When Mark Puddicombe moved out in 2023, he was most excited about the gadgets that came with his new smart home.

Unlike the detached period property he had previously lived in, Mark's new home in Exeter can be run via an app.

This allows him to control his lighting and heating, which is 100 per cent renewable, remotely from his phone. 

But there was another bonus, too: he'd no longer have to pay an energy bill.

And he's not alone. Mark is one of a growing number of homeowners who generate enough energy to have zero bills.

He has solar panels, an air source heat pump, and triple-glazed doors and windows.  

What is the zero-bills scheme?

The zero-bills scheme has been spearheaded by the supplier, Octopus Energy.

Homes signed up to the initiative have green technology installed, including a heat pump, solar panels and a battery, and are signed up to Octopus's Zero energy tariff.

The idea is that the property will generate more energy than is consumed, meaning energy bills are a thing of the past. 

It doesn't necessarily come cheap, though. The average cost for the required technology and installation ranges from between £5,000 to £20,000, depending on the size of the home and whether the home already has some tech installed.

Octopus guarantees each property will pay nothing for energy, even if it uses more than it generates, for five to 10 years.

Octopus says it makes enough revenue from exporting excess energy produced back to the grid to make it commercially viable.

The scheme started small with three eligible homes made by Bellway in Stafford's Victoria Gate estate, before expanding to hundreds more.

Last year, Octopus said it wanted to build 100,000 zero-bill homes by 2030. Currently, 1,200 homes have been accredited for the scheme. 

How does a zero-bill home work?

Since Mark moved in two years ago, he's not paid a penny towards his electricity usage.

The chartered building surveyor had stumbled across the scheme when he'd seen eco homes being built around Exeter.

Long interested in what he calls 'environmental stuff', Mark spoke with the developers and eventually moved into his four-bedroom home.

Although saving on bills is a bonus, he says being able to control his home remotely and reducing his impact on the environment were his main motivations.  

'It was more the renewables and smart home element. I really like gadgets and stuff, so all of that appeals to me. I was quite keen to have a smart home,' he says.

'I like the design as well, they're nice, modern-looking places. 

'The zero bills element came later on when there was an option to talk about having the battery pack and everything else. That's certainly been a positive.'

Every month, Mark receives an email from Octopus with his energy usage, and his bill is nil.

'I literally get a zero bill every month. I haven't gone beyond the fair usage policy, it would be way more than I'd be using it.'

Each home has a fair usage policy of 10 megawatt hours (MWh) of free electricity a year, and Octopus will charge you for anything you use over that amount. 

Electric vehicle charging is not included in a home's usage.

Energy regulator Ofgem says the average three-bedroom household uses around 14.2 MWh of energy a year, but Octopus estimates that a similar sized home signed up to its scheme would only use 6MWh of electricity.

Mark says his energy usage is already much lower than in his previous home, which had single-glazed timber sash windows.

His new home is better insulated, with all doors and windows triple-glazed and the house well-sealed.

'I think even if I were paying for the energy, I'd still be paying a lot less proportionately than if I were in a traditional, older home,' Mark adds. 

Which homes are eligible for zero bills?

Mark is a big fan of his smart home. He raves about the benefits of being able to control everything via an app, which he admits was 'a little clunky' when he first moved in.

After some fiddling around, he can now control his heating and lighting through voice commands.

'It knows I've got my phone with me, so if I come home at night and it's after dark, then the app starts and the lights will come on for a couple of minutes before I get into the house,' he says.

It means it's well placed to connect to Octopus' Kraken tech, which automatically imports and exports energy to the grid.

'The house has an air source heat pump. On the first floor, there's radiators and MVHR [mechanical ventilation with heat recovery] so it's always drawing air from the wet room, showers, kitchen and utility room,' explains Mark. 

'Then it harvests heat from there and then in the winter months, it blows back out to the living room, bedrooms and lounge.'

You do not need to have a smart home to be eligible for Octopus's zero-bill scheme, but it currently only works with new build homes that have been designed around the Zero tariff.

Octopus has partnered with housebuilders Vistry, Persimmon and Bellway, the latter of which has a 130-home zero bills development planned in Bedfordshire.

If it all sounds a little high-tech, that's because it is - but Octopus thinks it's the future. 

It estimates that half a million homes built since 2013 could be upgraded and eligible for zero bills.