The best sauna heaters 9kW, compared.
Top pick: CGOLDENWALL ST-90 9 kW Best value: Generic 9 kW stone heater – Lowest stone-heater shelf price at £245.00, with 9 kW and 9–13 m³ stated. Voltage, reviews and stones are missing from that price. Updated October 2026.
A 9 kW listing on amazon.co.uk is either an electric stone stove for a hot cabin or a steam generator for a wet shower. The kilowatt figure does not make those the same product. The useful checks are the stated room volume, the printed voltage, whether stones or a steam head are in the box, and whether anyone in Britain has reviewed that listing. At 230 V, 9 kW is about 39 A, so it is a dedicated circuit, not a 13 A plug. The highest score is a steam kit, and a UK review on that listing reports no steam. Stones and the electrician sit outside that price. The decision order is in the [9 kW sauna heater buying guide](/hub/steam-baths/sauna-heater-9kw/sub/sauna-heater-9kw-buying-guide). A cabin around 8–14 m³ needs a stone heater and an electrician. A sealed shower needs the steam generator, and the volts must match the house. A steam kit will not run a sauna at 80–100°C.
A 9 kW listing on amazon.co.uk is either an electric stone stove for a hot cabin or a steam generator for a wet shower. The kilowatt figure does not make those the same product.
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Personal buying guide
Question 1 of 2
What are you fitting?
The CGOLDENWALL ST-90 at £417.04 is a 9 kW steam generator with a default of 220 V, and the listing says a 380 V model is a different order. It states 8.5 m³, 35–55°C and a timer of 1–60 minutes. The box includes a steam nozzle, a 10 m control cable, a 3 m temperature probe, an LED controller, a drain valve and a safety valve. The star line is 5.0 from 2 ratings, which is too small to show a pattern. There is no UK review text on the listing. At about £66 more than the older CGOLDENWALL kit, you are paying for a fuller contents list, not for a larger evidence base.
Pros
Cons
Best for: A steam shower around 8.5 m³ where you want the drain and safety valve listed, and you can wait for more reviews.
Less suitable: A cabin that must reach sauna temperature, or a buyer who treats two ratings as a pattern.
Specifications
Common questions
Is the 380 V model included by default?
No. The listing says the default voltage is 220 V and that a 380 V model must be confirmed with customer service.
How long can the timer run?
The listing says automatic working time of 1–60 minutes, with temperature adjustable from 35–55°C.
What comes in the box?
Steam generator, steam nozzle, 10 m control cable, 3 m temperature probe, LED digital controller, drain valve and safety valve.
The Harvia Spirit SP90XW at £990.00 is the only named Finnish sauna oven in this set, and the listing claims a Xenio WiFi touch panel with the MyHarvia app. The amazon.co.uk star line is 4.9 from 14 ratings. The five review texts were written in Germany, and one of them says the WiFi function did not work. Another buyer reported a barrel of about 10 m³ coming up to heat in 20–25 minutes, which is that person’s cabin, not a lab figure. The technical table leaves voltage, room volume and temperature blank, and it does not say the stones are included. At 13 kg the shipping weight is light beside a stone-filled oven, so the rocks are unlikely to be in the carton. Confirm the panel, the volts and the room band on the data plate or with the seller before you treat £990.00 as a complete cabin kit.
Pros
Cons
Best for: A cabin owner who wants the Harvia name and will confirm voltage and room volume outside the amazon table.
Less suitable: A steam shower, or a buyer who needs the supply and the cubic metres printed on the page.
Specifications
Common questions
Does a control panel come with it?
The title and bullets say a Xenio WiFi touch panel, and that it can be controlled with the MyHarvia app.
Does the listing state voltage or room volume?
No. The technical table gives the model SP90XW, the brand Harvia and a weight of 13 kg, and it leaves volts, room volume and temperature blank.
Are the reviews from the United Kingdom?
The star line is 4.9 from 14. The five review texts were written in Germany, and one of them says the WiFi function did not work.
The CGOLDENWALL 9 kW kit at £350.55 states 220 V, a room of 8.5 m³, and a temperature band of 35–55°C with a timer of 1–60 minutes. Across 76 amazon.co.uk ratings the average is 3.7. A UK review from May 2023 says the unit produced no steam and that the seller did not reply. Other reviews, from the United States and several European countries, mention weak steam or a failed element. The listing specifies a 60 A breaker and 10 mm² wire, not a 13 A plug. The box lists a steam generator, a steam head, a control cable and a temperature probe. It will not run a Finnish sauna at 80°C, because the stated ceiling is 55°C.
Pros
Cons
Best for: A sealed steam shower near the stated 8.5 m³, if you accept the failure notes and an electrician’s circuit.
Less suitable: A hot wooden sauna, or anyone expecting a BS 1363 plug.
Specifications
Common questions
What temperature does the listing claim?
35–55°C. The page does not claim a Finnish sauna at 80–100°C.
Can it run from a 13 A plug?
No. The listing specifies 220 V, 10 mm² wire and a 60 A GFCI breaker, with two hot lines and a ground.
What room volume is printed?
8.5 m³. The listing does not define a smaller bathroom than that.
The Hanchen 9 kW generator at £489.00 states 380 V and a room within 7.5 m³, with the controller set between 35°C and 55°C. The countdown runs from 30 minutes to 12 hours, which is the longest timer in this set. The automatic water system is sold separately. Five amazon.co.uk ratings average 3.0, and both review texts report a failure after the unit had been in use. There is no BS 1363 plug on the listing. A 380 V nameplate does not belong on a normal 230 V single-phase supply unless an electrician confirms the house can feed it.
Pros
Cons
Best for: A small steam cubicle under 7.5 m³ only after the supply is confirmed as matching 380 V.
Less suitable: A single-phase 230 V house, or a sauna cabin.
Specifications
Common questions
What voltage does the title state?
380 V. The listing does not mention a BS 1363 plug.
What room and temperature does it claim?
A room within 7.5 m³, with the controller set between 35°C and 55°C.
Is there a timer?
Yes. The listing says 30 minutes to 12 hours, using a countdown.
The generic wall stove at £245.00 is the lowest shelf price in this set, and the listing states 9 kW for a 9–13 m³ room with a mechanical knob up to 90°C. Stones of 14–20 kg and the power cord are extra, and the page says the wiring is a professional job. Voltage is not printed, so you cannot tell from the listing whether the nameplate is 230 V. There is no amazon.co.uk star line. The technical table also prints a product size of 0.1 × 0.1 × 0.1 cm, which is not a usable cabinet measurement. Treat the £245.00 figure as the heater shell, then add stones and an electrician before you set it beside the Harvia at £990.00.
Pros
Cons
Best for: A buyer who already has an electrician and only wants the cheapest stone heater with a stated 9–13 m³ band.
Less suitable: Anyone who needs a printed voltage, UK reviews, or a steam shower.
Specifications
Common questions
What room size does the 9 kW line claim?
The listing says 9 kW is for 9–13 m³. The same page also prints room bands for 4.5 kW, 6 kW and 8 kW.
Are sauna stones included?
No. The listing says 14–20 kg of stones are sold separately.
Does it come with a power cord or plug?
No. The listing says the power cord requires professional wiring by the user.
The generic digital stone heater at £559.99 selects 9 kW on a page that also lists 3 kW, 4.5 kW, 6 kW and 8 kW. It states 200–240 V, an external digital controller, and a limit of 110°C. Stones of 10–20 kg are required and are not included. The room line of 2–13 m³ covers that whole power family, so it is not a measured band for this 9 kW part alone. There is no star rating. The page does not say whether a plug is included. You are paying a mid-set price for a voltage that looks UK-plausible, without reviews or a model-specific room volume.
Pros
Cons
Best for: A stone-heater buyer who wants a printed 200–240 V line and will confirm the 9 kW part number before paying.
Less suitable: Anyone who needs UK reviews, or a steam shower.
Specifications
Common questions
Is this the 9 kW version?
The part number is KM-2dIZNl--9KW. The same listing also prints 3 kW, 4.5 kW, 6 kW and 8 kW.
What voltage is printed?
200–240 V. The page does not say whether a plug is included.
Are the sauna stones included?
No. The listing says 10–20 kg are required and are not included.
The KXJQBM ST-90 at £331.79 is a steam generator, and the title selects 9 kW at 380 V. The page does not print a room volume or a temperature band, so you cannot check it against a shower cubicle from the listing alone. A digital controller for time and temperature is claimed, along with low-water and tank-pressure protection, without review notes to test those claims. There is no amazon.co.uk star line. The technical table lists the product size as 1 × 1 × 1 cm, which does not describe a steam unit. Most UK houses are 230 V single phase, so a 380 V title is a stop until an electrician has read the nameplate.
Pros
Cons
Best for: Only a buyer whose electrician has confirmed a matching supply and who still needs a steam generator.
Less suitable: A 230 V house, or a wooden sauna that needs stone heat around 80°C.
Specifications
Common questions
Which voltage does this listing select?
The title ends ST-90 9KW 380V. The same title mentions a 220/380 V family, and the selected variant is 380 V.
Does the page state a room size?
No. Room volume is not on the listing, and neither is a temperature range.
Is the cover stainless steel?
The listing says the cover is stainless steel and describes it as waterproof. It does not name a grade.
Seven amazon.co.uk listings are kept, shelf date 20 October 2026. The score is not a lab test. A 9 kW stone heater and a 9 kW steam generator are on the same sheet because both were in the listings. They are not the same product. Weights sum to 100. The highest total is a steam generator whose UK review reports no steam, so this comparison does not name a top pick. Best value is the £245.00 stone heater, the lowest stone-heater shelf price. The assessment names the missing voltage, the missing reviews and the extra stones.
Amazon stars
30%Star line divided by 5, then multiplied by 30. A listing with no star line scores 0 on this block.
Review sample
20%50 or more ratings score 16. 10–49 score 8. 5–9 score 4. 1–4 score 2. No ratings score 0.
Listing clarity
25%Points for a stated voltage, a room band for this model, a stated temperature and a clear contents line. A 380 V title scores low for a typical UK single-phase house. A family-wide room line scores less than a model band. A blank voltage or a blank room scores nothing on that part.
Review notes
15%A repeated UK pattern can score high. Documented failures, and review texts from outside the UK, score low. No review texts score 0.
Price
10%A lower shelf price scores higher only when the listing is usable. A 380 V title or a blank specification does not take this block on price alone.
Confirm whether you are buying a stone stove or a 35–55°C steam generator, then match the room volume and the printed voltage before the price. A 9 kW load at 230 V is about 39 A. It is not a 13 A plug. This is not a lab test. A missing star line means that listing has no reviews.
A 9 kW sauna heater on amazon.co.uk is not one product. It is either an electric stone stove for a hot Finnish room, or a steam generator for a wet shower at 35–55°C where a temperature band is printed. The power figure does not make those the same buy. A cabin around 8–14 m³ needs a stone heater and an electrician. A sealed shower needs the steam generator, and the volts must match the house. A steam kit will not run a Finnish sauna at 80–100°C.
The kilowatt figure does not make a stone stove and a steam generator the same product. A 35–55°C kit will not run a Finnish sauna at 80–100°C. Do not let the word sauna on a steam-kit title decide the buy.
Most UK homes are 230 V single phase. Hanchen and the KXJQBM title state 380 V. That is a stop unless an electrician confirms three-phase, or the actual supply, and the nameplate. 380 V is not the same as 400 V without that plate.
Add volume for glass and uninsulated walls before you lock 9 kW. Harvia’s average is 1 kW per cubic metre, plus 1.2 m³ per square metre of glass, stone or similar. The Harvia 4.9 from 14 is not a British sample. Those review texts were written in Germany.
Choose a stone stove if you want a hot sauna, or a steam generator if you want a 35–55°C wet room. Both types are in this set. They are not interchangeable. The stone heaters are the Harvia Spirit SP90XW at £990.00, the generic digital stove at £559.99 with a limit of 110°C, and the generic wall stove at £245.00 with a knob to 90°C.
Read 220 V, 200–240 V or 380 V on the listing and match it to the house. Most UK homes are 230 V single phase. A 9 kW load at 230 V is about 39 A, so it is a dedicated circuit, not a BS 1363 13 A plug. A 380 V-only title is a stop sign unless an electrician confirms the supply and the nameplate. The CGOLDENWALL kit at £350.55 prints a 60 A breaker and 10 mm² wire. The ST-90 page says 220 V is the default and 380 V is a different model. Check what the shelf price excludes.
Three typical situations, each with a recommendation from this comparison.
You already have a cabin and you want a stone heater with a printed room band. The generic wall stove at £245.00 states 9 kW for 9–13 m³ and a knob to 90°C. Voltage is not printed, there is no star line, and 14–20 kg of stones plus the cord are extra.
You want a 35–55°C steam generator, not an 80°C cabin. The CGOLDENWALL kit at £350.55 states 220 V, 8.5 m³ and a 1–60 minute timer. It is 3.7 from 76, and a UK review reports no steam. It needs a 60 A breaker and 10 mm² wire, not a 13 A plug.
You will not buy a stone stove until the page prints a voltage. The generic digital heater at £559.99 states 200–240 V, an external controller and a limit of 110°C. The 2–13 m³ line covers the whole 3–9 kW family. There is no star rating, and 10–20 kg of stones are extra.
There is no top pick. The highest listing score is 73, on the CGOLDENWALL 9 kW steam kit at £350.55. A UK review reports no steam, and the stated band is 35–55°C, so a top-pick badge would send a cabin buyer to a steam shower. Best value is the generic stone heater at £245.00, the lowest stone-heater shelf price. It states 9 kW, 9–13 m³ and a knob to 90°C. It does not state a voltage, it has no star line, and stones plus the cord are extra. The Harvia Spirit SP90XW at £990.00 is the only named Finnish stove. Its page leaves voltage and room volume blank, and the review texts were written in Germany.
Generic 9 kW stone heater
Lowest stone-heater shelf price at £245.00, with 9 kW and 9–13 m³ stated. Voltage, reviews and stones are missing from that price.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Public UK sources named below, taken from the research digest first. amazon.co.uk prices on these seven listings were taken from the listings, shelf date 20 October 2026. Page updated October 2026.
This page contains affiliate links to amazon.co.uk (tag pcuk26-21). If you buy through them, we may earn a commission at no extra cost to you. Prices are taken from those listings. Star lines are shown only where the listing has one. We did not run a lab test.
