24kW Electric Boiler

Electric boiler 24kW Output options

A 24kW electric boiler is a highly efficient and cost-effective alternative to oil, solid fuel, natural gas, or LPG boiler systems and even electric storage heating.

They are the ideal alternative for properties without mains gas supply and residences with gas boiler limitations or gas boiler restrictions, such as listed buildings or being sited in a bedroom, etc. An electric boiler can be used for a radiator wet central heating system and is also suitable for hot water underfloor heating systems for medium or small properties.

You will require a three-phase electric supply to be able to run the boiler; they do not make a single phase electric boiler at 24 kW of boiler output.

Our range of electric boilers can also be coupled to an indirect hot water storage cylinder to provide domestic hot water for hot water outlets such as showers, bath taps, or sink taps.

Our 24kW electric system boiler option has all the components required for a sealed heating system, such as an expansion vessel and an ErP-compliant modulating pump.

These boilers are not suitable for open-vented systems.

An eco-friendly heating and hot water solution

When you produce (such as a photovoltaic system, i.e., solar panels) or buy renewable electricity or “green” electricity from renewable sources to run your electric boiler, your electric heating system is carbon neutral and not impacting the environment.

When operating electric boilers, they emit no combustion gases or noxious fumes, unlike traditional gas boilers or oil boilers, as there’s no flue requirement with an electric boiler.

Electric boilers, with easier installation, are a very cost-effective alternative to existing tank-based fuels such as oil or LPG boilers and heat pumps. Air source heat pumps are expensive, and ground source heat pumps even more so, as the installation costs are extreme, to say the least, especially when compared to electric boiler installation costs, even when an upgrade to a three phase electric power supply is required.

Benefits

• Compact units compared to typical oil, solid fuel, or gas system boilers
• No mains gas supply to run to the boiler, only electrical cables.
• No bulky external tank that you require when heating with oil or LPG systems.
• Operates quietly—virtually silent
• No chimney or venting system is needed, making them a perfect solution for listed buildings or medium to small properties that may have gas boiler restrictions.
• No danger of carbon monoxide poisoning; there is zero risk.
• Superior inner design that includes a built-in pump for sufficient flow rates for radiators or underfloor heating circuit and an expansion vessel for the heating system
• Suitable for wet central heating, either radiator or underfloor heating systems
• Can produce domestic hot water via an indirect hot water cylinder for sufficient flow rates to serve your hot water outlets.
• Easy-to-use touch screen control panel interface for superior performance
• Can be used with renewable electricity from renewable sources such as photovoltaic system, wind or water generated electricity etc.
• Operating temperatures up to 80 °C
• Running costs are reduced due to the high modulation of the heating system.
• Electric boilers are a very cost-effective alternative to heat pumps, gas and oil boilers, or electric storage heating.
• When operating electric boilers emit no harmful gases, fumes, or pollutants.
• Warranty – 2 years
• Only suitable for properties with three phase electrical supplies

24kW Electric Combi Boiler

We also offer a 24kW electric combi boiler, a boiler capable of providing space heating and instantaneous domestic hot water. You can find this electric combi boiler range from Flexiheat UK on its dedicated webpage – electric combi boiler range from Flexiheat UK. Please note that you will require a three-phase electric power supply to run an effective electric combi boiler. Our 24kW electric combi boiler will produce an instantaneous domestic hot water flow rate of 12.8 litres per minute with a temperature rise of 30 °C (the DHW temperature outputs range are adjustable from 30 °C to 55 °C). This flow rate is sufficient to fill a bath tub in a suitable timescale. They do not make a 24kw electric combi boiler in single phase.

Electric combi boilers really require a 3 phase power supply to produce an adequate domestic hot water flow rate. It’s as simple as that.

24 kW Electric boiler outputs options

The first question is why a 24kW boiler? Well traditionally the smallest gas boilers were 24kW in output and many people assume that this is the smallest boiler available in electric. This is not true, as they go all the way from the smallest output of 0.5 kW all the way up to 45kW for our domestic size electric heating boilers.

So, if you’re replacing a gas or oil boiler that’s 24kW – then the first thing you should do is check that this boiler isn’t oversized for your location – please see this webpage for guidance – What size electric boiler do I need?

We have a couple of options for around 24kW of output – these are

Our Model FHEL23, which is a fully modulating boiler – this unit has a maximum output of 22.5 kW – and will ramp up and down the following outputs to suit the heating demand of the system. Modulation range / power steps = 2.5,5,7.5,10,12.5,15,17.5,20 or 22.5kW

FHEL23 boiler, with low heat output modulation – Output can be set to either – 2.5,5,7.5,10,12.5,15,17.5,20 or 22.5kW

The second option is our FHEL30 unit – this unit’s maximum heating power is 30kW – however this unit can be set to a maximum of 25kW output, so ever slightly over the 24kW, and the unit will ramp up and down this scale to suit the heating demand.

Output can be set to either 5,7.5,10,15,17.5,20,25,27.5 or 30kW

Please note – a heating expansion vessel need to be fitted external to the unit for this size boiler to make it a system boiler

The Amps required to power the unit at 25kW output is calculated as follows –

For Three Phase /415 Volt / 50 Hertz AC Circuit, that we use in the UK, then the calculation is –

Amps = (kW × 1,000) ÷ (√3 × volts)

Amps = (25 × 1,000) ÷ (1.73 × 415)

Amps = 25000 ÷ 717.95

Amps = 34.82 Per Phase – on the three phases of the electricity supply

Plus, you want to and the pump electricity requirements of one Amp per phase (3 Amps in total)

Thus, the maximum total electrical consumption would be 35.82 ( call it 36 Amps) per phase

The full brochure on these units is here –

Flexiheat Brochure For Electric Boilers

and the installation and technical manual is here –

Flexiheat Electric Central Heating Boilers – Installation & User Manual – FHEL Boilers

Domestic hot water production

Heating hot water for sanitary use – by using the heating electric boiler in conjunction with an indirect domestic hot water tank, you can supply plentiful amounts of domestic hot water for your bathing needs, be it showering, filling a bath, or washing up in the kitchen.

This hot water system ensures that the electric boiler does both your heating system and domestic hot water—the wet central electric heating system, be it radiators, underfloor heating, or a mixture of both and the domestic hot water via indirect cylinders. We refer to electric boilers in these circumstances as system boilers.

A diagram showing how an electric central heating boiler is connected to a Domestic Hot Water Cylinder or Hot Water Tank

Control options

Using an appropriate controller on our electric boilers can produce superior performance and lower monthly running costs.

OpenTherm is a communication protocol between heating controls and the boiler to modulate the temperature flow through a heating system.

Since it’s a standard protocol, any “OpenTherm” controller, such as Nest, Hive, Honeywell, Drayton, etc., can work with our electric boilers. There are so many manufacturers now that if the controller says “OpenTherm,” it will work and help reduce running cost.

Contact us

Should you require further assistance or information on the best 24kW electric boiler on the UK market, that we normally have in stock for express delivery or standard delivery then please contact our sales team on 01202 822221 or click here for our email contact form.

Whole house electric tankless water heater UK

Whole house electric tankless water heaters from Flexiheat UK an alternative or replacement for tank-type water heaters

A whole house electric tankless water heater has become highly desirable in the UK due to its ability to provide unlimited domestic hot water instantly, without any waiting time or the need for water storage. Instantaneous water heaters have a compact design and can be easily installed in tight spaces, such as a kitchen cupboard or something similar.

While the statements above are correct, it is important to recognise some limitations, such as the limit on the number of outlets that can be used simultaneously with instant hot water heaters, the need for close proximity to hot water outlets, and the need for a three-phase electric supply to power a whole home’s energy-efficient tankless water heater.

Key Point

1. You require a 3 phase power supply to have a viable whole house electric tankless water heater in the UK

Energy efficient water heating

With rising energy prices, many homeowners in the UK are looking for ways to cut energy costs and make their homes more energy efficient. One way to do this is by installing an electric tankless water heater, also known as an instantaneous water heater or demand-type water heater, is one way to do this. Tankless water heaters provide domestic hot water instantly, as needed, eliminating the need to constantly heat and reheat a tank of water like traditional tank-type water heaters. This can lead to significant energy savings, making whole house electric tankless water heaters an attractive option for eco-conscious homeowners.

How do tankless water heaters work?

Tankless water heaters work differently than traditional water heaters that use a storage tank. When you turn on a hot water tap, cold water travels into the tankless unit. Inside the unit, an electric element heats the water instantaneously before sending it to the tap or shower. The unit directly heats the water without storing it, ensuring you never run out of hot water. Even when hot water isn’t in use, traditional water heaters with storage tanks must constantly reheat and maintain water temperature, resulting in energy waste.

Benefits of whole house electric instant water heaters

There are several key benefits that make whole house electric tankless water heaters a smart choice in UK homes:

Energy efficient hot water

Instantaneous water heaters only heat water when needed, rather than maintaining a whole tank of water at temperature constantly. This results in major energy savings compared to traditional water heaters. Homeowners can save 20% to 60% on water heating costs.

Continuous domestic hot water

Instantaneous water heaters provide an unlimited supply of hot water on demand. You’ll never run out of hot water for showers, washing dishes, doing laundry, and more. The water heater activates when hot water is needed and shuts off when not in use.

Space Savings

Instantaneous water heaters are compact and mount on a wall, freeing up floor space that standard storage hot water cylinders water heaters use. This makes them a great choice for smaller homes or properties, such as flats, etc.

Long Lasting

Tankless heaters last up to 20 years, twice as long as traditional storage hot water cylinders. The lack of a water storage tank increases their lifespan as you heat water on demand

Environmentally Friendly

The energy efficiency of tankless heaters means lower carbon emissions. Less electricity is required for water heating.

Safety

With no hot water storage tank that standard water heaters have, there is less risk of leaks or rusting. Tankless water heaters are safer, provide more reliable hot water, are easier to install, and are space saving.

Factors to consider when choosing an entire house tankless unit

If you’re considering switching to a whole house tankless water heater, there are a few important factors to take into account:

Power Rating: The correct power rating ensures that your tankless unit can handle your household’s hot water demand. Look for a power rating of 18–27 kW for a whole house appliance or even 36kW depending on your demands.

Flow Rate: The water flow rate, measured in litres per minute (LPM), must meet your household’s peak hot water needs. The electric water heater appliance’s power ratings directly influence the heated water flow rate’s capacity or output.

A standard shower head has a hot water demand of 7 or 8 litres a minute

Please be aware drench showers – can have some huge flow rates from 15 litres to pretty much any flow rate – 30 litres per minute is not uncommon.

Kitchen sink taps – 4 to 6 litres per minute

Sink taps – 4 litres per minute – standard type.

Basin / cloakroom “spray taps” – 2 litres per minute – these water saving spray taps, are very popular now, as they save water and energy requirements.

Bath mixer taps – modern bath taps have an approximate demand rate of 12 Litres per minute.

So be adding all your potential hot water outlets demand, then applying a diversity factor (a factor that not all the hot water outlets will be used at the same time) you can calculate your hot water demand.

Energy Source: Electric tankless heaters often make the most sense for UK homes. Make sure your electric system can handle the power demands.

Size: Choose the appropriate size tankless heater for your home’s water heating demands, number of bathrooms, etc. An undersized unit won’t meet your hot water needs.

Location: Pick an appropriate indoor location with adequate space and accessibility.

Efficiency Rating: Look for a high energy efficiency rating to maximise savings.

Product range

Our electric tankless hot water heaters have four power ratings, or output ranges, in “one” tankless water heater unit. Except for the 27kW and 36kW electric instantaneous water heaters, which feature a single power setting.

For example, our 9kW to 15kW electric instant water heater allows consumers to pick power ratings of 9kW, 11kW, 12kW, or 15kW in one model, while our 17kW to 24kW instant water heater may be adjusted to 17kW, 18kW, 21kW, or 24kW output.

The cold water mains temperature at the deepest winter times is typically 10 degrees Celsius, thus an average temperature rise of 30 degrees Celsius is necessary to provide hot water for usage in the winter months. The data below shows the performance at a temperature rise or Δt = 30

Please note that this range of compact instantaneous water heaters requires a minimum flow of 2.5 litres per minute to start heating the water. If the flow rate is lower than this point, they will not operate.

Our 9kW to 27kW instantaneous water heaters feature a LCD display showing the tankless water heaters set temperature

The digital display on 9kw to 27kW , showing the hot water temperature set on the water heater

and our 36kW tankless water heater has a traditional temperature dial and look like this

36 kW Electric instant water heater

Benefits of Going Tankless for Whole House Water Heating

Switching to a whole house electric tankless water heater provides a range of benefits:

• Save significantly on energy costs by only heating water on demand
• Enjoy hot water with an unlimited supply of continuous hot water for all your needs
• Free up extra space by eliminating a storage electric water heater
• Reduce your home’s environmental impact with an energy efficient system
• Enjoy convenience, reliability, and safety with an electric on demand hot water tankless unit
• Get a long-lasting water heater that will serve your property for many years

By going tankless for your whole house, you can gain energy savings, unlimited hot water, extra space, and peace of mind knowing you have an eco-friendly, highly efficient water heating solution meeting your household’s needs.

Installing Your New Tankless Water Heater

Once you select the right electric tankless water heater model for your home, hire a qualified plumber for installation. Proper installation is key to maximising efficiency and providing hot water performance. Key steps include:

• Select an appropriate indoor location that allows access to the instant hot water heater; they are a very compact design, so this shouldn’t be an issue.
• Make any necessary electrical upgrades to handle the instant hot water heater requirements.
• Electricity supply: ensure you have properly sized electric cables and breakers.
• Connect the water supply pipes with components such as isolating valves and a filter on the cold water feed to the water heater.
• Insulate water pipes to limit heat loss to sinks or the shower.
• With a tankless water heater tailored to your specific home set-up, you’ll get the right choice with superior function without wasting energy and benefiting from energy savings for years to come.

Going tankless is the smart choice

With rising energy prices, whole house electric tankless water heaters make increasing sense for eco-friendly UK homeowners looking to save on costs. By only heating water on demand, tankless heaters provide endless hot water while being much more energy efficient than traditional storage tank heaters. Choosing the right size unit with professional installation provides a long-lasting, highly effective hot water solution with no standby energy losses and reduced energy consumption. Going tankless can make your UK home more sustainable while cutting your energy bills. It’s the smart choice to enjoy reliable heated water whenever you need it.

So if you require a price, check stock or to purchase one of electric water heaters for entire home hot water needs please contact us on 01202 822221 or use the email contact form .

Condensing water heaters

Condensing water heaters have become the norm since Part L of the UK building regulations came into force in June 2022.

The more stringent water heater requirements of the Part L building regulations apply to both newly built and existing non-domestic building stock.

This basically eliminates the option to swap out existing non-condensing water heaters with the same type of water heater. Any replacement hot water heaters must utilise condensing technology within the domestic hot water heater to produce savings on both a monetary and emission level i.e., carbon emissions, as a condensing water heater will deliver cutting edge efficiencies.

A low emission level hot water system helps the UK achieve our drive to a lower carbon economy and ErP compliant condensing water heaters help this.

However, in the rare event that the Building Control authority determines that replacing a non condensing gas fired water heater water is not suitable or feasible in non domestic buildings, a minimum seasonal efficiency of 80% for natural gas or 79% for LPG may be utilised.

But there are very few circumstances in which you can’t use a condensing water heater, to be fair, so these exceptions would literally be “once in a blue moon,” as they say, if at all.

The energy efficiency benefits of condensing water heaters now mean that the residential hot water systems market has also rapidly moved to this type of water heater’s installation, as they deliver cutting edge efficiencies and produce savings on your water heating bills.

As of yet, there are no regulatory requirements to use a gas fired condensing water heater in a domestic property, but the economic benefits of using less gas to produce domestic hot water for a home or flat through higher efficiency alone have driven the domestic market this way.

However, the commercial hot water regulations or the commercial water heaters market often lead with regards to regulations, and the domestic market then follows, so we can envisage that condensing water heaters will soon be mandatory in this sector before long.

Energy efficient water heating

Condensing gas fired water heaters have a hot water efficiency level of up to 105%. Which is essentially an extra 12 to 15% more performance than an older gas fired non condensing water heater.

A second heat exchanger in a condensing water heater preheats the incoming cold water by using waste heat from the exhaust gases. This process lowers the exhaust gas temperature, boosts energy efficiency, and increases the hot water flow rates of the water heaters.

A cooler exhaust allows for additional possibilities for flueing materials, such as polypropylene plastic flues. Condensing gas fired water heaters need to dispose of the acidic condensation water through a drain and possibly a pH neutralizer because water vapour condenses inside the appliance when the exhaust gas cools, and this is acidic in nature.

Gas fired water heaters

We have a large, high efficiency gas fired condensing water heater range that are direct fired water heaters for small or high hot water demand that can be required in commercial or industrial hot water heating applications such as hotels, leisure centres, and hospitals.

Wall hung water heaters

SFC or SFK Condensing water heaters range – in natural gas or LPG

Our wall hung condensing water heaters range consists of three models a 28kW, 34 kW or 50 kW output water heaters.

These water heaters benefit from various flueing options: horizontal or vertical flue systems, room sealed or conventional flued with various flue terminal options for easy installation.

The two smallest water heaters come with the option of a pump for a domestic hot water recirculation system (designated the SFK model) or without a pump (our SFC version) for straight through water heating, which are the most common appliances we sell. The larger 50kW model comes with a pump as standard, which is capable of being turned off for straight through direct water heating.

With a large 28mm single-pipe coil heat exchanger made of stainless steel, the “SFC” or “SFK” condensing water heater range benefits from very low pressure drops, less chance of blockage, increased thermal efficiency and easier cleaning and delivers high volumes of temperature accurate hot water. Other safety features such as protection to IPX5D rating are standard.

There is no water storage within these units, so there is no heat loss compared to a storage water heating system.

This is the basic rule: the higher the kW output, the higher the DHW flow rate performance

When heating cold water to a certain temperature, this is known as the temperature rise or Delta T (shown as Δt in the charts below). The normal bathing or showering water temperature is 38°C to 40°C, depending on personal preference.

For winter performance

We recommend sizing the water heater on a Delta T of 30 degrees C, shown as “Δt 30” for the majority of the UK, in Scotland, we recommend using “Δt 35”.

During the summer period

You can use “Δt 20” as the temperature rise.

SFK or SFC 28kW Gas fired condensing tankless water heater

Download the SFC 28kW Gas condensing water heater with no pump manual

Or with pump for hot water recirculation systems

Download the SFK 28kW Condensing water heater with pump manual 

SFK or SFC 34kW Gas fired condensing tankless water heater

Download the SFC 34kW Gas condensing water heater manual with no pump manual

Or with pump for hot water recirculation systems

Download the SFK  34kW Condensing water heater with pump manual 

SFK 50kW Gas fired condensing tankless water heater

Download the SFK  50kW Condensing water heater with pump manual 

Please be aware that the highest temperature that the water temperature can be set to is 60 degrees Celsius on the standard water heaters ; on request, we can, however, build a higher temperature unit that can reach up to 85 degrees Celsius. These water heaters are frequently used for the pasteurisation process in the dairy and farming industries, as well as in other applications that call for high-temperature washdowns and water for process applications.

For high demand hot water heating that commercial applications can require, these high efficiency commercial water heaters can be used in cascade for example- we go into more depth on the of this type installation here – Commercial gas water heaters

These on demand high efficiency gas water heaters have various essential safety features, and can be used to top up heat-pump water heaters, which can struggle to achieve the desired water temperatures.

Control options

You can set the water temperature on the control panel of the water heater; however, should you wish the facility to change the water temperature, then we have a remote controller that you can site in your kitchen to boost the water temperature to 50 °C for dishwashing, which is the recommended temperature for removing grease from cooking utensils and dishes.

Easy remote controller – Wired – for our condensing water heaters from Flexiheat UK

Storage options

We also supply three condensing storage tank water heaters options – which are available as either LPG or natural gas fired water heater and are all ErP compliant water heaters.

We do a 50kW water heater option with a 330-liter storage cylinder

Gas water heaters with storage systems for high volumes at intermittent times demand. These ErP compliant condensing water heaters are energy efficient and cost effective to run.

A 34kW water heater option with a 150 Litre stainless steel storage cylinder

or a 28kW water heater option with a 150 Litre stainless steel storage cylinder

SFKA 28 or 34 KW Output models – Natural gas or LPG powered

We go into more depth on these storage condensing water heaters that are often used in commercial buildings here – Condensing gas hot water tanks or cylinders

Where are condensing water heaters used?

Everywhere, from residential and smaller business settings such as homes, cafes, hair salons, bed and breakfasts establishments to industrial and large commercial applications such as sports complexes, hospitals, colleges, or schools, we have a complete range of high-efficiency water heaters for every warm water heating requirement.

Contact us

Should you require anymore assistance, information, check stock or get a price / cost on our effective (both in a monetary and emission level) condensing water heaters range please contact our customer services sales team on 01202 822221 or use our email contact above on the web page.

Electric System Boiler – Electric Wet Heating Systems

What is an electric system boiler? – In contrast to a conventional electric boiler, which just contains a heat exchanger or chamber, a system boiler incorporates an expansion vessel as well as a circulating pump within the boiler. So, you have all the required components for a sealed wet heating system, also known as an unvented heating system.

Because of the way that an electric boiler system is constructed, there is no requirement for a feed and expansion system in the roof area or circulating pumps exterior to the electric boiler.

The fundamental difference between a system boiler and a regular boiler is how it is constructed.

Types of electric boilers

The earliest boilers ever developed for central heating systems were regular boilers, often known as traditional, conventional, or heat-only boilers.

Due to the low system pressure required by these older types of boilers, they are often supplied via a feed and expansion cistern in the attic, which is known as an open-vent heating system.

With a system boiler, installation is also quicker, simpler, and more efficient thanks to the built-in components, i.e., the heating expansion vessel and a pump.

The boiler’s compact design makes it excellent for heating applications when space is limited, as having the pump and expansion vessel within the boiler casing will eliminate unnecessary external plumbing that would be required if these items were separate components.

The last type of electric boilers are electric combi boilers, which do heating and domestic hot water on demand and these are detailed on this webpage – electric combi boilers

System boilers: electric

Electric system boilers for a wet central heating system are by far the most popular electric central heating boilers, just like they are for gas and oil boilers these days. As sealed heating systems offer many benefits to the customer.

No feed and expansion tanks that must be cleaned on a regular basis; no letting oxygen into the heating system water, which will promote corrosion. To prevent freezing, the pipes from the tank position to the boiler will need to be insulated when using an open vented central heating system.

A central heating electric boiler provides heat for a building

Electric boilers are an energy-efficient alternative to gas or oil boilers for home heating, as an electric central heating boiler has 100% energy efficiency for the immersion heater or heaters . A gas or oil boiler, even a condensing gas boiler, is 90–91% efficient at full condensation efficiency.

Electric boilers

Electric boilers work in a very similar way to gas and oil boilers in that they produce heat via immersion heaters, that is imparted into the hot water of the heating system, providing central heating via radiators or underfloor heating systems for small properties or larger homes.

Our Full Range of System Boilers

First, our touch-screen range of electric system boilers. This range of electric boilers has a fully touch-screen controller (like a mobile phone screen) and can also be controlled by a thermostat, programmer, or suitable “OpenTherm” compatible controller such as your Nest or Hive controllers, which allows you to control the system boiler via the controller or a mobile phone, so you can control your heating form anywhere in the world if you have Wi-Fi and an internet connection.

Touch screen range of electric hydronic boilers

These electric system boilers have the lowest power steps on the UK and Irish markets; for example, the FHEL5, which has a maximum output of 4.5kW, has 500 watt or 0.5 kW power increments or steps, which means the boiler will modulate up and down from 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, or 4.5kW, which ensures maximum efficiency by closely matching the central heating and domestic hot water requirements when using an indirect hot water cylinder.

Users can set the maximum output of the electric boiler to one of the power output levels, and the boiler will modulate up and down to that set level. E.g., the FHEL 5 can be set to 3.5 kw maximum output, and the boiler will ramp up and down to that kW output point.

The FHEL9 modulates up and down the power steps in 1 kW increments, thus 1, 2, 3, 4, 5, 6, 7, 8, or 9 kW outputs. The same applies as above, and this applies to all of this electric boiler range.

And finally, the FHEL14, which has a maximum output of 13.5 kW, modulates up and down the power steps in 1.5 kW increments, thus 1.5, 3, 4.5, 6, 7.5, 9, 10.5, 12, or 13.5 kW. The same applies to the boiler, which can be set to a particular desired output kW value and will ramp up and down to this value.

Touch series electric boilers for underfloor heating or radiators central heating – can be powered by either a single phase or three phase electrical supply.

Next is our standard series of electric system boilers:

Electric heating boiler from Flexiheat UK – Standard Series – From 2.5kW to 45kW Output

These electric boilers still have a touch control panel, but it’s a partial one that’s still easy and intuitive to use.

Electric boilers standard series from Flexiheat UK

Please note the following:

• After 15 kW, i.e., our 22.5 kW to 45 kW electric boilers, require an electrical three phase supply -3 Phase 400 volts, 50 Hz.

• The 30 kW and larger size electric boilers—we physically don’t have the space within the boiler casing to fit an expansion vessel, but come with the pump integral to the boiler, so you have to fit an expansion vessel external to the boiler (by others) to complete the sealed system and make them system boilers.

Electric Central Heating Boilers – Standard Series- Technical data HVAC  – Flexiheat UK

The 7.5kW to 22.5kW electric system boilers modulate in 2.5kW power steps.

• The FHEL8 has only 3 power steps on this unit, and the output can be set to either 2.5, 5 or 7.5 kW. Use the FHEL9; it’s a much better boiler.

• The FHEL15 Electric Boiler’s outputs can be set to either 2.5, 5, 7.5, 10, 12.5, or 15 kW.

• The FHEL23 Electric Boiler’s output can be set to either 2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20, or 22.5 kW.

The 30kW and above jump in either 2.5kW or 5kW power steps.

FHEL30 – 30kw Electric Boiler: Output can be set to either 5,7.5,10,15,17.5,20,25,27.5 or 30kW.

FHEL38 – 38kw Electric Boiler: Output can be set to either 5, 10, 12, 5, 17.5, 22.5, 25, 30, 35, or 37.5 kW.

FHEL45 – 45kW Electric Boiler: Output can be set to either 5, 10, 15, 20, 25, 30, 35, 40, or 45 kW.

Download the Flexiheat Brochure For Electric System Boilers

Central heating with sustainable energy

When the electricity supplying your electric system boiler comes from renewable energy sources such as wind turbines, solar PV systems, or wave or water generated electricity systems, you are eliminating your carbon emissions, or at least reducing your carbon footprint, as well as reducing your running costs for your heating and hot water if you generate this electricity yourself.

Are electric boilers efficient compared to a gas boiler?

Yes, electric boilers achieve 100% efficiency by directly converting all the electricity that powers the heating element or elements into heating energy. Sometimes people refer to the overall efficiency as 99.9%, as the control panel of the boiler uses a minute amount of electricity.

A gas condensing boiler efficiency rate can reach up to 90–91% at full condensation (80% from fuel burning and 11% from flue gas condensation) when run at very low return temperatures.

Three phase electricity supply

When you have a three phase electric supply, you can install larger kW output electric boilers, as you have amps available in the electricity to power the electric boiler. We can go all the way up to 45 kW of heating element output.

Alternatives to gas boilers

Electric central heating boilers, especially electric system boilers, are a great replacement for traditional gas boilers, whether it be as a replacement or for a new installation. The benefits are:

• No combustion takes place in an electric boiler; thus, no flue system is required with an electric boiler to flue the products of combustion that gas boilers installed produce.

• A gas boiler has to be placed in certain locations, often to comply with flue system regulations—often on a wall that has external access so the flue can go straight out the wall—but with an electric boiler, you can locate them pretty much anywhere you want.

• No gas supply means there is no chance of gas leaks.

• There is no risk of carbon dioxide poisoning with an electric boiler installation.

• Carbon emissions: gas boilers produce CO2 as well as NOx as they use fossil fuel.

• If you use electricity to power your electric system boilers with renewable sources such as solar PV, wind turbines, or just purchase electricity that is produced by renewable sources, then you can reduce your carbon footprint or even have none at all for your central heating boiler.

• Quiet operation: electric boilers are virtually silent, i.e., you can’t hear the heating element or elements heating the hot water in an electric water heating system.

• Electric control panel: our electric boiler range has an inbuilt control panel that can be controlled by a thermostat or programmer. This can be an “OpenTherm” controller, such as a nest or hive type, allowing you to control these electric boilers from a phone, iPad, or computer as long as you have Wi-Fi or internet access.

What size of electric system boiler do you need?

We have a dedicated webpage on this which is here – what size electric boiler do I need ?

Who should consider an electric boiler?

Anyone who wants to have a wet central heating system but doesn’t have a gas supply or doesn’t want an oil tank at home. They are also a good alternative to a heat pump, in particular an air source heat pump in retrofit boiler replacement in wet central heating systems where the radiators, pipework, etc. were previously sized on the traditional flow and return temperatures of 82C/71C flow and return temperatures.

Most heat pump heating systems struggle to produce hot water over 55 °C, requiring the replacement of heat emitters, i.e., radiators, with units that can be up to four times larger and upsizing of pipework to accommodate the required flow rates for heating water. This issue also affects the demand for the domestic hot water tank demand, as domestic hot water needs to be stored at 60 °C to prevent legionella bacteria; thus, an immersion heating element or immersion heater is required to power the domestic hot water to this temperature.

Thus, in older properties, the additional cost of upgrading the wet heating system is prohibitive to many home owners, as the cost of materials and the cost of labour to fit all of the above will run into many thousands (even tens of thousands) of pounds.

This is where electric system boilers, when replacing a gas boiler for home heating and domestic hot water, are a suitable replacement with an easy install, as no heat emitters or pipework needs to be changed.

Electric system boilers for hot water and central heating

Electric system boilers can be installed anywhere in the house, are easy to operate, free from offensive fumes, do not need regular gas checks, do not require the installation of a flue, and have very few moving parts, minimizing the chances of malfunction. Get in contact with us for the best range of electric system boilers on the UK and Irish markets.