The most common question I hear about cooking with charcoal grills is how to control temperature. How do you hold a steady, ideal temperature when using charcoal? How do you prevent your grill from spiking or dropping while food cooks? Fortunately, there’s a device that addresses these concerns: the Thermoworks Billows Temperature Controller.
Enter the Thermoworks Billows
Thermoworks is well known for accurate temperature monitoring across many industries. Their popular products include the Thermapen Mk4 instant-read thermometer and the Signals and Smoke temperature monitors. Building on that reputation, Thermoworks introduced the Billows, a fan-based temperature controller designed for charcoal grills. I received a Billows unit to test and paired it with the Signals controller to evaluate how well it performs.
Overview and Setup
The Billows is a small fan that clips into the air intake of a charcoal grill to regulate airflow. It requires an external controller to operate; currently the only compatible controller is the Thermoworks Signals, a four-channel temperature monitor. The Billows retails separately and must be used with Signals. Together they cost more than the fan alone, but the Signals unit also functions independently as a capable thermometer and monitor.
Constructed from durable plastic, the Billows clips onto the grill’s bottom air vent—on a Big Green Egg, for example, it fits the lower intake. A custom cable connects the fan to the Signals unit. To operate, the Signals controller must be plugged into mains power using the supplied adapter. The installation process is straightforward and similar to other controller-and-fan setups on the market.
The Signals controller includes a grate probe that clips to the cooking surface and plugs into the unit. Once the Billows is mounted and connected and the grate probe is attached, the system is ready. The Signals automatically recognizes the fan when it’s connected via the provided cable. Set your target temperature on the Signals, and the Billows will speed up or slow down to maintain that temperature using the grate probe input.
Online and Remote Connectivity
Operating the system directly from the Signals device is simple, and Thermoworks also provides a mobile app for remote control. The app, available for iOS and Android, connects to Signals via Wi‑Fi or Bluetooth. Both connection options are useful—Wi‑Fi lets you monitor and control from farther away, while Bluetooth is handy for local setups without network access.
Once paired, the app displays grate and set temperatures and also shows readings from the other three probes supported by the Signals controller. Signals is a four-channel device: three channels are intended for internal food temperatures and the fourth for the grate. From the app you can adjust target temperatures and set high and low alarms. If charcoal runs low or the temperature spikes, the app alerts you—very useful for long smokes that run 12 hours or more.
Real World Performance
I tested the Billows on a Big Green Egg across several cooks. Here are the highlights from my experience.
What I liked
Installation and setup are quick and intuitive. The Billows clips on securely and connects easily to the Signals controller, and the grate probe attaches simply to the cooking grate. Pairing Signals with a phone was straightforward, and the app is user friendly, making temperature adjustments fast and convenient.
With the Billows running, warm-up time decreased noticeably because the fan provides consistent airflow into the firebox. Thermoworks states the grill will remain within 10 degrees of the set temperature; in my tests the temperature stayed within 7–8 degrees of a 275°F setpoint, which is very good for charcoal-based, low-and-slow cooking.
Keep in mind the system is designed for indirect, low-and-slow cooks. I would not recommend using Billows to maintain extreme high temperatures like 500–600°F—such heat risks damaging the grate probe and may exceed the fan’s effective range.
What I didn’t like
The primary limitation is that the Billows requires the Signals unit to be plugged into mains power. Signals can run on its internal battery when used as a monitor, but once Billows is connected you must use the power adapter to supply the fan. An optional external battery pack or a battery-powered fan would be more flexible for remote or off-grid cooking.
Another drawback is that Billows only works with the Signals controller. Not everyone needs a four-channel monitor, and it would be helpful if the fan were compatible with the smaller, less expensive Smoke controller or with other two-channel solutions.
Overall
Overall, the Billows makes charcoal cooking much more manageable, particularly for those who want consistent temperatures without constant tending. It combines the flavor advantages of charcoal with modern automatic temperature control and mobile connectivity. The Signals controller complements the fan with four-channel monitoring, Wi‑Fi/Bluetooth connectivity, and easy app control, though the combined cost is higher than some single-purpose alternatives.
If you enjoy low-and-slow charcoal cooking but want a more hands-off experience, the Billows paired with the Signals controller is a strong option to consider. It simplifies temperature management while preserving the charcoal flavor that many cooks prefer.