Earlier this year, Google revealed that all Nest accounts will require extra sign-in security starting this spring. For those who haven’t enabled phone—based two factor authentication or have migrated to a Google account yet, that means having to verify their identities via email-based authentication every time they log in. Now, the tech giant has announced that it will begin enforcing that extra security measure for its Nest products starting this month.

Users will soon receive an email from accounts@nest.com with a six digit code whenever they log in to verify that they truly own the account they’re trying to access. The only way users can avoid email verification — in case it’s too much of a hassle to check for an email every log in — is to activate two-factor using their phone numbers or to migrate to a Google account. The company says it will notify users before making the security change. For now, it’s advising Nest owners to ensure they still have access to the email they use for Nest.