A HeatAlgo account takes a minute to create and needs no payment card. This article covers everything about the account itself: signing up, confirming the address, signing in, resetting the password, the app language and the exceptions such as a blocked account. What is free and what a report unlocks is a separate article: the free plan and what a report unlocks. What changed in the app in October: the October 2026 update.
Signing up
You create the account at heatalgo.app/register. You need three things:
- an email address, where the confirmation link arrives,
- a password of at least 6 characters,
- a tick confirming you accept the Terms of Service and the Privacy Policy.
The account is free forever and asks for no card. Installers, designers and auditors create one, and so do homeowners who want to calculate their own house - the app works the same for everyone.
After you submit the form you see the "Check your inbox" screen. Open the message from HeatAlgo and click the link - that is what completes the sign-up. If there is no message, check the spam folder, then use "Send the link again". After each send the button is inactive for a moment and shows how many seconds until you can send another link.
Signing in
You sign in with your email address and password at heatalgo.app/login. The same screen has a "Sign in / Register" toggle, so a new account can be created from the same place.
The most common sign-in messages and what they mean:
- "Email address has not been confirmed" - you have not clicked the link from the sign-up email yet. Go back to your inbox or ask for a new link.
- "Invalid email or password" - check the spelling of the address and the case of the password. If you do not remember the password, reset it.
- "An account with this email address already exists" - this address already has an account; sign in instead of registering, or reset the password.
- "Too many attempts. Please try again in a few minutes" - protection against password guessing; wait a few minutes.
- "Session expired. Please sign in again" - the browser session ended; after signing in you return to the same place, and unsaved changes in modules are safe because saving is automatic.
- "This account has been blocked" - see the section on a blocked account below.
Resetting and changing the password
On the sign-in page click "Forgot password". Enter your email address and submit. If an account exists for that address, you receive a message with a link to set a new password. The link is valid for 24 hours. After clicking it you enter the new password twice - it must be at least 6 characters and differ from the current one.
Open Security in Settings and choose to set or change your password. We send the link to your verified account email. If two-step verification is enabled, receiving a password email does not disable it.
Changing the email address and deleting the account
Change your account email in Settings, under Security. Follow the verification instructions sent to your old and new addresses. The optional business contact email in your profile is for clients and documents; it cannot recover your account. Account deletion still requires contacting support through the account menu or the address in the Privacy Policy.
If you only want to tidy up, you do not need to delete the account: you delete individual projects yourself, from the project view. We describe that in the article about projects.
Where your data lives
Account and project data is processed on our behalf by infrastructure providers: Supabase (database, sign-in and files), Railway (application hosting), Resend (email delivery), PostHog (product analytics, EU servers) and the AI model provider behind the Algo assistant - each under a data processing agreement. Resend, Railway and the AI model provider may process data outside the European Economic Area, in the United States, under standard contractual clauses. The client data you enter in a project, or that a client gives in the form, we process on your instruction - you are its controller.
Account and project data is kept for the term of the agreement. After an account or project is deleted it is marked as deleted and purged for good within 90 days; billing records are kept for 5 years as the law requires. Conversations with Algo stay on the account for the term of the agreement, and the assistant's technical logs for 30 days. You have the right to access, correct, delete, restrict, port and object; you send a request to the address in the Privacy Policy, and you can complain to the Polish data protection authority (UODO). The full description is in the Privacy Policy.
App language
HeatAlgo works in Polish, English, German, French and Dutch. When you come to the app from heatalgo.com, sign-up opens in that page's language and the account remembers it. You change the language in three places:
- in the account menu at the bottom of the side menu: "Settings", "Profile" tab, "Language" field,
- in the account menu, item "Language",
- in the footer of the sign-in page, before you sign in.
The chosen language covers the interface, messages, notifications, emails from the app and the PDF reports you generate. The client form opens in your language, and your client can switch it to any of the five languages (the globe button in the form's header).
Blocked account
If after signing in you see the screen "Your account is blocked", you cannot reach your projects or calculations right now, but nothing has been deleted - it all comes back exactly where it was once the account is unblocked. The screen has a message field: describe the situation briefly and send it, and we reply to the address you sign in with. You can also sign out with the button on the same screen.
Signing out and working on several devices
You sign out from the account menu ("Sign out"). You can be signed in on several devices at once - projects live in the cloud and save automatically, so work started on one computer can be finished on another. Just avoid editing the same project in two open tabs at the same time; what you see then and how to resolve it is in the article on troubleshooting.
Google, Apple and extra account protection
If a Google or Apple button is shown on the sign-in page, you can use that provider instead of a password. On first entry, finish registration by accepting the current terms. Offers consent is separate and optional. Apple may share an email relay address instead of your personal address.
Connect an additional method to your current account under Settings, Security. If you have two accounts that should be one, write to support. Disconnecting methods is not available yet.
You can also turn on two-step verification there: a short guide shows which app to install, the QR code to scan and where the first code goes. Save the ten backup codes outside your browser. Each works once and lets you set up a replacement authenticator; it does not open your projects until replacement is complete. Without the codes, contact support and provide your case number. Support must verify account ownership first.