Shopping for a built-in steam generator can feel like comparing four different languages. MrSteam talks about iSteam controls and SteamLinx. ThermaSol talks about SmartSteam and ThermaTouch. Kohler talks about DTV+ and Fast-Response. Amerec talks about AK sizes and K2 controls. Each brand is describing the same job, a box that boils water and sends steam into your shower, but each one packages it differently.
This guide compares the four premium built-in brands side by side: MrSteam, ThermaSol, Kohler and Amerec. It covers what each brand is known for, how the controls work, how sizing differs, what installation involves, how cleaning and maintenance compare, what the warranties actually say, and who each brand suits best. Where a specification is uncertain or varies by dealer, this guide says so plainly instead of guessing.
One important distinction first. This is a comparison of built-in generators for a tiled steam shower or steam room, the kind installed behind a wall or in a nearby closet. It is not a roundup of portable steamers. Our guide to steam generators for saunas covers the portable and budget end of the market, including plug-in units. If you are building a proper steam room, start here.
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Please note: This article is general wellness information, not medical advice. Steam saunas are wellness tools, not treatments. If you are pregnant, live with a heart or circulation condition or low blood pressure, or take medication that affects heat tolerance, check with your doctor before using a steam sauna. Specifications and prices in this guide were checked against official brand sources at the time of writing in 2026, and readers should verify current specifications and listings before buying. All prices are planning estimates, not quotes.
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How to Compare Steam Generator Brands
Four generators can look identical on paper and behave very differently in your bathroom. The power rating is only the start. The real differences show up in what is included in the box, how the control works, how the tank cleans itself, how far the generator can sit from the shower, and what happens when something breaks in year three.
Use the six questions below as your shortlist test. Any brand that cannot answer one of them clearly is a brand you should question before you buy.
- What is actually included? Some brands sell the generator alone, and the control and steam head are separate purchases that can add a large sum. Others sell packages that include everything. Always compare the full system price, not the generator price alone.
- How does sizing work? Each brand publishes its own sizing chart, and the charts disagree. The same shower can need 6 kW from one brand and 8 kW from another. Size with the chart of the brand you are buying, never with a generic calculator.
- How good is the control? The control is what you touch every day. Check whether it is a simple timer, a touchscreen, or a full smart-home panel, and whether it manages steam only or also lighting, music and aromatherapy.
- How does the tank stay clean? Hard water leaves scale inside every generator. Some brands flush the tank automatically after each session. Others need manual draining and descaling. This one feature decides most of the long-term maintenance.
- What does the warranty cover, and for how long? A lifetime warranty on parts is not the same as in-home service. Read whether labour is covered, whether the unit must be shipped back to the factory, and whether registration or a water filter is a condition.
- Who supports it locally? A premium generator is a long-term appliance. Check whether your installer has fitted that brand before, and whether parts and service are available where you live.
The Four Brands at a Glance
The table below is the short version of this whole guide. Read it first, then read the brand sections for the detail behind each row. Prices are planning estimates for 2026, and generator-only prices exclude the control and steam head unless stated otherwise.
| Brand | Flagship line | Control highlights | Tank cleaning | Generator warranty | Best for |
|---|---|---|---|---|---|
| MrSteam | eSeries (MS and MSSUPER) | iSteam3 touchscreen, iTempo, AirTempo, SteamLinx app and voice control | AutoFlush automatic drain | Limited lifetime, with in-home parts and labour for the first 2 years | Smart-home users and the widest dealer network |
| ThermaSol | PRO Series III | ThermaTouch, SignaTouch and MicroTouch, plus light, sound and rainhead options | PowerFlush pressurised tank cleaning | 2 years in-home, then lifetime parts and labour at the factory | Luxury spa feel and the strongest warranty terms |
| Kohler | Invigoration Series | DTV+ digital showering, Anthem, Kohler Konnect voice control | Power Clean one-touch automatic cleaning | 3-year limited warranty on the generator | Homes already built around Kohler fixtures |
| Amerec | AK Series | K2 touchscreen, K3, KT3 and K4, plus SaunaLogic app | Manual drain and descaling, with an optional auto-drain control | Limited lifetime, check current terms for parts and labour | Straightforward reliability and larger rooms |
MrSteam: The Smart-Home All-Rounder
MrSteam is the oldest dedicated steam brand of the four, and it shows in the range. The residential line is built around the eSeries generators, in MS sizes for smaller rooms and MSSUPER sizes for larger ones. The generators use a stainless steel tank, industrial-grade heating elements and a microprocessor control system, and they run on a dedicated 240 volt circuit. The brand is sold mainly through dealers and bathroom showrooms rather than direct online, so prices vary by dealer and are rarely published.
What sets MrSteam apart is the control ecosystem. The flagship iSteam3 is a full-colour touchscreen that mounts nearly flush on the shower wall, is rated to IP67 for water immersion, and manages temperature, time, aromatherapy, chromatherapy lighting and audio from one screen. It supports up to eight user presets and can be programmed to start on a schedule. Simpler options exist too: the iTempo is a compact digital control, and AirTempo is a slim wireless-style option for cleaner wall finishes.
Smart-home integration is where MrSteam is strongest. The SteamLinx module connects the generator to a phone app and to Alexa and Google Home voice control, so you can start the steam from another room. That matters more than it sounds, because a steam room needs several minutes to warm up, and starting it from the bedroom means stepping into a ready room. Our guide to smart steam controls, timers and app shutoff explains how these features work in practice and what safety limits to check.
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MrSteam sizing and installation
MrSteam sizes by adjusted cubic feet, using the room volume plus allowances for wall material, ceiling height and glass. The MS range covers roughly 71 to 257 cubic feet, with the MS225 at 7.5 kW rated for rooms up to about 161 cubic feet. Larger rooms move into the MSSUPER range, which runs to 12 kW and beyond. Always use the brand’s own sizing chart, because MrSteam’s numbers do not match other brands for the same room, as the worked example later in this guide shows.
Installation is a licensed-trade job. The generator needs a cold-water supply, a steam line to the shower, a drain, and a dedicated electrical circuit. MrSteam offers an optional Express Steam feature that keeps the water warm so steam starts faster, and the AutoFlush system drains the tank automatically after use to slow scale build-up. A condensation pan is available to catch drips under the unit. Check your local code and permit office, and use a licensed electrician and plumber for the work.
MrSteam warranty and support
MrSteam warrants its residential generators for their lifetime against defects in materials and workmanship. If a claim is made within two years of purchase, the brand provides free in-home warranty service, parts and labour. After two years, the lifetime warranty covers parts. Controls and accessories carry a two-year limited warranty. The large dealer network is a practical advantage: most bathroom showrooms can order parts, and many installers have fitted MrSteam before.
Choose MrSteam if you want the broadest smart-home integration, a wide choice of controls at different price points, and the comfort of a large dealer and service network. It is the safest default choice for most buyers, and the one most installers will know best.
ThermaSol: The Luxury Spa Specialist
ThermaSol has built steam equipment in the United States for decades, and the PRO Series III is its flagship residential generator. The design centres on a stainless steel split tank, which the brand says delivers constant steam at a constant rate, without the bursts and lags that cheaper generators can produce. The range runs from 6 kW to 24 kW, serving rooms from about 84 to 1,200 cubic feet, so it covers everything from a small ensuite to a large custom steam room.
Three patented features define the PRO Series III. SmartSteam adjusts the steam output to hold the room temperature steady rather than cycling on and off. FastStart pre-heats the water so steam arrives in seconds rather than minutes. PowerFlush uses pressurised water to sweep the inside of the tank and clear mineral build-up, and the brand recommends running it regularly, roughly every 1,000 minutes of use, to protect the generator.
The generator can sit up to 50 feet from the shower, which gives more freedom in where the unit is hidden, in a closet, a vanity or a service space. It connects to the control over a two-way digital CAN bus cable, which the brand says improves reliability and safety. Smaller models ship with a plug and cord rather than a hardwired connection, so the electrician fits a matching receptacle instead.
ThermaSol controls: ThermaTouch, SignaTouch and MicroTouch
ThermaSol offers the most layered control range of the four brands, and it is also the most expensive part of the system. MicroTouch is the entry touchscreen, with temperature, time and PowerFlush control, plus an aromatherapy well in the steam head. SignaTouch adds a larger five-inch screen and control of lighting and audio. ThermaTouch is a 10-inch tablet-style panel that manages steam, lighting, temperature and audio, with Bluetooth streaming, built-in apps and custom user presets.
Beyond the controls, ThermaSol sells Serenity light, sound and rainhead packages that turn the shower into a multi-sensory room. These are genuinely impressive in a showroom, and they are also where the budget can grow fast. A buyer who wants the full ThermaTouch experience should budget for the control and the steam head on top of the generator, not just the generator alone.
ThermaSol sizing, pricing and warranty
ThermaSol names its models by maximum room size, which makes sizing easy to read: the PRO III-84 is 6 kW, the PRO III-140 is 8 kW and rated to 140 cubic feet, the PRO III-240 is 10 kW, and the PRO III-395 is 11 kW. The brand’s sizing guide also adjusts for ceiling height, telling buyers to go up one size for every foot over 8 feet, to a maximum of 10 feet. As with every brand, use the ThermaSol chart for a ThermaSol generator.
ThermaSol is the only one of the four brands that publishes generator prices on its own store, which makes honest budgeting possible. As a 2026 planning estimate, the PRO Series III generator alone starts at about $4,435 for the 6 kW model, with the 8 kW model at about $4,790. A complete system costs much more: the 8 kW generator with a MicroTouch control and a SteamVection steam head works out to about $6,010 before installation. Verify current listings before buying, because prices change and dealer pricing may differ.
The warranty is the strongest reason to pay the premium. ThermaSol covers the generator with two years of in-home parts and labour, followed by a lifetime parts and labour warranty at the factory. After year two, you pay to remove the unit and ship it to the factory, but the repair itself is covered. Few competitors match that combination of in-home cover and lifetime factory cover.
Choose ThermaSol if you want the most spa-like experience, the steadiest steam output, the largest control and sensory options, and the strongest warranty. It is the most expensive route to a finished system, and the control and steam head are essential extras to budget for.
Kohler: The Bathroom Ecosystem Choice
Kohler is the best-known bathroom name of the four, and the Invigoration Series is designed to fit inside a Kohler bathroom rather than stand apart from it. The generators are built in-house, in insulated stainless steel cases, and they integrate directly with Kohler’s DTV+ digital showering system. If your taps, shower valves and lighting are already Kohler, the steam generator joins the same system instead of adding a separate control on the wall.
Two technologies define the Invigoration line. Fast-Response technology produces steam in about 60 seconds from a cold start, which is noticeably quicker than most generators. Power Clean is a one-touch automatic cleaning cycle that flushes sediment through the steam head, so descaling needs less hands-on work. The generators also use a Constant Steam feature that holds steam output steady to reduce temperature swings.
Kohler publishes water use on its specification sheets: an Invigoration generator uses about one gallon of water per 20-minute session, which is far less than a standard shower. The system also shuts down automatically after 20 minutes if the user does not reactivate it, which is a useful safety net. A control kit is required for operation and is sold separately, either as a standalone digital control or as a DTV+ steam adapter kit.
Kohler controls: DTV+, Anthem and Konnect
The control story is the reason most buyers choose Kohler. With the DTV+ adapter kit, one touchscreen manages the steam generator, water temperature, chromatherapy lighting and audio together. The Anthem digital system offers a similar single-interface approach for newer Kohler bathrooms. Kohler Konnect adds voice control through Alexa and Google Home, plus phone control for pre-heating the shower.
The trade-off is that the best experience needs the rest of the Kohler system. A standalone Kohler generator with its basic control kit works well, but the single-interface magic only appears when the shower valves and digital controls are Kohler too. Buyers who mix brands will get a good generator but not the full ecosystem benefit.
Kohler sizing, pricing and warranty
Kohler rates its generators by maximum room volume, and the range is wide. The 5 kW model suits small showers, the 7 kW model is rated to about 112 cubic feet, the 11 kW model to about 317 cubic feet, the 13 kW model to about 447 cubic feet, and the 15 kW model to about 500 cubic feet. Tandem models, which pair two generators, reach 26 kW and rooms up to about 894 cubic feet. Use the Kohler specification sheet for the exact model you are considering, because the volume rating changes with each size.
Kohler does not publish a single list price for the range, and most buyers purchase through a Kohler dealer or showroom, so prices vary. Get a written quote that includes the generator, the control kit, the steam head and installation, and compare that total against the other brands. Kohler’s warranty is a three-year limited warranty on the generator, covering defects in materials and workmanship under normal residential use. That is shorter than the lifetime terms offered by MrSteam, ThermaSol and Amerec, but it is backed by Kohler’s large nationwide service network, which many buyers value more than extra years on paper.
Choose Kohler if you are building or remodelling a Kohler bathroom and want steam, water, lighting and audio on one control. It is also a strong choice if you want fast steam in about a minute and a brand with service technicians almost everywhere. It is the weakest choice if you want the longest warranty or a brand-agnostic system.
Amerec: The Straightforward Workhorse
Amerec is the quietest brand of the four, and that is part of its appeal. The AK Series was purpose-designed for home steam baths, and it avoids the showroom theatre of the other brands in favour of simple, serviceable engineering. The generators use a stainless steel tank, water-level probes and removable heating elements, so a failed element can be replaced without replacing the whole unit. That serviceability is a real long-term advantage.
The AK range runs from 4.5 kW to 14 kW in a single unit, covering rooms up to about 550 cubic feet. For rooms larger than that, two AK generators can be ganged together. Models are available for 240 volt and 208 volt supplies and can be wired in the field for single or three-phase power, which makes Amerec a good fit for homes and buildings with less standard electrical supplies.
The AK uses sequential temperature control: it runs at full power to heat the room quickly, then cuts power by one third or two thirds of its heating elements to hold the temperature steady. That staged approach gives a more consistent flow of steam and a more stable, comfortable session than a simple on-off cycle. The generators are ETL listed for the United States and Canada and tested to IEC standards.
Amerec controls: K2, K3, KT3 and K4
Amerec’s controls are simpler than the tablet-style panels from ThermaSol and MrSteam, and the prices reflect that. The K2 is a touchscreen control with time and temperature display, a 60-minute timer, a 24-hour time delay and a Wi-Fi module with the SaunaLogic app for phone control. The K3 is a compact three-button digital control for buyers who want the minimum. The KT3 adds a temperature sensor, and the K4 is a simple on-off control that pairs with an auto-drain option.
That simplicity is a deliberate trade. You will not get built-in music streaming or a 10-inch spa tablet from Amerec, but you also will not pay for one. The K2 covers the features most people actually use: set the temperature, set the time, start it from your phone, and let the generator do the rest. If you want music or coloured light in the shower, you can add them as separate fittings rather than buying them through the steam control.
Amerec sizing, pricing and warranty
Amerec publishes one of the clearest sizing charts of the four brands, with the room range and the breaker size printed side by side. The AK6 at 6 kW suits rooms of 80 to 150 cubic feet on a 40 amp breaker. The AK9 suits 150 to 300 cubic feet. The AK14 at 14 kW suits 350 to 550 cubic feet. The maximum recommended ceiling height is 8 feet. For rooms built from natural stone, Amerec tells buyers to multiply the cubic volume by 1.75 before choosing a size, because stone absorbs far more heat than tile.
Amerec does not publish list prices, and the generators are sold through dealers, so get a written quote before budgeting. Amerec offers a limited lifetime warranty on the generator. Dealer summaries of the warranty terms put parts cover at five years and in-home labour at two years, but warranty documents change, so confirm the current terms on the warranty sheet that comes with the model you buy. That check takes two minutes and avoids an unpleasant surprise later.
Choose Amerec if you want a straightforward, serviceable generator without paying for a spa tablet you will not use, or if your room is large, stone-lined or needs three-phase power. It is also a strong choice for a second steam room, a guest-house installation or a project where the budget needs to go into the room itself rather than the control.
Why the Sizing Charts Disagree
This is the single most confusing part of buying a steam generator, and it catches out almost every first-time buyer. Take one ordinary shower, 3 feet by 5 feet with an 8-foot ceiling, which is 120 cubic feet of tiled space. Run that room through each brand’s published sizing chart and you get four different answers.
| Brand | Model for a 120 cu ft tiled shower | Power | What the chart says |
|---|---|---|---|
| Amerec | AK6, rated 80 to 150 cu ft | 6 kW | 25 amps, 40 amp breaker |
| MrSteam | MS225 | 7.5 kW | Rated to about 161 cu ft |
| ThermaSol | PRO III-140 | 8 kW | Rated to 140 cu ft, up to 37 amps |
| Kohler | Next size above the 7 kW model | Above 7 kW | The 7 kW model tops out at about 112 cu ft, so a 120 cu ft room needs the next size up |
The gap between 6 kW and 8 kW is a third more power, a larger breaker, heavier cable and a higher price, all for the same shower. The reason is that each brand builds different safety margins into its chart, and each one adjusts differently for wall material, ceiling height and glass. Amerec’s stone multiplier is a good example: the same 120 cubic foot room in porcelain or natural stone becomes 210 cubic feet in Amerec’s maths, which moves the choice from a 6 kW unit to a 9 kW unit and the breaker from 40 to 50 amps.
The practical rule is simple. Pick your brand first, then size with that brand’s chart, not with a generic calculator and not with another maker’s table. Measure the room carefully, note the wall material and the ceiling height, and count the glass area. If the room is close to the top of a model’s range, go up one size rather than down. An undersized generator will run constantly, heat slowly and wear out sooner. If your room is small, our guide to steam saunas for small bathrooms and apartments covers the space and sizing questions that matter most in compact rooms.
Installation, Plumbing and Electrical Work
All four brands need the same four things: a sealed, waterproofed room, a cold-water supply, a drain, and a dedicated electrical circuit. The differences are in the details, and those details decide how easy the install is and what it costs.
- Generator location. ThermaSol allows up to 50 feet between the generator and the shower, which helps when the ideal hiding place is a distant closet. The other brands need the unit closer, so plan the location early, before the walls are closed.
- Electrical supply. Every residential generator in this comparison runs on 240 volts and needs its own dedicated circuit with the breaker size from the brand’s chart. Smaller ThermaSol models use a plug and receptacle, while most other models are hardwired. Amerec is the most flexible, with field wiring for 208 volt and three-phase supplies.
- Water supply and drain. The generator needs a cold-water line with a shut-off valve, a steam line to the shower, and a drain for the tank and the cleaning cycle. Hard water is the enemy of every generator, so ask your installer about a water filter or softener for the feed.
- Room sealing. The generator cannot fix a leaky room. The enclosure needs waterproofing, a sloped ceiling so condensation runs to the walls, a door that seals, and proper ventilation for drying. Our guide to steam room bench, door and glass layout mistakes covers the sealing errors that waste the most steam.
Do not treat installation as a do-it-yourself job unless you are a licensed professional. Steam generators combine high-voltage electricity, pressurised hot water and steam, and a mistake can damage the house or hurt someone. Use a licensed electrician and a licensed plumber, and check your local code and permit office before work starts. Our guide to steam shower drains and ventilation explains the drainage and drying side in detail, including why the room needs to dry out after every session.
Hydrate before and after every session, start with short sessions, and leave immediately if you feel dizzy or unwell. Do not drink alcohol before or during a steam session. A steam room is a wellness tool, not a treatment, and it will not cure illness, remove toxins or guarantee weight loss. If you are pregnant or live with a heart or circulation condition, low blood pressure, or take medication that affects heat tolerance, check with your doctor first.
Maintenance and Water Quality
Every steam generator boils tap water, and tap water leaves scale. How each brand handles that scale is one of the biggest differences between them, and it decides how much work you will do over the life of the unit.
| Brand | Cleaning system | What you do | What to watch |
|---|---|---|---|
| MrSteam | AutoFlush automatic drain | Let the system drain the tank after use | Check the drain line stays clear and the condensation pan is fitted |
| ThermaSol | PowerFlush pressurised cleaning | Run PowerFlush regularly, about every 1,000 minutes of use | Use the recommended water filter and change it on schedule |
| Kohler | Power Clean one-touch cleaning | Press one button to flush sediment through the steam head | Follow the water hardness limits on the specification sheet |
| Amerec | Manual drain and descaling, optional auto-drain | Drain and descale on the schedule in the manual | Removable elements make service easier when scale builds up |
Water quality matters more than most buyers expect. Hard water scales a tank faster, and some warranties expect a filter on the supply line. If your tap water is hard, talk to your installer about filtration before the generator is fitted, not after the first descaling bill. A steam room is never maintenance-free: it needs ventilation, drying after sessions, and regular checks of the grout, sealant and drain. Moisture left standing in a warm room will grow mould, whatever brand of generator you buy.
If the steam stops or weakens, the cause is usually scale, a water supply problem, a control fault or a tripped breaker, and it is rarely the brand that is at fault. Our guide to a steam generator not producing steam walks through the checks in a safe order, and when to stop and call a professional.
What Does a System Cost in 2026?
Comparing generator prices alone is misleading, because three of the four brands sell the generator, control and steam head separately. The honest comparison is the finished system price: generator plus control plus steam head, before installation. The table below uses verified figures where they exist and says plainly where they do not.
| Brand | Generator-only planning estimate, 2026 | Control and steam head | What to budget |
|---|---|---|---|
| MrSteam | Not published, dealer priced | Sold separately, several control options | Get a written dealer quote for the full package |
| ThermaSol | From about $4,435 for 6 kW, about $4,790 for 8 kW | MicroTouch from about $910, steam head about $310 | About $6,010 for an 8 kW system before installation |
| Kohler | Not published, dealer priced | Control kit sold separately | Get a written dealer quote for the full package |
| Amerec | Not published, dealer priced | Sold separately, K2 to K4 options | Get a written dealer quote for the full package |
Installation is a separate cost on top of the system, and it varies widely by region, by how far the generator sits from the shower, and by how much electrical and plumbing work is needed. Get at least two written quotes from licensed installers who have fitted the brand you are buying. A quote that is much cheaper than the others usually means something is missing, such as the drain, the ventilation, or the correct breaker size.
Do not judge value by the generator price alone. A cheaper generator with a short warranty, a basic control and manual descaling can cost more over ten years than a premium generator with automatic cleaning and a lifetime warranty. Ask each dealer for the ten-year picture: filters, descaling, control replacement and service visits, not just the day-one price.
Which Brand Should You Choose?
There is no single best brand. There is a best brand for your room, your bathroom, your budget and your patience for maintenance. Use the guide below as a starting point, then confirm the sizing and the quote with the dealer for your chosen brand.
- Choose MrSteam if you want the widest smart-home integration, the most control choices, and the largest dealer network. It suits buyers who want to start the steam from their phone or with their voice, and who want an installer who has fitted the brand many times before.
- Choose ThermaSol if you want the most luxurious steam experience and the strongest warranty, and you are willing to pay for it. It suits a primary bathroom remodel where the steam room is the centrepiece, and where the control, lighting and sound matter as much as the steam itself.
- Choose Kohler if your bathroom is already Kohler, or will be. The DTV+ integration is the best reason to buy Kohler, and it only pays off inside a Kohler system. It also suits buyers who want steam in about 60 seconds and a service network in almost every town.
- Choose Amerec if you want a straightforward, serviceable generator and would rather spend the budget on the room than on a spa tablet. It suits large rooms, stone-lined rooms, three-phase supplies, and buyers who like simple controls and removable heating elements.
Mistakes to Avoid When Buying
Most steam generator regrets come from the same few mistakes, and all of them are avoidable. Read this list before you sign a quote.
- Comparing generator prices instead of system prices. A generator that looks cheap can become the most expensive option once the control, steam head and installation are added.
- Sizing with the wrong chart. Using a generic calculator, or another brand’s chart, can leave you a full size too small or too large. Size with the chart of the brand you are buying.
- Forgetting the wall material. Stone and glass change the sizing maths. Tell the dealer the wall material, the ceiling height and the glass area before they size the unit.
- Skipping the water question. Hard water without a filter or a cleaning routine will scale any generator. Ask about filtration at the quoting stage.
- Treating the room as an afterthought. A great generator in a leaky, unsealed room gives a poor steam. Waterproofing, a sloped ceiling, a sealing door and drying ventilation matter as much as the generator.
- Not reading the warranty. Check whether labour is covered, whether the unit must be shipped to the factory, and whether registration or a filter is a condition. A lifetime parts warranty is not the same as in-home service.
- Buying on showroom features alone. A 10-inch spa tablet is impressive for ten minutes. The control you will use every day is the one with the temperature and timer you can set in seconds.
Frequently Asked Questions
Which steam generator brand is best overall?
There is no single best brand. MrSteam suits smart-home users and buyers who want the largest dealer network. ThermaSol suits luxury remodels and buyers who want the strongest warranty. Kohler suits homes already built around Kohler fixtures and DTV+. Amerec suits large rooms and buyers who want a straightforward, serviceable generator. Pick the brand that fits your bathroom first, then size it with that brand’s chart.
Why do sizing charts disagree between brands?
Each brand builds different safety margins into its chart and adjusts differently for wall material, ceiling height and glass. For the same 120 cubic foot tiled shower, Amerec recommends 6 kW, MrSteam recommends 7.5 kW and ThermaSol recommends 8 kW. That is why you should always size with the chart of the brand you are buying, never with a generic calculator.
Do I need to buy the control and steam head separately?
In most cases, yes. MrSteam, ThermaSol, Kohler and Amerec generally sell the generator on its own, and the control and steam head are separate purchases. Some dealers sell packages that include everything, so always ask for a written quote for the complete system, including installation, before comparing prices.
How much does a built-in steam generator system cost in 2026?
As a planning estimate for 2026, a ThermaSol PRO Series III 8 kW system with a MicroTouch control and steam head costs about $6,010 before installation, based on the brand’s own store prices. MrSteam, Kohler and Amerec do not publish list prices, so their systems are dealer priced. Get written quotes for the full system and the installation, and verify current listings before buying.
Which brand has the best warranty?
ThermaSol offers the strongest warranty terms of the four, with two years of in-home parts and labour followed by a lifetime parts and labour warranty at the factory. MrSteam offers a limited lifetime generator warranty with in-home service for the first two years, then lifetime parts. Amerec offers a limited lifetime warranty, with terms to confirm on the current warranty sheet. Kohler offers a three-year limited warranty on the generator, backed by a large service network.
Can I install a steam generator myself?
No, not unless you are a licensed professional. A built-in steam generator combines high-voltage electricity, pressurised hot water and steam, and it needs a dedicated circuit, a cold-water supply, a steam line and a drain. Use a licensed electrician and a licensed plumber, and check your local code and permit office before work starts.
The Bottom Line
All four brands make good generators, and all four will give you a proper steam room when they are sized and installed correctly. The differences are in the experience around the steam: the control you touch, the cleaning you do, the warranty that backs you, and the bathroom the generator lives in.
If you want the smartest system, start with MrSteam. If you want the most luxurious system and the strongest warranty, start with ThermaSol. If your bathroom is Kohler, start with Kohler. If you want the simplest reliable system for a large room, start with Amerec. Whichever you choose, size it with that brand’s chart, get the full system quoted in writing, use licensed trades for the install, and budget for water care and maintenance from day one. That is what turns a good generator into a steam room you will still love in ten years.