Grohe
Grohe Red Duo L-Size
The Grohe Red Duo L-Size is a 99°C boiling water tap from Grohe, at a typical UK price of £1,625, a 5.5-litre tank and a 2-year warranty.
Specs last updated 10 September 2026
99°C filtered boiling water plus a full hot-and-cold mixer
The Grohe Red Duo pairs 99°C filtered boiling water with a normal kitchen mixer in one tap, replacing both the kettle and the main tap. The L-size boiler holds 5.5 litres of near-boiling water (7 litres total). It sells for around £1,625 at UK tap specialists, well below Grohe's £2,578 list price. BWT carbon filter changed yearly, child-safe touch buttons, 2-year guarantee (3 with registration).
Where to buy
Buy the Grohe Red Duo L-Size
| Retailer | Price | Stock | Checked | |
|---|---|---|---|---|
| Amazon UK | Check price at retailer | In stock | 27 Aug 2026 | Check price ↗ |
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Visualised: the Grohe Red Duo L-Size in an English cottage kitchen, composed from the manufacturer's product photo.
What we like
- Boiling, filtered and a full hot-and-cold mixer in one tap, no second tap hole
- Large 5.5L boiling reserve (7L total) on the L-size boiler
- Child-safe touch-button dispensing with ChildLock as standard
- Sells around £1,625 at UK specialists, far below the £2,578 list price
Watch out for
- 99°C dispense, not a true 100°C boil (despite Grohe's "100°C" marketing)
- At around £1,625 it is still a premium tap, though far below its £2,578 list
- BWT filter must be changed yearly or every ~600L, an ongoing cost
- Standard guarantee is 2 years (3 only with registration), shorter than InSinkErator or Franke
Our take
The Grohe Red Duo L-Size reviewed
By Next Day Online editorial, the ex-retailer that sold boiling water taps from 2016 to 2024
The Grohe Red is the boiling-water tap from a brand most people know for mixer taps and showers, and the Duo version is the one that makes sense for a single-tap kitchen. It puts 99°C filtered water on a pair of child-safe buttons and keeps a normal hot-and-cold mixer on the lever, so one tap replaces both the kettle and your existing tap. The L-size boiler is the headline: 5.5 litres of near-boiling water, 7 litres in total, which is more usable reserve than almost anything else here and useful for filling pans.
The thing to understand before you shop is the price. Grohe's list price for the chrome L-size Duo is £2,578, but it is never sold at that. UK tap specialists list it around £1,625, which is the figure we show, putting it in mid-premium Quooker territory rather than up with the Zip. Judge it on the real £1,625, not the list.
Two caveats are worth weighing. The boil is 99°C, not a true 100°C, even though Grohe's own marketing says "100°C", so for sterilising or a proper rolling boil it falls a hair short. And the standard guarantee is two years, extended to three only if you register within three months, which is shorter than InSinkErator or Franke. The BWT filter needs changing once a year or every 600 litres. Buy the Red Duo for the big boiler, the full mixer and the German build, at its real £1,625 price rather than the list.
Features
- 99°C filtered boiling water
- Full hot and cold mixer (Duo)
- 5.5L boiling / 7L total L-size boiler
- Child-safe touch buttons (ChildLock)
- BWT filter, change yearly or every 600L
- Holiday eco mode caps at 60°C
Available finishes
- Chrome
- Supersteel
Running cost
What this tap really costs to own.
Headline price is half the story. The Grohe Red Duo L-Size reheats whenever the tank cools, and standby power adds up over a decade. Use the calculator with your own electricity tariff and household usage to see the 10-year total.
Installing soon? Installation costs and water hardness by UK city
- Idle draw
- - W
- Tank capacity
- 5.5 L
- Boiling temp
- 99°C
- Warranty
- 2 yr
Compare
Grohe Red Duo L-Size vs the rivals
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Owner reviews
Coverage in progress
We need 50+ verified reviews before we publish a confidence-weighted score. See our methodology.
Read public owner reviews for the Grohe Red Duo L-Size at the sources we will aggregate once coverage is complete. We summarise the patterns in our own words and never reproduce review text verbatim.
Common questions
Grohe Red Duo L-Size: your questions
- How much does the Grohe Red Duo L-Size cost?
- The Grohe Red Duo L-Size has a typical UK list price of £1,625, before installation.
- Does the Grohe Red Duo L-Size dispense water at 100°C?
- No. The Grohe Red Duo L-Size dispenses at 99°C, which is near-boiling rather than a true 100°C boil. That is hot enough for tea and coffee, but not a rolling boil.
- How big is the Grohe Red Duo L-Size's tank?
- The Grohe Red Duo L-Size has a 5.5-litre boiling water tank.
- Does the Grohe Red Duo L-Size filter the water?
- Yes. The Grohe Red Duo L-Size dispenses filtered water through a BWT active carbon.
- What warranty does the Grohe Red Duo L-Size come with?
- The Grohe Red Duo L-Size comes with a 2-year warranty on the tap and tank. Read the terms, as some brands limit cover if a non-brand filter is fitted.
Reader reviews
From people who own the Grohe Red Duo L-Size
Submitted by readers and read by a human before publication. We publish the wording as submitted and cannot independently verify ownership unless a reader shows proof, in which case the review is marked verified.
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