GermGuardian AC4825E
#6 in Small roomsFull review
A cheap, slim tower purifier for a small bedroom or office.
Amazon $80.74$80.74
The GermGuardian AC4825E and the KNKA APH2500P are evenly matched, rated 3.2 and 3.1. The GermGuardian AC4825E leads on warranty. The KNKA APH2500P wins on auto mode and efficiency. The GermGuardian AC4825E costs $9.25 less ($80.74 vs $89.99).
KNKA APH2500P
#8 in Small roomsFull review
A pet-oriented purifier for bedrooms up to about 185 sq ft. Its hair-catching pre-filter is the draw, but plain purifiers deliver more clean air per dollar.
Amazon $89.99$89.99
Prices were last checked October 22, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the GermGuardian AC4825E for warranty (3-year warranty vs 2-year warranty).
- Choose the KNKA APH2500P for auto mode (air quality (type not stated) sensor, auto mode vs no air-quality sensor or app) and efficiency (5.2 cfm per watt vs 3.5 cfm per watt).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every small rooms air purifier; a clear win is highlighted. How we rank explains each one.
| Factor weight | GermGuardian AC4825E | KNKA APH2500P |
|---|---|---|
| Overall rating | 3.2/5 | 3.1/5 |
| Value 25% | 79 $0.82 per cfm of smoke CADR | 83 $0.76 per cfm of smoke CADR |
| Filter cost 20% | 50 filter price or life not published (neutral score used) | 0 $119.96 a year in filters |
| Quiet 20% | 50 noise at top speed not published (neutral score used) | 50 noise at top speed not published (neutral score used) |
| Efficiency 15% | 19 3.5 cfm per watt | 40 5.2 cfm per watt |
| Auto mode 10% | 0 no air-quality sensor or app | 70 air quality (type not stated) sensor, auto mode |
| Warranty 10% | 50 3-year warranty | 25 2-year warranty |
Independent measurements
GermGuardian AC4825E
| Tested by | CADR | Noise | Conditions |
|---|---|---|---|
| HouseFresh | - | 55.6 dB | dB at 3 ft: 40 / 44.8 / 51.6 / 55.6 by speed; took 104 min to clear its test room |
KNKA APH2500P
No independent test published yet.
Specifications
| GermGuardian AC4825E | KNKA APH2500P | |
|---|---|---|
| Performance | ||
| Smoke CADR | 99 cfm | 119 cfm |
| Dust CADR | 116 cfm | 123 cfm |
| Pollen CADR | 129 cfm | 147 cfm |
| PM2.5 CADR | 111 cfm | 121 cfm |
| CADR certified by | AHAM Verifide | AHAM Verifide |
| Room size (AHAM) | 153 sq ft | 184 sq ft |
| Coverage (maker) | 743 sq ft | - |
| Efficiency | ||
| Efficiency (IEF) | 3.5 cfm/W | 5.2 cfm/W |
| ENERGY STAR | No | No |
| Energy use | 182 kWh/year | 137 kWh/year |
| Filters | ||
| Filter | HEPA with carbon pre-filter, optional UV-C bulb | HEPA-type |
| Activated carbon | Yes | Yes |
| Replacement | FLT4825 (Filter B) | APH2500P filter |
| Replacement cost | $19.88 | $29.99 every 3 months |
| Yearly filter cost | - | $119.96/year |
| CARB certified (ozone) | Yes | Yes |
| Controls and build | ||
| Air-quality sensor | None | air quality (type not stated) |
| Auto mode | No | Yes |
| Wi-Fi app | No | No |
| Fan speeds | 3 | - |
| Dimensions | 22 x 10.25 x 6.75 in | - |
| Weight | 8.6 lb | - |
| Warranty | 3 years | 2 years |
| Released | - | 2026-09 |