Exclusive: The ‘Flow Energy’ Boiler That Heats & Makes Electricity Too

When the guys from Flow Energy got in touch we were intrigued by their patented MicroCHP (combined heat and power) central heating boiler that makes electricity while heating your home.

We asked Flow’s CEO, Tony Stiff, to tell us a bit more about the technology and where he sees smart home micro generation heading in the next decade…

Hi Tony, can you tell us a bit about your background and what brought you to the world of heating innovation.

Hi Mark, thanks for having me. I’ve actually always had a history of working with energy and innovation.

Before I joined Flow group, I was the Commercial Director of Bglobal plc where I helped prove the concept of their smart-metering products and was responsible for securing commercial contracts with leading energy suppliers. In 2000, I founded Atlantic Electric and Gas Limited, a business backed by US-based Sempra Energy, Inc.

Flow Energy CEO, Tony StiffThe business quickly became one of the UK’s leading independent energy suppliers, with over 300,000 customers. In 1994, I founded Webbins Limited (“Webbins”). I wanted to exploit the gap in the market for a software product that customers could use to evaluate energy contracts. Having grown Webbins into a company with over 100 staff and £10m turnover, I negotiated the sale of the company to MMT Computing plc, and continued to manage the business for three years afterwards.


For someone that’s never heard of it before, can you explain the MicroCHP concept?

MicroCHP or ‘micro Combined Heat and Power’ is a technology which allows the production of electricity in the home. There are a few different versions of the technology but we use the Organic Rankine Cycle.

Our microCHP product is a domestic gas boiler. It uses patented technology inside the boiler to generate electricity at the same time as it’s heating a home. Gas enters the boiler as usual, but instead of heating the water directly, it heats a liquid – a coolant similar to that used in refrigerators. This liquid evaporates and moves through a scroll expander that begins to spin acting like a small dynamo. The electricity it generates can either be used in the home or exported to the Grid.


So why do I need a boiler that makes electricity as well as heat, can it possibly be as efficient as the power station supplying my home?

Big power stations tend to lose a lot of energy when they generate electricity. More of the energy is lost when that electricity is transmitted down power lines to customer homes.

The Flow boiler generates electricity in a highly efficient system in the home and the electricity is then used within the home so there are no losses in transmission. This means that the Flow boiler generates electricity more cost effectively and with less carbon emissions than big power stations do. The Flow boiler can generate electricity worth around £200 each year – worth £500 if you include Feed-in Tariff payments – and it does that by burning only about £50 of additional gas a year, reducing household carbon emissions by up to 20%, or 1,000 kg of co2.


Does your high-tech boiler come with high-tech controls so I can schedule and control it from my smartphone?

Tablet Heating ControlThe launch version of the Flow boiler is controlled with a standard thermostat. However, we are working to integrate remote and intelligent control for future versions – so watch this space.

The ultimate aim will be able to give customers better visibility and control over their energy use, all the while, reducing their carbon footprint and overall energy bill.


The Automated Home currently uses a conventional boiler fuelled by heating oil. Can the Flow boiler replace this setup easily?

The Flow boiler uses natural gas or LPG and doesn’t work with heating oil. However, it’s relatively easy to convert a home’s heating system to use LPG rather than oil and then a Flow boiler could be installed simply and quickly.


Do you have a range of models for different sized homes?

Our launch model is suitable for 3-5 bedroom homes that currently have a separate hot water tank. We plan to launch a Combination boiler in the future which doesn’t require a separate hot water tank and which will be suitable for both larger and smaller houses.

To make sure the Flow boiler is right for a customer’s home, we ask a few quick qualifying questions and then, if the answers match, we conduct a free home survey to confirm.

Flow Energy Boiler

Are there any government grants available to help with the costs and what’s the payback time for someone investing in the Flow system?

MicroCHP as a technology does attract a dedicated Feed-in Tariff. However, to celebrate the launch of the Flow boiler we’re actually providing our own support for the product with a guaranteed payback model over five years. If a customer installs a Flow boiler, switches their home energy to us and assigns Feed-in Tariff payments to us too, then we’ll reduce their home energy bill by £4,800 over five years. That’s more than the cost of the boiler.

Flow Energy Service


Does the Flow boiler require specialist support or can it be serviced by any heating engineer?

The Flow boiler will be installed by an accredited Flow installer and does have to be serviced and repaired by an accredited Flow installer also. The boiler comes with a 2 year manufacturer’s warranty on the boiler itself and a 2 year warranty on the electricity-generating power module housed within the boiler. However, the power module warranty continues for up to 10 years if the customer continues to stay with Flow for home energy.


With the challenges that lie ahead for the national grid and talk of in-home batteries and micro generation, what do you think the standard home energy system will look like a decade from now?

I believe microCHP will be the de facto heating system in 10 years’ time. We’ll still be using gas in 10 years, but the focus will be on using our gas much, much more efficiently, as the Flow boiler does. MicroCHP will probably be complemented in the home energy system by solar for the summer and augmented with a battery solution to store the energy produced. Undoubtedly, the whole system will be controlled via smartphone and will have intelligent features and functions built in, to optimise its performance.

Flow Energy Electricity Generating ScrollConnected devices in the home will operate automatically at times when the home energy system is producing most electricity and may power off when little electricity is being produced. Smart meters will allow the creation of smart energy tariffs, providing cheaper energy off peak and better rewards for the production of energy at peak times.

That vision is why I think the energy space is so exciting at the moment. Energy is so fundamental to our lives and the emergence of the connected, efficient home could put energy companies in a unique position to deliver innovative solutions to customers.


Thanks for talking to us today – where should people go to find out more?

You’re very welcome Mark, thank you for speaking with me. You can find out all the latest information about the Flow boiler on our website – www.flowenergy.uk.com where you can also register your interest.


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3 Comments on "Exclusive: The ‘Flow Energy’ Boiler That Heats & Makes Electricity Too"

  1. Robert Kendall | March 1, 2016 at 9:07 pm |

    Looks really innovative, interesting and seemingly worthwhile spending the extra if the return is as advise. Currently have a Combi that is quite old and inefficient, which we are looking at changing at the moment so keen to know when the Flow Combi is likely to be out to market?

  2. PlumbNation | April 11, 2016 at 4:55 pm |

    Very interesting, thanks.

  3. Mark Cooper | March 19, 2018 at 10:22 am |

    This is the future, at last consumers have a solution to the rip off energy suppliers who
    keep putting up prices annually for no acceptable reason. Take my modest 3 bed home, my energy provider increased my monthly d/d by £40 pm, I eventually go it for a £10 pm, which is still more than I needed to pay. I only hope that there are no added extras when it goes on the market, like service charges, maintenance etc., I want more info on cost, etc.,

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