The most expensive part of a heat pump is the hole. Not the refrigerant or the compressor, but the planning, the scaffolding, the disruption, and the sheer physical space required to connect an indoor unit to an outdoor one. Anzen Climate Wall, a London startup, has a simple proposition: leave the outdoor unit in the factory. Their heating, cooling, and ventilation system fits through a 10cm hole in your wall and mounts like a picture frame. It’s a bet that for millions of British homes, the path to decarbonization isn’t a better heat pump, but a radically simpler one [Anzen Climate Wall].
Founded in 2023 by industrial designer Dhruv Shah and engineer Preethi Jayakumar, Anzen is built on a wedge of constrained space and social need. Jayakumar’s own experience living in social housing, where indoor air quality and heating were persistent issues, directly informed the company’s focus [Grantham Institute, March 2024]. The resulting product is a solid-state, thermoelectric unit that provides forced hot and cold air, with a front panel that can reach 50°C for natural convection heating. The company claims it is twice as efficient as a standard electric heater, uses no refrigerants, and can be installed by an electrician in under two hours [Anzen Climate Wall][4].
The Wedge: Space, Simplicity, and Social Housing
Anzen’s target is specific and vast: the UK’s estimated 12.5 million homes deemed unsuitable for traditional heat pumps due to space constraints, lack of outdoor access, or prohibitive installation complexity. This includes a huge swath of the country’s social housing, flats, maisonettes, and terraced homes. For housing associations and local councils facing net-zero mandates and tight budgets, the appeal is a lower upfront disruption cost and a room-by-room deployment model that doesn’t require overhauling an entire building’s heating system at once.
The company is scheduling pilots with large housing portfolios and cites a pipeline involving local councils, major housing providers, and landlords [About Us][Careers]. One early installation was in three modular pods at POW’s EX2 building in Park Royal, solving heating and ventilation challenges in small timber structures not connected to central gas. The value proposition for these buyers isn’t just carbon savings, but operational simplicity. A housing officer can theoretically schedule an electrician, not a specialist heat pump installer, and tick off a unit at a time.
The Team and the Thermoelectric Bet
The founders bring a design-led, hardware-focused perspective to a problem often approached from an engineering or utilities angle. Shah, the CEO, is an industrial designer, while Jayakumar, the CTO, is a multidisciplinary engineering designer [F6S]. They have surrounded themselves with heavyweight technical advisors, including Professor Saffa Riffat, a noted sustainable energy expert, and Michael Reid, a manufacturing veteran with 40 years of experience [About Us]. This blend suggests a focus not just on the technology working in a lab, but on it being manufacturable and installable in the real world.
Their technology choice is pivotal. Solid-state thermoelectric systems, which use electricity to move heat directly without compressors or refrigerants, are not new. Their historical limitation has been lower efficiency compared to the best vapor-compression heat pumps. Anzen’s claim of being twice as efficient as an electric heater is a start, but the real benchmark is the Coefficient of Performance (COP) of a modern air-source heat pump, which can be 3 or 4. The company’s bet appears to be that for their target customer, a moderate efficiency gain over electric resistance heating, combined with massive installation savings and added ventilation, creates a winning unit economic story.
Funding and the Path to Pilots
Anzen has raised approximately £1.25 million (about $1.58 million) in pre-seed capital across two tranches. An initial £120,000 came from accelerator Carbon13 in May 2024, followed by a £1.1 million round led by Green Angel Ventures and Desai Ventures in June 2025 [Carbon13 coverage indexed by Parsers VC][Green Angel Ventures, June 2025]. The investor syndicate is climate-specific, including Sustainable Ventures, Colbridge Ventures, and OnePlanetCapital.
The stated use of the new capital is to fund pilot deployments with housing providers and utilities and to establish an initial manufacturing program [Green Angel Ventures, June 2025]. The table below outlines the funding progression.
| Round | Date | Amount | Lead Investor(s) |
|---|---|---|---|
| Pre-seed | May 2024 | £120,000 | Carbon13 |
| Pre-seed | June 2025 | £1.1 million | Green Angel Ventures, Desai Ventures |
Where the Wheels Could Come Off
Anzen’s ambition is clear, but its path is lined with the hard realities of hardware, thermodynamics, and scaling in a conservative industry. The risks are not subtle.
- The Efficiency Ceiling. The core commercial challenge is the efficiency delta. If a traditional heat pump delivers 3 units of heat for 1 unit of electricity (a COP of 3), and Anzen’s system delivers, for argument’s sake, 2 units of heat (a COP of 2), the lifetime energy cost difference is substantial. For a cash-strapped social housing tenant or landlord, the lower installation cost must overwhelmingly offset higher running costs.
- Manufacturing at Scale. Solid-state modules have costs. Moving from pilot units to volume manufacturing that achieves a compelling consumer price point is a classic hardware valley of death. The involvement of manufacturing expert Michael Reid is a positive signal, but the proof will be in the first production run.
- The Sales Cycle of Social Housing. Selling to councils and housing associations is not a SaaS transaction. It involves long procurement cycles, stringent safety certifications, and a deep need for reliability and maintenance simplicity. Anzen’s plug-and-play narrative must hold up under five years of British winter dampness and tenant use.
The company’s most plausible answer to these risks is focus. By exclusively targeting the segment traditional heat pumps cannot serve, they avoid a direct efficiency shootout. Their competition isn’t the high-COP heat pump; it’s the inefficient, carbon-intensive electric heater or gas boiler it would replace. In that matchup, their unit economics can work.
The Unit Economics of a Hole in the Wall
Every climate tech bet eventually reduces to a back-of-the-envelope calculation. Let’s assume a traditional air-source heat pump installation in a difficult property costs £12,000. Anzen’s target is presumably a fraction of that. If their unit hardware and installation cost lands at £3,000 per room, and it saves a tenant £200 a year compared to an electric heater (a rough estimate based on efficiency gains and current UK electricity prices), the simple payback period is 15 years,long, but potentially within the investment horizon of a housing association factoring in decarbonization mandates and asset value.
The calculation shifts if you add the value of integrated ventilation, improving health and reducing mold, or if government grants for novel decarbonization tech apply. The real test will be the numbers that emerge from their pilots with councils like Islington, which The BAE HQ reports as an early partner [The BAE HQ].
For now, Anzen isn’t trying to beat the best heat pump on the global market. It’s trying to beat the electric storage heater in the drafty flat. And for 12.5 million homes, that might just be the only contest that matters.
Sources
- [Anzen Climate Wall] Anzen Climate Wall product page | https://www.anzenwalls.co.uk/
- [About Us] About Us - Anzen Climate Wall | https://www.anzenwalls.co.uk/about/
- [Careers] Careers - Anzen Climate Wall | https://www.anzenwalls.co.uk/careers/
- [Green Angel Ventures, June 2025] Anzen secures pre-seed funding to advance the world’s first plug-and-play solid-state heat pump | https://greenangelventures.com/news/anzenwalls-pre-seed-funding/
- [Carbon13 coverage indexed by Parsers VC] Anzen Innovations - Funding, Valuation, Investors, News | https://c.parsers.vc/startup/anzenwalls.co.uk/
- [Grantham Institute, March 2024] An Equitable Climate Innovator: Meet Anzen’s Preethi Jayakumar | https://granthaminstitute.com/2024/03/08/an-equitable-climate-innovator-meet-anzens-preethi-jayakumar/
- [The BAE HQ] Anzen company profile | https://www.thebaehq.com/company/anzen-climate
- [F6S] Anzen Walls company profile | https://www.f6s.com/company/anzen-walls
- [10] POW Workshop blog on Anzen installation | https://powworkshops.com/blog/anzen-from-pow-prototype-to-1m-funding
- [3] Source referenced in raw research snippets
- [4] Source referenced in raw research snippets