Most upgrade paths work the way you expect: pay more, get more of everything. Proton’s does not, and the exception is the one feature people are currently shopping for. A privacy focused AI assistant under $15 looks like something a paid mail plan should already cover, and on Proton’s own comparison table it does not: the AI entitlement reads the same on the free plan as it does on the most expensive one.
This is an independent editorial review. Proton did not review or approve this article.
Proton AG is a Swiss company registered in Geneva and the plan details below were read from its own pages on the date of writing; its privacy and encryption statements are the vendor’s own claims rather than audited findings, and its terms provide that a claim brought in the United States is construed under the law of the state where the customer resides rather than under Swiss law, so the contract a US buyer signs is not the one the company’s address implies.
You can see Lumo’s current plans on Proton’s official site:
The cost breakdown behind a privacy focused AI assistant under $15
Lumo is Proton’s AI assistant, and it is sold in two places at once: as a feature line inside the mail and storage bundles, and as its own subscription. Those are not the same purchase, and the money works out differently.
- Free. Listed at $0.00 per month, with “No credit card required.” Limits are published as words rather than numbers: “Limited Max model usage,” “Limited messages & chat history,” “Limited image generations,” and “1 Project.”
- Lumo AI Plus. Listed at $9.99 per month against a struck-through $12.99, and “Billed at $119.88 every 12 months” on the annual term. It adds “More Max model usage,” “More messages & chat history,” “More image generations,” “Unlimited Projects,” and “Unlimited Custom Lumos.”
- The mail and storage bundles. Proton’s pricing page lists Free at $0.00 per month with 1 GB, Mail Plus at $3.99 per month “billed at $47.88 every 12 months” with 15 GB, and Unlimited at $9.99 per month “billed at $119.88 every 12 months” with 500 GB.
Two of those annual figures are identical. The bundle that gives you 500 GB of storage and the AI subscription that gives you more model usage are each billed at $119.88 every 12 months, and they are separate line items.
The suite subscription does not include the assistant
This is the finding that should decide the purchase, and Proton publishes it in its own comparison table rather than hiding it. Across Free, Mail Plus and Unlimited, the Lumo rows read the same: “Limited” model usage, “Limited” messages and chat history, “Limited” image generations. The paid mail plans do not raise the AI allowance at all.
So a reader already paying for Unlimited, who assumed the assistant scaled with the plan, is looking at a second subscription at the same annual price as the first. That is the arithmetic that matters here, and it is easy to miss because every other feature on that table does improve as you move right.
Work the decision in this order:
- Open your existing plan’s feature table and find the AI rows specifically, rather than assuming the tier covers them.
- Separate the two things on offer: privacy, which the free tier already provides, and capacity, which it does not.
- Price the assistant as a standalone annual commitment, because that is what it is.
- Only then compare it with the general-purpose assistants you may already be paying for elsewhere.
What the free tier already gives you
The privacy architecture is not the paid feature. Proton states that Lumo conversations are stored with “zero-access encryption, so no one (not even Proton) can access them,” that chats are not logged, that user data is never used to train AI models, and that the business model is ad-free so there is no advertiser to share data with. It describes Lumo’s code as fully open source so the claims can be verified, and the FAQ notes you can use Lumo through Tor with guest access and no account at all.
None of that is gated behind the subscription. If the reason you are here is that you do not want an assistant retaining your conversations, the free tier is the product and the paid tier is a quota increase on top of it. That is an unusually clean free-versus-paid split, and it is worth saying plainly because most privacy-marketed services put the actual protections behind the paywall.
Deciding is privacy focused AI assistant worth it without a published quota
Here is the catch for a value buyer. Deciding is privacy focused AI assistant worth it normally means dividing a price by a volume, and the volume is not published. “Limited” and “More” are the only figures given for messages, chat history, model usage and image generations on either tier. You can compute the annual price exactly and you cannot compute cost per use at all, which means the only honest way to evaluate it is to run the free tier until you hit a wall and see how long that took.
What an affordable privacy focused AI assistant covers at each tier
An affordable privacy focused AI assistant is mostly a question of which wall you hit first, since the protections do not change between the tiers and the allowances do.
| What changes | Free | Paid mail or storage bundle | Standalone AI subscription |
|---|---|---|---|
| Zero-access encryption on chats | Included | Included | Included |
| Model usage allowance | Limited | Limited, unchanged by the tier | Raised |
| Messages and chat history | Limited | Limited, unchanged by the tier | Raised |
| Projects | One | One | Unlimited, plus custom assistants |
| Mail and storage | Smallest allowance | The reason to buy this tier | Not included |
| Who it suits | Occasional use where confidentiality is the point | Someone buying storage, not AI capacity | Daily heavy use of the assistant itself |
Where the money is genuinely wasted
Three ways to pay for something you either already have or cannot measure.
- Upgrading the bundle to get the assistant. It does not work. The AI rows are identical on Free, Mail Plus and Unlimited, so a storage upgrade bought for AI capacity buys storage.
- Paying for privacy you already have. Zero-access encryption, no chat logging and no model training on user data apply on the free tier. Paying to secure something that is already secured is the clearest waste in this category.
- Committing annually before you have hit a limit. With no published message or usage caps, an annual term bought on day one is a guess. The refund window is the only safety net, and it has a condition attached: Proton’s terms allow a full refund within 30 days of the initial purchase but state that “Refunds can only be requested once per user,” and that purchases made through a third party follow that third party’s policy instead.
What privacy focused AI assistant deals 2026 pricing does not say
The monthly figure on the Lumo page is already shown as a reduction against a higher standard rate, which makes it the least durable number in this article. A privacy focused AI assistant deals 2026 headline is nearly always a discount on the first term rather than on renewal, and Proton’s terms are explicit that “the subscription is renewed automatically for the duration as specified during your initial purchase” unless you cancel before the renewal date from your account dashboard. Note the renewal date when you buy, because that is the point at which a promotional price stops being the price you pay.
You can check Lumo’s current free and paid limits on Proton’s official site:
Frequently Asked Questions
Four questions a value-minded buyer should settle before the first payment.
Does paying make the assistant more private?
Proton applies the same stated protections on both tiers: zero-access encryption on stored conversations, no chat logging and no training on user data. The paid tier raises allowances rather than protections.
Will my existing paid mail plan cover it?
Not for capacity. On Proton’s own pricing comparison, the AI rows read “Limited” on Free, Mail Plus and Unlimited alike, so the entitlement does not improve with the bundle.
How many messages do I actually get?
No number is published. The tiers are described as “Limited” and “More” for model usage, messages, chat history and image generations, so the practical allowance has to be discovered by using the free tier.
Can I get my money back if I change my mind?
Proton’s terms provide a full refund if you cancel within 30 days of the initial purchase, add that “Refunds can only be requested once per user,” and state that refunds go to the original payment method in the original currency. Cash and bank transfer payments are not refundable, and purchases made through a third party follow that party’s refund policy.
Bottom line
Proton’s assistant is unusual in that the thing people want from it, confidentiality, is free, while the thing that costs money is an allowance nobody has published a number for. Run the free tier until it stops you, and if it never does, you have your answer. If it does, price the subscription as a separate annual commitment rather than as an upgrade to a plan you already hold.
