SolarFreezer

What SolarFreezer does

SolarFreezer BV is a Dutch private limited company founded in 2013 and headquartered in Hengelo, Overijssel, Netherlands. The company develops and sells an integrated thermal energy storage and heat pump system designed to replace natural gas for residential and commercial heating. The core technology comprises three components: (1) proprietary Thermische Collectoren — UV-stabilized polypropylene roof-mounted thermal collectors (99 x 165 x 4 cm, 13.6 L internal volume, 3.7 GJ/year yield at De Bilt reference climate) that harvest heat from sunlight and ambient air via a water-glycol mixture; (2) a custom-sized SolarFreezer Bufferzak — a flexible underground thermal storage tank (~10–11 m³ water) installed in the crawl space, leveraging the latent heat of water crystallization for seasonal energy storage; and (3) integration with a third-party water-water heat pump (primarily NIBE 6–16 kW, also validated with Daikin, Bosch, and Weishaupt). The system can also be configured as SolarFreezer RAIN, co-developed with GEP Watermanagement since June 2021, which substitutes underground rainwater pits with integrated heat exchangers for thermal storage.

The company operates an exclusive channel-partner go-to-market model: all systems are sold through a national network of 30+ certified ProPartner installation companies across the Netherlands; end customers (homeowners, housing corporations, construction firms, developers, architects) cannot purchase directly. Revenue is generated through hardware sales of configured thermal energy systems to the installer channel, with project-specific pricing determined by certified installers. Customer segments span new-build residential construction, deep residential renovation/retrofit (targeting gas elimination and energy label upgrades from D/E to A), and light commercial/utility buildings (e.g., the 2022 Ederveen installation). Notable enterprise engagements include social housing corporation Domijn (Enschede NOM renovation) and ProWonen (Lichtenvoorde 4-home pilot), alongside strategic partnerships with Volker Wessels Stevin and De Groot Installatiegroep. Marketing is content-driven, centered on 20+ detailed case studies, a YouTube channel, and industry events such as the Inspiratie 6-daagse. The company remains small and founder-led (Director Jacques Mathijsen), with no disclosed funding rounds or external institutional investors confirmed.

Name

SolarFreezer

Legal name

SolarFreezer BV

Website

https://solarfreezer.nl

Company type

Private

Founded year

2013

Operating status

Operating

Headcount range

1–10 employees

Short description

SolarFreezer BV is a Dutch climate-tech company that designs and sells an integrated thermal-energy storage and heat-pump system for gas-free residential and commercial heating, distributed exclusively through a nationwide network of 30+ certified ProPartner installers across the Netherlands.

Ownership category

akta.pro rank

Product category

Thermal Energy Storage and Heat Pump Systems

NAICS

Power Boiler and Heat Exchanger Manufacturing (33241), Heating Equipment (except Warm Air Furnaces) Manufacturing (333414), Ventilation, Heating, Air-Conditioning, and Commercial Refrigeration Equipment Manufacturing (33341)

SIC

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

akta.pro primary industry

Heat Exchangers & Thermal Transfer Equipment (IMAHAKAC)

akta.pro secondary industries

Underground & Geothermal Thermal Storage (ATES/BTES/CTES, Borehole Fields) (EUAFANAG), Hydronic/Baseboard Radiant Heating Service (HSAOACAE)

Keywords

• Thermal energy storage
• Heat pump systems
• Gas-free heating
• Solar thermal collectors
• Seasonal heat storage

Headquarters

HQ city

Hengelo

HQ country

Netherlands

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

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

Revenue model

1. SolarFreezer System Sales (Complete System or Components): SolarFreezer BV manufactures and sells its thermal energy storage systems (bufferzak, thermische collectoren) and configures them with third-party heat pumps (primarily NIBE) as complete SolarFreezer branded systems. The systems are sold and installed exclusively through a network of certified ProPartner installers. Revenue comes from the sale of configured thermal energy systems to the installer channel, who then sell and install complete solutions to end customers.
2. ProPartner Program (Certified Installer Network): SolarFreezer authorizes and trains certified installation companies (ProPartners) who are fully trained in SolarFreezer methodology, capable of installing, managing, and maintaining the systems, with 24/7 emergency service capability. The ProPartner network is the exclusive distribution route for end-customer sales, suggesting revenue flows through this channel partner model.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels5 records

Core offering

SolarFreezer BV manufactures and sells a proprietary gas-free heating system that combines roof-mounted thermische collectoren (thermal collectors) with a flexible underground thermal energy storage tank (bufferzak) and integrates with water-water heat pumps to provide space heating and domestic hot water. The system exploits the latent heat of water crystallization for seasonal thermal energy storage, capturing solar and ambient heat in summer for use in winter, and is sold exclusively through a network of certified ProPartner installers in the Netherlands.

Product overview

SolarFreezer offers a modular heat pump system with proprietary thermal energy storage that replaces natural gas for residential and commercial heating. The core system consists of three main components: (1) Thermische Collectoren - thermal collectors mounted on roofs behind PV panels that harvest solar and ambient heat; (2) SolarFreezer Bufferzak - an underground thermal energy storage unit using water with phase-change (crystallization) properties for seasonal heat storage; and (3) integration with water-water heat pumps (primarily NIBE) to distribute heating and domestic hot water. The system is available in multiple configurations ranging from 6 kW to 16 kW capacity, with variants including the SolarFreezer RAIN system that substitutes underground cisterns for the buffer bag in rainwater management applications. The company operates through a network of certified Pro Partner installers across the Netherlands.

Differentiator

Problem solved

Functional benefit

Brands

• SolarFreezer: Heat pump system with thermal collectors and buffer storage for gas-free heating and hot water
• SolarFreezer RAIN

Products and services

• SolarFreezer Bufferzak (Thermal Storage Tank) A flexible underground thermal energy storage tank placed in the crawl space of buildings, storing approximately 10-11 m³ (10,000-11,000 liters) of water. Standard dimensions 4.0 x 6.0 x 0.5 m³, custom measured and produced on-site per installation. Serves as long-term seasonal heat storage using water crystallization (latent heat of fusion), bridging dark and cold winter periods.
• Thermische Collectoren (Thermal Collectors) Roof-mounted thermal collectors (99 x 165 x 4 cm) using a water-glycol mixture (-20°C) with 13.6 L storage volume per panel and 12,800 cm² heat-absorbing surface. Made of UV-stabilized polypropylene with maximum temperature +70°C, producing 3.7 GJ/year thermal energy per panel. Placed behind PV panels on sloped or flat roofs, or as standalone solar roof modules.
• Thermische Zonnedak Module (Solar Roof Module) A custom thermal collector cassette system designed for flat roofs where PVT panels cannot be installed, allowing discrete placement of thermal energy collectors. Used in place of standard roof-integrated thermische collectoren for installations on flat-roof new-builds.
• SolarFreezer RAIN System A variant of the SolarFreezer system that uses underground rainwater collection pits with integrated heat exchangers as thermal energy storage instead of the bufferzak, plus a third pit for rainwater collection for household use. Developed with GEP Watermanagement. Standard configuration includes 15,000L rainwater + 30,000L thermal storage with 12 collectors.
• SolarFreezer Pro Partner Certification Program A certification and authorization program for installation companies in the Netherlands who sell, install, manage, and maintain SolarFreezer systems. ProPartners are fully trained in SolarFreezer methodology and must provide 24/7 emergency service. The network spans the entire Netherlands with 30+ certified installation companies.

Quantifiable outcome

• Up to 100% natural gas savings — the SolarFreezer can entirely replace natural gas for heating and hot water when combined with electric cooking
• +2 more outcomes

Named customers6 records

Segments3 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Partnerships

Five partnerships are on record, tiered core, major and minor.

• GEP Watermanagement BVcoreStrategic or Co-development Partner · 1 June 2021SolarFreezer and GEP Watermanagement formed a strategic partnership in June 2021 to jointly develop integrated solutions for sustainable heating/cooling and rainwater management. Their first co-developed product is SolarFreezer™ RAIN, which uses underground rainwater pits with heat exchangers as thermal energy storage instead of the traditional bufferzak. GEP contributes over 23 years of expertise in decentralized water management; SolarFreezer provides the thermal energy system and heat pump integration. The partnership extends to co-marketing at events and joint market approach.
• De Groot Installatiegroep B.V.coreChannel Partner/ Reseller/ DistributorDe Groot Installatiegroep is a long-established family installation company founded in 1965, grown to one of the leading installation companies in the Netherlands with nine branches nationwide. They provide electromechanical and fire protection solutions and serve as a certified SolarFreezer installer, delivering installation, service, and maintenance of SolarFreezer systems.
• Volker Wessels Stevin N.V.majorStrategic or Co-development PartnerVolker Wessels Stevin N.V. is a major construction and real estate development company operating across the Netherlands through specialized subsidiaries organized in four regional divisions (Noord-Oost, West, Midden, Zuid). They focus on design, development, realization, and maintenance of the built environment. Listed as a strategic partner for SolarFreezer, likely involved in incorporating SolarFreezer systems into new construction projects.
• Bouwen4jouminorChannel Partner/ Reseller/ DistributorBouwen4jou is a construction company using the unique 100% reusable Japanese Suteki timber-frame building system. They are listed as a strategic partner on SolarFreezer's About page and have completed at least one project (Oostzaan villa, 2020) combining the Suteki timber-frame system with SolarFreezer. The partnership integrates sustainable construction with gas-free heating.
• NIBEcoreTechnology or IntegrationNIBE is a Swedish manufacturer of water-water heat pumps (including NIBE F-1255 and F-1155 series in 6kW, 12kW, and 16kW capacities) that are integrated into SolarFreezer system configurations as the heat pump component. NIBE heat pumps with integrated or separate boilers (180L–500L) are the primary heat pump brand specified across SolarFreezer's standard product configurations. The partnership was showcased at the Inspiratie 6-daagse event.

Scale indicators3 records

Recent moves6 records

Expansion highlights5 records

Broad incumbents

• Vaillant Group: European manufacturer of heat pumps and gas-free heating systems including the aroTHERM and geoTHERM ranges. Comparable as a broad incumbent offering residential heat pump solutions, with overlaps in the Dutch new-build and retrofit market.
• Itho Daalderop: Dutch manufacturer of heat pumps, ventilation, and domestic hot water solutions. Comparable as a Netherlands-based residential heating brand competing in the same Dutch gas-replacement market, including hybrid heat pump offerings.
• Inventum Technologies: Dutch manufacturer of heat pumps, boilers, and hybrid heating solutions. Comparable as a Netherlands-based residential heating brand with focus on gas-free and hybrid heat pump systems for the Dutch market.
• ATAG Verwarming (Bosch): Dutch heating brand under Bosch supplying heat pumps and boilers for residential gas-free heating. Comparable as a competing Dutch-installed heating brand serving similar housing-corporation and homeowner customers.
• NIBE Energy Systems: Swedish manufacturer of water-water and air-source heat pumps (F1255, F1155 series) that SolarFreezer integrates as its primary heat pump. Comparable as a provider of residential gas-free heating systems, though NIBE is far larger and offers full heat pump solutions without seasonal thermal storage.
• Daikin (heating division): Global manufacturer of HVAC and heat pump systems including Altherma, used in SolarFreezer installations (Lelystad). Comparable as a heat pump OEM serving the same residential gas-free heating opportunity, with much broader product portfolio.
• Remeha (BDR Thermea Group): Major Dutch heating manufacturer offering hybrid heat pumps and gas-free residential heating solutions. Comparable as a Dutch-headquartered provider of residential heating replacements for gas disconnection, competing for the same housing-association and installer channel.

Emerging players

• Sunamp: UK-based maker of compact phase-change thermal batteries for hot water and space heating. Comparable as a residential thermal energy storage innovator, though Sunamp's storage is product-level (hot water tanks) versus SolarFreezer's whole-house seasonal storage approach.
• CTC (Enertech): Swedish heat pump manufacturer specializing in air-source and ground-source heat pumps for residential and commercial applications. Comparable as a European heat pump specialist serving similar Scandinavian/Northern European gas-replacement use cases.
• EnergyNest: Norwegian thermal energy storage company using solid-state concrete-based storage for industrial and commercial heat. Comparable as a European thermal energy storage innovator, though focused on industrial scale rather than residential.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks6 records

Key highlights7 records

Customer concentration

• YouTubeyoutube.com/channel/solarfreezer

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

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 SolarFreezer