ThermaSol Pro Series I vs II vs III: Which Steam Generator?

The three ThermaSol Pro Series generators differ in output range, steam control, cleaning and included parts. The Pro Series I Essential is a single 11 kW model. The Pro Series II Advanced adds PowerFlush cleaning and six outputs. The Pro Series III Ultimate adds SmartSteam, a drain pan and a relief valve, and costs the most at every size.

We sell all three in our steam shower generators and packages collection. Everything below comes from the product pages, and prices can change, so confirm them before you order. This is a comparison by specs: we have no customer reviews on these generators yet.

What do all three Pro Series generators have in common?

The shared foundation is the same on every page. Each is listed as made in the USA, with a stainless steel body and Incoloy low-watt-density heating elements. Each uses a split tank that separates the heating function from the water feed to extend the unit's life. Each links to ThermaSol controls over two-way digital CAN-bus communication, and each is described as delivering steam in seconds with Fast Start or FastStart.

So you are not choosing between a good generator and a poor one. You are choosing which extras you want to pay for.

How do the three compare side by side?

What does each tier actually add?

Pro Series I: when is the simple one enough?

The Pro Series I is rated for rooms from 241 to 395 adjusted cubic feet, and it can sit up to 50 feet from the shower. It works with ThermaTouch, SignaTouch, the Serenity Light and Music Series and HydroVive controls. Because it is one model at one price, it is the easiest to shop. It suits a medium steam shower where 11 kW is the right size and you do not need the extras of the higher tiers.

Pro Series II: who benefits from the middle tier?

The Pro Series II is the flexible one. Six outputs from 8 to 24 kW mean you can match the generator closely to your room, and it is the lowest-priced option at 8 kW. Its headline feature is PowerFlush, which uses pressurized water to clear sediment. That matters most where the water is hard and mineral buildup is a concern. Choose it when you want that cleaning feature and a precise output without paying for the top tier.

Pro Series III: what do you pay extra for?

The Pro Series III adds patented SmartSteam, which is described as keeping the steam flow constant without lags or temperature swings. It also ships with a pre-plumbed safety relief valve and a stainless steel drain pan. Those included parts can reduce what your plumber has to supply. It is the only tier offered down to 6 kW, which helps in a small enclosure. It is also the most expensive at every size.

How much more does each step up cost at the same output?

Same-size models make the price difference clear. These are the prices on the product pages today:

At 11 kW, the Pro Series I costs $4,399.97, which is $300 less than the Pro Series II and $1,500 less than the Pro Series III at the same output. The step from II to III is therefore a $1,000 to $1,500 decision, and the question is whether SmartSteam plus the included drain pan and relief valve are worth that to you. If your plumber would otherwise buy a drain pan and valve separately, part of that gap comes back.

How do you pick the right output?

Output is a room-size decision first and a tier decision second. Use our steam generator size calculator to estimate the kW your steam room needs, then pick a tier. The only room range we state from a product page is the Pro Series I: 241 to 395 adjusted cubic feet. For the II and III, send us your shower dimensions before you order and we will check the output. Your electrician then needs the kW rating to size the circuit, so settle the generator before the wiring. Our steam shower installation guide covers what else to plan.

Which control package pairs with these generators?

The controls are the other half of the purchase. The ThermaSol touchscreen packages we carry include the ThermaTouch 7-Inch Round package at $6,499.97 and the SignaTouch 5-Inch HydroVive package from $8,999.97. Check each page for what is in the box, because a package may or may not include a generator. The SignaTouch 5-inch package, for instance, does not list a digital valve. If you want a broader view of the brand first, read our ThermaSol brand review, and for the different generator categories see the types of steam generators explained.

What should you check before you order?

Run through five items before you pay. First, confirm the room's adjusted cubic feet and the output that matches it. Second, confirm the electrical supply your electrician will provide for that kW rating. Third, decide where the generator will live, remembering that these units can be installed up to 50 feet from the shower. Fourth, decide which touchscreen you want, since the control affects how you use the system every day. Fifth, read the return terms on the product page, because they are specific to each item and we pass along what the supplier states.

It also helps to think about service access. A generator tucked in an attic or closet still needs to be reachable for maintenance, and a feature such as PowerFlush exists because mineral sediment is a real maintenance topic in steam systems. The product pages list the manuals and spec sheets, so have your builder read them before the rough-in is closed up.

Is the top tier ever the wrong choice?

Yes. A bigger tier does not make a room bigger, and a higher price does not fix a poorly sealed enclosure. If your shower is small and your water is soft, the Pro Series II or even the Pro Series I may serve you just as well as the Pro Series III. The Ultimate tier earns its price when you value included parts, steady output and the widest range of sizes. Be honest about which of those apply to you before you spend the extra $1,000 or more.

Who should buy which?

Buy the Pro Series I if 11 kW fits your room and you want the lowest-cost route to a US-made generator with a compatible control. Buy the Pro Series II if you want to match output closely and value pressurized sediment cleaning. Buy the Pro Series III if steady steam, the included drain pan and relief valve and a 6 kW option for a small enclosure matter more than the extra cost.

If you are still unsure, the wrong move is to guess on output. Undersizing is the mistake to avoid, so send us your room dimensions and we will help you check a model against your space. All three generators are shown together in the collection, where you can open each page and compare.

Related reading: How much is it to make your shower a steam shower?

Frequently asked questions

What is the difference between ThermaSol Pro Series I, II and III?

The Pro Series I is a single 11 kW model. The Pro Series II offers 8 to 24 kW with PowerFlush sediment cleaning. The Pro Series III offers 6 to 24 kW with patented SmartSteam, PowerFlush, and a drain pan and relief valve included.

Which ThermaSol Pro Series is the cheapest?

The Pro Series II 8 kW model is the lowest priced at $3,799.97. The Pro Series I is $4,399.97 and the Pro Series III starts at $4,499.97, based on current product pages.

What is PowerFlush?

PowerFlush is the Pro Series II and III feature that uses pressurized water to clear sediment from the generator, according to the product pages.

What is SmartSteam?

SmartSteam is the patented system on the Pro Series III that keeps the steam flow constant without lags or temperature swings, as described on its product page.

How do I know which kW I need?

It depends on your steam room volume. Use our steam generator size calculator and send us your shower dimensions, and we will check the output before you order.

Are ThermaSol Pro Series generators made in the USA?

Yes, all three are listed as made in the USA with a stainless steel body and Incoloy heating elements.