Assess First. Recommend Second.
An electric system boiler with six ratings and built-in heating-system components.
CH means central heating; DHW means domestic hot water. Nominal model labels are shown separately from verified ratings. Gas CH maximum/minimum values use the non-condensing basis; a second maximum is shown only where a verified condensing rating is available. The source basis below controls the comparison. No missing value is calculated from another variant.
| Model / fuel | Nominal label (kW) | CH maximum (kW) | DHW output (kW) | CH minimum (kW) | DHW at ΔT 35°C |
|---|---|---|---|---|---|
| Amptec S4 · Electricity | 4 | 4 | Stored water / separate design | Not verified | Not a verified instantaneous flow rating |
| Amptec S6 · Electricity | 6 | 6 | Stored water / separate design | Not verified | Not a verified instantaneous flow rating |
| Amptec S8 · Electricity | 8 | 8 | Stored water / separate design | Not verified | Not a verified instantaneous flow rating |
| Amptec S12 · Electricity | 12 | 12 | Stored water / separate design | Not verified | Not a verified instantaneous flow rating |
| Amptec S14 · Electricity | 14 | 14 | Stored water / separate design | Not verified | Not a verified instantaneous flow rating |
| Amptec S18 · Electricity | 18 | 18 | Stored water / separate design | Not verified | Not a verified instantaneous flow rating |
The product page advertises up to 9:1 modulation. A variant-by-variant minimum kW table is not verified here; no minimum is calculated from that ratio.
Baxi documents certified OpenTherm compatibility and an advertised modulation ratio up to 9:1. The ratio is a range-level statement, not a verified minimum output for every variant.
The 14 and 18 kW versions require three-phase supply; the lower ratings use single-phase supply. This distinction must be checked before any recommendation.
Electrical supply capacity, phase, protective devices, wiring, heating distribution and hot-water storage need a qualified assessment. High point-of-use efficiency does not establish low running costs; tariffs and the home’s heat loss matter. No gas or LPG conversion is implied.
Up to 2 years, subject to Baxi terms, product eligibility, registration, commissioning and annual servicing. The eligible installation package is confirmed in your written quotation.
Manufacturer warranty, SwiftHeat installation cover and qualifying Care+ services are separate. Keep the required registration, commissioning and service records. Your quotation confirms the exact terms before purchase.
Manufacturer warranty information · Ongoing servicingCertified OpenTherm compatibility, including Baxi uSense 2, is stated by Baxi. Confirm wiring and accessories for the exact electric appliance.
Only the verified fuel configurations are shown. LPG is not inferred from the Baxi brand name.
Discuss heating controlsAssess electrical capacity, hydraulic design, hot-water storage and safety requirements before comparing electric heating packages. A flue-free appliance still needs safe positioning and servicing access.
A same-arrangement replacement, relocation and conversion involve different work. SwiftHeat confirms the appliance and complete installation scope after survey. Assess First. Recommend Second.
The guide separates nominal model labels from verified heating output. Electrical supply voltage and phase also matter. A heat-loss calculation and installation assessment are still required.
Up to 2 years, subject to Baxi terms, product eligibility, registration, commissioning and annual servicing. The eligible installation package is confirmed in your written quotation.
No. The official manual identifies S4, S6, S8 and S12 as 230 V single-phase, and S14/S18 as 400 V three-phase. Confirm the available supply and electrical design before selection.
Checked 1 October 2026. Availability and terms can change; the exact appliance and current instructions are confirmed again at quotation.
Official Baxi product photography and trademarks remain the property of their respective owners. Manufacturer warranty graphics do not confirm the eligibility of a SwiftHeat package.
The installed price for your selected boiler is confirmed after assessment. The quotation covers the appliance, controls, flue, system preparation and any required pipework. A conversion or relocation can have a different scope from a straightforward replacement.
New boiler installations from £1,790 inc. VAT apply to a qualifying standard, straightforward replacement: one bathroom, fewer than 10 radiators and a standard horizontal flue, subject to survey. Specification and warranty selection affect the final cost. This is a general starting offer and is not a price for every model in this catalogue.
Read the starting-package conditions0% options over 3, 6, 9 or 12 months through Humm Group Limited, subject to application, affordability, eligibility, approval and provider terms. Any applicable deposit, fees and repayment conditions are confirmed during your enquiry/application. Acceptance is not guaranteed.
Finance terms and chargesTwo free annual services and a Hive Mini are available on qualifying installations only. Every model is considered under the qualification rules; inclusion in this catalogue does not confirm eligibility. Ask us to confirm the offer in your quotation.
Ask about Care+ eligibilityPlan the maintenance your appliance requires and keep its service records. If you are considering replacement because of a fault, diagnosis can help establish whether repair is a suitable option first.
Boiler servicing · Repair advicePrice confirmed following assessment for this configuration. The general New boiler installations from £1,790 inc. VAT offer does not apply to every model or property.
From or indicative prices remain provisional. SwiftHeat issues a written fixed quotation for the agreed scope after the appropriate property and installation assessment, technical checks and warranty-package verification. Remote information gathering may be suitable initially; a home survey is required where the necessary checks cannot be completed remotely.
We assess heat loss, heating and hot-water requirements, water supply, controls and installation access before recommending an appliance. Bedroom count or a catalogue model number alone cannot establish the right boiler.
Gas Safe registration 978273 · Serving Cardiff, South Wales and across the UK.
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