Are Custom Saunas Tax Deductible? Understanding IRS Rules and Prescriptions
You’re investing in a custom sauna. Maybe your doctor has mentioned that regular heat therapy could help with your chronic pain, arthritis, or respiratory issues. Or maybe you’ve been reading about the well-documented wellness benefits, and you’re wondering—can I write any of this off on my taxes?
The honest answer: sometimes yes, sometimes no—and the difference comes down to specific IRS rules, proper documentation, and whether a qualified medical professional has put your need in writing. This guide cuts through the confusion and gives you a practical, accurate picture of how the IRS views sauna deductions, what forms and publications apply, and exactly what steps you need to take if you want to pursue this deduction legitimately.
Understanding Medical Expense Deductions
Before we talk saunas specifically, it helps to understand how the IRS defines deductible medical expenses in the first place.
According to IRS Publication 502, medical expenses are costs paid for “the diagnosis, cure, mitigation, treatment, or prevention of disease, or for the purpose of affecting any structure or function of the body.” That definition is broader than most people realize—it’s not limited to doctor visits and prescriptions.
However, there’s a critical threshold to clear: you can only deduct medical expenses that exceed 7.5% of your adjusted gross income (AGI). So if your AGI is $80,000, the first $6,000 in medical expenses doesn’t generate a deduction. Only what you spend above that floor is deductible—and only if you’re itemizing deductions rather than taking the standard deduction.
This matters because it immediately filters out a large portion of taxpayers. If your total medical expenses (sauna included) don’t clear that 7.5% AGI threshold, or if the standard deduction is higher than your itemized total, a sauna deduction won’t save you anything on paper.
Where saunas fit in: A sauna itself is not automatically a deductible medical expense. But under the right conditions—specifically, when it’s medically prescribed and primarily used for treatment—the IRS has allowed home medical equipment and permanent installations to qualify. The key phrase in Publication 502 that opens the door is “equipment and supplies” that a physician recommends for a diagnosed condition.
The Role of Doctor Prescriptions
This is where many homeowners either make their case or lose it entirely.
For a custom sauna to have any realistic shot at qualifying as a deductible medical expense, you need written documentation from a licensed physician stating that sauna therapy is medically necessary for a specific diagnosed condition. A vague “it would probably help you” won’t cut it. What the IRS wants to see is a clear medical justification linking the treatment to a specific condition.
Conditions that have historically supported sauna prescriptions include:
- Chronic pain conditions such as fibromyalgia or arthritis
- Cardiovascular conditions where heat therapy supports circulation [source needed for individual case law]
- Respiratory conditions, including some cases of chronic bronchitis or COPD
- Muscle and joint disorders, including recovery from certain injuries
- Dermatological conditions that respond to heat therapy
The prescription letter should ideally include:
- The patient’s diagnosed condition
- The physician’s recommendation that regular sauna therapy is part of the treatment plan
- The approximate frequency or duration of recommended use
- The physician’s contact information, license number, and signature
Without this documentation, you’re essentially asking the IRS to take your word for it. They won’t.
One more thing worth knowing: a doctor’s prescription doesn’t guarantee the deduction. It’s necessary but not sufficient. The IRS still evaluates whether the expense is primarily medical in nature, or primarily personal. A $3,000 infrared sauna used mostly for relaxation and occasionally for a minor health complaint is unlikely to survive an audit.
IRS Guidelines and Relevant Forms
Let’s get specific about the paperwork side of this.
IRS Publication 502
Publication 502 is your primary reference document. It’s updated annually and lists what is and isn’t deductible as a medical expense. You can access it directly at IRS.gov. It specifically addresses home improvements and equipment in the context of medical needs, noting that expenses for home modifications made primarily for medical care can be deductible—minus any increase in home value the improvement creates.
This is an important nuance for custom sauna installations. If your sauna installation increases your home’s market value, the IRS generally requires you to subtract that added value from the deductible amount. So if your sauna cost $15,000 to install and increases your home value by $8,000, only $7,000 may qualify as a potential medical deduction (subject to all other rules).
Schedule A (Form 1040)
Medical expense deductions are claimed on Schedule A, which is the form used to itemize deductions. Line 1 through Line 4 walk you through calculating your allowable medical expense deduction after applying the 7.5% AGI threshold.
What the IRS Specifically Says About Home Improvements
Publication 502 has a section titled “Capital Expenses” that deals directly with permanent home installations. The IRS applies a reasonable cost test: the deductible amount is the cost of the improvement reduced by any increase in the property’s fair market value. If the improvement doesn’t increase property value (or decreases it), the full cost may be deductible.
For a custom sauna, you’d typically want a written assessment from a real estate appraiser both before and after installation to document any value change. This protects you in the event of an audit and gives your deduction a defensible basis.
Step-by-Step: How to Proceed
If you believe you may qualify for a sauna tax deduction, here’s a clear path forward.
Step 1: Talk to your doctor first. Before you purchase anything, have a candid conversation with your physician about whether sauna therapy is genuinely appropriate for your condition. Ask them to document their recommendation in writing if they agree it’s medically indicated.
Step 2: Get the prescription letter formalized. Ask your doctor to write a letter that includes your diagnosis, the recommended treatment (sauna therapy), frequency or duration of use, and their professional credentials. Keep the original and make copies.
Step 3: Get a home appraisal before installation. Have a licensed real estate appraiser assess your home’s current market value. This creates a baseline you’ll compare to the post-installation value.
Step 4: Obtain detailed installation quotes and invoices. Work with your sauna builder—like Willamette Carpentry—to get itemized invoices for all costs: materials, labor, permits, and any structural modifications. The IRS wants to see real numbers, not estimates.
Step 5: Get a post-installation appraisal. After your sauna is built, have your home appraised again. The difference between the before and after values determines how much of the installation cost you can subtract from your deductible amount.
Step 6: Calculate your potential deduction. Subtract the increase in home value from the installation cost. Then factor in the 7.5% AGI threshold. Work with a CPA or tax professional to determine your actual deductible amount.
Step 7: File using Schedule A (Form 1040). Itemize your deductions and include the medical expense on the appropriate lines. Retain all supporting documentation—doctor’s letter, appraisals, invoices—for at least seven years in case of an audit.
Step 8: Consider consulting a tax professional. This is not a standard deduction that every accountant handles daily. Find a CPA who has experience with medical expense deductions and home improvement tax treatment.
Common Mistakes to Avoid
Even well-intentioned taxpayers make errors when pursuing this kind of deduction. Here are the most common ones:
Skipping the appraisal. Without documented pre- and post-installation home values, the IRS has no way to verify your deductible amount—and neither do you.
Using vague physician documentation. A note that says “patient enjoys sauna therapy” is not a medical prescription. It needs to tie a specific diagnosis to a specific recommended treatment.
Forgetting the 7.5% AGI floor. People sometimes assume any medically justified expense is deductible dollar-for-dollar. It’s not. The threshold dramatically reduces the benefit for many taxpayers.
Claiming the full cost when the home value increased. This is an audit risk. Always subtract the increase in fair market value from the installation cost before calculating your deduction.
Taking the standard deduction and also claiming medical expenses. You can’t do both. If your itemized deductions don’t exceed the standard deduction for your filing status, this whole exercise doesn’t affect your tax bill.
Claiming the deduction without primary medical use. If your family also uses the sauna for general relaxation, the IRS may view it as a personal expense. Document your medical use consistently.
Key Takeaways
- Custom saunas can be tax-deductible as medical expenses, but only when prescribed by a physician for a specific diagnosed condition and used primarily for medical treatment.
- IRS Publication 502 is the governing reference document. It allows deductions for medically necessary home equipment and improvements, reduced by any increase in home value.
- The 7.5% AGI threshold means most of your medical expenses don’t generate a deduction until they exceed 7.5% of your adjusted gross income.
- Documentation is everything: physician’s prescription letter, pre- and post-installation appraisals, and itemized invoices from your contractor.
- You must itemize deductions on Schedule A to claim any medical expense—the standard deduction and medical expense deductions are mutually exclusive choices.
- Personal use undermines the deduction. The sauna must be primarily used for documented medical treatment, not general wellness or recreation.
Conclusion
Can a custom sauna be tax deductible? Yes—under specific, well-documented circumstances. It’s not a loophole, and it’s not automatic. It requires a real medical need, a physician’s formal recommendation, careful documentation of costs and home value changes, and itemized filing with the right forms.
For homeowners managing a chronic condition where heat therapy genuinely supports their treatment, the financial case can be real and meaningful. The key is to approach it the right way: get the prescription first, do the appraisals, keep every record, and work with a qualified tax professional.
If you’re considering a custom sauna installation and want to understand your options, Willamette Carpentry is here to help with the build—and can provide the detailed, itemized invoices your accountant will need for proper tax filing.
Thinking about a custom sauna for health and wellness? Willamette Carpentry builds precision-crafted custom saunas designed to meet your exact needs—and we provide detailed, itemized documentation that your tax professional will appreciate. Schedule a free consultation today.
FAQs
Q: Can any doctor prescribe a sauna, or does it need to be a specialist?
A: Any licensed physician (MD or DO) can write a prescription letter recommending sauna therapy. However, a specialist treating your specific condition—such as a rheumatologist for arthritis or a pulmonologist for respiratory issues—carries more credibility if your deduction is ever audited.
Q: What conditions are most likely to support a sauna prescription?
A: Conditions that have historically supported heat therapy recommendations include rheumatoid arthritis, fibromyalgia, certain chronic pain disorders, some respiratory conditions, and recovery from musculoskeletal injuries. Your physician is the appropriate person to assess whether your specific condition qualifies.
Q: Does the entire cost of the sauna count as a medical deduction?
A: Not necessarily. If the installation increases your home’s market value, you subtract that increase from the total cost before calculating your deduction. You’ll need professional appraisals to document this accurately.
Q: Where do I find IRS Publication 502?
A: Go directly to IRS.gov and search “Publication 502.” It’s updated annually and available as a free PDF. The “Capital Expenses” section specifically addresses home installations and medical equipment.
Q: Can I deduct a sauna I've already installed if I get a prescription later?
A: Generally, the expense must be incurred because of the medical need, not retrofitted with one after the fact. However, if you had a documented medical condition at the time of purchase, a CPA may be able to build a case. This is a gray area—get professional tax advice before trying this approach.
Q: Does an outdoor sauna qualify, or does it need to be built into the home?
A: The IRS evaluates medical necessity and primary use, not specifically indoor versus outdoor placement. However, a permanent installation that becomes part of the property is treated differently than a portable or freestanding unit. Permanent installations may also affect home value, which triggers the appraisal requirement.
Q: What if my total medical expenses don't clear the 7.5% AGI threshold?
A: Then unfortunately no medical expense deduction applies that year, including for your sauna. You cannot carry the excess forward to the next tax year for this type of deduction.
Q: Do I need a tax professional to claim this, or can I file it myself?
A: You technically can file it yourself, but given the documentation complexity, audit risk, and nuanced calculations involved, working with a CPA who understands medical expense deductions is strongly recommended.
