The exact physics of the reaction impact burner design and how much work is needed to adapt a burner designed for one fuel to another (sometimes impossible even if you're replacing gas with gas).
Methanol is highly toxic; it is important to consider how we can make pumping it into people's homes as safe as possible.
Is methanol more toxic than gasoline?
Not sure if you meant something else but just in case, "the majority of gas, at least in EU, is burned in residential heating units" means natural gas i.e. methane, not petrol/gasoline