Calculate the property’s heating requirement. Bedroom count and radiator count alone do not establish the required boiler output.
A BUYING GUIDE FOR LANDLORDS & HOMEOWNERS
Which electric boiler
fits your property?
The useful question is what your property needs. Start with hot water, then check heat loss, electrical capacity and installation space.
Published by ECBC, supplier of Elektra and Guival.
Sources reviewed 13 October 2026. Recommendations remain subject to suitability.
THE SHORT ANSWER
For shower-focused hot water, assess an instantaneous combi. For a bath with limited cylinder space, assess a compact combi with built-in storage. If you already have, or need, a separate unvented cylinder, compare heating-only boilers or complete boiler-and-cylinder configurations.
Electric boilers are not cheaper to run than gas. Suitability, practical constraints and the required heating and hot-water service should drive the decision.
YOUR PROPERTY COMES FIRST
Four situations. A clearer shortlist.
These are starting points within ECBC’s range, not automatic recommendations based on bedroom count.
| Your situation | ECBC models to assess | Why consider them? | What could change the choice? |
|---|---|---|---|
| Heating, shower and tapsNo built-in DHW cylinder wanted | EASY.C / Guival Small C | Instantaneous domestic hot water without a separate cylinder. | Required shower flow, winter inlet temperature and available electrical capacity. |
| Heating, bath and showerLimited space for a separate cylinder | EASY.BPC / Guival Small BPL | Built-in storage combines heating and bathing provision in a wall-hung unit. | Bath volume, filling time, recovery, multiple outlets and installation clearances. |
| Existing compatible cylinderOr heating-only requirement | SMART.N / Guival Small N | Heating-only boilers; the cylinder can be assessed as part of the existing system. | Cylinder condition and compatibility, heat loss and control arrangement. |
| New unvented-cylinder solutionA complete configuration to specify | SMART.N + specified indirect unvented cylinder | Choose the cylinder capacity and configuration around the property’s hot-water demand. | Total footprint, draw-off and recovery, mains supply, safety components and complete installed cost. |
01Heating and showers:
Heating and showers:
when to consider EASY.C or Small C.
Start with the C range when the requirement is shower-focused and you want instantaneous hot water without a built-in DHW cylinder. EASY.C offers built-in app controls; Guival Small C is a simpler digital-control option. Check the control specification of the exact model and any thermostat required.
The practical limit is hot-water flow at the required temperature. A shower that works in summer can demand a greater temperature rise in winter. ECBC’s 12 kW C models are positioned for showers; do not assume the same model will satisfy a bath or simultaneous outlets.
Compare fairly
EASY.C and Small C belong alongside instantaneous combis such as the Strom E-Boiler and EHC Mercury. Compare the exact output, electrical supply and flow conditions.
Product basis: EASY.C · Small C · Strom · EHC Mercury
Compare instantaneous combis ↗02Bath and shower,
Bath and shower,
without a separate cylinder.
EASY.BPC and Guival Small BPL deserve a place on the shortlist when bathing is required and a separate cylinder is impractical. Their built-in DHW storage addresses a different requirement from a purely instantaneous combi. This is the practical reason to assess the BP range.
The 12 kW EASY.BPC product page lists a 37.5-litre DHW cylinder and ECO / COMFORT modes. Guival Small BPL lists a 30-litre cylinder. Those capacities are not the same as the volume of mixed bath water they can deliver. Storage temperature, incoming water, mixing and heat added during draw-off all matter.
For a landlord replacing heating in a flat, assess the tenant’s actual bathing needs and the available installation space. For a homeowner, assess the bath and shower you use, including how long you expect to run them.
Where ECBC has a relevant proposition
A compact wall-hung heating-and-bathing solution without a separate cylinder. EASY.BPC adds built-in app controls; Small BPL offers a shallower casing in this comparison. Neither is an automatic choice for every bath or multiple bathrooms.
Know the limits: Small BPL’s product guidance calls for restricted bath-filling flow and one hot-water outlet at a time. EASY.BPC’s headline flow figure is not proof of sustained delivery at a fixed temperature rise. Verify draw-off and recovery for the selected output and operating mode.
Direct comparisons include the Elnur Mattira MAC15 and Trianco Aztec Maxi, both designs with internal storage. An EHC Comet boiler-and-cylinder package belongs in the complete-configuration comparison instead.
Product basis: EASY.BPC · Small BPL · Mattira MAC15 · Aztec Maxi
Compare compact storage combis ↗03Heating only, or
Heating only, or
a cylinder already in place.
Assess SMART.N or Guival Small N when the boiler’s job is to heat the wet heating circuit, with a compatible cylinder providing stored domestic hot water where required. They are separate from the C and BP combi ranges.
SMART.N includes a pump, expansion vessel and built-in app controls. Small N is ECBC’s simpler heating-only option. Existing-cylinder compatibility and the complete control arrangement still need checking before replacement.
System boiler versus flow boiler
Compare the complete set of components. For example, EHC offers SlimJim as a standalone flow boiler or with boiler packs. Heatrae Sadia Amptec works with external system components. A bare boiler price is not automatically the price of a complete equivalent installation.
Product basis: SMART.N · Small N · EHC SlimJim · Amptec
Compare heating-only boilers ↗04Specify the boiler
Specify the boiler
and unvented cylinder together.
Compare other boiler-and-unvented-cylinder packages with SMART.N paired with a compatible indirect unvented cylinder. A Megaflo indirect model is an example to assess, not a preselected ECBC package. Its exact model and capacity must be specified.
This is the route to investigate when storage provision is central to the property’s requirements. Determine the needed draw-off, recovery and simultaneous-outlet service, then assess the cylinder, mains supply and heating capacity as a configuration.
Keep the comparison at configuration level
EHC Comet Combination and Strom A.I.One are package alternatives in this group. Electromax also belongs here, with its different DHW heating arrangement made explicit: its direct cylinder uses an immersion heater. These are not direct BP-range competitors.
- Total installed footprint and service clearances, rather than boiler dimensions alone.
- Cylinder capacity, heating method, usable draw-off and recovery under stated conditions.
- Boiler, cylinder, controls, valves, safety components and electrical work included in the quote.
- Separate warranty conditions for the boiler and cylinder.
Product basis: SMART.N cylinder compatibility · Comet Combination · A.I.One · Electromax
Compare boiler-and-cylinder configurations ↗THE CHECKS THAT MAKE THE SHORTLIST USEFUL
Four checks before confirming a boiler.
Check phase, available capacity and other household loads with a competent electrician. The main-fuse label alone does not confirm suitability.
Record bath volume, shower flow, outlet use and expected filling time. Compare delivery and recovery using stated temperature conditions.
Measure the casing, cylinder where applicable, clearances and access. Confirm wall support and pipework with the installer.
COMMON BUYING QUESTIONS
Answers before you choose.
Can an electric boiler fill a bath without a separate cylinder?
A compact built-in-cylinder combi is a relevant design to assess. ECBC’s EASY.BPC and Small BPL are positioned for baths and showers, but the selected output, flow setting, storage mode and bath demand must be checked. Do not treat a peak flow figure as a sustained bath-filling guarantee.
Is a 12 kW boiler suitable for every house?
No. Suitability depends on calculated heat loss, available electrical capacity and the heating and hot-water design. An output rating alone does not establish the service the property will receive.
Does a larger cylinder mean a better boiler?
A larger cylinder may support a different hot-water requirement, but it changes storage, recovery and space needs. Compare complete boiler-and-cylinder configurations with each other; compare compact built-in-cylinder combis within their own group.
Which boiler should I compare with an EHC Comet package?
Compare a Comet Combination Unit with SMART.N plus a specified compatible unvented cylinder. Compare a heating-only Comet model with heating-only boilers. “Comet” alone does not identify an equivalent product.
Does choosing ECBC mean I must use ECBC installation?
Installation support is an optional follow-on. Boiler selection comes first, with suitability and the installation requirements confirmed before the purchase decision.
YOUR NEXT STEP
Get a boiler recommendation
for your property.
For a rental property, describe the tenant’s heating and bathing needs. For your own home, describe how you use hot water. Tell us what boiler or cylinder is already installed and what space is available.
Before confirming any boiler, we check suitability so there are no surprises later.
We’ll help you shortlist the relevant ECBC models and establish what needs checking before a quote is confirmed.
Discuss my property on WhatsApp ↗Call 020 8998 2024WhatsApp opens a draft for you to review and send. Installation support is available as an optional next step.
OWNERSHIP & EVIDENCE
How to read these recommendations.
This guide is published by ECBC, which sells Elektra and Guival. Its starting points explain the role of our models; they are not independent test rankings. Manufacturer and distributor documents are linked beside the relevant comparisons. Product claims have not been independently performance-tested.
Source review: 13 October 2026. Exact variant manuals, current availability and warranty terms need confirmation before ordering. EASY.BPC and SMART.BPC are the same product under the ECBC-confirmed rebranding. Where equivalent hot-water test conditions are missing, we do not claim a performance winner.
Open the full comparison source register ↗