How Loud Is SWERV? Window ERV Noise Levels by Fan Speed
SWERV runs at about 35 dBA at its lowest setting, about 50 dBA at half speed, and about 59 dBA at full speed, measured 1 meter from the unit. Most customers sleep with it at around 50% speed.
Noise and airflow by fan speed
| Fan speed | Sound level at 1 m | Airflow | Typical use |
|---|---|---|---|
| 10% | ~35 dBA | Low trickle of fresh air | Quietest setting, light ventilation |
| 50% | ~50 dBA | ~50 CFM | Overnight in a bedroom |
| 100% | ~59 dBA | ~110 CFM | Short bursts, clearing cooking smells or a stuffy room fast |
Most people run SWERV between 30% and 70% speed, which moves roughly 28 to 75 CFM.
What it sounds like
At sleep speeds SWERV sounds like steady airflow, similar to a small quiet fan, rather than a mechanical hum. The airflow reverses direction every 45 seconds as the energy recovery core switches sides, so you may notice a gentle change in the sound when it flips. Full speed is noticeably louder and is meant for quick air exchange, not overnight use.
How to keep it quieter at night
- Size the speed to the room. To hold a bedroom around 700 ppm CO2, plan on about 38 CFM per person. One person rarely needs more than half speed.
- Cap the fan speed in Auto Mode. With the sensor package, you set a maximum speed so it never gets louder than you want while you sleep.
- Use two units for bigger spaces. Two paired units running slower are quieter than one running fast.
- Keep the filter in. The filter protects the fans and core and helps keep the unit quiet.
- Seal the foam well. A straight, square cut on the foam side blocks keeps the seal tight and cuts whistling and outside noise.
Where we are improving
V3 is quieter than our earlier beta units thanks to new fans and a new core, and over-the-air updates keep smoothing out the sound when the airflow flips. If noise is a concern for your room, you have free 30-day returns to try it.
More answers in the SWERV FAQ, or see the full specs on the SWERV V3 product page.