Methodology

Show the math.

Each calculator documented here gets the same treatment: the formula, where each default comes from, when it was checked, and what the tool cannot tell you. This collection is new and currently covers the heating cost calculators; if a number looks wrong, tell us.

Heating cost comparisons

The delivered-heat formula, the conversion factors and efficiency assumptions behind it, every default price with its source and date, and what the comparison deliberately leaves out.

Corrections: email [email protected] with the page URL and the figure in question. Source dates are shown on each methodology page and next to the defaults on the calculators themselves; a site rebuild date is never presented as a verification date, and a value you enter yourself is never presented as source-verified.