a dedicated, variable speed fresh air fan to allow precise adjustments to pressurize your home sufficiently to push against smoke entry through cracks you could  not find and seal..
  7. Disable all exhaust fans during smoke. GOOD IDEA:  You may wish to block them off to prevent them from bleeding off the pressurization that you are seeking to create. BEST IDEA: You may prefer to install adjustable pre-load barometric dampers on exhaust duct outlets. (they will help to maintain pressurization but can be forced open by higher pressure exhaust fan operation when needed.)
  8. Make sure that the interior of the home is positively pressurized during periods of wildfire smoke, it may be necessary to adjust the speed of the fresh air ventilation air fan frequently. A micropressure controller can automatically and quickly (within 1-2 seconds) adjust fan speed as necessary to automatically maintain sufficient pressure regardless of most outdoor conditions, subject to ventilation system performance limitations. Changes in wind are much better handled by automatic, electronic fan speed / pressurization control. A REMARKABLY SIMPLE AND ACCURATE INDICATOR MAY BE AVAILABLE FROM HEALTH AND ENERGY, OMAHA NEBRASKA.
  9. Experience in SW Florida during everglades fires confirms the success of this approach using a MERV 14-15 filter to filter all air entering the home.. You will not even smell the smoke no matter how dense it may be outside. (so long as  you keep all doors and windows closed.)
  10. DURING WILDFIRE SMOKE, DO NOT USE EXHAUST VENTILATION, EVER, EXCEPT AS SHORT RUN SPOT EXHAUSTS IN AREAS OF THE HOME WITH AIR POLLUTANT SOURCES. YOU CAN EXPECT SMOKE ENTRY ANY TIME YOU USE EXHAUST SYSTEMS.