What Warmflow does

Warmflow Engineering Co. Ltd is a privately held Northern Ireland-based manufacturer of home heating appliances, founded in 1968 and headquartered in a 150,000 sq ft automated facility in Lisburn. The company designs and produces three core product lines: the Agentis range of oil-fired boilers (Internal, External, Boilerhouse, Professional variants, and Combi models), the Zeno renewable heating range comprising R290 and R32 air source heat pumps and ground source heat pumps, and the Nero range of hot water cylinders and buffer tanks. Underlying technology is centred on a patented 5mm stainless steel heat exchanger, Riello low-NOx burners, R290 natural refrigerant with GWP of 3, automated production using ABB robotic welding and Salvagini panel benders, and the Warmlink remote monitoring platform with built-in 4G SIM cards. The portfolio holds UK & Ireland-only AAA oil boiler and AA Combi oil boiler ratings and MCS 010 plus ISO 9001/14001/45001 certifications, qualifying products for the Boiler Upgrade Scheme and SEAI grants.

The company generates revenue primarily through B2B hardware sales distributed via OFTEC-registered installers, plumbing and heating merchants, and dedicated regional sales teams covering Northern Ireland/Republic of Ireland and Great Britain, with a new Spanish sales office supporting European expansion. The go-to-market is heavily channel-partner-led, reinforced by the Warmflow Connect points-based loyalty scheme, a network of nine training centres delivering free product education, and the Heat Pump Assist+ programme that helps non-MCS installers access MCS certification. A separate Warmflow Engineering division provides sheet metal design, fabrication, kitting, and assembly services. Customer segments centre on heating engineers and installers, residential homeowners in off-gas areas, property developers, the agricultural sector, and heritage properties, with secondary revenue from contract engineering work.

Name

Warmflow

Legal name

Warmflow Engineering Co. Ltd

Website

https://warmflow.co.uk

Company type

Private

Founded year

1968

Operating status

Operating

Headcount range

51–100 employees

Short description

Warmflow is a Northern Ireland-based, family-owned manufacturer of oil boilers, air source and ground source heat pumps, and hot water cylinders, selling exclusively through OFTEC-registered installers and merchants across the UK, Ireland, and Spain.

Ownership category

akta.pro rank

Product category

Heating Equipment Manufacturing

NAICS

Heating Equipment (except Warm Air Furnaces) Manufacturing (333414), Power Boiler and Heat Exchanger Manufacturing (332410), Ventilation, Heating, Air-Conditioning, and Commercial Refrigeration Equipment Manufacturing (33341)

SIC

Heating Equipment, Except Electric & Warm Air Furnaces (3433), Heating Equip, Except Elec & Warm Air; & Plumbing Fixtures (3430), Air-Cond & Warm Air Heatg Equip & Comm & Indl Refrig Equip (3585)

akta.pro primary industry

Boilers, Furnaces & Process Heating Equipment (IMAHAKAD)

akta.pro secondary industries

Heat Pumps (Air/Water/Ground Source) (IMAHAKAF), Heat Exchangers & Thermal Transfer Equipment (IMAHAKAC)

Keywords

• Oil-fired boilers
• Air source heat pumps
• Hot water cylinders
• Renewable heating solutions
• HVO compatible boilers

Headquarters

HQ city

Lisburn

HQ country

United Kingdom

HQ region

Europe

Offices11 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Supply Chain, Operations, Personnel, Technology or R&D, Marketing or Sales, Infrastructure

Revenue model

1. Oil Boiler Sales: Warmflow manufactures and sells oil-fired boilers including Agentis Internal, External, and Boilerhouse ranges. Revenue is generated through wholesale distribution to installers and merchants across UK, Ireland, and expanding European markets.
2. Heat Pump Sales: Zeno R290 Air Source Heat Pumps and GS03 Ground Source Heat Pumps sold to installers and specifiers. Units qualify for government grants including Boiler Upgrade Scheme (£7,500 in England/Wales, up to £9,000 in Scotland) and SEAI grants (up to €12,500 in Republic of Ireland).
3. Hot Water Cylinder Sales: Nero cylinder range including Direct, Indirect, Twin Coil, Triple Coil, Heat Pump, and Buffer Tank models sold through installer channel. Available in volumes from 110 to 290 litres.
4. Warmflow Connect Loyalty Program: Installer loyalty scheme where registered installers earn points for product registrations that can be redeemed against rewards catalogue including tools, merchandise, gift cards. While not itself a revenue stream, it drives repeat purchases and customer retention.
5. Engineering & Fabrication Services: Warmflow Engineering division offers design, manufacturing, and fabrication solutions working primarily with sheet metal (0.6mm to 8.0mm). Services include kitting, sub-assembly, full production line manufacturing, automated tube cutting, and welding (Mig/Tig/Plasma).

Pricing tiers

Go-to-market motion3 records

Distribution channels4 records

Marketing channels7 records

Core offering

Warmflow manufactures and supplies oil-fired boilers (Agentis Internal, External, Boilerhouse, Professional, and Combi ranges), renewable heating systems (Zeno R290 Air Source Heat Pumps and Ground Source Heat Pumps), and a comprehensive line of hot water cylinders and buffer tanks (Nero Direct, Indirect, Twin Coil, Triple Coil, Heat Pump, and Buffer Tank models). The company sells exclusively through a network of OFTEC-registered installers and plumbing/heating merchants across the UK, Republic of Ireland, and expanding European markets, supported by free training programmes, the Warmflow Connect loyalty scheme, and a separate Engineering division offering sheet metal fabrication services.

Product overview

Warmflow is a manufacturer of home heating appliances offering a comprehensive portfolio of oil-fired boilers and renewable heating solutions. The product portfolio comprises three main categories: Agentis oil boiler range (Internal, External, and Boilerhouse models) including Professional variants with factory-fitted accessories; Zeno renewable technology including R290 Air Source Heat Pumps (9-22kW) and Ground Source Heat Pumps (GS03 up to 18kW); and Nero hot water cylinders (Direct, Indirect, Twin Coil, Triple Coil, Heat Pump, and Buffer Tank models) ranging from 110-290 litres. The Agentis Combi boilers are notable as the UK's only AA-rated combination oil boilers. Products feature proprietary technologies including patented stainless steel heat exchangers, Riello low NOx burners, and Warmlink remote monitoring capability. All products are manufactured at the 150,000 sq ft facility in Lisburn, Northern Ireland, and are designed for the UK and Ireland markets.

Differentiator

Problem solved

Functional benefit

Brands

• Agentis: Oil boiler range including internal, external, and boilerhouse models with patented stainless steel heat exchanger technology.
• Nero
• Zeno
• Professional

Products and services

• Agentis Internal Oil Boiler High-efficiency internal oil-fired boiler combining the patented 5mm stainless steel heat exchanger with Riello low NOx burner technology. AAA-rated efficiency, with a compact slimline white casing designed for kitchen and utility room installations; intended for off-gas residential properties.
• Agentis External Oil Boiler Outdoor oil-fired boiler with IP45-rated weatherproof casing using the patented stainless steel heat exchanger and Riello low NOx burner technology; multi-directional flue included as standard, outputs from 15 to 44 kW, intended for external installation at off-gas residential properties.
• Agentis Boilerhouse Oil Boiler Oil boiler specifically designed for boilerhouse and garage applications, employing the patented stainless steel heat exchanger and Riello low NOx technology; features single-socket operation with outputs from 15 to 33 kW.
• Professional Oil Boiler Market-leading high-efficiency oil boiler range with factory-fitted accessories including the Adey Magnaclean Pro 2 filter, Teddington fire valve, Crosland oil filter, Grundfos UPM3 Flex AS circulating pump, and condensate installation kit (accessories valued at over £250 included as standard). Available in Internal and External models from 15 to 33 kW, with HVO compatibility across the entire Agentis range.
• Agentis Internal Combi Oil Boiler UK and Ireland's only AA-rated combination oil boiler offering both heating and hot water from a single unit. Features the patented stainless steel heat exchanger, factory-fitted 24-litre hinged expansion vessel, pressure relief and reducing valve, and a 515mm-wide slimline form factor.
• Agentis External Combi Oil Boiler AA-rated outdoor combination boiler with IP45 weatherproof casing; includes factory-fitted 24-litre expansion vessel, pressure relief valve, and DHW mini expansion vessel; outputs 15 to 33 kW, intended for off-gas residential properties.
• Zeno R290 Air Source Heat Pump High-efficiency air source heat pump using natural R290 (propane) refrigerant with low Global Warming Potential of 3. Available in 9kW, 15kW and 22kW modulating outputs, with built-in 4G Warmlink technology for remote monitoring and control, flow temperatures up to 75 degrees C, and ultra-quiet operation at 41-48 dB(A); qualifies for Boiler Upgrade Scheme (£7,500 in England/Wales, up to £9,000 in Scotland) and SEAI grants.
• Zeno Ground Source Heat Pump Ground source heat pump with 508% efficiency (claimed as one of the most efficient in Europe), featuring a Copeland inverter-driven compressor, variable speed pumps, and plate heat exchangers; output up to 18 kW on single-phase electricity, intended for residential renewable heating installations.
• Nero Direct Cylinder Electric hot water cylinder with two immersion heaters featuring Economy 7 tariff compatibility. Volumes from 110 to 290 litres, designed for properties where fossil fuels are impractical.
• Nero Heat Pump Cylinder Hot water cylinder designed to work with Zeno air source heat pumps. Available in 170 to 290 litre sizes with a large surface area plate heat exchanger achieving 25-minute heat-up times and an ERP rating of C.
• Nero Indirect Cylinder Indirect hot water cylinder with market-leading large surface area heat exchange coils. The 170 litre model reaches 60 degrees C in 25 minutes and is designed for mains water pressures up to 16 bar.
• Nero Twin Coil Cylinder Hot water cylinder with two heat exchanger coils—one for primary heating and one for a renewable heat source such as solar thermal or an additional boiler—and features large dedicated renewable volumes.
• Nero Triple Coil Cylinder Hot water cylinder with three 22mm heat exchanger coils enabling connection to multiple heat sources such as solar thermal, wood pellet boiler, and oil/gas boiler; duplex stainless steel construction.
• Nero Twin Vented Coil Cylinder Vented twin coil hot water cylinder with immersion heater and cylinder thermostats; designed for use with solar thermal systems and additional boilers, with secondary return connection on 200 litre and above models.
• Nero Buffer Tank Buffer tank for heating systems with various heat sources including heat pumps, biomass boilers, and liquid-fuelled appliances. High insulation reduces heat loss. Available in 110 litre and 200 litre models.
• Warmflow Engineering Fabrication Services Design, manufacturing, and fabrication services primarily with sheet metal from 0.6mm to 8.0mm, including kitting, sub-assembly, full production line manufacturing, automated tube cutting, and welding (MIG/TIG/Plasma); offered as a separate contract service to external customers.

Quantifiable outcome

• 5 litres of fuel savings per week compared to other combi oil boiler brands
• +5 more outcomes

Named customers7 records

Segments5 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature6 records

Partnerships

Seven partnerships are on record, tiered core and minor.

• Friends of the Cancer CentrecoreStrategic or Co-development PartnerLong-standing partnership spanning over 40 years supporting cancer patients and families in Northern Ireland. Warmflow sponsors key fundraising events including Tower Abseil, Slieve Donard Walk, and Winter Ball. Raised £186,000 in most recent partnership year.
• The Cancer Fund for ChildrenminorStrategic or Co-development PartnerPartnership supporting construction of Daisy Lodge facility in Co. Mayo. Warmflow hosted customer golf day at Carton House with all costs covered by Warmflow so funds went directly to charity.
• MCS Accredited Partners (Heat Pump Assist+)coreImplementation/ SI/ Consulting PartnerNetwork of MCS accredited partners who assist non-MCS certified installers with heat pump installations, providing MCS sign-off, commissioning, and BUS voucher application support. Helps installers deliver MCS accredited installations without costly personal accreditation.
• AdeycoreTechnology or IntegrationAdey Magnaclean Pro 2 filter included as standard in Professional range boilers. Partnership provides quality filtration solution for oil systems.
• GrundfoscoreTechnology or IntegrationFactory-fitted Grundfos UPM3 FLEX AS circulating pump on pumped, system, and combi Professional models. Saves installation time and maximises space within appliance.
• RiellocoreTechnology or IntegrationLatest Riello low NOx burner technology across entire Agentis oil boiler range. Exceeds legislative requirements for emissions.
• OFTECcoreOthersOFTEC (Oil Firing Technical Association) is the certification body for oil-fired heating technicians. Warmflow requires installers to be OFTEC registered to access warranty and join Warmflow Connect scheme.

Scale indicators9 records

Recent moves10 records

Expansion highlights5 records

Direct peers

• Grant UK: Grant UK is one of the UK's largest oil boiler specialists, manufacturing oil-fired boilers and renewable heating products for UK and Ireland markets. Highly comparable to Warmflow on product mix (oil boilers + heat pumps), installer channel model, and geographic footprint.
• Firebird Heating Solutions: Firebird is a UK and Ireland oil boiler manufacturer based in Ireland, directly competing with Warmflow's Agentis range in the same off-gas and rural installer channel. Comparable on technology (condensing oil boilers), customer base (OFTEC installers), and end markets.
• ATAG Heating: ATAG Heating (part of ATAG Benelux) supplies boilers, heat pumps and heating controls to UK installers. Comparable product mix to Warmflow (boilers, heat pumps, accessories), distributed through similar installer channels in UK and Ireland.

Broad incumbents

• Worcester Bosch: Worcester Bosch is the UK's leading gas boiler brand (part of Bosch Thermotechnology) and a major heat pump player. Comparable to Warmflow on product categories (boilers, heat pumps, cylinders) but operates at vastly larger scale and across gas-fired as well as renewable technologies.
• Baxi: Baxi (part of BDR Thermea Group) is a major UK boiler and heating brand offering gas boilers, heat pumps, and commercial heating solutions. Comparable on residential heating portfolio and installer-led GTM but with a gas-led rather than oil-led heritage.
• Ideal Heating: Ideal Heating is one of the UK's largest boiler manufacturers (part of Stelrad Group), supplying combi, system and heat-only boilers plus commercial heating. Comparable on boiler manufacturing and UK installer channels, but primarily gas-focused rather than oil-focused.
• Vaillant Group: Vaillant is a major European heating manufacturer offering gas boilers, heat pumps and hot water cylinders across UK and Europe. Comparable product portfolio to Warmflow (boilers, heat pumps, cylinders) with substantially greater scale, R&D and European footprint.
• Viessmann: Viessmann is a leading German manufacturer of heating, industrial and refrigeration systems with strong UK presence in boilers, heat pumps and cylinders. Comparable on full heating portfolio and installer-led GTM, with significantly greater international scale.
• Daikin UK: Daikin is the global leader in air conditioning and heat pump technology with a major UK heat pump business. Comparable to Warmflow's Zeno ASHP range on product technology and installer network but operates at much larger scale with broader HVAC portfolio.
• Mitsubishi Electric Living Systems: Mitsubishi Electric is a major UK heat pump manufacturer (Ecodan range) with deep installer programmes. Directly comparable to Warmflow's Zeno on air source heat pumps, MCS-certified installations, and government grant eligibility, but with vastly greater scale.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

• Xx.com/warmflowuk
• Facebookfacebook.com/Warmflow

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Warmflow