About this site

Andrew Flores, working alone, with AI assistance used for drafting and checking and never as a source. Nathan Management publishes this site, and Andrew is the person who answers for what it says and makes corrections. He is not a plumber, a gas fitter or a mechanical engineer, and nothing here is a substitute for someone who is.

Use the methodology page to inspect sources, calculations, and assumptions. For an assessment of a specific installation, consult a qualified local professional.

How the numbers got here

Every sourced figure names the page it came from, and the methodology page lists each one with the date it was checked. The register holds 106 figures in all, checked on 2026-08-06, 2026-08-24, 2026-10-05 — more than one date because sources were added or re-checked at different times, and printing a single date for all of them would be tidier and untrue. Some are sentences quoted from the source; some are cells transcribed from a published table; a few are our own arithmetic over sourced values, labelled derived, or values we chose ourselves, labelled assumed. Several sources are cited through a dated archived copy rather than the live page, and the pages say so where those figures are used. On 2026-10-05 the cited quotes were re-matched by script against copies of the source pages saved that day.

Where a figure is our own arithmetic, it says derived and shows the working. Where nobody publishes it and we picked a number, it says assumed and appears as an editable input, so our judgement is something you can overwrite rather than something you have to accept. The assumptions are listed on the methodology page.

What this site will not do

It will not invent a regional multiplier so the estimate feels personalised. It will not floor a negative saving so a payback calculation returns a tidy number. It will not fill a gap in a published series with a neighbouring state and hope nobody checks. Each of those makes a calculator feel more useful and makes it less true, and the second thing outlasts the first.

If you find a figure that is wrong, out of date, or attributed to a page that no longer says it, the contact page has the address. Corrections are recorded in the update log on the methodology page, with the date and what changed.