Depending on your home wiring, you may experience flickering lights while using Joule. To maintain the precise temperature needed to cook sous vide, Joule’s heater power cycles many times a second; think of a microwave’s defrost cycle or a refrigerator compressor turning on and off. If your lights flicker while you’re cooking with Joule, it’s because the heater is cycling on and off.
Here are a few ways you may be able to reduce flickering:
• Using Joule on the same circuit as the light bulbs can lead to flickering. (If you don’t know whether this is the case, see whether flipping the breaker for the lights also turns off any appliances on the outlet you’re using for Joule.) Most modern wiring actually puts the lights on a separate circuit from high-power-draw appliances to avoid these kinds of issues. To reduce flickering, you can try moving Joule to an outlet on a different circuit.
• The type of light bulbs you’re using can also cause flickering. High-wattage bulbs such as incandescents are more sensitive to high-power-draw devices like your microwave, refrigerator, or Joule. Lower-wattage LED bulbs seem to hold up much better to the large initial power draw of Joule’s (or any sous vide device’s) heater.
• There is also a small chance that your home electrical service isn’t receiving enough power from the power company’s transformer. If the lights in your entire house dim while you’re using Joule, it may be useful to have the power company come out and test their equipment.