Faucet Set for Sink, Bathtub, or Countertop: Which Type Suits My Bathroom or Kitchen

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Basin, bathtub or wall-mounted faucet: which type of set is suitable for my bathroom or kitchen?

When a customer decides to switch to a tankless water heater with a traditional faucet, the first question that almost always comes up is: "Which type of faucet do I actually need?" At first glance, this seems trivial – after all, a faucet is a faucet – but in reality, it is a decision that will affect not only the comfort of daily use, but also whether the entire set can be installed without breaking the tile or drilling new holes. From experience, I know that choosing the wrong type of faucet is one of the most common reasons why installation ends up being more expensive or complicated.

This article will guide you through the differences between basin, bathtub, and wall-mounted faucets in the context of HAKL PL IconicLine tankless heater sets – that is, sets where the heater and faucet form one functional unit designed to work seamlessly together. We will look at dimensions, installation requirements, performance needs, and specific real-life scenarios so you can accurately choose what your bathroom or kitchen actually needs.

What is a "set" of a tankless heater + traditional faucet?

A tankless heater heats water on the fly – only when it is flowing. It does not require a boiler, a tank, or separate hot water lines. The entire thermal system is concentrated in one compact unit that is mounted directly on the wall next to the sink, basin, or bathtub.

A traditional faucet in this context is not a thermostatic lever mixing faucet, as we are used to from standard hot and cold water lines. It is a two-ball faucet with two taps – left (hot water) and right (cold water) – or another type of faucet with longer connecting hoses, designed for direct connection to the heater's output. Temperature regulation does not occur by mixing two flows from different lines, but by opening or closing the taps directly on the faucet.

A set as such means that the manufacturer – in this case HAKL – has assembled the heater and faucet so that they are hydraulically and performance-wise mutually compatible. You do not have to combine components from different manufacturers and hope that it will work. This is a practical advantage that customers appreciate especially in the case of complaints or service.

Three basic types of faucets in sets – how do they differ?

Basin faucet: for kitchen sink and bathroom basin

A basin faucet is designed for mounting directly on the edge of a sink or kitchen basin. Typically, it has an outlet height of about 20 cm, which is a standard height suitable for deep sinks in the kitchen and for shallower bathroom basins. The taps or levers are operated directly on the faucet, and the water flows down into the sink.

Installation is done through one or two holes in the edge of the sink (depending on the design). The faucet is secured with a nut from below, and the connecting hoses go up to the heater, which is mounted on the wall above or next to the sink. In HAKL PL IconicLine sets, the standard spacing of the connecting hoses is designed to fit typical dimensions commonly found in mass-produced sinks in Slovakia.

Practical example: a customer had an old water heater in the kitchen that started leaking. She decided to switch to a tankless heater. The kitchen sink has a standard 35 mm hole with a 15 cm spacing. Therefore, we chose HAKL PL SET 3.5kW with a 20cm traditional basin faucet IconicLine. We mounted the heater on the wall above the sink, the faucet fit directly into the existing hole, and the entire installation took less than two hours, including electrical connection to an existing circuit.

For slightly higher comfort, or if you have a higher sink, or need a bit more pressure when washing dishes, it is worth considering HAKL PL SET 4.5kW with a 20cm traditional basin faucet IconicLine. This is particularly advantageous when the incoming water is colder – for example in winter months or in houses with longer cold water supplies from a well.

The basin faucet in the HAKL PL set is designed so that the entire temperature regulation takes place directly at the heater (you set the power) and at the taps (you open hot or cold water, or mix them). It is not a thermostatic faucet – you do not set the temperature automatically, but manually. For a sink used for hand or dish washing, this is a fully sufficient and reliable solution.

Shower Valve: For Bathtub with Handheld Shower

The bathtub shower valve is structurally designed for wall mounting along the bathtub. It features a longer handheld shower with a hose – in the case of HAKL PL IconicLine sets, it is a 150 cm hose and a shower holder, with a rod or hook for hanging the handheld shower also included in the set. The standard installation height of the valve on the wall is approximately 18 cm from the top edge of the bathtub, which corresponds to common construction practice.

Important detail: the bathtub shower valve in the HAKL PL set is not intended for filling the bathtub itself – this would require significantly higher power (usually 18 – 27 kW, which is the range of three-phase devices). A flow heater with 4.5 kW or 5.5 kW is dimensioned for showering with a handheld shower, where the water flow is significantly lower than when filling the entire bathtub. To fill the bathtub, you need a traditional water heater or a storage heater – this is a practical limit that should always be clearly communicated to customers.

The bathtub shower valve is installed in the wall using concealed or surface-mounted connections. Supply hoses lead from the valve to the heater, which is usually mounted on the wall above the bathtub or in its immediate vicinity. The distance between the connection holes is 18 cm (standardized for most bathtub valves on the Slovak and Czech markets).

For showering with a handheld shower at normal water temperatures (10–15°C cold water in summer), a power of 4.5 kW is usually sufficient – you will achieve pleasant warm water at a flow rate of around 3 l/min. In winter or in mountainous areas, where cold water arrives at a temperature of 5–8°C, we recommend opting for the HAKL PL SET 5.5kW with a classic bathtub valve 18/150cm IconicLine, which can provide water a few degrees warmer at the same flow rate.

Practical example: an older apartment building with a bathroom and bathtub, without a central hot water supply (old boiler shut down, no replacement in sight). The tenant wanted to solve the showering issue without major construction work. Surface mounting of the HAKL PL heater with a bathtub valve solved the situation without demolition – the heater on the wall next to the bathtub, the valve with hoses and a shower on the side wall of the bathtub. The electrician ran the wiring along the surface, without cutting grooves. Overall costs were significantly lower than the installation of a storage heater and new piping.

Wall-Mounted Valve: For Freestanding Sink or Bathtub with Higher Valve

The wall-mounted valve – sometimes also called a standpipe or column valve – is a valve that does not sit on the edge of the sink, but is mounted directly on the floor (for freestanding bathtubs) or on a higher base (stand) next to the sink. It is characterized by its height, respectively longer plumbing taps and shape, which visually dominates the bathroom space.

In HAKL PL IconicLine sets, the wall-mounted valve has a height of 22 cm, which is a standard height for compact installations on sinks with single or triple-hole connections. This valve is suitable especially for bathroom sinks with a lower rim, where the standard height of a sink valve would appear unnecessarily high, or for design-oriented bathrooms, where emphasis is placed on aesthetics and the vertical line of the appliance.

Practical example: the customer renovated a bathroom with a freestanding sink from a store with a toilet fixture. The sink had a 35 mm hole for the valve in the center, without side holes. A standard 20 cm sink valve was too short and looked disproportionately small. We installed the HAKL PL SET 3.5kW with a classic wall-mounted valve 22cm IconicLine, which visually matched the overall height of the sink much better. Technically, it is the same construction – just a different geometry of the valve.

Comparison of Valve Types – Table of Dimensions and Uses

Valve Type	Outlet Height	Connection Spacing	Typical Use	Set Power
Sink (20 cm)	20 cm	standard 15–16 cm	Kitchen sink, bathroom sink	3.5 kW / 4.5 kW
Bathtub (18/150 cm)	18 cm (wall-mounted)	18 cm	Bathtub – showering with a handheld shower	4.5 kW / 5.5 kW
Wall-mounted (22 cm)	22 cm	standard 15–16 cm	Freestanding sink, design-oriented bathroom	3.5 kW

Choosing by Power: 3.5 kW, 4.5 kW or 5.5 kW?

The power of the heater is not a matter of taste, but of physics. A simple equation applies: the higher the water flow you want to heat and the greater the temperature jump you need (the difference between the cold water from the water supply and the desired temperature at the outlet), the higher the power you need. A more detailed discussion of this topic is covered in a separate article in this Knowledge Center: What power of flow heater do I need for a sink, bathtub or wall-mounted valve?

Practical rule for choosing a set with a valve:

3.5 kW – sink or wall-mounted valve: Suitable for hand washing and light dishwashing. The water at the outlet will be pleasantly warm at a flow rate of about 2.5 – 3 l/min, if the incoming cold water is 10–15°C. In winter (cold water 5–8°C), the outlet temperature will be lower or the flow rate will need to be reduced. For a kitchen sink in an apartment with central heating, this is acceptable.
4.5 kW – sink or bathtub valve: Better comfort, higher temperature at the same flow rate or the same temperature at a higher flow rate. Suitable for a kitchen where you want really hot water for dishwashing or for showering with a handheld shower in summer.
5.5 kW – bathtub valve: Recommended for showering with a handheld shower throughout the year, including winter months. In mountainous areas or in family homes with a well, where cold water can have a temperature of as low as 4°C, this is the minimum for comfortable showering.

Differences between individual power levels are elaborated in the article Differences between HAKL PL 3.5 kW, 4.5 kW and 5.5 kW sets: when a lower power is sufficient, where you will also find specific temperature tables.

Electrical requirements: what must your installation meet?

This is an aspect that is most often overlooked when choosing a water heater – and then comes the surprise during installation. Each heater power has specific electrical requirements. These are detailed in the article What electrical requirements does a 3.5–5.5 kW flow heater have and what must the home installation meet? I will list only the basic parameters here:

3.5 kW: Single-phase supply 230 V, current draw approx. 15.2 A. Requires a separate circuit with a C16 circuit breaker and 2.5 mm² cables. It can usually be connected to a standard socket network if the appropriate circuit is available – but always consult an electrician.
4.5 kW: Single-phase 230 V, current draw approx. 19.6 A. Requires a C20 circuit breaker and at least 2.5 mm² cables, ideally 4 mm² for longer runs. A separate circuit is essential.
5.5 kW: Single-phase 230 V, current draw approx. 23.9 A. Circuit breaker C25, cables at least 4 mm². An electrician is truly irreplaceable here – not every home distribution board can handle this easily without modifications.

Practical impact on the choice of heater: if you only have an existing C16 circuit available, you realistically only have a choice of 3.5 kW sets – that is, a sink or countertop heater. A bathtub heater with a flow heater requires at least 4.5 kW, which means a larger circuit breaker. This is the reason why HAKL PL bathtub heater sets are available only in 4.5 kW and 5.5 kW versions.

Installation: what influences the type of heater?

The type of heater directly determines the method of installation and the extent of construction work. It is good to know this in advance so you can accurately estimate the total cost of the project.

Sink heater – easiest installation

The heater is mounted through an existing hole in the sink (standard 35 mm). The heater hangs on the wall, the connecting hoses are compact and hidden behind the heater. The electrical wiring runs from the distribution board to the heater – most often along the surface or in a groove. Only one cold water connection is needed (supply to the heater). No further hot water connection is required. The entire installation is usually completed in half a day by an experienced plumber.

Bathtub heater – requires wall mounting

The bathtub heater is mounted on the wall, typically 18 cm above the top edge of the tub. It is necessary to ensure watertightness at the point where the faucet passes through the wall (silicone seal, or possibly wall plugs). The connecting hoses run either on the surface or in an installation groove from the heater to the heater. If the tub does not have an existing bathtub heater connection, a new installation or surface piping is required, which increases the installation requirements. The heater is usually placed next to or above the tub on a free wall.

Countertop heater – depends on the sink configuration

The countertop heater uses a central hole in the sink (or is installed on a stand next to the sink). The key is that the hose connections must direct upwards to the heater. For some types of countertop heaters, it is necessary to check whether the space under the sink (in the cabinet) allows a sufficiently short hose route. Details on dimensions and compatibility can be found in the article Classic IconicLine heater: dimensions, spacing and compatibility with various types of sinks and tubs.

Typical scenarios from practice: which set is for whom?

Scenario 1: Kitchen in an apartment without central hot water

Older panel building, hot water is not provided or is expensive and poor quality. The customer wants a simple, cheap and reliable solution for dishwashing and handwashing. Choice: 20 cm sink heater, power 3.5 kW or 4.5 kW depending on the available electrical circuit. Installation above the existing sink, no demolition required. Low initial costs, zero operating costs for standby heating.

Scenario 2: Bathroom in a cabin or garden house

Cabin bathroom with a bathtub, basic electrical connection, no hot water distribution. Seasonal use (spring–autumn), the cabin is closed during winter. Cold water from a private well has a temperature of 12–14°C in summer. Selection: bathtub mixer with a 4.5 kW heater. For seasonal use, 4.5 kW is fully sufficient, the cold water is not too cold, and showering with a handheld shower will be comfortable. It is necessary to check whether the cabin's electrical connection can handle a C20 circuit breaker.

Scenario 3: Bathroom renovation in a family house with a private well in the Low Tatras

Family house at an altitude of 700 m a.s.l., with a well, cold water in January has a temperature of 4–6°C. A bathroom with a bathtub, showering for the whole family including children. Selection: bathtub mixer with a 5.5 kW heater. Only this power ensures that even in the coldest winter, the shower will be pleasant without drastically limiting the flow. The electrician must ensure a circuit with a C25 circuit breaker and 4 mm² cable.

Scenario 4: Design bathroom with a freestanding sink

The customer is renovating a bathroom with a special urn-style sink on a column, without side holes. They want clean lines, no visible piping. Selection: 22 cm wall-mounted mixer with a 3.5 kW heater. Piping is routed inside the sink column, and the mixer visually complements the overall style of the room. For handwashing, 3.5 kW is fully sufficient.

What to pay attention to before purchase – checklist

Type of sink/basin/bathtub: Check the number and dimensions of the holes, the spacing of the connections, and the available space for the mixer.
Available electrical circuit: Find out what circuit breaker you have available (or what an electrician can install) and determine the maximum power of the heater accordingly.
Temperature of the incoming cold water: It can be significantly lower in winter than in summer – plan for the worst case.
Installation height of the heater: The heater must be as close as possible to the mixer to keep the connecting hoses as short as possible and minimize heat loss.
Water pressure in the connection: Flow-through heaters require a minimum pressure (usually 0.3–0.5 bar) to start heating. Too low pressure = the heater will not start. More details in the article Common faults of flow heater + mixer sets: low pressure, cold water, dripping.
Water hardness: In areas with hard water, limescale forms faster in the heat exchanger. Consider using a water softener or regular descaling – more in the article Maintenance and cleaning of flow heater with a classic mixer: how to extend the lifespan of the set.

Most frequently asked questions (FAQ)

Can I use a sink mixer on a bathtub or vice versa, a bathtub mixer on a sink?

Technically, this exchange is not suitable. A bathtub mixer is designed for wall mounting and has a hose with a handheld shower – on a sink, it looks unnatural and uncomfortable. A sink mixer, on the other hand, does not have a hose with a shower, so it does not provide the function of a handheld shower when used on a bathtub. In addition, the dimensions and spacing may differ. Always use a mixer intended for the specific type of fixture – combinations in HAKL PL sets are pre-matched.

Is a 4.5 kW flow heater really sufficient for showering?

It depends on the temperature of the incoming cold water and the desired shower temperature. At 12°C cold water and a desired shower temperature of 38°C, a 4.5 kW heater can heat about 3.2 l/min, which is functional but modest. If you want comfortable showering with a flow of 5–6 l/min, you will need 5.5 kW or more. For summer months or occasional showering, 4.5 kW is practically sufficient.

Can I install the HAKL PL set myself, without a plumber or electrician?

The hydraulic part (mixer, connecting hoses, water supply valves) can be handled by a skilled DIY enthusiast following the procedure. The electrical part – connecting the heater to the home network – must be done by a qualified electrician, otherwise you have a serious safety issue and void the warranty. The installation procedure can be found in the article Installation of a flow heater + classic mixer set: procedure, water and electricity connection.

Why do sets with a bathtub mixer start from 4.5 kW and not 3.5 kW?

A bathtub mixer is primarily for showering – and a shower requires a higher water flow than a sink. At the flow rate needed for a comfortable shower (minimum 3–4 l/min), a 3.5 kW heater would not be able to heat the water to a pleasant temperature if the cold water is colder than 15°C. Therefore, the manufacturer HAKL correctly offers bathtub sets starting from 4.5 kW as a realistic minimum for functional use.

How long does it take for hot water to come out after turning on the tap?

Since the heater is installed directly at the mixer and has no tank, the water is heated instantly during the flow. A short distance from the heater to the mixer (typically 20–50 cm) means that hot water arrives within a few seconds after opening the tap. The shorter the hose between the heater and the mixer, the faster the hot water arrives – this is one of the major advantages of the flow system over a central hot water distribution throughout the apartment.

How many years will such a set last without major repairs?

With proper installation, adequate water pressure, and regular descaling (once every 1–2 years in areas with hard water), the HAKL PL flow heater has a lifespan of 8–15 years. The IconicLine mixer is made of brass with a chrome finish, and the seals are replaceable. Practical tips for extending the lifespan can be found in the article Maintenance and cleaning of a flow heater with a classic mixer: how to extend the lifespan of the set.

Conclusion: How to decide quickly and correctly?

If you are facing the choice of a flow heater + classic mixer set and are unsure which type of mixer to choose, answer these three questions:

Where will the set be installed? Kitchen or bathroom sink = sink or wall-mounted mixer. Bathtub = bathtub mixer.
What electrical circuit do you have available? C16 = max. 3.5 kW. C20 = 4.5 kW. C25 = 5.5 kW.
What is the typical temperature of the incoming cold water in the coldest month? Below 8°C = better to choose a higher power. Above 12°C = lower power is sufficient.

Answers to these three questions will clearly indicate which set is right for you. And if you are still unsure, a detailed technical comparison of all parameters can be found in the article How to choose a flow heater + classic mixer set: what to pay attention to, or you can look at specific products – for example, HAKL PL SET 4.5kW with a classic bathtub mixer 18/150cm IconicLine for a bathtub in normal conditions, or HAKL PL SET 3.5kW with a classic sink mixer 20cm IconicLine as an ideal and economical solution for a kitchen sink.

Do you have a question about this topic?

Are you unsure or dealing with a specific situation in your household? Write to us – we are happy to help.