Terms of use
Short, because this site sells nothing, stores nothing and asks for nothing.
By using this site you accept the terms below. They were last changed on 31 August 2026.
What this site is
HeatPumpMath is an independent, free, non-commercial publication written by Ashutosh Banerjee. It carries no advertising and no affiliate links, sells nothing, and requires no account. There is nothing to buy here and no contract to enter into beyond these terms.
The figures are estimates
Everything published here is modelled output, not a quote and not professional advice. The disclaimer sets out what the figures are, the specific ways they can be wrong, and the limits of liability. It forms part of these terms and you should read it.
Using the data
The computed figures, and the CSV and JSON files at /data/, are published under the Creative Commons Attribution 4.0 International licence. You may use, adapt and redistribute them, including commercially, provided you credit HeatPumpMath and indicate whether you changed anything. No separate permission is needed and you do not have to ask.
The underlying fuel prices are U.S. Energy Information Administration data and are in the public domain.
Using the writing and the design
The prose, page design and code are not covered by that licence and remain the author's copyright. Quoting a passage with attribution and a link is fine and welcome. Republishing pages in full is not.
Images
Three different things, under three different terms, so it is worth separating them.
- Photographs are third party works, almost all from Wikimedia Commons, used under their own licences. Every one is listed on the image credits page with its author, its licence and a link back to the source. Those licences travel with the photographs, come from their creators rather than from this site, and are not affected by anything here. If you want to reuse one, take the terms from its source rather than from this page.
- The HeatPumpMath wordmark and logo are © 2026 Ashutosh Banerjee, all rights reserved. They identify this site, so they are not offered for reuse and are not covered by the CC BY licence on the data. Reproducing the mark to refer to this site, in a link or a citation, is fine.
- Personal documents, meaning the degree certificate photographed on the about page, are © Ashutosh Banerjee, all rights reserved. They are published as evidence of a credential, not as stock imagery.
To ask about using anything in the second or third group, write to banerjeeashutosh01@gmail.com.
Machine access
Automated access is allowed. Every major search and AI crawler is permitted in robots.txt, there is an llms.txt describing the site, and the data files exist precisely so that nobody has to scrape the pages to get the numbers. Please fetch the files rather than crawling 84 pages, and please do not fetch at a rate that would degrade the site for readers.
What you should not do
- Present these figures as a quote, a guarantee, or the output of a professional assessment.
- Attribute altered figures to HeatPumpMath without saying that you changed them.
- Attempt to interfere with the site or with anyone else's use of it.
Things that will change
The figures are updated as new price data is published, and pages are edited as the reasoning improves. Corrections are logged publicly with the old and new numbers. These terms may change too; the date at the top of this page says when they last did.
If this site ever carries advertising, analytics or any commercial relationship, that will be disclosed on the privacy notice and in the editorial standards before it goes live, not after.
No warranty
This site is provided as is and as available, without warranty of any kind. It may be offline, out of date, or wrong. To the fullest extent permitted by law, no liability is accepted for any loss or damage arising from its use or unavailability, including any decision made about a heating system.
Getting in touch
Questions about these terms, and corrections to anything on the site, go to banerjeeashutosh01@gmail.com.