Adding a Steam Shower to an Existing Bathroom

Steam showers are humid rooms, not saunas

Adding a steam shower means turning part of your bathroom into a small, sealed room that can hold moisture. A steam room uses humidity, while a traditional sauna uses dry heat at a higher temperature. That difference affects the whole construction: a steam enclosure must hold steam and shed condensation, while a sauna room is built to tolerate heat and lower humidity. Read the steam room versus sauna comparison if you are still deciding which experience fits your bathroom.

Work through five checks before you buy anything: the enclosure, the ceiling, water and drain routing, electrical power, and moisture control. If those are satisfied, the remaining decision is the generator. A unit sized to the enclosure volume and wall materials is the heart of the system, and the steam generator buying guide walks through the options.

Check one: space and a steam-tight enclosure

The enclosure does not need to be large. MrSteam states that an opening as small as 3 feet by 3 feet is enough for a steam shower. An existing walk-in shower with tile walls and a glass door may already be close to what you need if the door seals and the glass is suitable for steam service. Start by measuring the interior footprint and checking the steam shower enclosure sizing notes.

The ceiling matters more than the footprint. Amerec says the ideal ceiling height is 7 feet, which avoids the uncomfortable temperature variations common in steam rooms with ceilings greater than 8 feet. The ceiling should also be sloped so condensation runs to a wall instead of dripping onto bathers. If your shower has a flat 8-foot ceiling, plan to lower and slope part of it during the remodel. That is why this project is usually a construction job rather than a simple fixture swap. The steam shower ceiling requirement page covers the details.

Check two: water supply and drain routing

Every steam generator needs a cold water supply line. Amerec recommends a cold water connection because the generator uses it both to make steam and, on models with an auto drain cycle, to cool the tank before flushing. A drain line should also be installed so the generator can be drained and flushed regularly. The generator uses less than 2 gallons of water during 30 minutes of operation, so the water demand is modest, but the supply and drain must be real connections. See the steam generator water supply page for the hookup details.

Place the generator as close to the shower as practical. Steam travels through a copper line from the generator to the steam head, and a shorter line is easier to insulate and drain. Amerec recommends mounting the steam head 18 inches above the shower floor on a wall as far as possible from where bathers sit. The steam line length page explains why long runs need extra planning.

A floor drain is convenient in a steam room because you can rinse the enclosure after use. It is not required for the generator itself, but the generator does need a drain connection for flushing. If you can add a floor drain during the remodel, cleaning becomes much easier. The floor drain page looks at what changes when you add one.

Check three: generator power and electrical

A steam generator is installed much like a residential water heater. Amerec lists the needed utilities as a dedicated 240V electrical circuit and a cold water supply line run to the space where the generator will sit. This is heavier power than a plug-in heater typically uses, so the job usually involves a new breaker and a load calculation before work begins. The steam generator electrical needs article covers the circuit requirements.

The generator can be installed under a bench, in a closet, in a cabinet, in a basement or in an attic, as long as the space is dry, ventilated and not exposed to freezing temperatures. You also need service access, because the tank will be flushed and inspected over the life of the unit. Check the load calculation page before you commit to a location far from the panel.

Look for an independent certification mark when comparing generators. The ETL Listed Mark, for example, means Intertek, an OSHA-recognized Nationally Recognized Testing Laboratory, tested and certified the product to applicable safety standards. Inspectors and authorities accept the ETL mark as proof of compliance with the same safety standards used by other NRTL marks.

Check four: moisture control and ventilation

Inside the enclosure, walls and ceiling must handle constant wetness and heat. Amerec recommends insulation in the walls and ceiling because it makes the room easier and more economical to heat and reduces outside noise. The construction should also include a dedicated vapor barrier and waterproof membrane behind the finish material, because steam will find small gaps over time. The vapor barrier in a steam room page explains the layers.

Ventilation follows a different rule than a normal bathroom. Amerec does not recommend ceiling vents inside the steam room and says they are not necessary, because steam dissipates quickly when you turn on the shower water after the steam bath. Instead, many people install an exhaust fan outside the steam shower door so excess steam is removed when the door opens. See the steam room ventilation after use page for the routine.

What to expect once it is installed

Steam generation is fast. Amerec says steam begins flowing into the shower within 3 to 5 minutes after the system is turned on, and depending on wall materials and construction, it takes another 10 to 15 minutes for the enclosure to reach the desired setting. A traditional sauna, by comparison, generally takes 30 to 60 minutes to fully heat up according to Finnleo. Wait until the enclosure is warm before you settle in, because entering too early means the full steam effect has not developed yet.

Steam bathing is a moist-heat experience, while a traditional sauna uses dry heat at a higher temperature. Cleveland Clinic notes that when it comes to dry heat versus wet heat, there is no clear indication that one is better than another. If you have heart problems, high blood pressure, are pregnant, or have another health condition, check with your healthcare provider before starting a steam routine.

Check five: maintenance and water quality

A steam generator has a water tank and needs regular flushing. Amerec says that if you do not buy the auto drain, the tank will need to be flushed monthly, or more often depending on local water conditions. MrSteam's AutoFlush system flushes the generator of sediment two hours after every steam bath. An automatic flush and drain feature removes the most common maintenance task.

Water quality affects generator life. Amerec recommends a whole house water treatment system if water quality is a concern, and offers a scale filter that can be installed on the supply line to reduce scale buildup inside the tank. With proper maintenance and good water, a generator can perform reliably for at least 10 years, often longer. The hard water and scale page covers treatment choices.

Whenever the generator is opened, inspect for water leaks, signs of overheated wiring, and loose connections. Choose a location where service access is easy enough that you will actually do this. That inspection habit, plus a flush schedule, protects the rest of the steam system.

What to pick for your use

Questions

Can any shower be converted to a steam shower?

Most enclosures can be converted if they become steam-tight: a sealed door, tile or waterproof panel walls, and a ceiling at a reasonable height with a slope. A typical walk-in shower already has most of the structure, but the door and ceiling often need work.

Do I need a dedicated electrical circuit for a steam generator?

Yes. Installation is similar to a residential water heater and requires a dedicated 240V circuit and a cold water supply line run to the generator location.

Do I need a floor drain?

Not strictly, but it helps. Finnleo notes that a drain is not a requirement for a sauna, and a steam generator can be installed with its own drain line for flushing. A floor drain in the enclosure makes cleaning and rinsing much easier.

How long does a steam shower take to heat up?

Steam begins flowing within 3 to 5 minutes after the system is turned on, and the room can take another 10 to 15 minutes to reach the desired temperature, depending on construction.

Where can the steam generator be installed?

Under a bench, in a closet, in a cabinet, in a basement or in an attic, provided the space is dry, ventilated and not exposed to freezing. Keep it close to the shower so the copper steam line stays short, and provide service access.

Is a steam shower the same as a sauna?

No. A steam room uses humidity, while a traditional sauna uses dry heat. Cleveland Clinic says there is no clear indication that dry heat is better than wet heat, so the choice usually comes down to moisture comfort and construction.

How often should I flush the steam generator?

Without an auto drain, flush monthly or more often depending on local water conditions. Automatic systems can flush after every bath, so they handle the task for you.

What certification should a steam generator have?

Look for a mark from an OSHA-recognized Nationally Recognized Testing Laboratory, such as the ETL Listed Mark from Intertek. It means the product was independently tested and certified to the applicable safety standards.