AHAM vs Saturation PPD
AHAM PPD is measured at 80°F and 60% relative humidity. Saturation PPD is measured at higher temperature and humidity, typically 90°F and 90% RH. Crawl spaces are usually cooler (50-60°F), so actual water removal will be lower than both ratings.
AHAM PPD (Association of Home Appliance Manufacturers)
AHAM PPD is the standardized rating for dehumidifiers in the United States. Test conditions:
- Temperature: 80°F (26.7°C)
- Relative Humidity: 60%
This is the number you see in product names: "90 pint dehumidifier" means 90 pints per day at AHAM conditions.
Saturation PPD
Saturation PPD (also called "max PPD" or "saturation capacity") is measured at maximum load conditions:
- Temperature: Typically 90°F (32°C)
- Relative Humidity: 90%
At these extreme conditions, the dehumidifier removes more water per day. The AlorAir Sentinel HDi90, for example, removes 90 pints/day at AHAM conditions but 198 pints/day at saturation.
Why Both Numbers Matter
AHAM PPD is useful for comparing units on a standardized basis. All manufacturers must test at 80°F/60% RH for AHAM certification.
Saturation PPD shows peak capacity in extreme conditions (hot, humid summer). This is closer to what you might see in a flooded crawl space after heavy rain in warm weather.
What About Crawl Spaces?
Most crawl spaces are cooler than 80°F. Typical crawl space temperatures:
- Summer: 60-70°F
- Winter: 45-55°F (or colder in northern climates)
At lower temperatures, dehumidifier output decreases. A unit rated for 90 PPD at 80°F/60% RH might produce 65-75 PPD at 60°F/60% RH.
We do not invent "crawl space PPD" estimates. We report manufacturer AHAM ratings and note that crawl space output will be lower due to cooler temperatures.
Which Manufacturers Publish Saturation PPD?
| Brand / Model | AHAM PPD | Saturation PPD |
|---|---|---|
| AlorAir Sentinel HDi90 | 90 | 198 (90°F/90%) |
| Santa Fe Advance90 | 90 | Not published |
| AprilAire E070 | 70 | Not published |
| AprilAire E080 | 80 | 65 at 73°F/60%* |
| Argendon Guardian 60 / 60P, Shield 60 / 60P | 60 | 145** |
| Argendon Sandidry 55C | 55 | 120** |
| Argendon Shield 35M / 35P | 35 | 70** |
*AprilAire publishes capacity at 73°F/60% RH (65 PPD for E080), not true saturation. This is not saturation PPD.
**Argendon lists "saturation removal capacity" on each argendon.com product page (fetched 2026-09-29). The Guardian 60 page states 90°F/90% RH; the other pages do not state test conditions. Each row's models share the same AHAM and saturation ratings. See all Argendon crawl space models →
We may earn a commission from AlorAir and Argendon via Awin when you use our links; it does not change the price. Other brands remain unsponsored.
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