Your Retrofit Partner to Net Zero

We’re Here To Help Housing Providers Achieve Success At Every Stage Of Their Retrofit Journey

Whether you’re looking to better understand the size of your challenge, or you have funding and need a PAS 2035 compliant coordinator to get you started, we offer a range of services to help you assess and deliver on your Net Zero commitments.

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Assess The Scale of Your Challenge With Portfolio Pathways

If you’re looking to size up the scale and cost of your Retrofit journey or make a strong bid for funding, then Portfolio Pathways is for you.

Using a unique algorithm built by industry, PAS 2035, and data analytic experts, we’ll quickly pull together all your property information at scale and provide you with the management information you need to make informed decisions.


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Using our Portfolio Pathways solution will enable you to:

Size up your challenge
To gain a clear understanding of your housing stock and what’s required to achieve Net Zero.

Gain invaluable MI at a glance
Through a dashboard that visually tells you your top-level costs, and expected energy savings for your tenants, along with the impact on your carbon emissions and EPC ratings, across your entire portfolio.

Make informed decisions
With a breakdown of costs, measures, suggested sequence and timeframe for works and an idea of when you can reach EPC and Net Zero targets.

Create individual Pathways
With base level plans created for each home, that can be used as part of your decision making on where to carry out your retrofit projects first.

Spend your money wisely
With pragmatic and cost-effective solutions to achieving Net Zero, using considerations and data such as your home disposal plans and building performance in real life

Have a central repository
For your property EPC data.

Be Retrofit Ready With Our Retrofit Co-ordination Service

Our PAS 2035 qualified experts work with you and your retrofit team to develop and coordinate your Medium Term Improvement Plans (MTIP). We’ll use our experience, expertise, and technology, to build not only a compliant plan but one that actually delivers on your net zero and EPC targets. What’s more, our Customer Experience Managers will support you to engage your residents so they can live in a healthy and affordable home. 

How we work with you:

We want to make sure that we’re making careful use of your capital budgets and hitting all your requirements and intended outcomes. That’s why before developing your plan, our experts will sit down with you and get a full understanding of your requirements.

We’ll review and analyse your Retrofit Assessment data once we receive it from your Retrofit Assessor, in order to produce your Improvement Options Evaluation (IOE) and Medium Term Improvement Plans (MTIP).

Whilst reviewing we’ll flag any necessary rectification work and build a sequence of works for each home, that will fit in line with both your intended outcomes and/or issues raised within your assessments. 

Now that we have all the information we need, we’ll get to work on developing your bespoke IOE’s and MTIP’s. We’ll use our expertise, experience and wealth of data to ensure you get the right technical solutions, in the right order for maximum benefit, minimising any delays to your program or unplanned spend.

Our PAS 2035 compliant plans include:

  • Individual stepped plan for each property including measures/technology to be implemented and in which order
  • Total spend both at Project and individual property level
  • Graphs demonstrating when you’re likely to reach your EPC and Net Zero targets, you’re carbon emissions and the likely saving to resident’s energy bills.

We’ll work with your Retrofit designers and installers at every stage of delivery, to make sure their works are scoped and done to an acceptable quality and meet all your PAS 2035 and compliance standards.

Our experts will review and sign off their paperwork, as well as undertake spot checks on site, keeping you up to date on progress and reporting back to you any issues or concerns.

Once all of your planned works have been delivered to a satisfactory standard, we’ll compile all of the required documents and lodge into the TrustMark Data Warehouse.

Our Customer Experience experts will support your teams in developing a Resident Engagement strategy, by providing workshops, training, and materials.

Why Work With Us?

We’re With You Every Step Of The Way

We understand that you’re juggling a lot of other priorities and need a trusted partner that can do the heavy Net Zero lifting for you.

Our products and services are designed to help housing providers achieve success at every stage of their Net Zero journey – simply and affordably. Where here not just to make housing compliant but to make a real impact, future proofing homes for both the residents and the planet.

We see ourselves as an extension to your organisation, from developing your retrofit plans to supporting you with your resident experience. We’re committed, collaborative and promise to always act with integrity.

We Put Your Residents At The Heart Of Our Approach

Our offering is built on the principle that winning the trust of the Resident to support their home on the decarbonisation journey is critical to success.

With in-house resident engagement experts, outputs and content designed specifically for Residents, we’ll support you in developing an engagement strategy that will empower your residents to both take-up and make the most of the measures within their homes.


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We Understand That Every Home Has A Different Story

We take a different approach to other software platforms. We’ve utilised our years of experience in how homes and buildings perform in real life, to make sure our digital platform is using the right data to get the most pragmatic results at scale.

Our digitally-driven service is centered on ensuring the money you spend on measures is carefully and successfully spent.

Unlike other platforms who solely use EPC/SAP spreadsheets, our platform uses all available data for your individual homes. From real energy pricing and ‘unregulated’ electricity use, to granular machine-learning forecasts of future Grid decarbonisation.

What’s more, by gaining a full understanding of your intended outcomes and considering things like your home disposal plans and new build programs; you’ll be pleasantly surprised with how little capital spend you might need to get your homes to Net Zero, in comparison with other systems.

Got A Project?

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Contact Us

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Call us: 02920 001415

Westgate House,
Womanby Street,
Cardiff, Wales,
CF10 1BR

Net Zero homes,
simply and affordably

Who Are We?

Here at Sero, we believe a green, Net Zero Carbon home should be possible for everyone. We’re a team of over 80 passionate individuals, who are experts and innovators in technology, construction, product development, energy, customer service, sales, marketing, and people.

Together, we work across homes, energy, and finance, combining expertise with our technology, to help our clients, develop and implement trusted Net Zero strategies.

Find out more about us

What Do We Do?

Achieving Net Zero is a journey, done in incremental stages.  We bring our passion, independent expertise, and technology, to the entire journey; helping housing providers decide on the right approach and measures to retrofit their homes.

Whether you’re looking for a strategic partner to work with you across your entire journey or have a project that needs one or more of our services, we’re here to get you to Net Zero, simply and affordably.


Take a look at our Retrofit services

Download our brochure

Assess with Portfolio Pathways

If you’re looking to better understand your housing stock and what’s required to achieve Net Zero, then Portfolio Pathways is for you. Our digital solution will provide you with all the information you need to make informed decisions and a strong bid for funding.

Fund with Solar Share Scheme

If you need an alternative way to fund your Retrofit programs, then our Solar Share Scheme could be your solution.  By installing renewable measures and our in-home metering technology into your homes, you can provide your residents with cheaper and cleaner electricity, whilst generating an income stream.

Implement with Retrofit Co-ordination

If you’re looking to get your Retrofit project up and running, then our PAS 2035 compliant Retrofit Co-ordination service is for you.  Using our experience, expertise, and technology, we can help you both develop and coordinate Medium Term Improvement Plans.

Why We Do What We Do

Put simply – because we need to
40% of the UK’s carbon emissions come from households, how we build and live in our homes, makes up a big proportion of this. As a nation, we will not succeed in fighting the Climate Emergency if we don’t effectively eliminate carbon emissions from every one of our homes.

We do this for ours, for yours and for future generations. Sero is for our future.

Get In Touch

To speak to one of our friendly experts, simply complete the form below and we’ll be in touch.

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We are Sero

Who We Are

Born from a passion for making a real impact on the carbon emissions we produce from our homes, Sero was founded in 2017. Over the last 6 years, we’ve been busy bees, leading the way on some of the UK’s biggest research projects and developing market-leading technologies and solutions.

Today we’re a team of over eighty individuals, who are proud to be a trusted partner for some of the UK’s largest housing providers, helping them retrofit their homes to Net Zero.

Our experts and technology support housing providers to better understand their housing stock and develop simple and affordable solutions to improve their homes. Together we’re not just tackling climate change but fuel poverty, making sure their residents live in sustainable, affordable, and healthy homes.


Interested in joining us

The Sero Journey

Sero was founded by James & Andy.

We achieved B Corp status and commenced works on two new build sites – The Mill and Parc Eirin, delivering low carbon technology in 228 homes.

Sero led the Optimised Retrofit Project for Welsh Government, retrofitting 1,728 homes across Wales with 28 social landlords. We also moved into our Cardiff Hub and received our series A funding from Legal & General and Hodge.

Works commenced on Penderi Retrofit Energy Project – UK’s largest renewable retrofit project of its kind. Sero working with Pobl provides a range of retrofit services including our innovative solar share scheme. 

Hodge and Legal & General, provide us with a second round of investment, enabling us to further invest in our people and expand our team to over 80 experts. 

We partner with Sovereign Housing Group to deliver Retrofit Co-ordination services for 1,000 homes.  

Meet Our Founders

Having worked in Energy and Housing for a long time, James and Andy felt strongly that if they could develop simple and affordable solutions for building and retrofitting greener homes, they could make a real impact.

James is our CEO and is on a mission to help housing providers fund their journey to net zero beyond grant funding, maximising value from our energy systems.  Andy is our Chief Innovation Officer and has a passion for using real-world results in both our algorithms and the insight we provide our clients.

Meet our Team

Jack Preece

Data Scientist

Hannah Thompson

Customer Experience Specialist

Han’s happiest when she is traveling in Buster, the family camper van. From the breath taking scenic roads of Snowdonia to the gravel tracks of forgotten beaches and undiscovered picnic spots. Getting lost is always bonus adventure!

Josh Trewartha

Senior Systems Analyst

Josh enjoys almost all sports but loves playing or watching rugby. He also has a soft spot for caravanning with his young family. When he can, he tries to travel round the UK finding new destinations to make great and long-lasting memories.

Shijith Sasidharan Pillai

System Engineer

Fuchsia Wildgoose

Zero Carbon Project Coordinator

Fuchsia’s happy place would either be wandering around Westonbirt Arboretum in the Spring, or watching live music surrounded by my friends 😊

Alex Weaterton

Finance Manager

Loves playing with his two small children, but any occasion that he can leave their incessant demands behind has now become precious! Alex particularly enjoys watching live music in Cardiff when he can escape.

Tom WoodWard

Project Manager

Tom is easy to please: he is happiest adventuring around by foot or bicycle whenever and wherever he can. Bonus points awarded when accompanied by sun, trees or at least one dog.

Rhys Thomas

Business Development Manager

Rhys loves nothing more than going home to help out on his family farm, it’s only 15 minutes from where he lives now but is definitely his favourite place. After that it would be Italy, especially the Amalfi Coast, simply stunning even if their roads are terrifying.

James Williams

Co-founder and Chief Executive Officer

James is happiest when exploring the Welsh forestry, pure escapism, get as far away from civilisation as possible and be surrounded by the amazing natural environment we have. Usually accompanied by small people carrying sticks.

Iolo Morgan-Jones

Business Development Manager

Iolo is happiest spending his time with his partner and their 2 beautiful daughters. When time/weather allows, he can be found spoiling a good walk with bad golf or tempting Trout with a home-made fly. Wherever he is, a healthy supply of hot coffee or cold beer won’t be far away!

Julie Andrews

Customer Care Advisor

An adventurer at heart, Julie is happiest while on holiday with her friends, be it in the wilds of Mayo, Ireland, or Washington D.C in the USA. Throw in a tasty food place and it is smooth sailing from there! 

Dan Murray

System Engineer

Dans favourite place is anywhere with his partner, whether that’s chilling watching Netflix or out having adventures and travelling together.

David Easton

Product Owner

Andrew Wong

Senior Software Engineer

Architha Shylaja

Data Engineer

Architha finds joy in exploring new destinations under sunny skies and is happiest when surrounded by coastal landscapes.

Jayesh Mistry

Head of Commercial and Strategic Partnerships

Holly Evans

Head of Finance

Holly is happiest on the beach with her family. In the wind, rain or shine there is nothing better than the sound of the waves and the feeling of sand underfoot.

Penelope Jones

Head of Marketing

Penny adores spending time with her daughter, and after her bedtime being nerdy reading books, or playing a board or video game. When she gets the chance, she also absolutely loves doing something crafty like folding origami, sewing a new handbag, or making something funky with resin.

Jonny Green

Lead Software Engineer

Jonnys favourite things to do are going on adventures with his partner, getting lost on his bike in the hills with friends and family, and playing endless board games with the help of his two cats! Oh, and pizza!

Matt Burton


Matt loves a BBQ, especially on a warm sunny day with a cold beer. Walking his two dogs or watching his sons play rugby is often where you will find him on the weekends. Matt’s other passion is of course Disney & Lego.

Raphael Sibille

Head of Product

Raph loves getting lost on his bike. Pack some supplies, fill his pockets with pastry and point him towards the countryside. He will see you in a couple of days!

Dafydd Jones

UX Designer

Daf enjoys nothing more than hitting the golf course (family permitting). Any remaining spare time is spent watching sport or a good documentary.

Colin King

Technical Lead

When Colin isn’t working he is never happier than being with his wife Michelle, their 2 Labradors and too many horses. He still competes and enjoys the thrill of show jumping and x country.

Mick Ashley

Program Manager

Mick loves being in the great outdoors, whether it’s out on the hills in the lake district, dressed in spandex and exploring on the road bike or pottering in the garden, he is happy! The addition of a cold cider and his wife make it all the more better!

Natalie Jopling

Project assistant

Natalie loves visiting beautiful locations around the world (her favorite so far being Bali), learning about the variety of different cultures, whilst watching the sunset on a beach with a cocktail in hand.

Matt Kane

Head of Home Controls

Matt’s absolute favourite day out is a trip to Durdle Door beach along with his family, dog, dinghy, body boards and plenty of food!!

Jacob Ujanga

Software Developer

Jacob’s favourite things to do outside work are to lift weights or practice martial arts and combat sports with a particular passion for boxing. He also enjoys learning new things about the world and reading.

Steph Willis

Senior Data Scientist

Aaron O’Hagan

Software Engineer

Keiron Lloyd

Senior Operations Manager

Keiron is happiest whilst in the Sea, be that dipping his toe during a beach walk with his partner or whilst Scuba Diving in the warmer months (which is ironic given his allergy to Fish).

Alex Layton

Project Administrator

Outdoors in nature, especially in the mountains.

Steve Hepton

Scrum Master

Steve actually enjoys running 🏃 up and (especially) down the hills and mountains ⛰️ of South Wales 🏴󠁧󠁢󠁷󠁬󠁳󠁿. Happiest out in the wilds with family in tow, whether walking 🥾 the Beacons Way, orienteering 🧭 or cycling 🚵 around the Black Mountains. He cannot resist a good quality bar of milk chocolate 🍫 with nuts in and a nice cup of coffee ☕️ (and a sit down after all of that). 🤣

Katie Wiliams

Creative Lead

Katie loves nothing better than trekking up the Sugar Loaf mountain with the family to indulge in the breathtaking views of the Monmouthshire valley… (also nothing to do with the vineyard conveniently placed at the foot of the mountain!)

Claire Downey

Customer Care Advisor

Claire’s happy place is wherever her dog Loki is, which is a good job as he follows her everywhere! She loves nothing more than cwtching up on the sofa with him, a cuppa and of course a big bar of chocolate 😊

Cerys Williams

Finance Partnerships Manager

Cerys’ happy place is anywhere with her husband and son, however if that place also happens to have ice cream then she’ll be smiling from ear to ear!

Andrew Palmer

Senior Firmware Engineer

Andrew loves spending time on his mountain bike, the occasional trail run, adventures outdoors, and working on his latest project in his garage. These days, he is more likely to be towing one or more of his young family along with him!

Andy Sutton

Co Founder & Chief Innovation Officer

Andy likes to be amongst nature or great design (preferable both), whether DIYing, walking, swimming or cycling, though in all instances he’ll want it to be in the sunshine and ending up in a good pub. Or three.

Callum Murray

UI / UX Designer

When Callum isn’t at home expertly crafting digital user experiences, he can be found roaming the Welsh Coast in his van, looking for that perfect left and a sunset shore. 🌊 🏄‍♂️

Kris Ablett

Senior Customer Service & Experience Manager

Kris’ favourite places are the kitchen and the dining table and would gladly spend his life simply moving between the two only venturing outside to light a barbecue.

Rebecca Edwards

Executive Assistant

Bex is happiest when the sun is shining and the weather is warm. She loves being outdoors, surrounded by nature. She is an avid yogi and travelling the world with her partner is where it’s truly at. She is a bread lover, coffee snob and is not opposed to a glass of wine or two.

Kylie Baker

Head of Software Development

Kylie is happiest being surrounded by home comforts or going on holiday to the coast with her husband and dog.

Luke Quinnell

Software Engineering Manager

Luke is found happiest when at home with his wife, two children and their dog. He enjoys anything car related and has a big passion for reading (mostly fiction) and music too! When not asleep, you will likely find Luke drinking coffee.

Chris Quinn

Billing Analyst

Chris is happiest either out exploring the Welsh countryside or mixing ice cream flavours 😊

Antonia Cosgrove

Customer Care Advisor

Often one to take the road less travelled, Toni is a curious adventurer in love with exploring new places and discovering hidden gems. Be it a city stroll down a quirky lane, or finding herself getting lost in a book.

Louise Simons

People Co-Ordinator

Louise’s happy place is with her husband and family.  Her favourite place is Pembrokeshire especially Bosherston Lily Ponds and Tenby.  An animal lover (dogs are her fave!) and would have a house-full, given the chance.  Cappuccinos are an obsession and so is watching movies accompanied with a big bar of chocolate (and a glass of vino!) but does enjoy the gym to make up for it!

Ciara Murphy

Head of Customer

Ciara is happiest when sampling her favourite street food or waking up to a nice new view in the VW (weather permitting!).

Lee Fisher

Technical Manager

Lee is happiest when relaxing at home with his son and Border Terrier dog. In his spare time Lee is a keen musician and loves all live music. Whether it’s a busker, open mic night or following his ageing 00’s Indie heroes….. If there’s a guitar, and a pint, he’ll be there.

Nathan Chiverton

Senior Software Engineer

Nathan is happiest when spending time with friends, whether that is at the pub, a local gig or a trip away. When he isn’t spending time with friends, he loves listening to music & adding to his ever growing collection of records.

Simon Morris

Manual Test Engineer

Attending the UKGamesExpo with his daughter, where he plays non-traditional board games and role playing game systems he has not experienced before. Especially loves those that he can bring back to play at home with his family and friends or bring to his local gaming group (as well as stories from the expo).

Josh Skyrme

Systems Engineer

Josh loves spending time with his partner and daughter whether that be chilling at home or adventures out in the sun.

John Lloyd

Data Engineering & Science Manager

Caffè della Seggiovia in Sauze d’Oulx. John’s favourite bar in his favourite village, tucked away in the Italian Alps. Where they bring you free home cooked Italian food & snacks while you have a few drinks, invariably under bright blue skies surrounded by the snowy mountains.

Shawni Singh

Talent Manager

Shawni is happiest when in the garden with her husband and dog Archie or exploring a new part of Wales. Her particular favourite places to visit again and again are Rhossili and Aberystwyth. 

Ethan Flynn-Harding

Senior Software Engineer

Ethan’s happy place is riding a motorcycle cross country, whether it be through the valleys in Wales, the mountains of the Lake District or being lost with no sat nav in Normandy, France at 3 am with a vending machine pizza and trying to cut electrical cables from a camera to jerry-rig a phone charger without any tools.

Ellie Lancaster

Head of People

Ellie loves nothing better than visiting Tintern, Wye Valley near Monmouthshire for the breath taking scenery. A little haven of escapism!

Lizzy Wood

Marketing Manager

When Lizzy isn’t being kept busy by her son, you’ll find her cold water dipping in the sea, at the gym, or visiting her place of calm – New Quay, in West Wales.

Ross Holleron

Head of Innovation

Ross lives a life of contradictions. He loves a crowded ideas workshop but adores the solitude of working from random places in his van. One day he’ll build that sketch of a PV powered canal boat and disappear into the Llangollen countryside.

Jack Thomson

Lead Developer

Jack was once a music producer & produced tracks with artists across the country and over seas. Jack enjoys long walks, cold swims and most recently, golfing.

Lianne Hartley

Junior Developer

Lianne is happiest when backpacking in sunny places, whether that’s road tripping through California or island hopping in Greece. If there’s a quiet spot to read a good book and enjoy an ice cream along the way, even better!

Tiago Ferreira

Product Owner

Tiago is happiest when he puts on a dinner jacket and joins Orchestras around Wales and England on stage playing the clarinet. When not performing, you’ll most likely find him dancing salsa in Latin parties!

Steve Rummels

Partnership Manager

Steve’s favorite place is wherever his kids and/or partner are. Although walking the dog around local Cardiff parks comes a close second. If a holiday is on the cards he will head to the Devon / Dorset coast or once every few years he might make it to Puerto Pollensa as a special treat.

Victoria Jacques

Project Manager

Victoria loves nothing more than going to New Quay in Wales on sunny days. Sitting on the sea front with an ice cream from Crème Pen Cei and watching the Dolphins out at sea.

Soorya Premsagar

Cyber Security Engineer

Dancing is my favourite activity, especially when I dance with my husband. I love cooking. The kitchen is a place where I can express myself via the art of cooking, whether I’m experimenting with new recipes or preparing cherished family dishes. I treasure every moment I spend with my husband and our adorable child.

Julien Caudron

Senior Data Scientist
Julien’s favourite place is the Belgian rural countryside. His parents inherited an old family building, and he spent a big part of his childhood holidays renovating the house, taking care of the garden and enjoying walks in the surroundings.

Jason Casati

Software Developer

Jason loves when he’s at home fixing broken hardware with endless amount of open browser tabs and a cup of tea/coffee attached to his hand.

James Dix

Senior Data Engineer

James enjoys big Turkish dinners and hitting the open road on two wheels. His leisure time is filled with D&D, camping, and electronics projects. At home, he cherishes relaxed evenings with his partner, dog, and cat.

Anne-Marie Ratcliffe

Senior Project Manager

Anne-Marie’s favourite place is the Arctic. With each dropping degree in temperature, she gets a degree more alive (though this has only been tested to about 20 so there are probably limits…)

Jim McArdell

Head of Projects

Jim loves to be in, next to or just generally within sight of the sea be that surfing the waves, walking on the beach or spending time with the family.

Don Liyanage

Technical Architect

Don is happiest when driving through a quiet & peaceful countryside sounded by nature, but focused on the road.