Which is Better: Portable Room Air Purifiers or Whole Home Air Purifiers?
- Dan Dearden
- Aug 19, 2025
- 3 min read
Updated: Sep 11, 2025
Response by Dan Dearden, CAFS – Certified Air Filtration Specialist, Essential Air Products Founder, NovusAer Inventor
Great question! The answer is: it depends.
Before we get into the differences, let’s talk about what Portable Room Air Purifiers (PRAPs) and Whole Home Air Purifiers (WHAPs) have in common:
How They’re Alike
Same basic job: Both use high-efficiency air filters to trap particles from the air passing through them.
Sized the same way: To keep air clean, experts recommend filtering all the air in a space about five times an hour. This is called Air Changes per Hour (ACH).
Optional extras: Both can be upgraded with add-ons like UV lights or ionizers for germ-killing power.
Odor reduction: Adding charcoal to the filter can help reduce smells in both systems.
Affected by home “leaks”: Both work less effectively if your home has a high air infiltration rate—dirty outside air sneaking in through cracks and gaps. Sealing and weatherizing your home boosts performance for either option.
Examples
PRAP Example: For a living room 14′ × 20′ × 9′ tall, you’d need a purifier with a Clean Air Delivery Rate (CADR) of 357 cubic meters per hour (m3/h) or about 210 Cubic Feet per Minute (CFM) to achieve the recommended 5 ACH. The IQAir Atem X ($1,399) is one example that meets this need.
WHAP Example:For a 1,400 sq. ft. home with 9′ ceilings, you’d need an HVAC system delivering about 1,050 CFM to hit 5 ACH (equivalent to a 2.5-ton AC system).
How They’re Different
Coverage:
A PRAP is designed to clean one room, and one room only.
A WHAP cleans every room connected to your central HVAC system.
Room sealing:
A PRAP works best in a room that’s sealed from other air sources (except for natural infiltration). If the room is connected to a forced-air system, unpurified air can constantly replace the cleaned air—canceling out the purifier’s work.
Improper application of a PRAP. A PRAP in an unsealed room, connected to a forced-air system.
A WHAP pushes clean, purified air through every room and replaces the dirty air throughout the house.
Number of units needed:
To clean an entire home with PRAPs, you’d need one in every room.
With a WHAP, you need just one unit for the whole home (as long as it’s all served by the same HVAC system).
Filter lifespan:
PRAP filters are small and often need replacing every 3 months.
WHAP filters can be much larger—some last up to 3 years.
Installation compatibility:
PRAPs work anywhere in any home.
WHAPs require a compatible HVAC system—some systems in confined spaces may not be able to accommodate one.
Best fit situations:
PRAP: Perfect for ductless or radiant heating/cooling systems.
WHAP: Great for homes with central forced-air HVAC.
When to Choose a PRAP
Your home or a specific room uses ductless or radiant heating/cooling.
Your HVAC system can’t accommodate a WHAP.
You rent and want to take the unit with you when you move.
You need to isolate a contagious person in a sealed room. To keep the room isolated, you will also need to provide independent heating and cooling services.
When to Choose a WHAP
You want HEPA-level pirified air in every room of your home.
You want low-maintenance filters that last up to three years.
You want to protect your HVAC equipment by keeping it clean inside.
You’d like to reduce dusting by adding an infiltration mitigation duct to your filtration system.
You want the lowest possible annual maintenance cost while maintaining HEPA level air purificaiton.
Bottom Line:
If you only need to clean the air in one room—or can’t install a WHAP—go with a PRAP.
If you want whole-home coverage and have a compatible HVAC system, a WHAP is the best long-term solution.
Don’t waste your money by putting a PRAP in a ventilated room. (Caution: If you close off the ventilation, you essentially close off the heating and cooling.)
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