Upgrading Filters















I strongly recommend using an upgraded filter. The standard for media filters is based on the MERV (Minimum Efficiency Reporting Value) rating. The list below explains industry guidelines:

MERV 1–MERV 4: Throwaway Fiberglass Media

MERV 10–MERV 11: Pleated Media Air Filters 30% ASHRAE

MERV 13: Pleated Media Air Filters 65% ASHRAE (65% ASHRAE is about 20% effective on particles of less than 1 micron)

MERV 14: Pleated Media Air Filters 95% ASHRAE

I recommend a 4-inch-thick MERV 12, which provides longer filter life, as the amount of actual filter media is significantly larger than a 1-inch-thick filter. A good heating contractor can easily install these.


Example: Whole-House Ventilation Calculator Here's how you'd calculate the required cubic feet per minute of fresh air required in a four-bedroom home:

Bedrooms: 7.5 CFM/ x 3 bedrooms + 7.5 for Master Bedroom = 30 CFM
Square footage: 2000ft2 X .01 CFM/ft2 of floor area = 20CFM
Total fresh air required: = 50 CFM

Number of bedrooms:

Total square feet:

Total fresh air required: