Collide Group — London's HIU Specialists
HIU Service & HIU Repair
in London
Same-day callouts across Greater London. All major brands. Fixed pricing, no hidden fees.
Trusted by property managers, housing associations and developers for 10+ years. We fix what general plumbers can't.
- 5 ★ Google RatedTrusted by London property managers
- 500+ HIUs ServicedAcross Greater London last year
- Gas Safe & WRASFully qualified specialist engineers
- Same-Day CalloutsEmergency HIU repair in London
Our HIU Services
Specialist HIU repair, servicing, installation, powerflushing and maintenance contracts across London. Fixed pricing, no hidden fees, every major Heat Interface Unit brand covered.
HIU Service
Annual servicing to keep your HIU running efficiently. Inspection, descaling, testing and maintenance of all major brands.
Book a ServiceHIU Repair
Fast, reliable repair service for all HIU faults. We diagnose and fix issues to restore your heating and hot water quickly.
Book a RepairHIU Installation
Professional installation of new Heat Interface Units for residential and commercial properties. All major brands supplied and fitted.
Get a QuoteBulk Servicing
Group servicing packages for property managers and landlords. Discounted rates for multiple HIU services across your building.
Request ProposalHIU Powerflush
Powerflushing to remove sludge, scale and debris from your HIU and heating system. Restores efficiency, improves flow and extends unit lifespan.
Book PowerflushHIU Service Plans
One fixed monthly fee. Unlimited callouts. No surprise bills. Two simple plans — all with a free first service.
Basic Plan
Free repairs. You cover the parts.
- ✓ £0 labour costs on all repairs
- ✓ FREE annual HIU service (£120 value)
- ✓ Unlimited callouts*
- ✓ 12-month parts & labour warranty
Premium Plan
Total HIU cover, zero hassle.
- ✓ Everything in Basic
- ✓ 12-month parts & labour warranty
- ✓ All replacement parts included
- ✓ 24/7 priority support
* £60 excess per callout claim · 12-month minimum term · Subject to initial inspection · T&Cs apply
Turn To Our Team
Why Our Clients Recommend Us
No Hidden Fees
You will only pay what you have been quoted. Transparent pricing always.
10+ Years Experience
Over a decade of experience in repairing, servicing and installing HIUs.
5-Star Company
99% of our clients who used our services are happy with us.
1st Visit Diagnostic
We diagnose your HIU right on the first visit — no return trips needed.
12-Month Parts Warranty
All parts we supply and fit carry a 12-month warranty. Installations include a 5-year workmanship warranty.
Heat Interface Unit
HIUs are installed in large new apartment complexes with multiple dwellings. They transfer heat from the communal/central heating (primary side) network into your hot water and heating system (secondary side).
Collide Group specialises in all aspects of HIU maintenance — from new installations and annual servicing to emergency repairs and powerflushing. With over 10 years of experience, our qualified engineers deliver expert workmanship with fast response times and transparent pricing across London. View our full range of HIU services.
What our customers say
5-Star Rated on Google
lina mehraban
I had been struggling with no hot water and no heating in my flat for days. After searching for HIU repair specialists in West London, I came across Collide Group and I’m so glad I did. From the first call, the team were professional, knowledgeable and genuinely helpful. The HIU engineer arrived on time, quickly diagnosed the fault with my heat interface unit and had it fully repaired within the same visit. No unnecessary upselling, no pushing for a full HIU replacement — just honest, expert HIU repair at a fair price. My heating and hot water were back up and running the same day. If you’re in West London and need an HIU repair, HIU service or any heat interface unit work, Collide Group are absolutely the people to call. Highly recommend!
Kishan Rajdev
Excellent service from Ilyas - really went above and beyond to make sure our hot water (HIU) issue got sorted quickly, including a temporary fix while we awaited a part.
Anmar Mehdi
I can’t praise Collide Group’s performance enough. I had a complicated issue with my HIU. Several different companies tried to resolve it and failed. They suggested I get a new HIU which would have been expensive. I got in touch with Collide Group to get another opinion. They were able to fix my HIU and saved me a lot of money. Many thanks for your honest work!
Sharon Coley
A great service. Rapid response, on time arrival and speedy diagnosis of the fault all delivered with a friendly approach to the customer.
Sally Kaissi
I highly recommend Ilyas, he is very polite, knowledgeable and has provided excellent service in inspecting our HIU unit and also replacing a part that required changing. He was very informative and responded very quickly to inquiries. I will sure contact him again in all my HIU issues.
Sumit Gupta
Quick and trusted service. We are happy with the provided services and guidance. Very helpful, especially the engineer Ilyas. We would strongly recommend to hire him for all problems pertaining to your heating units.
Magdi Rashad
Ilyas and his colleague demonstrated a high level of professionalism, expertise, and technical knowledge throughout the works carried out. The power flushing, passivation, and refilling of my five-radiator system and HIU were completed to my full satisfaction. As a Chartered Engineer with extensive experience in building services, I found the quality of workmanship to be of an excellent standard. I would have no hesitation in recommending Collide Group at any time.
Amina Sheik
I highly recommend HIU Service & Repairs - Collide Group. I was completely impressed with their performance and professionalism changing the HIU!
Nikhil Khandelwal
Ilyas is very helpful and hard working.
Our Simple Process
Getting started is easy. Send us your enquiry and our dedicated team will handle everything.
Get in Touch
Make an enquiry online or by phone. Our friendly bookings team will respond promptly.
Receive A Quote
Clear, no-obligation quote with transparent pricing. No hidden fees.
Work Completed
Our engineers arrive on time, work efficiently, and leave your space spotless.
Frequently Asked Questions
What services does Collide Group offer?
How quickly can you respond to an emergency?
What is a HIU service?
How often should a HIU be serviced?
Are your engineers qualified?
What HIU brands do you work with?
Is there a call-out fee?
What areas do you cover?
Local HIU engineers
Areas We Cover Across London
Same-day Heat Interface Unit repair, servicing, installation and powerflushing across every London borough.
About HIU Service & HIU Repair in London
Collide Group is a specialist Heat Interface Unit (HIU) engineering company based in Northolt and serving all of Greater London. We are Gas Safe registered and WRAS certified, with over 10 years' experience and a 5-star rating across 19 Google reviews, specialising in HIU service, HIU repair, HIU installation and HIU power flushing. A Heat Interface Unit (HIU) is the compact heat exchanger fitted in flats and apartments connected to a communal or district heating system. It transfers heat from the building's central plant room into your home for hot water and central heating, replacing the traditional individual boiler.
Because HIUs run constantly and rely on tight tolerances, they need regular servicing to stay efficient. A neglected unit can cause no hot water, lukewarm taps, low flow, banging or whistling pipes, leaks and high heat charges for residents. Our manufacturer-trained engineers service, repair and install every major HIU brand used across the UK including Danfoss, SAV, Switch2, Caleffi, Alfa Laval, Heatweb, Thermal Integration and Redan.
Annual HIU Service from £120
Our annual HIU service follows a 30-point checklist covering strainer cleaning, plate heat exchanger inspection and descale, valve and actuator testing, temperature and flow performance, control verification and a full written report. Regular servicing typically extends the life of a Heat Interface Unit by 5–8 years and reduces resident complaints by over 70%.
Same-Day HIU Repair Across Greater London
Lost hot water or heating? We offer same-day emergency HIU repair across Camden, Islington, Hackney, Tower Hamlets, Southwark, Lambeth, Wandsworth, Westminster and the wider Greater London area. Common faults we fix first time include faulty PICV valves, blocked plate heat exchangers, failed actuators, perished diverter valves, leaking unions, sticking thermostatic cartridges and PCB control errors. We carry the most common Danfoss, SAV and Switch2 spares on the van so the majority of HIU repairs are completed in a single visit.
Bulk HIU Servicing for Property Managers
We work with managing agents, housing associations, ESCOs and developers to deliver bulk HIU servicing programmes across entire blocks. Discounted per-unit pricing, coordinated resident access, full PPM reporting and digital service records keep your heat network compliant with the Heat Network (Metering and Billing) Regulations and ready for any audit.
Why Choose Collide Group?
Over a decade of HIU experience, fully insured Gas Safe and WRAS-trained engineers, transparent fixed pricing with no hidden call-out fees, free no-obligation quotes within one working hour, and a 5-star average across 19 Google reviews from London residents and property managers. Whether you need an annual HIU service, an emergency HIU repair, a brand-new HIU installation or a full power flush, our team is on call 7 days a week.
Call 020 3951 5133 for a free quote, or book online — we respond within one working hour.
Get a Free Quote
Book a Same-Day Callout
Tell us your postcode and the issue — we'll call you back within 1 working hour with a transparent quote.
- 1-hour callback
- Free, no-obligation quote
- Specialist HIU engineers