For most homes with a gas supply, a gas boiler remains the cheaper option to run by a clear margin, because a unit of electricity costs several times a unit of gas and an electric boiler cannot claw that back with efficiency. An electric boiler makes sense where there is no gas, where the heating demand is small, such as a flat or an annexe, where a flue is impossible, or where a home has its own solar generation and battery storage. In rural Cornwall and Devon, the more common comparison is electric against oil or LPG, and the same logic applies.
This guide compares the two on the things that matter: installation, running costs, hot water, efficiency, lifespan and maintenance. It ends with the situations where each is the sensible choice.
Installation
An electric boiler is smaller, needs no flue, no gas supply and no condensate drain, and can go almost anywhere with a suitable electrical supply. That makes it the easier installation, though a larger model may need a dedicated circuit from the consumer unit and occasionally an upgraded supply. A gas boiler needs a flue to outside, a gas connection and a drain, and must be installed by a Gas Safe registered engineer. Electric boilers need a competent electrician and a heating engineer for the wet side.
Running costs
This is the decisive factor. Electricity per kilowatt hour costs a multiple of gas, and although an electric boiler converts nearly all of it to heat, a modern gas boiler converts over 90 per cent of a much cheaper fuel. For a typical house the electric boiler costs considerably more to run each year. The gap narrows for a small, well-insulated property with low demand, and closes further if you have solar panels and a battery, or an off-peak tariff and a system that can make use of it.
Hot water
Electric combi boilers exist, but their hot water output is limited by the electrical supply. Many deliver a modest flow rate, enough for a basin and a shower in a flat, but not for a family bathroom and a kitchen tap at once. Electric system boilers paired with a hot water cylinder perform better because the cylinder stores heat over time. A gas combi delivers stronger flow rates on demand, and a gas system boiler with a cylinder handles multiple outlets comfortably.
Efficiency
Electric boilers are close to 100 per cent efficient at the point of use, since there is no flue to lose heat through. Gas condensing boilers reach the low nineties. Efficiency is not the same as cost, though: what matters is efficiency multiplied by the price of the fuel, and on that measure gas wins comfortably for most homes.
Lifespan and maintenance
Electric boilers have fewer moving parts, no combustion and no flue, so they need less maintenance and have no gas safety requirement. Elements and controls do eventually fail. Gas boilers need an annual service to stay safe and keep their warranty, and have more components that can wear. Both should last ten to fifteen years with proper care.
Environmental considerations
Electric heating produces no emissions at the property, and as the grid moves towards renewables its overall footprint falls. Gas produces carbon dioxide at the boiler. For anyone weighing low-carbon options, a heat pump delivers far more heat per unit of electricity than an electric boiler and is usually the better electric route, though it suits some homes better than others. Our guide to heat pumps versus boilers in Cornwall and Devon covers that comparison.
When an electric boiler makes sense
- no gas supply and no wish to install oil or LPG
- a flat, annexe, holiday let or small well-insulated home with low demand
- nowhere for a flue, such as a listed building or a flat with no outside wall
- solar panels with battery storage or a favourable off-peak tariff
- a property where gas safety requirements are a burden, such as some lets
When a gas boiler makes sense
- a gas supply already at the property
- a family home with normal or high heating and hot water demand
- a priority on lowest running costs
- two or more bathrooms
Off-gas homes in Cornwall and Devon
Much of the South West has no mains gas, so the real choice for many homeowners is between oil, LPG, electric and a heat pump. Oil remains the cheapest of these to run for most rural homes, LPG is convenient but usually costs more than oil, and electric boilers suit small properties. Our guides to oil versus gas boilers and LPG boilers cover the rural options.
How DCI Boilers can help
DCI Boilers installs gas and oil boilers across Cornwall and Devon with Gas Safe and OFTEC registered engineers, fixed pricing and manufacturer warranties of up to 12 years, and will tell you honestly if an electric boiler or a heat pump would suit your property better. Read about our gas boiler replacement and oil boiler replacement services.
Need help now? Call DCI Boilers on 07888 862 603 or get a free quote.
Frequently asked questions
Is an electric boiler cheaper to run than gas?
No, not for a typical home. Electricity costs several times more per unit than gas, and an electric boiler cannot make up the difference with efficiency.
Can an electric boiler heat a whole house?
A large one can, but the electrical supply and the running cost make it best suited to smaller, well-insulated properties.
Do electric boilers need servicing?
Less than gas boilers, and there is no gas safety requirement, but an annual check of the elements, controls and system is still sensible.
Is an electric boiler the same as a heat pump?
No. An electric boiler turns electricity directly into heat. A heat pump moves heat from outside and delivers several units of heat for each unit of electricity, which makes it far cheaper to run.