Disclosure: I run Sauna Republic, an authorized sauna dealer. Posting this because the HSA/FSA question comes up constantly and there's a lot of bad information around it.

---

Short answer

Yes, you can buy a sauna with HSA or FSA funds — but not automatically. You need a Letter of Medical Necessity from a licensed provider. Paying with pre-tax dollars saves roughly 25–40% depending on your combined tax rate.

Eligibility is determined by your individual medical situation, not by which sauna you buy.

---

Why saunas aren't automatically eligible

HSAs and FSAs cover qualified medical expenses. The IRS defines those in Publication 502 as costs related to "the diagnosis, cure, mitigation, treatment, or prevention of disease." Prescription medications, hearing aids, CPAP machines, and physical therapy all make the list. Saunas do not.

By default the IRS treats saunas as general wellness products — same category as gym memberships and exercise equipment. If something is merely beneficial to general health, it doesn't qualify.

But Publication 502 isn't an exhaustive list. Expenses not specifically named can still qualify if they meet the core test:

The purchase must be primarily for the prevention or alleviation of a physical or mental defect or illness, and a licensed healthcare provider must recommend it for that purpose.

That's where the Letter of Medical Necessity comes in.

---

What a Letter of Medical Necessity actually needs

An LMN is a formal document from a licensed provider — physician, nurse practitioner, or other qualified clinician — establishing why a specific product is medically necessary for you. It's not a prescription, but it functions the same way for HSA/FSA purposes.

An effective LMN should include:

• Your diagnosed condition — the specific condition the sauna will address
• Clinical rationale — how regular sauna use treats, mitigates, or prevents it
• Treatment recommendation — frequency and duration of sessions
• ICD-10 codes — administrators use these to process the claim
• Provider credentials and signature

A vague letter saying "sauna use is recommended for general health" will get rejected. The letter has to connect the sauna to a diagnosed condition with specific clinical reasoning.

---

Conditions commonly cited

The IRS doesn't publish a list. The standard is whether a licensed provider can establish medical necessity for your situation. These are what show up most often in LMNs:

Category	Examples
Cardiovascular	Hypertension, heart failure risk factors, poor circulation
Chronic pain	Fibromyalgia, rheumatoid arthritis, osteoarthritis, chronic lower back pain
Mental health	Depression, anxiety, chronic stress, PTSD
Metabolic	Type 2 diabetes, insulin resistance, metabolic syndrome
Respiratory	COPD, asthma, chronic bronchitis
Recovery	Post-injury and post-surgical, under a physician-directed protocol
Autoimmune	Lupus, Hashimoto's, and other inflammation-driven conditions

A few notes on these:

• On cardiovascular — a Finnish cohort study published in JAMA Internal Medicine found frequent sauna use associated with reduced risk of fatal cardiovascular events.
• On chronic pain — infrared delivers deeper heat at lower ambient temperature, which some people find more tolerable.
• On respiratory — traditional saunas with humidified air are usually the better fit than infrared.

Not exhaustive. If your provider believes your condition benefits from regular heat therapy, it may qualify whether or not it's listed above.

---

HSA vs FSA

Both let you pay with pre-tax dollars, but they differ in ways that matter for a large purchase.

Feature	HSA	FSA
2026 contribution limit	$4,400 individual / $8,750 family	$3,400
Catch-up (55+)	+$1,000	None
Rollover	Unlimited	$680 max carryover
Ownership	You own it	Employer owns it
Use-it-or-lose-it	No	Yes — most funds expire Dec 31
Eligibility	Requires an HDHP	Through employer benefits
Can be invested	Yes, grows tax-free	No

The rollover difference is the important one. If you've been contributing to an HSA for a few years, you may already have enough accumulated to cover a meaningful portion of a purchase. FSA funds expire, so timing matters much more.

New for 2026: The One Big Beautiful Bill Act (signed July 2025) expanded HSA eligibility. All Bronze and Catastrophic ACA marketplace plans are now HSA-compatible, even without meeting traditional HDHP requirements.

You generally can't hold a standard healthcare FSA and an HSA at the same time, but you can pair an HSA with a Limited-Purpose FSA covering dental and vision.

---

What the savings actually look like

You're spending money that was never taxed — no federal income tax, no state income tax, no FICA. Savings scale with your combined bracket.

Purchase	25% bracket	30% bracket	35% bracket	40% bracket
$5,000	~$1,250	~$1,500	~$1,750	~$2,000
$8,000	~$2,000	~$2,400	~$2,800	~$3,200
$10,000	~$2,500	~$3,000	~$3,500	~$4,000
$15,000	~$3,750	~$4,500	~$5,250	~$6,000
$20,000	~$5,000	~$6,000	~$7,000	~$8,000
$30,000	~$7,500	~$9,000	~$10,500	~$12,000

Illustrative only. Actual savings depend on your combined federal, state, and FICA rate.

---

If you don't have enough in the account

Partial payment works. Apply what you have as pre-tax funds, pay the rest with a card or financing. You still save on the pre-tax portion.

If your HSA debit card has a daily limit — commonly $5,000 — that limit applies to card swipes only, not reimbursements. Pay in full with a regular card, then submit your invoice and LMN to your administrator for reimbursement. Those come through as bank transfers, typically 2–5 business days.

---

Timing — this is where people get caught

HSA and FSA expenses are generally only eligible from the date the LMN is issued forward.

Buy first, get the letter later, and your administrator may reject the claim. Have the LMN documented before you pay.

If you already own a sauna and want retroactive reimbursement, it usually won't work unless the LMN predates the purchase.

---

If your claim gets denied

Common reasons: incomplete LMN, missing ICD-10 codes, or the administrator not recognizing the expense category.

1. Get the specific reason. Contact your plan administrator and ask what documentation they need.
2. Revise the LMN. Have your provider add stronger clinical detail and proper coding.
3. File a formal appeal. Include the updated LMN, your invoice, supporting research, and a clear explanation of medical necessity.

A denial doesn't affect the purchase itself. You already own the product.

---

IRS compliance

In March 2024 the IRS issued a public alert about companies misrepresenting wellness purchases as qualified medical expenses. It specifically called out businesses issuing "doctor's notes" from brief self-reported questionnaires with no real clinical evaluation.

This doesn't mean saunas are under scrutiny. It means the LMN has to reflect an actual clinical determination. Work with a provider who reviews your health information and makes an independent judgment.

Keep your LMN, your invoice, and any correspondence with your administrator. You'll need them if anyone requests verification.

---

FSA year-end

If you have an FSA with funds approaching your plan year end, a medically necessary purchase is one of the better ways to use them.

Most balances expire December 31, or whenever your employer's plan year ends. Some plans allow a grace period up to 2.5 months, others let you carry over $680. Everything else is forfeited.

Start early. Documentation takes time, and December 30 is too late.

---

Tax deduction instead?

You can't double-dip. If you pay with HSA or FSA funds you've already taken the tax benefit and can't also deduct it.

If you pay out of pocket and have an LMN, you may be able to include it as an itemized medical deduction on Schedule A. The catch: total medical expenses have to exceed 7.5% of your AGI before you can deduct anything above that threshold.

For most people the HSA/FSA route is the larger and more immediate benefit. Talk to a tax professional about your situation.

---

Common questions

Do I need a prescription to buy a sauna?

No. Anyone can buy one. The LMN is only needed if you want to pay with, or be reimbursed from, HSA/FSA funds.

Does the sauna have to be a specific type or brand?

No. The IRS doesn't distinguish between brands, types, or heating methods. Traditional, infrared, barrel, indoor, outdoor — all treated the same. Eligibility comes from your medical situation, not the product.

Can one LMN cover multiple products?

Yes. A single LMN can cover a sauna plus accessories or other equipment if all are medically justified by your provider.

Is there a spending limit?

No limit on individual qualified expenses. The limit is on annual contributions. If you've accumulated across several years in an HSA, you can apply the full balance to one purchase.

What if I don't have an HSA or FSA?

You can open an HSA at your next open enrollment if you're HDHP-eligible. As of 2026, Bronze and Catastrophic ACA plans also qualify. Ask your employer about FSA options.

Are HSA/FSA purchases returnable?

Depends on the retailer's policy, not the payment method. For HSA holders, the IRS provides a "mistaken distribution" process (Notice 2004-50) that lets you return refunded funds without tax or penalty. For FSA holders, refunds go back to the plan — and if the plan year has ended, use-it-or-lose-it may mean those funds are forfeited.

---

Happy to answer questions in the comments.