5 Best Over Sink Water Heaters on the Market

Hot water is a necessity for modern life, but often times you’ll have basins disconnected from the main boiler. If you’d rather not wash your hands or do dishes in frigid cold water, check out our list of the best over sink water heaters. These units require little in the way of installation space or long-term maintenance, and work a treat to deliver warm water to your cloak room, workshop, building add-on, or bathroom.

Best residential/commercial usage over sink water heater

There’s a massive array of water heaters on the market, but in the end you’ll likely only pick one for purchase. How do you make sense of all the competing claims to greatness, and how can you match the right feature set to your needs?

Allow us to make your search a little easier. We’ve handpicked five of the best over sink water heaters across a variety of price points. Below, we review each by their performance, aesthetics, ease of installation and usage, maintenance required, and available warranties. We wrap up each section with a few words on who will get the best usage out of each water heater.

1. Triton T30i Handwash

If you’re a commercial builder, you’re likely already well-familiar with the T30i. For everyone else, Triton Showers makes an exceptional handwashing unit that slots in perfectly anywhere in the house where there’s only the cold mains available. If you’re looking for “Made in Britain” quality for a low price, you’ll be hard-pressed to do better than the T30i.

Triton T30i Handwash 3kW Over Sink Water Heater

In short, the Triton Showers T30i is:

  • Compact
  • Highly efficient
  • Maintenance-free
  • Built by a reputable UK name

Performance

This diminutive over sink water heater puts out a respectable 3kW of power, which yields 0.8-2L/min. of warm water. You won’t be filling entire basins full of boiling water at this rating, but it is more than enough to bring moderately cold mains up to a comfortable handwashing temperature. The Handwash features smart temperature stabilisation, so you don’t have to worry about sudden scalding or freezing if the pressure should change.

Triton Showers are well-known for the efficiency of their designs, and the Handwash is no exception with a Class A energy rating. Because the T30i doesn’t maintain a heating tank and just warms what you pull from the mains, no electricity is wasted. Average annual usage of the T30i amounts to 526kWh–which, depending on where you live, costs less than a night out to the pictures.

Aesthetics

The T30i isn’t what anyone would call glamourous, but it isn’t hard on the eyes either. Indeed, it may be a testament to Triton Showers’ deliberate design ethos to say this has a wallflower aesthetic, allowing it to blend seamlessly into any modern (or modern-ish) bathroom. Sporting an unassuming white gloss plastic shell with stainless steel fittings, it is decidedly utilitarian without looming brutally over your sink.

Installation and usage

Over sink water heaters tend to be permanent or semi-permanent installations, and as such require professional installation. The T30i is no exception to this rule, though it will be a fairly easy (and cheap) job for a qualified technician.

Just be aware that the outlet acts as the Handwash’s vent, thus you should not modify the nut and olive in any way or add extra fittings. The T30i does not come pre-wired, either. At 3kW, you won’t need special wiring to avoid tripping the fuse box, so rest easy!

In terms of usage, it really doesn’t get any easier. There’s a single rotary dial with an oversized thumb grip allowing for on/off plus temperature control. You only really have relative, rather than exact, control over what temperature you get, but this is hardly a knock against the T30i.

Maintenance and warranty

The T30i is the dictionary definition of simplicity, and as such it requires little in the way of maintenance. There’s no tank to corrode nor anode to replace. The vent is integrated into the outlet, and mechanically extremely simple.

Triton Showers offers the choice of a 100mm, 200mm, or 300mm swivel arm to best fit the size and shape of your basin. These are easily interchangeable without professional assistance, making for cheap and easy replacements.

Indeed, Triton Showers is quite good about stocking replacement parts, so you won’t have to shop around for expensive boutique solutions if something goes wrong or wears out. What’s more, there’s a 1-year warranty on parts and labour, showing that Triton Showers stands by their work.

Who’s it for?

As we’ve previously mentioned, the Triton Showers T30i is an incredibly popular choice amongst property developers and homeowners alike. These are highly reliable, imminently affordable over sink water heaters that boast a long, uneventful service life. The most modern incarnation of the T30i is a drop-in replacement for its predecessors, slashing the cost of retiring an aged-out fleet.

We wish there was some sort of anti-frost protection, so be advised that the T30i will do best outside of applications with direct exposure to freezing temperatures. This is doubly true considering its power rating; near-freezing mains water will struggle to achieve greater than lukewarm temperatures through the 3kW Handwash.

However, in its intended applications (cloakrooms, workshops, building add-ons), the Triton Showers T30i provides unrivalled value for money. Indeed, this workhorse water heater appears over so many sinks throughout the UK specifically because it works just as advertised.

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2. Stiebel Eltron DN 3

Stiebel Eltron are a well-respected German manufacturer of superior water heaters since 1924. In the ensuing decades, they have not compromised on their pursuit of quality. And that shows through even amongst smaller-box items like their DN 3 over sink water heater.

Stiebel Eltron 231573 DN 3 Hand wash

In short, the Stiebel Eltron DN 3 offers:

  • Reliable German engineering
  • A miniscule footprint upon your precious wall space
  • Minimalist good looks
  • Exceptional consistency

Performance

Like most Stiebel Eltron products, the DN 3 offers exceptional performance. Rated at 3.1kW, it produces a consistent 1.8L/min. @ at a 25° temperature rise. Whether it’s summer or winter, or you have low mains pressure, the DN 3’s on-board temperature stabilisation works a treat to deliver highly consistent warmth for hand washing.

We particularly love the low-velocity spray plate, which yields a gentle, consistent spray pattern that won’t splash. Of course, if water does splash, you’ll never have to worry about your DN 3, thanks to its incredible IPX5 waterproofing.

The Stiebel Eltron DN 3 is hydraulically controlled; once you’ve set a temperature, you don’t have to worry about drawing power you’re not using. Just turn on your tap, and your over sink hand washer will (silently) hum to life to deliver the warmth you desire. Indeed, the DN 3 boasts a Class A energy rating, and does its job without massive impact on your power bill.

Aesthetics

While Stiebel Eltron tends towards utilitarianism almost as a rule, there’s something a bit special about the DN 3. It’s minimalistic but not avant-garde; compact yet substantial; modern but unpretentious. It’s just 9.9x 15.1 x 23.5cm to boot, so it really fits absolutely anywhere regardless of space constraints. It’s more smart than luxurious, and that might just do it for many applications.

Installation and usage

Installing the DN 3 is incredibly simple thanks to its manageable weight (just 1.2kg), tiny footprint, and push-fit piping connections. You won’t need an expansion vessel either, further cutting down your initial investment. If its size wasn’t a dead-giveaway, the DN 3 is only appropriate for supplying a single basin.

Just keep in mind you’ll still need to call a professional for safe installation.

An exemplar of its kind, the Stiebel Eltron DN 3 presents just a single grippy rotary knob, by which you can accurately control the flow and temperature output without hassle of any kind. Just twist to your desired setting, turn the tap, and you’re good to go!

Maintenance and warranty

Stiebel Eltron builds product to last, and it’s not unusual to see units in service for 20+ years. While there’s no guarantee your DN 3 will last that long, the manufacturer does provide a generous warranty for 2 years. What’s more, there’s an option to purchase an extension to 7 years, covering parts and labour.

Replacement parts are easy to come by, as Stiebel Eltron keeps a healthy stock. Of course, due to the simple design of the DN 3, you’re unlikely to have anything break. We do wish the tap were modular for easier replacement, but its integrated design offers the compromise of exceptional durability.

The DN 3 features overheat protection, with 52° as the cut-off point and 42° as the reset point. There’s also a pressure relief device to protect against blockages and freezing.

Who’s it for?

If you’re concerned about your budget but don’t want to compromise on quality, Stiebel Eltron’s DN 3 demands a second look. Its minimalist styling complements dead-pan delivery of consistently warm water–no matter the season.

Please note, the DN 3 is not suitable for pressurised water systems, and is incompatible with pressurised fittings.

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3. HEEPDD Mini Water Heater

We’ve spoilt you for choice between our British- and German-made recommendations thus far. That said, take a moment to consider the value offered by Chinese manufacturer HEEPDD’s solid (though uncreatively named) Mini Water Heater.

HEEPDD Mini 5500W Electric Instant Water Heater

The HEEPDD Mini Water Heater is:

  • Affordable
  • Well-equipped with safety features
  • Powerful enough to supply both sinks and showers

Performance

Despite its “mini” designation, this over sink water from HEEPDD offers quite a lot of horsepower. At 5.5kW, it can easily manage near-instantaneous delivery of water between 30-55°.

While the manufacturer doesn’t specify a nominal flow rate, we found it performed admirably at 38°. On-board temperature stabilisation ensures consistent performance, even in the face of pressure spikes and sages.

Aesthetics

It won’t win any design competitions, but we do like the red. More seriously, the HEEPDD takes up about as much wall space as an iPad, and its platonic shaping allows it to blend in almost anywhere. The LCD temperature display is bright red and uncomplicated, and contrasts nicely with the bold, blue control buttons beneath. It’s aesthetically unremarkable, which can be a strength as much as a weakness.

Installation and usage

You’ll want to hire a professional technician to handle the install, even though there’s no warranty to validate in doing so. After all, HEEPDD doesn’t include the ≥2.5mm2 copper wire needed to safely draw electricity with their Mini Water Heater–and that’s no job for inexperienced DIYers. It installs readily wherever you have space, and has the heating capacity to serve either a basin or a shower with aplomb.

Controlling the HEEPDD is a cinch as well, with a simple digital thermostat and easy-press buttons for on/off and temperature control.

Maintenance and warranty

For an inexpensive Chinese unit, there’s a good amount of thought put into durability and safety. HEEPDD includes anti-dry detection and overheat protection, both of which cut the power before reaching unsafe operational levels of water and temperature. Not only does this protect your property, but it ensures the components won’t burn out.

Further protection comes from the HEEPDD’s IPX4 rating, and superior hydroelectric insulation of the electronics and heating element. After all, water and electricity are a poor (and dangerous) match.

There’s no warranty on offer, so keep that in mind when making your purchase.

Who’s it for?

If you’re looking for a bit more heating power than is normally available with over sink water heaters, the HEEPDD provides a lot of wattage per £. It doesn’t come with the service or guarantee you might expect from a European manufacturer, but it features robust construction and durability. Consider this a decent budget pick that allows for a bit more utility than other similar water heaters.

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4. Stiebel Eltron SN SL GB

Similar to our previous recommendation, the SN SL GB is robust enough to supply both showers and basins. Here, however, you get the benefit of German manufacturing from a reputable brand and some premium features to round out your investment. It is the most expensive entry on our list of the best over sink water heaters, but it is offers much to justify its price tag.

Stiebel Eltron 222192 SN SL GB Small Electric Water Heater

The Stiebel Eltron SN SL GB has:

  • A superior warranty
  • Durable build quality
  • Robust heating performance
  • Highly accurate thermostatic control

Performance

Unlike our other recommendations thus far, the SN SL GB is a tank-storage water heater, rather than tankless. This means it doesn’t offer endless amounts of hot water on demand, but has a limit according to its tank size: 10L. However, you’ll find this is more than suitable for most applications.

Under the hood, you’ll find a 2kW heating element, which offers plenty of overhead for high heat production. Indeed, the operational temperature range is between 35-85°, which is certainly enough for a comfortably steamy shower. Additionally, there are four discrete limiter presets (38°, 45°, 55°, and 65°), which you can use to put a hard cap on how much energy you want your SN SL GB to use. You can trust these settings, as there is a high-precision temperature capture sensor immersed in the water for consistent accuracy.

It wouldn’t be a Stiebel Eltron if it weren’t extremely energy efficient, and this model boasts a Class A rating. This is in large part due to the EPY thermal insulation surrounding the tank; though special mention must be made to the Thermstop function, which keeps heat from escaping through the spout, as well.

Aesthetics

The SN SL GB is surprisingly attractive in the flesh, featuring a gently curved plastic shell with a sleek satin finish. It isn’t the smallest unit on our list (quite the opposite at 27.5 x 29.5 x 50.3cm), but it is compact enough to not hog too much space above your sink. The dial is smartly positioned, ringed by a high-contrast temperature gauge. The neon heating indicator light is bright enough for its task without presenting a nuisance to the ambience of your home.

Installation and usage

Anywhere you have a draw-point that isn’t connected to a central boiler, you can readily install the SN SL GB. Once again, you’ll need the services of a qualified technician to do it safely (and to validate your warranty). If you’ve got excess cable after installation, there’s storage in the rear to keep the area nice and tidy. You won’t need to buy a separate venting system, as vent taps come included in the box.

Note: You will not be able to use the SN SL GB with pressurised taps, as this will damage the unit.

Stiebel Eltron always provides an excellent user experience, and their over sink water heater is no exception. Simply set the dial to your desired setting, then draw from the tap as needed for fast delivery of warm water.

Maintenance and warranty

It’s not enough to simply praise Stiebel Eltron for being, well, German. They’ve put a lot of effort into ensuring the SN SL GB provides a long service life in exchange for your GBP. For one, the heating tank is made of a corrosion-resistant polypropylene. Inside, you’ll find a low-surface load copper heating element, rated for near 100% efficiency and longevity alike.

Additionally, the SN SL GB is perfectly suited to placement within Zone 2 or 1 of your bathroom thanks to IP24 waterproofing. And even if the pipes freeze, you won’t need to worry about your Stiebel Eltron, thanks to the automatic frost protection, which kicks in when the unit turns off.

Need more? So long as you had it professionally installed, Stiebel Eltron guarantees your SN SL GB purchase with a 2-year warranty on parts and labour. As with all their products, you can purchase extended, 7-year coverage for a small sum more.

Who’s it for?

The SN SL GB provides incredible value for money in both residential and commercial applications. You’re just as likely to see it in a public restroom as your neighbour’s home–and for a long while at that. It’s not unusual to see Stiebel Eltron electric water heaters in service for over 20 years. If your budget and wall space can accommodate the extra heft, you’ll find the SN SL GB delivers value for money in spades.

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5. Hyco Handyflow

Hyco’s Handyflow is a workhorse over sink water heater appropriate for supplying a single basin. It provides outstanding performance without demanding too large a budget, and is a popular choice in homes and commercial premises alike.

Hyco HF05LQ Handy Flow - Water Heater Oversink

The Hyco Handyflow offers:

  • Workmanlike durability and reliability
  • Eco-friendly insulation and efficiency
  • Excellent heating capacity per £

Performance

The Handyflow features a 5L tank and 2kW heating element. Because this isn’t a tankless design, we can’t exactly say that it offers hot water on demand; however, the capacity is large enough to fulfil the needs of a single basin with aplomb, from handwashing to dishes and more.

What’s more, the Hyco Handyflow is a great option for anyone living in a particularly cold climate, as having a tank full of warm on reserve is more efficient than trying to raise the temperature of near-freezing mains water on the fly.

For the eco-conscious consumer, Hyco’s CFC-free polyurethane insulation is equally friendly to your monthly power bill as it is to the planet.

Aesthetics

There’s no way around it, the Hyco Handyflow is a bit of a Plain-Jane. However, that means it fits unobtrusively into virtually any bathroom, cloakroom, workshop, or kitchen. Despite its generous capacity, the Handyflow only takes up 45 x 28 x 18.6cm of wall space.

Installation and usage

At a lightweight 3.5kg, installing the Hyco Handyflow is manageable affair. While this is a vented unit, you won’t need to spend extra on a special valve, as it vents through the spout. Both tap and spout come included, so you can save even more out the box. The Handyflow is also pre-wired, further slashing the cost of install.

A nice feature of the Handyflow is that it self-resets the thermal cut-out whenever you switch the unit’s power off. Admittedly, this is unlikely to do much more than save you a small expense replacing fuses. However, it’s much more useful in commercial/industrial applications, especially for temporary/portable buildings where over sink water heaters get drained frequently.

Hyco, as a rule, makes simple-to-use products, and the Handyflow is no exception. Simply select your desired temperature with the rotary dial, and watch as the neon springs to life indicating heating.

Maintenance and warranty

Opening the box, the Hyco gives an immediate impression of durability. The casing is made of a robust, corrosion-proof plastic which also holds an impressive IP24 rating vs debris and moisture.

A word of advice: the Handyflow displays what may seem like a bug, yet is actually a feature. We’ve already mentioned how it vents out of the tap, and as such you will see a bit of dripping whilst the tank is heating up. This is entirely normal, and indeed desirable as water waste is minimal whilst providing protection against over-pressurised piping. Just make sure you don’t over-tighten the tap to get rid of this necessary drip-vent feature!

Hyco offers a 1-year policy to replace defective units. It’s not quite a full-blown parts and labour guarantee, but it does show the manufacturer’s confidence in their product.

Who’s it for?

The Hyco Handyflow is an ideal choice for anyone living in colder climates, thanks to its generous tank capacity and swift heating. Installation costs are minimised, while durability is high. Combined with a mid-range price point, and you’ve got good value for money both in the immediate and long term.

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The comparison shopper’s guide to over sink water heaters

If you’re anything like us, you’re not always satisfied to simply take a recommendation on what to buy; you need to do your own shopping around to compare what’s out there. While we stand by our list of the best over sink water heaters, we’d like to point out a few key points to help you make your own decision:

  • Remember, the total cost of your water heater doesn’t stop at the price tag. You’ll have to factor in installation labour from a qualified technician. As a rule, any heaters installed over or under the sink will require an electrician to handle the wiring such that it is safely waterproofed, which runs about £40/hr. You may also have to hire a plumber at a similar rate if adequate piping is unavailable for your over sink water heater.
  • Maintenance should be minimal on most small heaters. However, you will eventually have to replace the sacrificial anode in tank storage heaters. On average, these last about 5 years. If you neglect the anode, it can slash the life of your heater by half! They’re not very expensive, ranging from £10-£50 depending on your model, making this a good way to protect your investment.
  • Make sure your heater has the capacity to fit the task. For hand washing, tank storage heaters perform best with 5L tanks, while tankless over sink heaters should produce between 1 and 2L/min. Otherwise, you’ll either run out of water prematurely, or you’ll struggle to get the desired warmth on cold days.
  • Always pay attention to the warranty. Not all guarantees cover parts and labour, and some offer a longer period of coverage than others. Manufacturers are more likely to offer robust warranties on products they know are less likely to break, so buy accordingly.

Wrapping up

We’ve spent a good deal of time researching the best value over sink water heaters for money, and reviewed our top five picks. Each offers a unique balance of features to suit your needs and budget. Whatever direction you decide to go, keep our four key points in mind whilst doing your comparison shopping and you’ll not go wrong.

Have any experience with our recommended over sink water heaters? Any points you’d like to add to our buyer’s guide? Leave a comment below!

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