Negligible? Electric heating is less than half of oil heating as recently as 2003 link
page 76.
And what argument speaks for taxing oil highly but neither nat gas nor coal? Why is one third a non-issue, when two thirds are such a big problem?

And what kind of additional sales taxes are there in other countries?

The measure is not at all regressive, it is progressive, although still selective. And that is a very big problem.

Der Amerikaner ist die Orchidee unter den Menschen
Volker Pispers