Steam Shower Generator Size Calculator

Calculate Your Generator Size

Preferred Brand

Shower Enclosure Dimensions

WIDTH

DEPTH

HEIGHT

Primary Wall Material

Additional Factors

Glass wall or door (adds 15%) One exterior wall (adds 15%) Two exterior walls (adds 30%) Window or skylight present (adds 10%)

Your Generator
Recommendation Awaits

10 kW

Recommended Generator Size

Recommended Generators For Your Shower

Questions? Call us at (888) 833-2305

Key Factors for Sizing Steam Generators

Selecting the correct generator size involves more than just measuring your shower. Wall materials, particularly natural stone, can double the required power. Here's how different materials affect your sizing:

Material Type	Multiplier	Effect
Acrylic / Fiberglass	x0.65	Reduces required kW
Ceramic Tile (Thin Set)	x1.0	No adjustment (baseline)
Ceramic Tile (Mortar Bed)	x1.2	Adds 20%
Porcelain Tile	x1.35	Adds 35%
Natural Stone (Marble, Granite)	x2.0	Doubles the cubic footage
Concrete	x2.0	Doubles the cubic footage

How to Measure Your Steam Shower

1. Measure the interior dimensions: Measure the width, depth, and ceiling height of your steam shower enclosure in feet. Multiply these three numbers to get total cubic feet.

2. Identify your wall material: The wall material has the biggest impact on sizing. Ceramic tile is standard (x1.0), but natural stone requires double the power (x2.0). This is the most important factor!

3. Check for additional factors: Glass doors, exterior walls, and windows all increase heat loss and require additional power. Check any that apply in our calculator.

4. Use our calculator above: Enter your dimensions and select your wall material to get a precise recommendation tailored to your preferred brand.

Why Correct Generator Sizing Matters

Fast Heat-Up Time

A properly sized generator reaches steam temperature quickly, typically within 1-10 minutes depending on the brand and model. Undersized generators struggle to produce steam, leading to frustrating wait times.

Consistent Steam Output

The right size ensures steady, comfortable steam throughout your session. Undersized units produce intermittent steam with temperature swings, while oversized units may create excessive condensation and dripping.

Energy Efficiency

Matching generator power to room size optimizes energy consumption. An undersized generator runs constantly at maximum output, consuming excess electricity while struggling to maintain temperature.

Equipment Longevity

Generators operating within their intended capacity experience less stress and last longer. With proper sizing and maintenance, quality steam generators typically last 15-20 years.

Electrical Requirements

Steam generators require a dedicated 240V circuit. Here are typical amperage requirements by kW:

4-6 kW: 25-30 amp circuit
7.5-9 kW: 40 amp circuit
10-12 kW: 50 amp circuit
15-20 kW: 60-80 amp circuit
24-30 kW: 100+ amp circuit (may require multiple circuits)

Always consult a licensed electrician before installation to ensure your electrical panel can support the load. Steam generators should be installed within 25-30 feet of the steam head (ThermaSol allows up to 50 feet).

Steam Generator Brands We Carry

ThermaSol - Premium Choice

Founded in 1958, ThermaSol is the original wellness company that invented the residential steam shower. Their PRO Series generators feature FastStart technology that produces steam in just 60 seconds-compared to 4-8 minutes for competitors.

ThermaSol's patented Split Tank design preheats water separately, extending heater element life significantly. Their top-tier PRO Series III models include Smart Steam for continuous steam delivery that eliminates the temperature cycling common in other brands. Made in Round Rock, Texas with a lifetime warranty.

Shop All ThermaSol Generators

Mr.Steam - Best Value

American-made since 1917, Mr.Steam offers premium features at accessible prices-typically 20-40% below ThermaSol for comparable capacity. Their 65,000 square foot manufacturing facility in Queens, NY produces generators trusted by hotels and homeowners worldwide.

Mr.Steam generators feature AutoFlush self-cleaning technology that automatically drains the tank 2 hours after use, reducing mineral buildup. Their SteamLinx app provides smartphone control with Alexa integration, letting you preheat your steam shower remotely. Lifetime warranty included.

Shop All Mr.Steam Generators

Delta SimpleSteam - Affordable Entry

Delta's SimpleSteam kits include everything you need in one box: generator, digital control, steam head, and 35 feet of cable. Built on proven Steamist technology (acquired by Masco/Delta in 2021), these complete packages are perfect for first-time steam shower buyers.

At 40-60% less than comparable ThermaSol or Mr.Steam packages, SimpleSteam offers reliable performance at an entry-level price point. Ideal for DIY renovators and contractors looking to add steam to standard bathroom projects. Lifetime generator warranty included.

Shop All Delta Generators

FAQ

An undersized generator will struggle to maintain temperature, running constantly without producing enough steam. This leads to long heat-up times, inconsistent steam output, higher energy bills, and premature wear on the unit. Always size properly or go slightly larger.

A slightly oversized generator is generally fine and will heat up faster. However, significantly oversizing can lead to excessive condensation, dripping, and uncomfortable temperature spikes. Stick within the manufacturer's recommended range for best results.

Dense materials like natural stone, marble, and granite absorb significant heat before the room reaches temperature. This "thermal mass" requires substantially more steam output. Stone walls effectively double your cubic footage for sizing purposes-a critical factor many people overlook.

ThermaSol is the premium choice with continuous (not cyclic) steam, 60-second startup, and the most advanced controls. Mr.Steam offers the best value with excellent features like AutoFlush and app control at 20-40% lower prices. Delta SimpleSteam is the budget-friendly option with complete kits at entry-level prices-40-60% less than the premium brands.

Steam generators should be installed within 25-30 feet of the steam head (ThermaSol allows up to 50 feet). Common locations include heated closets, vanity cabinets, basements, or utility rooms. The generator needs access to a water supply, drain, and dedicated 240V electrical circuit. Use copper or brass plumbing only-no PEX or PVC for steam lines.

With proper maintenance, quality steam generators typically last 15-20 years. Regular descaling (especially in hard water areas), using auto-flush features if available, and annual inspections will maximize lifespan. All three brands we carry-ThermaSol, Mr.Steam, and Delta-include lifetime warranties on the generator.

Ready to Transform Your Shower Into a Spa?

Explore our steam generators to start your wellness journey today.

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How To Use Our Steam Generator Size Calculator

Step 1: Choose Your Brand

Different manufacturers use slightly different sizing formulas, so selecting a brand helps us give you the most precise recommendation. Pick the brand you are considering, and we will tailor the calculation accordingly.

Step 2: Input Your Shower Dimensions

Measure the interior width, depth, and ceiling height of your steam shower enclosure. Enter these measurements using either feet or inches (toggle between units as needed). Our calculator will compute the total cubic footage automatically. Already know your cubic feet? Enter that value directly instead.

Step 3: Select Your Wall Material

This is critical! Wall material significantly affects sizing. Ceramic tile is standard (x1.0), but natural stone (marble, granite) requires DOUBLE the power (x2.0). Porcelain adds 35%, mortar-bed tile adds 20%, and acrylic/fiberglass reduces requirements by 35%.

Step 4: Check Additional Factors

Glass walls, exterior walls, and windows all increase heat loss. Check any boxes that apply to your steam shower. Each factor adds a percentage to your calculated cubic footage.

Step 5: View Your Results

Click Calculate Generator Size to see your recommended kilowatt rating along with specific generator models that match your shower. Each recommendation links directly to the product page.

Questions? Call or Text an Expert

Steam Generator Size Calculator