Why London Builders Are Outsourcing Heat Pump Installation
The UK construction industry is in the middle of a significant shift. The Future Homes Standard, tighter Part L Building Regulations, and the phasing out of gas boilers in new builds mean that heat pumps are no longer a niche product — they are becoming the default heating solution for residential projects across London and the South East. For builders, general contractors, and M&E firms, installing air source heat pumps demands specific certifications, specialist knowledge, and access to the MCS framework. That is why an increasing number of London builders work with a dedicated heat pump subcontractor rather than developing in-house capability from scratch.
Related reading: MCS umbrella explained: what builders and installers need to know | White-label heat pump installation for builders and contractors
What Does a Heat Pump Subcontractor Actually Do?
A heat pump subcontractor handles the specialist elements of an ASHP installation so that you, as the main contractor, can focus on what you do best — whether that is general building, renovation, extension work, or new build construction.
Our scope as your heat pump subcontractor typically includes:
Design and specification
Before any installation begins, we carry out a full heat loss calculation and system design. This includes selecting the correct heat pump capacity for the property, specifying the hot water cylinder, designing the hydraulic pipework layout, and ensuring the system meets MCS Technical Standards (MIS 3005).
Equipment procurement
We source all heat pump equipment through our established trade accounts — including the ASHP unit, unvented cylinder, expansion vessels, controls, and ancillary components. This means you do not need to worry about sourcing unfamiliar equipment or managing specialist supply chains.
Installation
Our qualified engineers carry out the full mechanical and electrical installation. This covers mounting and commissioning the outdoor unit, connecting the hydraulic connections (for monobloc units), integrating with the heating distribution system (radiators, underfloor heating, or both), installing and commissioning the hot water cylinder, and setting up the controls and weather compensation.
MCS certification and BUS Grant
As an installer working under an MCS Umbrella Scheme, we can certify the installation to MCS standards and process Boiler Upgrade Scheme (BUS) Grant applications worth £7,500 per qualifying installation (subject to eligibility criteria set by Ofgem). This is a significant selling point for your end clients.
Handover and aftercare
We provide full commissioning documentation, homeowner handover packs, and MCS certificates for every installation. Your client gets a properly documented, warrantied system, and you maintain your professional reputation.
Our Certifications: Why They Matter to You
When you subcontract heat pump installation, you need confidence that the work will meet all regulatory requirements. Here is what Electromatic M&E brings to the table:
G3 Unvented Hot Water Systems
Our lead engineer holds a current G3 qualification (LCL Awards, valid to 2030). This is a legal requirement for installing unvented hot water cylinders — which are part of virtually every heat pump system. Without a G3-qualified installer, you cannot legally sign off an unvented cylinder installation, and Building Control will flag it.
Gas Safe Registration
Our team includes Gas Safe registered engineers, qualified across domestic gas categories including CCN1, CENWAT, CKR1, HTR1, and MET1. This is particularly important for retrofit projects where the existing gas boiler needs to be safely decommissioned and disconnected before the heat pump is installed.
Level 3 Award in ASHP Installation and Maintenance
This is the Ofqual-regulated qualification (603/7790/2) that demonstrates competence in the installation and maintenance of air source heat pumps. It covers system design, installation, commissioning, fault-finding, and ongoing maintenance.
MCS Certification (via Umbrella Scheme)
We operate under the MCS Umbrella Scheme, which means every installation we carry out is completed under MCS certification. This is the gateway to the £7,500 BUS Grant for your clients (subject to eligibility) and ensures the installation meets all required technical standards.
How the Subcontracting Model Works
Working with Electromatic as your heat pump subcontractor is straightforward. Here is how a typical project flows:
1. Initial enquiry and site assessment
You contact us with the project details — property type, location, any existing heating system information, and your client’s requirements. We arrange a site visit (or work from plans for new builds) and carry out a full heat loss calculation.
2. Design and quotation
We provide a detailed quotation covering the complete heat pump system — equipment, installation, MCS certification, and BUS Grant processing. This quote is to you, the main contractor, at trade pricing. You then mark up and present to your end client as part of your overall project.
3. Programme coordination
We work to your project programme. Whether the heat pump installation needs to happen at first fix, second fix, or as a standalone retrofit, we coordinate our schedule with your site manager to minimise disruption and avoid trade clashes.
4. Installation
Our engineers attend site, carry out the installation, and commission the system. Typical installation time for a standard residential ASHP system is two to three days, depending on complexity.
5. Certification and handover
We complete all MCS documentation, process the BUS Grant application (if applicable), register the system warranty, and provide the full commissioning pack. You get copies of everything for your project file.
6. Aftercare
Should any post-installation issues arise, we handle them directly — either liaising with your client or working through you, depending on your preference.
Areas We Cover
Electromatic M&E is based in South West London and provides heat pump subcontracting services across:
- Richmond, Kingston, and Twickenham — our core operating area
- Hampton, Teddington, and Sunbury — immediate surrounds
- Greater London — all boroughs, including Central, West, South, and North London
- Surrey — including Guildford, Woking, Epsom, and Weybridge
- Berkshire and Middlesex — Windsor, Staines, Hounslow, and surrounding areas
For larger or multi-unit projects, we can extend our coverage further afield.
Response Times and Availability
We understand that when you are managing a building project, delays cost money. That is why we prioritise responsive communication and reliable scheduling.
- Initial quotation: Typically within 48 hours of receiving project details
- Site survey: Within 5 working days (often sooner)
- Installation start: Subject to programme, but typically 2–4 weeks from order confirmation
- Emergency callbacks: Same-day response for urgent post-installation issues
We maintain dedicated capacity for subcontract work, so you are not competing with our residential pipeline for installation slots.
Why Builders Choose to Outsource Heat Pump Installation
If you are weighing up whether to develop in-house heat pump capability or use a subcontractor, here are the practical reasons most builders opt for the latter:
The certification barrier is high
Getting set up under MCS as a standalone company requires significant investment — both in time and money. You need qualified engineers, quality management systems, ongoing audits, and continuous professional development. For a builder who needs occasional heat pump installations, this is rarely cost-effective.
The technology is specialist
Heat pump system design is not intuitive for someone whose background is in traditional gas heating. Getting the heat loss calculation wrong, undersizing the cylinder, or specifying the wrong flow temperatures can result in a system that underperforms, generates complaints, and damages your reputation.
The grant process is complex
BUS Grant applications require MCS certification, specific documentation, and adherence to strict technical standards. If you are not set up for this, the administrative burden can outweigh the profit margin.
Liability is transferred
When you use a subcontractor with appropriate professional indemnity insurance and public liability cover, the specialist risk associated with the heat pump installation sits with us, not with you.
What We Do Not Do
To be clear about scope: we are a specialist mechanical and electrical subcontractor focused on heat pump and solar PV installation. We do not provide general building services, carpentry, decorating, or other construction trades. Our scope begins and ends with the renewable energy and heating system. This clean delineation of scope is precisely what makes the subcontracting model work so well — you handle the build, we handle the heat pump.
Pricing: Transparent and Trade-Friendly
Our subcontract pricing is structured to give you margin while remaining competitive for the end client. We provide fixed-price quotations for each project, so you know exactly what the heat pump element will cost before you commit.
For builders who send us regular work, we offer preferential pricing and priority scheduling. The more you work with us, the better the arrangement — it is that straightforward.
Frequently Asked Questions
Do I need any qualifications to subcontract heat pump work to Electromatic?
No. As the main contractor, you do not need MCS certification, Gas Safe registration, or any heating-specific qualifications to subcontract the heat pump installation to us. We hold all the necessary certifications and take full responsibility for the specialist installation work.
How does the BUS Grant work when a subcontractor installs the heat pump?
The BUS Grant is applied for by the installer working under MCS certification — in this case, Electromatic M&E via our MCS Umbrella Scheme. The grant (subject to eligibility criteria set by Ofgem) is deducted from the total installation cost at the point of sale, meaning the homeowner pays the reduced price. This is seamless from your perspective as the main contractor.
Can you work to our programme and schedule?
Absolutely. We understand that subcontractors need to fit within a wider project programme. We coordinate our installation schedule with your site manager and can adjust timing to avoid trade clashes. We just need reasonable notice — typically 2–4 weeks from order confirmation.
What areas do you cover for subcontract work?
Our core area is South West London and Surrey — Richmond, Kingston, Twickenham, Hampton, and surrounding postcodes. However, we cover all of Greater London and can travel further for multi-unit or commercial-scale projects.
What if there is a problem with the heat pump after installation?
We provide full aftercare and warranty support for every system we install. If a fault arises, we handle it directly — either communicating with the homeowner or working through you, depending on the agreed arrangement. Our installations carry manufacturer warranties (typically 5–7 years) in addition to our own workmanship guarantee.
Ready to Partner with a Reliable Heat Pump Subcontractor?
If you are a builder, contractor, or M&E firm in London looking for a dependable heat pump installation partner, we would like to hear from you. Whether you have a single retrofit project or a multi-unit development, Electromatic M&E has the certifications, experience, and capacity to deliver.
Call us: 07718 059 284 | Email: admin@electromatic.uk
The information in this article is for general guidance only and does not constitute legal or commercial advice. Certification details are correct as of April 2026. The Boiler Upgrade Scheme (BUS) grant of £7,500 is subject to eligibility criteria set by Ofgem — not all properties qualify. Electromatic M&E Ltd operates under MCS certification via our accredited umbrella partner. All installations comply with Building Regulations Part L and MCS standards. E&OE.
Written by Electromatic M&E Ltd — ASHP & Solar installer, London & Surrey (electromatic.uk)
Last updated: April 2026 | Electromatic M&E Ltd, Company No. 13837345
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