In order to find the best humidifiers, we tested everything from their humidifying performance to how easy they are to maintain and use. We divided our tests into four separate metrics, which we have outlined below.
We tested humidifying performance using a 150 square foot testing room, as it correlates to about an average sized bedroom. We assured that this room was at the same temperature and same starting humidity when we tested each model, with the help of a dehumidifier. We then ran each model on its highest setting in this room for 3 hours, monitoring the humidity using an Extech RHT20 Humidity and Temperature Data Logger to monitor the humidity. For the models that have their own built-in humidity meters that regulate mist output, we compared the readings on these meters to our Extech meter to ascertain their accuracy. We awarded scores based on speed of humidification, maximum level of humidity reached, and the accuracy of the built-in humidity meters.
Ease of Cleaning
Our testing required multiple rounds of cleaning for each model. In doing so we kept careful notes on how easy it was to scrub each water tank, whether there were nooks where mold could hide, and whether there was any scale buildup. We also assessed the clarity and specificity of the manufacturers' cleaning recommendations.
Our user friendliness testing focused on two things: each model's interface and how easy it was to fill each water tank. Interface testing involved having everyone in the office change the settings on each model and then score how intuitive and easy it was to do so. Our other metrics required many tank refills, so we kept careful notes whether each tank could be filled directly from a sink, and whether there were any specific annoyances involved in the refilling process.
Our operating cost testing took three things into account: upfront cost (list price), electricity usage, and, for applicable models, the costs of any replacement filters or wicks. To determine electricity usage we plugged each model in a wattage meter and ran them on medium for 2 hours. In order to calculate an estimated lifetime cost we assumed a 5-year lifespan, an average of 12 hours of use per day, average electricity costs ($0.12/kWh), and that any replacement filters would be replaced according to manufacturer specifications.