What Are Electric Combi Boilers and What Are Their Advantages

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When we say “electric boiler” most people will think about the undersink boilers used to get instant hot water in a single tap where pipework installation would be inconvenient. However, there are electric combi boilers available too.

As the name suggests, it’s an alternative to a gas combi boiler only it uses electricity as the energy source. Although the technology is almost as old as the invention of electricity, only recently have the electric boilers seen an increased interest from customers whose properties are not served by the gas grid or who simply want to get rid of their gas supply and convert to a greener energy source.

As we all know, natural gas is a fossil fuel so it can’t be considered green. As for electricity, if your power supplier uses renewable sources or you have solar cells on the roof, you can go completely green. Using electric combi boilers makes a lot of sense to people who have equipped their houses with solar cells. Up to recently, the concerns about heating was the only barrier for people to make the leap of faith and go off the grid.

One of the main advantages apart from having a potential to be eco-friendly, an electric boiler is smaller than an equivalent gas boiler so it will fit in your kitchen cupboard or other narrow spaces where you previously struggled to fit a gas boiler.

Electric Combi Boilers

Price-wise, they are no different than their gas alternatives with prices hovering around the £1,500 and £2,000 mark. Heat-only electric boilers are much cheaper than that – just around £400. The installation cost for a typical electric combi boiler can be comparable to the gas alternative but it may actually incur additional costs because some older heating systems may require an upgrade to make sure that radiators further from the boiler can heat up in a timely manner. The only way to find out is to get about

Electric boilers are a popular choice in high-rise buildings because they don’t need a flue. Getting a boiler replaced on the 5th floor or above might prove a very costly job because we would have to erect scaffolding to be able to work on the flue. This is, unfortunately, completely out of reach for a large portion of people living in multi-storey apartment buildings. There is no such issue if you choose an electric combi boiler. It doesn’t need a flue and can be installed as high as on the top floor of a sky-scraper. All it needs is water supply and electric feed and you’re sorted.

Also, from the point of view of safety and maintenance, electric alternatives have an edge. You can’t control the temperature of a gas flame. With natural gas, the average temperature inside the flame is 1960 degrees. With such extreme temperatures, heat exchangers and other parts are subject to overheating and excessive wear. There is no such problem with electrical heating elements – electricity allows you to regulate temperature precisely, so the boiler parts never heat up more than it’s actually required. It’s very rare for an electric boiler to develop mechanical faults – something that can’t be said about gas boilers.

Unlike some other big name companies, who don’t yet install electric boilers, we at Glow Green do. If you think your home would benefit from an electric boiler, give us a call on 0330 113 9488 and speak to one of our advisors to discuss your options.

What electric boiler brands are available?

The main brands currently on the UK market are Elnur Mattira, Heatrae Sadia Electromax, Thermaflow and EK.C Elektra. Only Elnur and EK.C are wall-mounted. The rest of them are too heavy so they are floor-standing boilers. We at Glow Green work with Elnur Mattira which is a reasonably-priced and well built option with variable outputs ranging from 3 to 15 and 2-year warranty.

People who’ve exprienced on-demand boilers are often worried about the hot water flow rate in electric boilers. The Elnur Mattira incorporates a 50-leater pre-heated water cylinder allowing it to optimise hot water usage and achieve similar flow rate to gas boilers – allowing it to deliver up to 12 litres per minute.

Mattira will work on both single phase or 3-phase power supply. It will work within 3 – 12kW range on single phase and up to 15kW on 3-phase. It also features heating modulation that allows the advanced control board to automatically modulate heating output to match the demand and reduce wasted energy. It re-calculates consumption every 20 seconds and continuously adapts heating output achieving close to 100% energy efficiency.

The table shows some of the technical details of Mattira Combi MAC15 model. For example, on its max setting it takes 5 minutes and 49 seconds to replenish the 50 litre cylinder with hot water.

Selected output, kW567891011121315
kCal per hour4300516060206880774086009460103201118012900
Current, 3-phase13.08.713.013.013.021.721.721.721.721.7
Current, 1-phase21.726.130.434.839.143.547.852.2n/an/a
Domestic hot water recovery time17’26”14’32”12’27”10’54”9’41”8’43”7’56”7’16”6’42”5’49”

Glow Green Electric Combi Boiler Quote

  • Small monthly repayments

    Taking on a New Boiler Pay Monthly plan you can expect a low monthly repayment – £17 per month, £14 per month or even as little as £9.99* dependant upon your credit score and other factors. This is often offset by the monthly savings on your energy bills, a direct result of an energy efficient boiler.

  • Flexible Plans

    We have finance plans to suit your budget. Our plans range from 2 years right up to ten years.

  • 0% Interest Free

    In addition to monthly payments, we also offer 0% interest for up to 2 years.

  • Zero deposit

    Unlike many of our competitors, there are absolutely no upfront payments, and zero deposit on plans between 3 and 10 years.

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What’s Inside an Electric Combi Boiler

List of the main parts and components

  1. Heating elements
  2. Drain valve
  3. Temperature sensor
  4. Connection block
  5. Main oontactor
  6. DHW 7 bar relief valve
  7. Insulated tank 50L
  8. Anti-electrolysis DHW hose
  9. DHW expansion vessel 3L
  10. Automatic purge
  11. DHW power electronic PCB
  12. Heating power electronic PCB
  1. Heating flow detector
  2. Heating expansion vessel 6L
  3. Circulation pump
  4. Insulated heating header tank
  5. Heating resistance
  6. Heating safety thermal limit switch
  7. ON/OFF switch
  8. Heating 3 bar relief valve
  9. Pressure gauge
  10. DHW safety thermal limit switch
  11. Main electronic PCB
electric boiler insides

Pros and Cons

Advantages of Electric combi boilers

1. Built to be green. An electric boiler easily integrates within your existing system. If you’re already using solar cells or solar heating panels, the installation is going to be easy.

2. An opportunity to go off grid completely. You can give up your gas supply and generate your own electricity meaning a total independence and full control.

3. No fossil fuel. You don’t need gas, oil or diesel to power your house.

4. Maximise space! Electric combi boilers are smaller and lighter than their gas counterparts permitting installation in standard kitchen cupboards or narrow spaces that are too awkward to be used for anything else.

5. Enjoy the silence. Electric boilers are silent. The only moving part is a small circulation pump that can’t usually be heard with the cupboard doors shut. No hissing, buzzing, grunting or other noises that are typically associated with a gas boiler.

6. You don’t need a flue, which is great for apartment blocks as you save thousands of pounds on scaffolding cost.

7. Legionella protection. Experts of the HVAC industry are seriously concerned about Legionella bacteria that can affect almost any heating system. Modern electric boilers, such as Elnur Mattira, are equipped with a Legionella protection system that once a week raises the water temperature to maximum to rinse out any Legionella formations that might be building up within the boiler or pipes.

Disadvantages of Electric combi boilers

1. Higher monthly costs unless you produce your own electricity. If you’re feeding off the grid, your heating bill will be higher

2. Lower Energy efficiency rating. You can buy an A-rated gas boiler but you can’t yet buy an A-rated electric boiler. This shouldn’t really matter unless you’re getting a boiler on government grant or another help scheme.

3. Shorter warranty periods. Most electric boilers come with just 2 years warranty. That doesn’t mean they’re all going to break down during their 3rd year, however, you don’t get the same peace of mind as with the major gas boiler brands that give you 10 year warranty.

4. Might not be suitable for older pipework requiring an upgrade to the whole system.

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††Estimated figures based on installing a new A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator controls (TRVs) in a gas-heated detached home from an older boiler without controls. Savings will vary depending on the size and thermal performance of your home. Correct as at May 2015. Source: Energy Saving Trust.

*Representative Example: Cash Price £2,100. Deposit Payable £1,327. Total Amount of Credit £773. Total Interest £425.80. Total Amount Repayable £2,525.80 Repayable by 120 monthly instalments of £9.99. Representative 9.9% APR (fixed). Rate of Interest 9.9% a year (fixed). Duration of Agreement 120 months. Subject to Status

**The 12 year warranty is only available for customers who have a Worcester Bosch boiler supplied and fitted by Glow Green Ltd and is subject to a Glow Care 100 service contract for the 12 year period.