Research · Allergies

Pollen vs Smoke CADR: What 247 ENERGY STAR Records Show for Allergy Sizing

Most purifiers report a higher clean-air rate for pollen than for smoke — 222 of 247 records, with a median pollen figure 14% above smoke. But 24 records report lower pollen CADR, and no record in the snapshot exceeds 450 cfm for pollen. If you size for allergies, the number on the box you should read depends on how large the unit is.

ENERGY STAR V3.0 · Captured 2026-10-20 (UTC) · 247 records · Analysis of certification data, not independent measurements

Why pollen and smoke CADR differ

CADR is measured separately for three test contaminants: tobacco smoke (the smallest particles), dust, and pollen (the largest). Larger particles are generally easier for a filter to catch and also settle out of the air on their own, so a purifier usually scores higher on pollen. That is why smoke CADR is treated as the conservative sizing figure — and why our calculators use it. See CADR explained for the basics.

How far apart the two numbers are

The 450 cfm pile-up

No record in this snapshot reports pollen CADR above 450 cfm, yet 25 records sit at exactly 450, while smoke and dust figures run higher (up to 577 and 586 cfm). A cluster at one round number like this is consistent with an upper reporting limit for pollen, but the dataset does not say so and we have not confirmed the current limit in the test standard, so treat it as a pattern, not a fact about the machines. 9 of the 24 "pollen below smoke" records are in this group: their smoke CADR is above 450, so their pollen figure could not be shown as higher even if it were.

Practical reading: for these models, a lower pollen figure is not good evidence of weaker pollen performance. Smoke CADR is the more informative number for comparing them.

Smaller purifiers that report lower pollen CADR

15 records report pollen CADR below smoke CADR while staying below 450 cfm. The dataset does not say why, and we do not speculate about design causes. For an allergy buyer looking at these models, the pollen figure is the lower and therefore more cautious number.

What the gap means for room size

Take a purifier with 200 cfm smoke CADR and the median ratio, so about 228 cfm pollen CADR. At 4.8 air changes per hour and an 8 ft ceiling, smoke CADR supports about 313 ft², while pollen CADR supports about 356 ft². Sizing by smoke gives you headroom for pollen in most cases; sizing by pollen alone could leave you under-sized for finer particles such as smoke.

• For most models: size by smoke CADR and treat pollen performance as a bonus.
• For the 15 smaller models above: check that the pollen CADR alone also covers your room.
• For units at 450 cfm pollen: ignore the pollen figure for comparisons between large units.

Largest pollen-over-smoke gaps

Listed to show the top of the range, not as recommendations. A large gap means the smoke figure is much lower — it does not mean a model is especially good for allergies.

Method and limits

• Source: ENERGY STAR Certified Room Air Cleaners (V3.0); all 247 records report smoke, dust and pollen CADR.
• Ratios are pollen CADR ÷ smoke CADR as reported. Room areas are calculated scenarios (CADR × 60 ÷ (air changes × ceiling height)).
• CADR is measured at the highest fan speed. Lower-speed performance, noise and real-world allergy outcomes are not in the dataset and are not assessed here.
• The 450 cfm cluster is an observation in the data; we have not verified a reporting limit in ANSI/AHAM AC-1 and did not test any unit.
• See the methodology and the bedroom sizing guide.