Frequently Asked Questions

Key technical and practical guidance on modern electric heating technology, running costs, consumer unit requirements, and trusted system manufacturers.

What is an electric combi boiler?

How much does installation cost?

An electric combi boiler is a compact, all-in-one heating appliance that supplies both instantaneous domestic hot water and central heating on demand without requiring a flue, gas supply pipework, or external fuel storage.

Installation costs vary depending on existing system pipework, radiator suitability, and property electrical capacity. We provide transparent, fully scoped quotations following a comprehensive technical site survey.

Are electric boilers cheaper to run than gas?

Can I replace gas heating with electric?

Electric boilers are usually more expensive to run per kilowatt-hour than mains gas. However, high efficiency, zero flue losses, minimal servicing requirements, and pairing with solar PV or battery storage significantly reduce operating expenses.

Yes. Replacing a gas boiler with an electric system is straightforward, though property electrical supply capacity must be checked first to verify adequate amperage before disconnecting gas supplies.

Is three-phase electricity required?

Can electric boilers heat large homes?

Smaller domestic electric boilers operate reliably on standard single-phase 230V supplies with appropriate fuse ratings. High-output units exceeding 12kW generally require a three-phase electrical connection.

Yes. Larger properties can be effectively heated using high-capacity electric boilers or electric system boilers paired with unvented hot water cylinders to meet high simultaneous heating and hot water demand.

Electric combi vs system boiler: what's different?

Do electric boilers need servicing?

An electric combi provides instantaneous hot water directly on demand without storage cylinders, while an electric system boiler heats an unvented cylinder, making it preferable for homes with multiple bathrooms.

Yes. While electric boilers eliminate combustion flues and burners, annual inspections ensure heating elements, safety relief valves, internal wiring, system pressure, and inhibitors remain in peak working order.

What are the benefits of battery storage?

Which brands do you install?

We install market-leading electric heating systems from trusted specialists including Luthmore electric boilers, compact BOLT electric units, and high-efficiency ECBC electric combi systems tailored to domestic and commercial properties.

Battery storage systems store low-cost off-peak electricity from smart energy tariffs or rooftop solar PV, powering electric boilers and household appliances during expensive peak daytime hours to minimize grid bills.

Gas Boilers & Heating

Essential guidance on statutory gas servicing intervals, boiler replacement timing, pressure drops, and complete heating maintenance contracts.

How often should gas boilers be serviced?

When should a boiler be replaced?

Gas boilers should be serviced annually by a Gas Safe registered engineer to ensure efficient combustion, verify safety controls, reduce breakdown risks, and maintain valid manufacturer warranty terms.

Boilers should usually be replaced after 10 to 15 years of continuous service, or earlier if repair costs escalate, replacement components become obsolete, or overall energy efficiency declines significantly.

How long does installation take?

Why does boiler pressure drop?

A direct like-for-like boiler replacement typically completes within one working day. Complex heating conversions, system relocations, or comprehensive pipework upgrades typically take two to three days.

Pressure losses are commonly caused by minor leaks in radiators, valves, or hidden pipework, recent radiator bleeding, or a failed internal expansion vessel requiring professional inspection.

What if central heating stops working?

Do you offer gas boiler maintenance?

Check thermostat batteries, confirm the electrical spur is powered, and inspect the system pressure gauge. If error codes persist, contact our heating engineers for rapid diagnostics and repair.

Yes. Alliance Contractors provides tailored domestic HomeCare maintenance plans and commercial planned preventative maintenance contracts delivered by certified Gas Safe engineers nationwide.

Air Conditioning & HVAC

Understanding reverse-cycle heat pumps, seasonal efficiency ratings, ongoing maintenance regimes, and commercial climate engineering.

How does air conditioning work?

Can AC heat and cool?

Yes. Modern air-to-air heat pump air conditioning units provide reverse-cycle climate control, providing powerful cooling throughout summer and exceptionally efficient, rapid space heating during winter months.

Air conditioning uses a closed refrigeration cycle to absorb thermal energy from indoor spaces and discharge it outdoors, circulating filtered, dehumidified, and temperature-controlled air.

What affects AC installation cost?

How often should AC be serviced?

Costs are determined by room dimensions, building thermal loads, system capacity, the quantity of indoor units, interconnecting pipe run lengths, and condenser mounting positions.

Domestic air conditioning should be serviced once annually. Heavy-use commercial environments and office buildings benefit from bi-annual or quarterly servicing to sanitize filters and verify refrigerant integrity.

Do you provide commercial HVAC services?

Is AC energy efficient?

Modern inverter AC systems achieve high Seasonal Energy Efficiency Ratios (SEER), routinely producing three to four kilowatts of heat output for every single kilowatt of electricity consumed.

Yes. We design, install, and commission comprehensive commercial HVAC solutions including VRF and VRV multi-splits, air handling units (AHUs), ducted heat recovery ventilation, and plant room chilled water systems.

Answers covering certified electrical contracting, EICR inspections, incoming power upgrades, low water pressure troubleshooting, and commercial plumbing.

What electrical services do you provide?

When is an electrical inspection needed?

We deliver full electrical design, consumer unit replacements, rewiring, commercial distribution boards, three-phase power supplies, EV chargers, emergency lighting, and building services containment.

Domestic rental properties require inspection every five years or at tenancy changeover. Commercial facilities need testing every three to five years, while owner-occupied homes should be checked every ten years.

Can electrical supplies be upgraded for boilers?

What is an EICR?

An Electrical Installation Condition Report (EICR) is an in-depth statutory assessment of an existing electrical installation, identifying deteriorated circuits, overloaded switchgear, and safety hazards against BS 7671 standards.

Yes. Our electrical team conducts site surveys to calculate maximum demand, upgrades consumer units and cabling, and liaises directly with your Distribution Network Operator (DNO) for main fuse or three-phase upgrades.

What causes low water pressure?

Do you offer plumbing installation and maintenance?

Low water pressure can result from incoming municipal mains restrictions, corroded pipework, partially closed stopcocks, limescale buildup, or unvented system expansion vessel faults.

Yes. We handle domestic and commercial plumbing projects, including unvented cylinders, cold water booster sets, commercial washrooms, drainage systems, and ongoing planned maintenance.

Commercial & Industrial

Details on integrated MEPGH contracting, planned preventative maintenance, multi-site portfolio support, and major development partnerships.

What commercial services do you provide?

What does MEPGH mean?

MEPGH stands for Mechanical, Electrical, Plumbing, Gas, and Heating. It defines Alliance Contractors' unified multidisciplinary contracting model, coordinating all essential building services under a single accountable team.

We provide end-to-end building services including commercial heating, industrial ventilation, sub-station and electrical distribution, BMS controls, fire protection, and comprehensive mechanical plant maintenance.

Do you undertake commercial installations?

What is planned preventative maintenance (PPM)?

Yes. Our mechanical and electrical engineering teams execute turnkey installations across office complexes, distribution warehouses, industrial processing facilities, schools, and multi-occupancy residential towers.

Planned Preventative Maintenance (PPM) is a structured schedule of routine inspections and servicing designed to maintain asset performance, eliminate operational downtime, ensure statutory compliance, and protect lifecycle value.

Can you maintain multiple properties?

Do you work with developers and property managers?

Yes. We manage nationwide property portfolios with centralized account management, unified service level agreements (SLAs), dedicated engineering teams, and round-the-clock emergency support.

We work alongside principal building contractors, commercial property managers, and property developers from initial engineering design and pre-construction procurement through to commissioning and facility maintenance.

Bookings & Aftercare

Everything you need to know about requesting estimates, project timelines, warranty provisions, post-install support, and contacting Alliance Contractors.

Do you cover the UK nationwide?

How can I request a quote?

You can request a quote by submitting our online enquiry form, emailing our technical estimating team, or telephoning our customer service centre with your site specifications and project requirements.

Yes. Alliance Contractors operates across England, Scotland, and Wales, deploying regional engineering teams and mobile service vans to deliver consistent installation and maintenance standards across the UK.

How long do installations take?

Are quotations free?

Yes. We provide free, transparent, no-obligation quotations following an initial project consultation, desk assessment, or preliminary on-site survey conducted by our estimating engineers.

Standard residential boiler or single air conditioning installations typically complete in one to two days. Commercial and industrial plant installations follow phased engineering schedules agreed prior to commencement.

Do you provide installation and maintenance?

What warranties apply?

Warranty terms vary by product and conditions, with leading equipment manufacturers providing comprehensive multi-year coverage alongside our certified workmanship guarantees.

Yes. We oversee the entire engineering lifecycle, from technical design and physical installation to planned statutory inspections, reactive emergency repairs, and full lifecycle equipment maintenance.

Can I book maintenance after installation?

How do I contact Alliance Contractors?

Yes. Following commissioning, you can enroll in our ongoing HomeCare maintenance packages or commercial service agreements to ensure ongoing compliance, efficiency, and continuous manufacturer warranty validation.

Contact our nationwide team through our online contact page, email our engineering helpdesk directly, or phone our national operational office to speak directly with a technical specialist.

Ready to Discuss Your Project?

Whether you require a residential electric boiler replacement, commercial HVAC installation, or ongoing multi-site building maintenance, our technical team is ready to assist.