How do sensor dryers work?

The short version: Sensor dryers use two metal strips inside the drum to detect changes in electrical conductivity - wet fabric conducts electricity more readily than dry fabric. As clothes tumble past, the control system uses these readings to determine when the load has reached your chosen dryness level, rather than running for a fixed time. This can help prevent over-drying, reduce unnecessary heating and tumbling, and may trim your energy bills.

When you pull a warm, perfectly dried load of laundry out of the dryer, you've probably got moisture sensing to thank. Sensor dryers are designed to end the drying cycle when their sensors detect that the load has reached the dryness level you've selected, rather than running for a fixed amount of time. This can help avoid unnecessary heating and tumbling, which may cost you more and put extra wear on fabrics.

Timed dry is the older, more basic approach - you set a duration based on what you think might be necessary, and the dryer runs for that long regardless of how wet or dry the load actually is. Sensor dry takes a more responsive approach, using moisture sensing to judge dryness as the cycle progresses rather than relying on your guesswork. This generally means less over-drying, since clothes aren't left tumbling and heating long after they've reached the desired dryness level. It may also modestly reduce energy use, since the dryer isn't running longer than necessary.

Ever find that some of the clothes you pull out of the dryer are bone dry in parts but still damp under the arms? A dirty sensor could be the culprit, although uneven drying can also have other causes, including overloading, tangled items, an unsuitable cycle or restricted airflow. A sensor dryer is only as effective as its sensing system, so a bit of regular upkeep goes a long way.

Cleaning the lint filter after every load is one of the most useful maintenance habits. Built-up lint can restrict airflow and contribute to longer drying times. It's also worth regularly wiping down the metal sensor strips themselves with a soft, damp cloth, following the manufacturer's cleaning instructions, as residue from fabric softener and dryer sheets can build up on them over time and interfere with moisture sensing. Some manufacturers recommend cleaning the sensors periodically with vinegar or another specified cleaning method, so check your dryer's manual before choosing a cleaning product.

For vented dryers, keeping the exhaust vent clear helps maintain good airflow. For heat pump dryers, clean the lint filters and heat exchanger or condenser as directed by the manufacturer. Keeping these areas clear can help maintain drying performance and avoid unnecessarily long cycles.

Sensor drying is a genuinely useful bit of technology for everyday laundry, using a relatively simple sensing system to detect changes in moisture as clothes tumble through the dryer drum. A little care - a clean lint filter and sensor bars, and clear airflow - helps your dryer sense moisture effectively, cycle after cycle, whether you're running a heat pump or vented model.