We offer an optional (accessory) kit that includes a 12V adhesive heating pad, a digital temp controller module (and yes if you already have an FTSs it is the same controller!), and a power supply.
The heating pad is installed by taking off a removable panel from the bottom of the Mash Tun and sticking the pad on the underside of the 5-degree conical bottom. The heating pad is toggled on and off by the digital controller which is powered by the plug pack (6 amp).
The intention of this system/configuration is to HOLD A STABLE TEMPERATURE of your choosing (anywhere from 150F to 160F typically). It is not intended or capable of increasing temps from say 120F up to 155F.
While this may not do what all of you are wanting it to do, it is still a lot better than most current plastic cooler type setups that see a pretty big temp decay over time and have no ability to stabilize/hold a flat temp for any period of time. And like all of our gear, we have made this optional kit very affordable