Understood. My boiler/furnace is the single most important "appliance" in my house. I guess I still need an electrician and/or use the traditional gas generator/panel switch approach.
Some furnaces are still 120 volt (same as an outlet) so depending on how the furnace is connected, Pila could be an option or at least could work with some minimal electrical work. But definitely recommend chatting with a good local electrician to pick the right path
If you get an electrician to rewire it to have a plug, you could certainly back it up with Pila.