If your London flat has no gas supply or no workable flue route, an electric boiler is often the practical answer, and the ECA Arceus is the range most landlords and managing agents ask us about. Where gas and a flue are available, the ECA Proteus gas combi is the alternative. Below we compare both, set out the real running costs, explain the compliance duties (including the EICR) and show how installation works through UpKeep UK.
Key takeaways
- The ECA Arceus electric combi and system boilers come in 12kW and 15kW versions and need no gas supply, no flue and no chimney, which makes them suited to many city-centre flats.
- Electricity costs more per kWh than gas. An electric boiler can still make sense, but only with good insulation and a sensible tariff.
- Electric boilers need no gas safety certificate, but the circuit that feeds them is part of the electrical installation covered by the EICR.
- ECA includes a 3-year parts and labour warranty, and UpKeep UK installs with Gas Safe and NAPIT registration.
- Check the consumer unit and incoming supply before you choose a model. A 15kW boiler is not a like-for-like swap for most gas boilers.
Who ECA is and how UpKeep UK works with them
E.C.A. is part of the Elginkan Group, an international family-owned manufacturer of heating products, sold in more than 100 countries. In the UK the boilers are supplied by ECA Online, the UK distributor, which holds stock and supports the range locally. UpKeep UK works alongside ECA Online so that landlords, managing agents and developers can buy a boiler and have it fitted and signed off by one contractor, rather than coordinating a supplier and a separate installer.
That matters in a block of flats. A boiler is rarely a standalone decision: it touches the electrical supply, the hot water system, Building Regulations and, for rented homes, your safety paperwork.
ECA Arceus electric boilers: what you get
The Arceus range is offered as combi and system boilers in 12kW and 15kW outputs. It is designed for properties with no gas supply or no viable flue route. Because an electric boiler burns nothing, it needs no chimney or balanced flue, and as the manufacturer’s product page explains, that is exactly the scenario it solves.
Listed prices on the ECA Online store at the time of writing (October 2026) are £1,303 for the 12kW and £1,393 for the 15kW. These are the boiler prices only. Installation, any electrical upgrade, commissioning and Building Regulations notification are separate.
| Arceus 12kW | Arceus 15kW | |
|---|---|---|
| Configurations | Combi and system | Combi and system |
| Listed price (Oct 2026) | £1,303 | £1,393 |
| Best suited to | Smaller flats, one bathroom, good insulation | Larger flats, higher hot water demand |
| Gas supply needed | No | No |
| Flue needed | No | No |
Combi or system?
A combi heats water on demand and removes the need for a cylinder, which saves space in a compact flat. A system boiler feeds a stored hot water cylinder, which helps where several bathrooms are in use at once, but it needs somewhere to put the tank. In a one-bedroom conversion the combi is usually the sensible choice. For a larger flat with two bathrooms, the system version deserves a proper look, and we size it on site rather than by guesswork.
12kW or 15kW?
The higher output is not automatically better. A well-insulated one or two bedroom flat rarely needs the extra capacity, and the larger unit places a heavier demand on your electrical supply. Choose the smallest model that meets the heat loss of the property and the hot water demand of the occupants. A survey tells you far more than a rule of thumb.
The ECA Proteus gas combi for flats that do have gas
Not every flat is a candidate for electric. Where there is a gas supply and a compliant flue route, the Proteus Premix gas combi is the other ECA option we install. The 24kW model is listed at £660 on ECA Online, with a stated efficiency of 97.5% and silent operation at 49 dB. The range is also available in 30kW and 35kW.
Gas remains cheaper per unit than electricity, so for a property with a sound existing gas connection it often has the lower running cost. The trade-off is the compliance load: gas appliances and flues need an annual gas safety check. The HSE explains that all permanent and portable gas appliances and flues in a let property require one. For the cost and process, see our guide to gas safety check costs.
Electricity costs more than gas: the honest numbers
Electric boilers convert all the electricity they draw into heat, so the Energy Saving Trust points out that efficiency is not the problem. The problem is price per unit. ECA’s own product page quotes electricity at around 27.03p/kWh against gas at 6.99p/kWh, figures dated to mid-2025. Unit rates change, so check your current tariff before you commit.
The same page estimates running costs of roughly £800 to £1,800 a year for a typical one to three bedroom home, depending on insulation, usage and tariff. That is a wide range, and it should shape your decision:
- Tenant bills. If your tenants pay the energy bills, a high running cost affects how easy the flat is to let and keep let. Be upfront about it.
- Insulation first. Heat that stays in the flat costs nothing to replace. Heating costs for a well-insulated outbuilding show how far good insulation can cut a winter bill, and the same principle applies to a flat.
- Tariff choice. Time-of-use tariffs and a smart thermostat can reduce the average unit cost for some households, but only if the occupants can shift their usage.
- Lower servicing cost. With no flue, no combustion and no gas check, annual servicing is lighter than on a gas boiler.
If you are weighing electric boilers against heat pumps and gas for a London rental, our heating comparison for landlords sets the options side by side. Underfloor heating can also change the sums, as we cover in underfloor heating versus radiators.
When electric is the right call
Electric usually wins when the alternative is expensive or impossible: a top-floor flat where a flue would need to run through other people’s property, a conversion where the gas riser is out of reach, or a refurbishment where the freeholder will not permit a new flue. In those cases the question is not electric versus gas but electric versus nothing, and the Arceus fills the gap at a modest upfront cost.
Compliance: gas safety certificate, EICR and Building Regulations
No gas safety certificate, but the EICR applies
An electric boiler has no gas appliance and no flue, so no annual gas safety certificate is needed for it. That does not take the boiler out of your safety obligations. The circuit that feeds it is part of the fixed electrical installation, and for private rented homes in England the government’s electrical safety guidance requires the installation to be inspected and tested by a qualified person at least every five years. That guidance was updated in 2025 to cover the social rented sector too. The inspection is the Electrical Installation Condition Report (EICR).
In practice, a new high-load circuit for a 12kW or 15kW boiler should be installed, tested and certificated properly so it passes the next EICR without remedial work. If a gas block is also being converted, our guide to fire safety obligations for London landlords covers the other items on the checklist.
Building Regulations
New or replacement boilers are among the works listed in the government’s guidance on building work, and they must comply with Building Regulations. Using a registered competent person allows the installer to self-certify, which avoids arranging a separate local authority inspection. UpKeep UK is Gas Safe and NAPIT registered, so the installation, certification and notification are handled together. Electrical work is the NAPIT side, while gas work, such as a Proteus installation, is the Gas Safe side.
Check your electrical supply before you order
This is where electric projects most often go wrong. Swapping a gas boiler for an electric one is rarely like for like. An electric boiler draws a sustained, high load, and ECA notes on its 15kW product page that the property’s supply must be suitable. If the consumer unit or incoming supply is under-specified, you risk repeated breaker trips, or you need an upgrade you did not budget for.
Before ordering, we recommend this sequence:
- Survey the supply. A qualified electrician checks the incoming supply, the consumer unit and the available capacity.
- Size the boiler. Match 12kW or 15kW to the heat loss and hot water demand, not to the old gas boiler’s rating.
- Plan the cable route. In a flat, the run from the consumer unit to the boiler location affects both cost and disruption.
- Agree the access. Managing agents and freeholders often need notice for works affecting shared risers or the supply.
- Install, test and certificate. Commissioning, electrical certification and Building Regulations notification are completed before handover.
Warranty and aftercare
ECA includes a 3-year parts and labour warranty, as set out in its terms of service. Check the conditions on installation and servicing before you rely on it, and keep the commissioning paperwork. For a landlord with several flats, a consistent boiler across the block means one spares route, one set of documents and one engineer who knows the system.
Our perspective: choose the heating around the building
We see the same mistake across London lets: the boiler is chosen first and the building is made to fit. Our approach is the reverse. Start with the flat’s gas availability, flue options, insulation and electrical supply. Then pick the boiler.
Electric is not a cheap way to heat a home, and we will say so to any landlord who asks. What it offers is certainty: no flue negotiations, no gas safety visit, a compact unit and a predictable installation. For flats where gas is not realistic, that certainty is worth a great deal. For flats where it is, the Proteus gas combi is the better running-cost option, and we will tell you so.
What matters most is that the installation is certificated, the electrical supply is proven before the boiler arrives and the paperwork is ready for your next EICR. A boiler that is cheap to buy but fails an inspection costs more than one installed properly the first time.
— Drahim Hasula
Add the bathroom range
A boiler replacement is often the right moment to look at the bathroom, especially when pipework is already being altered. ECA Online also sells an all bathroom products collection covering taps and bathroom fittings. If you want the room redone as a whole, our bathroom renovations service can specify, fit and finish it in the same visit programme as the heating work, so you are not coordinating several trades across a tenanted building.
Boilers, installation and maintenance with UpKeep UK
We fit, certificate and maintain heating for London flats, and we cover the other trades under one contract. If you manage a block or a portfolio, our planned maintenance service keeps servicing and compliance dates on schedule, and our reactive maintenance team handles breakdowns. To discuss a boiler project, start at our property maintenance page and request a survey.
FAQs
Are ECA boilers any good?
ECA is an international manufacturer, part of the Elginkan Group, selling in more than 100 countries, with a UK distributor holding stock locally. For flats without gas, the key questions are supply compatibility and UK support rather than brand ranking. Reliability tables for gas boilers do not directly cover this range, so judge it on warranty, installer competence and aftercare.
Do electric boilers need a gas safety certificate?
No. A gas safety certificate applies only to gas appliances and flues. The electrical installation feeding the boiler is still covered by the EICR, which for private rented homes in England must be carried out at least every five years.
Is an electric boiler more expensive to run than gas?
Yes, per unit. ECA’s figures from mid-2025 put electricity at about 27.03p/kWh against 6.99p/kWh for gas. Insulation, usage and tariff decide how much that matters for a given flat, so get a heat loss assessment first.
Which ECA models do you install?
We work with the Arceus electric combi and system boilers in 12kW and 15kW, and the Proteus gas combi. The right one depends on whether the flat has a gas supply and flue route, plus its hot water demand and electrical capacity.
What warranty comes with an ECA boiler?
ECA offers a 3-year parts and labour warranty. Keep your commissioning certificate and follow the servicing conditions in the terms, so that any claim goes smoothly.
Sources
- ECA Online: electric boiler collection
- ECA Online: 12kW Arceus electric combi boiler
- ECA Online: 15kW Arceus electric combi boiler
- ECA Online: 24kW Proteus Premix gas combi boiler
- ECA Online: terms of service
- ECA Online: bathroom products
- Energy Saving Trust: electric heating
- HSE: gas safety checks for landlords
- GOV.UK: electrical safety standards guidance
- GOV.UK: building work, replacements and repairs to your home
