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The Best Instant Hot Water Heater on the Market

Hot water is a cornerstone of modern comfort, but choosing the right instant water heater is anything but a simple task. With so many units covering so many niches across the market, how can you possibly make a decisive choice?

Today, we present a range of instant heaters that you can use under the sink, on the wall, or even outdoors.

Towards the end of the page, you’ll also find a short buyer’s guide to help you narrow down your comparison shopping beyond our recommendations.

Most Efficient Instant Water Heaters on the Market 

Our market research indicates the following units to offer the best value for money. Each fills a different niche, so go through the full list to find the best unit for your needs.

1. ATC 5L Water Heater (2kW, Undersink)

Under sink Water Heater by ATC 5L 2kW

What this undersink water heater from ATC lacks in verve, it makes up for in pure functionality. It features a respectable 5 litre tank running through 2000W of robust heating for warm water on demand. What’s more, the ATC supports two sinks–perfect for spa-style bathrooms or dual kitchen sinks.

While categorized as an undersink unit, you can just as easily mount the ATC 5L on your wall. The tank is insulated with high-density polyurethane foam, which does a great job of retaining heat and shrinking your monthly power bill. Combined with an external thermostat for fine temperature control, and you’ve got a durable, highly efficient unit that occupies any role your home requires.

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2. BuoQua 15L Electric Water Heater (1.5kW, Undersink)

BuoQua 15L Electric Water Heater 1500W Instant Water Heater Under Sink

If you’re looking for a large-capacity instant water heater that won’t break the bank, the BuoQua is well worth your consideration. We especially recommend this unit for households with many people sharing a sink. 15 litres is positively cavernous, and equal to the task of prolonged usage without running out of hot water.

What’s more, BuoQua has clearly built this unit to last–with robust, corrosion-resistant materials and IPX 4 waterproofing. The electrical and water systems are well separated for safety, and the 15L features high-efficiency piping to prevent heat loss. Dial in the perfect temperature between 30–70℃ and you’ve got perfect hot water delivery for the whole family, even throughout the coldest months.

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3. Stiebel Eltron DHC-E12 Instantaneous Water Heater (12kW, Oversink)

Stiebel Eltron DHC-E12 Electronic Instantaneous Water Heater

If you’re looking for a premium investment, we recommend the Stiebel Eltron DHC-E12. A true workhorse, the DHC-E12 features a whopping 12000W of power, which makes a storage tank and venting entirely unnecessary. This allows for more flexible installation; its sleek, single-unit design takes up a non-offensive amount of space in your kitchen or bathroom.

A single, easy-to-read dial belies advanced technology underneath, which uses a microprocessor to ensure output at exactly the temperature you specify. While you can bring the water up to scalding to comply with health advisories, normal operation ensures instant, but always comfortable hot water delivery.

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4. Triton T30i Handwash (3kW, Oversink)

Triton T30i 3kW Handwash

If you’ve got a room where hot water delivery would otherwise be impossible, try the Triton T30i Handwash. This compact design fits right above your sink, acting as both heater and tap for seamless functionality. Indeed, Triton has clearly prioritised usability; this unit sports a single numbered knob which simply turns the unit on directly to the temperature you specify, or off. With 3000W of power, you won’t have to worry about waiting around for hot water, either.

Not enough? You can easily adjust the direction of the stream with the T30i’s modular swivel head, which comes in 200mm and 300mm variants. Combined with easy installation that doesn’t require a plumber, and you have a flexible unit that delivers respectable performance in hard-to-heat areas of the home or workshop. 

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5. Hyco Handy Flow HF05LQ (2kW, Oversink)

Water Heater Oversink 5 Litre Tank Handy Flow Hyco HF05LQ

The Hyco Handy Flow is just as its name suggests–a handy way to install water heating almost anywhere. Billed for use in portable buildings, offices, garages, and workshops, it can easily fill residential purposes as well, such as sheds and guesthouses. The only restrictions you’ll face with the HF05LQ is the need for a plumber to install it to account for venting. Thankfully, it’ll be an easy, cheap job.

On its own merits, the HF05FLQ features robust 2000W heating, easy external controls, frost protection, and a neon indicator light. We also love its slim line design, at just 180mm deep. Despite its diminutive profile, durability won’t be an issue, with high-impact plastic casing and IP24 waterproofing.

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6. Camplux BW158BC 6L Instant Gas Water Heater (12kW, Portable)

Camplux BW158BC 6L Instant Gas Water Heater with Rain Cap

Billed as providing “endless hot water”, the Camplux BW158BC offers an astounding 12kW of gas-powered, tankless heating to make good on their claim. What’s more, this massively capable unit is portable, with D-battery operation that can be used (fitting to the brand’s name) even whilst out camping. If that prospect makes you somewhat nervous–keep in mind that the BW158BC can get 180 days of use out of two batteries.

No need to rough it indoors or out­–the BW158BC’s design is ultimately user-friendly, with simple water and heat knobs and an LED temperature display. There’s also a 37mbar CE gas regulator, which is conveniently compatible with any propane tank. With 6 litres of heating capacity, you’ll enjoy the same level of comfort outdoors as you would showering at home. 

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7. Camplux BW264C 10L Gas Water Heater (20kW, Portable)

Camplux BW264C Tankless Gas Water Heater with Rain Cap

Similar to its little brother, the Camplux BW246C is a robust, portable hot water heater with even more power. It still requires two D batteries to operate, but outputs 20000W of power when attached to virtually any type of propane tank. It also features the same robust, weather-proof design, allowing it to fit virtually any application. Both units also come in your choice of black (BWxxxBC) or white (BWxxxC).

The biggest differences between Camplux’s series are the capacity and weight. The BW264C features 10 litres per minute, which is enough for a family gathering of any size, though it is admittedly slightly less portable at 11.1 vs. 7.34 kg. There is a moderate increase in price, so we recommend you choose the best size for your needs to avoid over-payment or under-performance.

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8. HEEPDD Mini Water Heater (5.5kW, Wall-mounted)

Mini Water Heater, 5500W Electric Instant Water Heater Tankless Shower Hot Water System for Bathroom Kitchen Washing

Last but not least is the aptly named Mini Water Heater from HEEPDD. Don’t let its small size fool you–this is a highly capable heater for showers and sinks in most homes. Boasting 5500W of electric power, you’ll get your desired water temperature in 5 seconds or less. Like other top-tier instant water heaters, it features an easy-to-read LCD display and simple temperature controls with adjustments between 30-55°C.

The HEEPDD Mini is easily to install with a universal G½” water pipe connector, and doesn’t require a plumber. You can rest easy knowing that the Mini features robust safety protections. These include triple-layer hydroelectric isolation, a waterproof motherboard, and anti-dry protection.

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Buyer’s guide – Instant water heaters

We’ve given you a nice assortment of the best instant water heaters on the market, but if you’d like to continue with your own market research, keep the following factors in mind:

Match the heater to the application

As you can see in our list above, not all water heaters are intended to fill the same purpose. You wouldn’t, for example, choose a small tap heater to power your hot showers in the morning. Neither would you wish for an industrial-scale, wall-mounted, tanked heater on a camping trip.

It’s not just a matter of convenience either; picking the right instant water heater for the job ensures lower power bills, better safety, and more comfortable warming.

Be aware of differing capacities between similar units

You might look at product listings and think “well, these two look virtually identical. How should I choose between them?” Besides colour differences, many brands group sister units together in a single listing, which may vary greatly in their capacity.

Capacity, by the way, measures how much hot water is produced per minute. This unit is used for both tank-equipped and tankless heaters, so don’t confuse it for how much water your heater will physically store.

Understand safety features

As with any device which holds heating as a primary function, there will be failsafes in place to guard against component failure or, to a lesser extent, misuse. For example, anti-dry protection will shut your unit off when there is no water inside the unit. After all, water is itself a heat sink, and in its absence there will otherwise be nothing to stop your unit from overheating.

You’ll also want to make sure that your electronics are well isolated from the water itself, otherwise you run the risk of shorting out or even causing fire. If you’re using a gas heater, make sure your unit has freeze protection, a cut-off fuse, limiter switches, and adequate venting.

In all cases, you want an instant water heater which boasts superior material durability, and adequate waterproofing to guard against splashes from normal use.

Tankless vs. tank storage water heaters

Tankless heaters are typically billed as “instant” water heaters. They use high-powered heating elements to infuse cold water with warmth as it passes through the unit. Conversely, tank storage units keep hot water reserved in a massive water tank to be drawn upon as needed.

Besides the obvious difference in space required, tankless heaters are typically more energy efficient. This is because there’s no loss of heat from water sitting around unused in a tank. That said, tank storage heaters tend to be cheaper upfront, and require little in the way of expensive maintenance long-term.

Tankless heaters are by definition more portable, with some models designed specifically to be used on the go. Whether you’re remodelling your home, building an add-on, or simply need to bring hot water to a standalone workshop with only basic plumbing, a tankless heater will give you the flexibility to achieve hot water anywhere you need it.

ALTERNATIVE: The best instant hot water dispensers


We’ve covered a lot of ground in this article. But hopefully, you should have a better idea of what sorts of instant water heaters are out there–and which might best serve your purposes. Our reviews contain undersink, tankless, oversink, and shower-ready units, some fix and some portable. In any case, each is ready to provide quick access to warm, comforting water any time of year.

What are you looking for in an instant water heater? Do any of our recommendations appeal to you? Leave us a comment below.

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