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Electric boiler cost and advice for home heating

22/11/2020

 

What can electric boilers offer homeowners as we move towards low-carbon heating?

For decades electric heating systems have had a reputation as expensive and ineffective. My memories of electric storage heaters go hand in hand with damp living accommodation and black mould. Fortunately electric heating has moved on. Modern electric boilers work with radiators or underfloor heating to provide us with warm and comfortable homes.

Running costs are a real concern however as the cost of electricity is three-four times that of mains gas, but electricity tariffs are likely to come down as we move to low carbon heat sources and their potential to run off 100% renewable electricity gives them long term potential. For those off-grid, electric boilers might already prove a viable alternative when everything is taken into account. We explore all, in our ultimate guide to electric boilers.

Contents

  1. What is an electric boiler?
  2. Types of electric boiler
  3. Electric boiler prices comparison
  4. How much does an electric boiler cost to install?
  5. Electric vs LPG vs Oil vs heat pump installation cost.
  6. How much does an electric boiler cost to run?
  7. Should I replace my gas or oil boiler with an electric boiler?
  8. Advantages and disadvantages
  9. What size electric boiler do I need?
  10. Electric boiler efficiencies
  11. Electric boiler warranties
  12. Decarbonising UK homes

1. What is an electric boiler?

For the most part electric boilers look and work like standard gas boilers, but use electricity to power the boiler. Electric boilers work with a ‘wet’ heating system, i.e. radiators or underfloor heating, which makes them a suitable replacement for gas and oil boilers.

2. Types of electric boiler

Electric boilers are as flexible as gas boilers in terms of their set up, with a boiler type for most circumstances:

Electric combi boiler:

Exactly like a combi gas boiler, it provides all of the heating and hot water to the home from a single usually wall hung unit.

Electric boiler with inbuilt hot water cylinder:

Good for compact spaces, a number of manufacturers offer the boiler and hot water cylinder in a single floor standing unit that is simple to fit.

Electric system boiler with separate hot water cylinder:

This comprises a wall hung electric boiler with a separate unvented hot water cylinder for great hot water supplies.

Electric combi thermal store for maximising Economy 7 tariff:

This looks like a very large cylinder, which it is, but it uses the stored water for your heating system. This is called a ‘thermal store’. The unit will heat up fully at night when electricity is at its cheapest and then use it through the day to heat your home. This keeps running costs in line with LPG and oil heating systems.

Electric warm air unit:

Electric boilers can replace gas fired warm air units in homes where there is ducting and vents rather that radiators.

3. Electric boiler prices comparison

The tables below group together electric boilers by type so you can compare prices directly. Electric boilers tend to be more expensive than gas boilers for the unit, but the installation costs are much lower.

Wall hung combi boilers

Prices for combi boilers vary and this is based entirely on the litres per minute flow rates for hot water. The cheaper models provide 5-6 litres per minute, which is still a reasonable shower but impossible to run a hot tap elsewhere in the home. The more expensive models provide much higher flow rates for faster hot water supplies. If you need lots and lots of hot water, best to look at the electric system boilers with separate hot water tank (tables below).

Manufacturer Boiler Price Size kW LPM for hot water
Electric Heating Company (EHC) Fusion Astro combi boiler £1,288 12kW 5 lpm
Electric Heating Company (EHC) Fusion Astro combi boiler £1,341 14.4kW 6 lpm
Trianco Aztec combi boiler £1,794 6-12kW 10 lpm
Trianco Aztec mini combi boiler £1,305 8kW 5 lpm
Trianco Aztec mini combi boiler £1,330 10kW 5 lpm
Trianco Aztec mini combi boiler £1,366 12kW 5 lpm
Elnur Mattira combi boiler £2,189 3-15kW 12 lpm
Electric combi company EK.C £1,480 12kW 8 lpm
Electric combi company EK.BLP £1,800 12kW 8-13 lpm
Electric combi company EK.BLC (compact) £1,920 12kW 8-13 lpm

Floor standing electric boiler with in-built hot water cylinder

These are single units designed to fit in an airing cupboard or similar. 'Based on home flow rates' means that the hot water cylinder will produce hot water based on your flow rates, which might be 14 lpm or more, and will be set up by your installer.

Manufacturer Boiler Price Size kW LPM for hot water
Heatrae Sadia Electromax £1,830 6kW Based on home flow rates
Heatrae Sadia Electromax £1,854 9kW Based on home flow rates
Electric Heating Company (EHC) Comet £2,228 9-14.4kW Based on home flow rates

Electric system boiler (for use with a separate hot water cylinder)

Prices below show the cost of standalone system boilers and system boiler/hot water cylinder packages. NB the Electric Heating Company provide other boiler and cylinder packages for their full range of electric system boilers and with larger hot water cylinders.

Manufacturer Boiler Price Size kW LPM for hot water
Elnur Mattira system boiler £1,029 3-15kW Based on home flow rates
Electric combi boiler company EK.N system boiler £1,140 12kW Based on home flow rates
Thermosphere Electric system boiler £1,069 4.5kW Based on home flow rates
Thermosphere Electric system boiler £1,083 6.0kW Based on home flow rates
Thermosphere Electric system boiler £1,423 9.0kW Based on home flow rates
Electric Heating Company (EHC) Comet system boiler with 150 litre direct cylinder £1,925 9kW Based on home flow rates
Electric Heating Company (EHC) Comet system boiler with 150 litre indirect cylinder £1,965 9kW Based on home flow rates
Electric Heating Company (EHC) Comet system boiler with 150 litre indirect pre-plumbed cylinder £2,299 9kW Based on home flow rates

Electric boiler/thermal store for Economy 7 use

For homes with a big hot water requirement, these thermal store combis offer high flow rates and the opportunity to heat a large tank of heating water overnight on the Economy 7 tariff. The stored hot water will be used during the day to heat your home. The downside is that product comes with a 1 year labour-only warranty.

Manufacturer Boiler Price Size kW LPM for hot water
THERMAflow TH9 210 litre combi thermal store £2,834 10kW upto 20lpm
THERMAflow TH12 210 litre combi thermal store £2,923 13kW upto 20lpm
THERMAflow TH9 250 litre combi thermal store £3,058 11kW upto 20lpm
THERMAflow TH12 250 litres combi thermal store £3,149 14kW upto 20lpm
THERMAflow TH9 330 litre combi thermal store £3,247 13kW upto 25lpm
THERMAflow TH12 330 litre combi thermal store £3,351 16kW upto 25lpm
THERMAflow TH12 450 litre combi thermal store £4,859 18kW upto 30lpm

 

4. How much does an electric boiler cost to install?

We have applied some rough installation costs to an electric boiler installation using the boilers listed in the tables above. Cost will vary according to boiler and cylinder size. The prices below include parts and labour.

Wall hung combi boiler Electric boiler with inbuilt cylinder System boiler with hot water cylinder Thermal store for economy 7
£2,500 - £3,000 £3,000 - £3,500 £3,000 - £3,500 £4,500 - £6,500 

 

5. Electric vs LPG vs Oil vs heat pump installation costs

We give a rough guide here to comparative installation costs for different fuel types. A good deal depends on the system size. Heat pumps installation costs are significantly higher however grants are available. We give a detailed guide to heat pumps and funding our Ultimate guide to heat pumps.

Gas boiler Electric boiler Oil boiler Heat pump
£2,000 - £4,500 £2,500 - £4,500 £2,834 £7,000 - £12,000 (reducing to approx. £3,000 - £6,000 with the various grants)

 

6. How much does an electric boiler cost to run?

The simplest way to work out how much an electric boiler will cost to heat your home is to check your annual heat use via your energy bill. This will be shown in kilowatt hours (kWh). Multiply the number of kWh by your electricity tariff, usually around 12.5p per kWh.

You may find the number of kWh used by your electric boiler is lower than your gas or oil boiler because it is more efficient, so that figure will come down. If you opt for the ‘thermal store’ the overall tariff will be lower as Economy 7 tends to be around 7.5p per kWh.

In the example below, we take an existing annual heat requirement of 15,000 kWh for heating and hot water and look at comparable energy costs for electric, Economy 7 electric, oil, gas and heat pumps. We assume a 15% efficiency improvement for electric boilers over the gas and oil options and 10% efficiency improvement for the thermal store.

Fuel costs scenarios

Mains gas LPG Oil Electric Economy 7 Heat pumps
3.5p per kWh 7p per kWh 6p per kWh 12.5p per kWh 7.5p per kWh 12.5p per kWh electric / £0 for renewable element
£525 £1,050 £900 £1,593 £1,012 £625

As our energy priorities change, it is likely that the cost of electricity will reduce and gas and oil will rise to deter long term use. Whilst air source heat pumps are likely to be the main replacement to gas boilers, they are not suitable in all circumstances, for example off-grid flats.

 

 

7. Should I replace my gas or oil boiler with an electric boiler?

If you are on mains gas then almost definitely not. Electric boilers are three times more expensive to run at the current tariffs. If you are off grid then an electric boiler is a viable alternative, particularly the thermal store option as prices are in line with LPG and oil fuel costs and actually less inclined to fluctuation.

Even without the thermal store, whilst you will pay around a third more for your energy you will experience reduced maintenance costs. Electric boilers do not require an annual service (a saving of £70 - £120 per annum) and there is no on-site fuel storage, which can be particularly costly for oil boiler owners in terms of maintenance, replacement and the potential for spillages. So the cost different maybe smaller that it first appears.

8. Advantages and disadvantages

Advantages

  • Easy to fit anywhere (no flue required)
  • No on-site fuel storage compared to LPG and oil
  • Low carbon when using a 'green' electricity supplier
  • Little to no maintenance costs

Disadvantages

  • More expensive to run
  • Hot water flow rates are limited on some combi models

9. What size electric boiler do I need?

Sizing your heat requirements is same irrespective of whether you have an oil boiler, gas boiler, electric boiler or heat pump. The capacity of the heat source must be able to heat your home on the coldest day. For the vast majority of UK homes that is around 6-8kW and certainly no bigger than 10kW. For more see our Guide to boiler sizing.

10. Electric boiler efficiencies

Electric boiler efficiencies are quoted at 99% which is very impressive as it means that almost no energy is wasted. However electric boilers are D-rated. This is because electricity is not an efficient energy to produce and it often uses fossil fuels to do so.

As we move to zero carbon and renewable electricity generation, this will improve. How you control your boiler remains important and it should be programmed to run as efficiently as possible to meet your living requirements.

11. Electric boiler warranties

Electric boiler warranties are 2 years across the board (with the exception of the THERMAflow which has a 1 year labour warranty), which compares poorly with gas boilers that offer warranties of 7-12 years. However they do not require an annual service and there are far fewer parts to go wrong. The Electric Heating Companies offer an extended warranties for some of their models to 5 years for a one off cost of £249.

12. Decarbonising UK homes

As we transition away from fossil fuels, the UK government have identified a number of alternative, low carbon heat sources to replace gas and oil boilers. Whilst electric boilers are not strictly renewable in the sense the can utilise free energy from air, ground or water, they can run on electricity that is generated by 100% renewable sources. For this reason they are included in mix of future heating systems.

 

Jo Alsop

Heating Hero

The Heating Hub

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