Last updated: October 1, 2026
These terms are an agreement between you and Thermist LLC ("Thermist", "we", "us") and cover thermist.com, its free calculators (including the Psych Chart, duct, pipe and steam pipe sizers and the psychrometric calculator), your Thermist account, and the Thermist add-in for Autodesk Revit (together, the "Services"). By using the Services, you agree to these terms and to our Privacy Policy. If you use the Services for a company, you agree for that company too. If you do not agree, do not use the Services.
The Services are design aids. They calculate results from published methods (for example, ASHRAE Fundamentals) and from the inputs you give them, and they can contain errors. They do not replace the judgment of a qualified professional and are not engineering, design or code compliance advice.
You are responsible for every input you enter, for checking every result against independent calculations, manufacturer data and the codes and standards that apply to your project, and for every design, drawing, model, selection and decision you make with them, including anything you issue under a professional seal. Do not rely on the Services alone where an error could cause injury, property damage or financial loss.
Some features need an account. Keep your sign-in details secure and tell us through the contact page if you think someone else has used your account. You are responsible for what happens under your account.
Paid plans are billed in advance through Stripe and renew automatically each billing period until you cancel. You can change seats or cancel from your account page; a cancellation takes effect at the end of the current period. Seat increases are charged right away, prorated. Except where the law requires otherwise, payments are non-refundable. We may change prices for a future billing period after telling you in advance.
While you follow these terms, we give you a personal, non-exclusive, non-transferable license to use the Services, and the PDFs you make with them, in your own work. Each paid seat is for one named user. You may not:
Charts and other content you create stay yours. You give us permission to store, process and display them as needed to run the Services for you. A share link lets anyone who has it view the shared chart, so share links only with people you trust.
The Services rely on others, including Autodesk (Revit), Stripe and Google Firebase. Their own terms apply to your use of them, and we are not responsible for them.
We may change, suspend or stop any part of the Services, including the free tools, at any time. We do not promise that the Services will always be available or that saved content will be kept forever; keep your own copies of anything important.
THE SERVICES AND EVERYTHING THEY PRODUCE ARE PROVIDED "AS IS" AND "AS AVAILABLE", WITHOUT WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, TITLE AND NON-INFRINGEMENT. WE DO NOT WARRANT THAT ANY RESULT IS CORRECT OR COMPLETE, THAT THE SERVICES WILL MEET YOUR REQUIREMENTS, OR THAT THEY WILL BE UNINTERRUPTED OR ERROR FREE.
TO THE FULLEST EXTENT THE LAW ALLOWS, THERMIST AND ITS MEMBERS, OFFICERS, EMPLOYEES AND SUPPLIERS WILL NOT BE LIABLE FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL OR PUNITIVE DAMAGES, OR FOR LOST PROFITS, REVENUE, DATA OR BUSINESS, OR FOR THE COST OF DESIGN REVISIONS, REWORK, REPLACEMENT EQUIPMENT OR CONSTRUCTION, ARISING FROM OR RELATED TO THE SERVICES, EVEN IF WE WERE TOLD THEY WERE POSSIBLE. OUR TOTAL LIABILITY FOR ALL CLAIMS RELATED TO THE SERVICES IS LIMITED TO THE GREATER OF THE AMOUNT YOU PAID US FOR THE SERVICES IN THE 12 MONTHS BEFORE THE CLAIM AROSE OR US $100. FOR THE FREE TOOLS, INCLUDING THE PSYCH CHART, THAT AMOUNT IS US $100.
Some places do not allow some of these exclusions or limits, so they may not all apply to you.
You will defend and indemnify Thermist against claims, losses and costs (including reasonable legal fees) brought by third parties that arise from your use of the Services, your designs or projects, your content, or your breach of these terms.
You can stop using the Services at any time. We may suspend or end your access if you break these terms or if we stop offering the Services. Sections 1, 5 and 8 to 13 continue after these terms end.
We may update these terms. We will post the new version here with a new date, and for a material change to a paid plan we will tell account holders in advance. Using the Services after a change takes effect means you accept it.
These terms are governed by the laws of the Commonwealth of Massachusetts, without regard to its conflict of law rules, and any dispute will be heard in the state or federal courts located in Suffolk County, Massachusetts. If any part of these terms is unenforceable, the rest still applies. Our not enforcing a right is not a waiver of it. You may not transfer these terms without our consent; we may transfer them with the business. These terms, together with the Privacy Policy, are the whole agreement between us about the Services.
Questions about these terms: use the contact page.
