Sizing & ownership
Indoor Air Guides
Practical explainers for CADR, air changes per hour, filter costs, carbon, electricity, placement and basement humidity.
What CADR Do I Need? A Room-by-Room Sizing Method
Calculate the clean-air delivery rate you need from room area, ceiling height and target air changes per hour.
ACH explainedAir Changes per Hour for an Air Purifier: 1 ACH vs 4.8 ACH Explained
Why air purifier room-size claims change dramatically depending on the air-change rate used.
Filter guideHEPA vs Activated Carbon for Odors: They Solve Different Problems
HEPA-style particle filtration versus activated carbon for smells, smoke particles and gases.
Ownership costHow Often Should You Replace an Air Purifier Filter?
A practical filter-replacement guide based on loading, runtime, air quality and manufacturer guidance.
Operating costHow Much Electricity Does an Air Purifier Use?
Estimate annual air purifier electricity cost from watts, hours per day and your electricity rate.
Dehumidifier sizingWhat Size Dehumidifier Do I Need for a Basement?
Basement dehumidifier sizing based on moisture severity, temperature, square footage and drainage.
Setup guideWhere Should You Put an Air Purifier?
Air purifier placement rules for bedrooms, living rooms and open spaces.
Mold and moistureAir Purifier vs Dehumidifier for Mold: Which Problem Are You Solving?
When to use an air purifier versus a dehumidifier for mold-related indoor-air concerns.
Smoke sizingHow to Size an Air Purifier for Smoke Using CADR
A smoke-specific air purifier sizing method using room volume and desired air changes per hour.
Ownership economicsAir Purifier Filter Cost per Year: The Number to Compare Before Buying
How to calculate annual and five-year replacement-filter cost before choosing an air purifier.
HVAC filtrationMERV 13 for Wildfire Smoke: When an HVAC Filter Upgrade Makes Sense
A practical MERV 13 wildfire-smoke guide covering EPA recommendations, HVAC compatibility, filter fit and replacement timing.
Ownership costHow Much Does It Cost to Run an Air Purifier 24/7?
Calculate 24/7 air purifier electricity cost and compare it with replacement-filter cost and total ownership cost.
Multi-unit sizingHow Many Air Purifiers Do I Need? Use CADR and Room Volume
A room-volume method for calculating whether you need one purifier or multiple units to reach a target air-change rate.
Wildfire smokeMERV 13 vs Portable Air Cleaner for Wildfire Smoke
When to use a MERV 13 HVAC filter, a portable air cleaner, or both during wildfire smoke events.
DIY air cleanerCorsi-Rosenthal Box Room Size: What EPA CADR Research Suggests
Use EPA-published DIY air-cleaner CADR measurements to estimate how a Corsi-Rosenthal box may perform in different room sizes.
Dehumidifier costHow Much Does a Dehumidifier Cost to Run Per Month?
Calculate monthly dehumidifier electricity cost from wattage, active runtime and your electricity rate, with guidance on capacity and efficiency.