The coolest way to heat up your home this winter

When Breakthrough Magazine first spoke to Minus7 in the spring of 2017, the Isle of Wight-based company had already come a long way with the technology that aimed to cut costs, tackle fuel poverty and offer a renewable energy solution for heating our homes.

Based on an idea that had first been put forward in the 1980s, their product is described as ‘a system in three parts: roof, energy processor and energy storage.’ With the ability to take advantage of modern technologies and a more environmentally-minded public and political climate, Minus7 had created a single integrated solution that encompassed the best of solar thermal, photovoltaic, energy storage and heat pump technologies.

As Director, Hamish Wilson explained to us at the time: “The solution didn’t gain traction [in the 1980s] as it was ahead of its time. The appetite for renewable energy solutions just wasn’t strong enough…"

“The more sophisticated technology available today enables much finer control of a three-stage system. This capability means the combined solution is now a viable alternative to traditional heating methods, in both its effectiveness through temperature management and its efficiency through accurate levels of control.”

Unlike traditional systems that typically heat water to hundreds or even thousands of degrees Centigrade, before cooling it to a useable 70˚C or so, Minus7 takes a much more environmentally-friendly approach. They use a roofing system made of liquid-filled solar thermal panels that can harvest energy day and night, at temperatures as low as -7˚C.

This captured energy is transferred to underground thermal stores via heat exchangers. Minus7 can control the carefully-balanced system with their own Solar Energy Processor (SEP) while building occupants control the water and heating temperature with a conventional thermostat and timer. 

At this spring’s Ecobuild event, Minus7’s Head of Business Development Ed Suckling gave us a recap of why their solution represents such a significant shift in heating technology.

“It’s a hybrid solar thermal heating system that combines existing robust technologies in an innovative way and controls those technologies by a proprietary system that we’ve written in-house,” he said. “So, we’re providing space heating and hot water to multiple buildings, whether they’re new build or retro fit. Ours is the cheapest renewable energy technology per SAP (Standard Assessment Procedure) point so we offer a significant uplift in the EPC ratings for retro fit buildings."

“We can deliver heat at less than the cost of gas, so our target audience mainly comprises local government and housing associations, for whom fuel poverty is a big issue. We want to drive fuel poverty out.”

In real terms, how much of a difference can a system like Minus7 make to the average tenant? The answer is, a considerable one.

“Installing our system makes the heating of domestic houses much cheaper for tenants,” Suckling said. “If an electric storage heating system was replaced with ours, the cost would typically be £250 per year instead of £800. So, it makes a material difference to tenants who are choosing whether to eat or heat.”

Despite these eye-catching figures and the helpful evolution of both technology and ideology since the 1980s, bringing Minus7 to market was no easy task. Bureaucracy proved to be the biggest minefield - the Minus7 team had to work with BRE to develop a new subsidy category for Solar Assisted Heat Pumps, as there had been no existing recognition for such a thing.

That achieved, the company still had some major challenges ahead. A key objective was to improve their competitive edge by bringing manufacturing costs down by 40% - how had they fared?

“We’ve achieved 30% cost reduction this year and are looking to further that over the next couple of years,” Suckling said. “We’re doing that by potentially outsourcing production and working with a production engineering house to look at how we can drive costs down without affecting efficiency. Finding the right partner is going to be key, but they will be based in the UK. Everything we have here is UK-manufactured and that’s one of our core drivers.”

Another plan was to work on a new roof system with embedded photovoltaic cells that could be cooled by water in the roof and achieve a significant uplift in the yields from the PV cells. This integrated solution was proudly adorning Minus7’s stand at Ecobuild and was already attracting significant attention, as Suckling explained.

“We’ve done a couple of projects with the product since it launched last year. It’s commercially available now and we’re working with a private rental sector developer who is looking to roll out energy positive homes, which is a really exciting opportunity for us. These will be new builds where the predictive heat loads and energy loads of a home will be covered by the generation on that building. They’ve got several hundred new homes in the pipeline over the next few years.”

Next up for Minus7 will be a focus on demand side management, when ‘time of use’ tariffs could be exploited to bring energy costs down even further. They will also be looking at the potential of integrating demand side management with battery storage and smart home technology.

Minus7’s heating solution is not currently optimised for individual householders, but Suckling believes that as the cost of their technology comes down, the future for efficient and warm homes will be available to all.

“Because our systems can generate enough energy to heat many homes, typically the economics work better across multiple houses,” he said. “So, for asset owners - such as housing associations, local Government and the private rental sector - our solution makes perfect sense."

“But we’re also looking at new builds, where great estates of homes are being constructed. The government is looking to drive the decarbonisation of heat by 2040 - the way to do that is through the electrification of heat and the only way to do that is through the application of heat pumps. We’re right at the forefront of that concept.”

Minus7 has worked with Breakthrough funding, a company that helps UK SMEs achieve R&D tax credits - a government scheme created to enhance and reward innovation amongst UK businesses. Could you be eligible? Click here to learn more.

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