Is a sauna HSA eligible? The rules for saunas, cold plunges and red light panels

Search this question and every answer on the first page is written by someone who profits from the answer being yes. Tub manufacturers. Sauna retailers. Services that sell the letter. The headlines are “Up to 40% in savings” and “Save 30% with an LMN”, and the substance underneath is thinner than the confidence on top.

The banner at the top of this page is our standard disclosure: this site does earn commissions, on most pages, and says so on all of them. This is not one of those pages. There are no affiliate links below and no product cards, which is deliberate — a page that earns a commission when you conclude “yes, it qualifies” is not a page you should take tax guidance from, and that would include ours. The equipment links below go to our own guides, not to a checkout.

What the IRS actually tests

Two sentences in Publication 502 do most of the work.

The first defines medical care, and it is the one that decides most of these purchases:

Medical care expenses must be primarily to alleviate or prevent a physical or mental disability or illness. They don’t include expenses that are merely beneficial to general health.

Publication 502 gives vitamins and a vacation as its examples of the second category. That is the line a sauna has to get across. “It helps me recover” and “I sleep better” describe general health. “My clinician recommended heat therapy for a diagnosed condition and I use it on that schedule” describes medical care. The equipment is identical; the purpose is what differs, and purpose is what the rule is about.

The second sentence catches installed equipment specifically, and almost no merchant page mentions it:

The cost of the improvement is reduced by the increase in the value of your property.

More on that below, because it is where the arithmetic gets uncomfortable.

The absence that should tell you something

Publication 502 runs to a long alphabetical list of what counts. Bandages, breast pumps, guide dogs, wheelchairs, capital improvements for accessibility — the document is specific and it is long.

It does not mention saunas. It does not mention cold plunges. It does not mention hot tubs.

That absence is not an oversight and it is not a loophole. It means there is no category listing to point at, so every one of these purchases is argued from first principles against the “primarily to alleviate or prevent” test, one taxpayer at a time. A merchant badge saying “HSA/FSA eligible” is not citing a rule that exists. It is asserting the outcome of an argument nobody has had yet.

Three products, three different arguments

The equipment this site covers does not face one test. It faces the same test from three quite different positions, and lumping them together is the most common error in the pages that rank for this.

The red light panel has the best case, and the reason is worth understanding rather than just noting: an FDA-cleared device has a written, specific indication attached to it. That gives a provider something concrete to tie a letter to. It does not make the panel eligible — clearance and eligibility are unrelated regimes — but it makes the medical-purpose argument a shorter walk.

An installed cold plunge has the worst case. It is absent from the publication, it sits closest to the “merely beneficial to general health” exclusion, and it drags in the capital-expense rule on top.

The capital-expense trap

If you permanently install equipment — a barrel on a pad with a circuit run to it, a plunge plumbed in — you are no longer buying a device. You are improving a property, and Publication 502 reduces the qualifying amount by the increase in your property’s value.

Which produces an awkward result for anyone using both arguments at once. Our own best home sauna guide notes that a permitted, permanently installed sauna is generally treated as a feature in a sale. If that is true, it raises property value, and every dollar of that rise comes off the qualifying medical expense. The resale argument and the HSA argument work against each other, and you cannot lean on both. The stronger the “it adds value to the house” case, the weaker the “it is a medical expense” case.

Where an improvement adds no property value, the full cost can qualify. That is the situation Publication 502’s accessibility examples describe — entrance ramps and widened doorways rarely raise a valuation. A finished backyard sauna is not that situation.

What a Letter of Medical Necessity is, and is not

An LMN is a letter from a licensed provider stating three things: your diagnosed condition, how the item treats it, and how long or how often you are expected to use it.

What it is not is an IRS form. There is no statutory LMN, no approval number, and no filing. It is evidence that the purchase was primarily for medical care — which is the actual test — and its weight depends entirely on whether it is true and whether the provider writing it has actually assessed you.

That distinction matters because of who is selling them. A service that charges a fee and returns a letter after a brief questionnaire has an obvious incentive: it is paid for issuing letters, not for declining to. A letter produced that way is still evidence, and it is weak evidence, and it is evidence with your name on it. If the underlying claim does not hold, the letter does not save you — you were the one who took the distribution.

The strong version of this is unglamorous and free: you have a condition, you are already being treated for it, and you ask the provider treating you whether heat or cold therapy belongs in your plan. If the answer is no, you have learned something worth more than the tax saving.

What being wrong costs, and it differs by account

This is where HSA and FSA part company, and most pages treat them as one thing.

With an HSA, nobody stops you. There is no pre-approval. You take the distribution, you self-certify, and you keep records. The card clearing at the till is a merchant transaction — it is not a determination that anything qualified. If the expense is later found not to qualify, the amount is included in your gross income and, if you are under 65, subject to a 20% additional tax on top. On a $6,299 sauna in a 24% bracket that is roughly $1,500 in tax and about $1,260 in penalty — meaningfully worse than having simply paid retail.

With an FSA, someone usually does stop you. Employer plans typically require substantiation before or shortly after reimbursement, so a dual-purpose item like this gets challenged up front. That is friction, and it is also protection: a denial costs you nothing but time. If an improper reimbursement does get through and is later caught, the plan generally has to recoup it or report it as wages. There is no 20% penalty on the FSA side.

The practical read: the HSA is the easier account to spend from and the more expensive one to be wrong in.

What to actually do

In this order, because doing it in a different order is how people end up committed before they know.

1. Ask the question before you buy, not after. Every step below can end in “no”, and a “no” is cheap in September and expensive after delivery.
2. Start with the condition, not the product. If you are not being treated for something, there is no argument to build, and no letter will manufacture one.
3. Ask the provider who already treats you. Not a service that sells letters.
4. Call your plan administrator with specifics. The equipment, the price, the condition, the letter. Ask what substantiation they require and whether they have handled this category. Their answer governs the FSA case entirely.
5. Ask a tax professional about the capital-expense side if the equipment will be installed. This is the part where a general answer is least likely to fit your situation, and the amounts are large enough to be worth an hour of someone’s time.
6. Keep everything. The letter, the invoice, the correspondence. HSA substantiation is your job, and the moment you need it is years after you have forgotten where you put it.

What we have not verified

This page has no bench measurements in it, so the usual measurement section does not apply. The equivalent disclosure is this.

We have read Publication 502 and quoted it directly, and the two tests above are stated as the publication states them. Everything past that is our reading applied to a product category the publication does not name, which is reasoning rather than citation, and a tax professional may reasonably read it differently.

We have not submitted an HSA or FSA claim for any of this equipment, so we cannot tell you what any administrator does in practice — only what the rules say they should be doing. We have not surveyed plan administrators. Where this page says a category is “stronger” or “weaker”, that is an assessment of how the argument reads against the two tests, not an approval rate we have counted.

The legislative position is current as of September 2026: the PHIT Act, which would allow a limited amount of fitness spending from these accounts, has been introduced repeatedly and has not become law. A version passed the House in the 2025 reconciliation bill and was removed in the Senate. If that changes, this page changes, and the change would be large enough that a stale version of it would be actively misleading — so if you are reading this well after the date at the top, check.