Tony and Becs Wadley say they can’t spend Christmas at home after insulation installed under a government scheme has caused black mould in several rooms, and their asthmatic son can’t be inside the property.

Mr Wadley says the situation is tearing the family apart: ”It’s awful. Elliott can’t come into our house, it’s as if he’s been ostracised from his own home.”

The couple are among more than 300 people who have contacted the BBC in recent weeks to tell us about insulation that has gone wrong in their homes.

The Department of Energy Security and Net Zero (DESNZ) said it was taking action to ensure consumers are no longer let down by poor installations.

Mr and Mrs Wadley got a government grant to have energy efficiency measures fitted in their Gower Peninsula house because they hoped a warmer home would help Elliott’s asthma. The grant covered the cost of insulating his bedroom walls.

But months after the work was completed, the Wadleys discovered black mould was growing behind the insulation boards. It was removed by the installer and replaced with a new insulation system. But this also had to be removed along with all the plaster after it became damp. Elliott, 19, hasn’t entered the house since April, instead staying with his grandmother during university breaks.

”I miss him like you wouldn’t believe’,” says Mrs Wadley.

The family are going to stay with Mr Wadley’s sister for Christmas so they can all be together.

Billions of pounds of public money has been spent on insulating homes over the last 15 years.

The Wadleys’ home was insulated under a government scheme known as ECO4. In October, the National Audit Office (NAO) spending watchdog found that 98% of homes fitted with external wall insulation under ECO4 and the Great British Insulation Scheme since 2022 had major issues that needed to be repaired.

It added that 29% of homes that had internal wall insulation fitted under the schemes had major issues.

The report also said there had been “weak” government oversight and regulatory ”failure”.

DESNZ said it had “inherited a flawed system of oversight and regulation”. A spokesman for the department said it was “committed to introducing comprehensive reforms through the Warm Homes Plan to ensure that consumers get the quality installations they deserve and failures like these are not repeated”.

The spokesman added: “People should not be expected to navigate a complex web of organisations when they want to improve their homes – and with this government, they won’t.”

In the downstairs rooms of the Wadleys’ home the insulation has also failed and has had to be removed. There is black mould on the walls while electric sockets hang loose with the wires exposed. The family says it has been in this condition for months.

The installer, Stellar Energy, says it has ”no record of any immediate safety hazards being flagged.” It says the descriptions of the exposed wires and sockets was “highly inconsistent” with their standard operating procedures, which required all such work to be made safe.

Building surveyor, David Walter, says the insulation wasn’t fitted correctly and says the installer ”didn’t understand what they were doing and what they were doing to the building which is why we’ve got these problems.”

Stellar Energy told the BBC the design was ”technically correct for a stone house and was installed…in strict accordance with the mandatory technical specifications of ECO4.”

Mr Wadley says he wouldn’t have signed up for the grant if he’d known what would happen. ”You wouldn’t put your family through this. Nobody would. Somebody needs to take responsibility.”

Stellar Energy says it ”sincerely regrets any distress this situation has caused the family” and says its priority is ”providing a final resolution to ensure the home meets the high standards” it strives for.

Scott Proudman contacted the BBC about the botched external wall insulation fitted to his Bristol home in 2021.

His family had been eligible for a government grant because of his eight-year-old daughter’s disabilities. Born 24 weeks premature, she has cerebral palsy, a partial visual impairment and was recently diagnosed with autism.

”I feel like a failure every time I come home because this was meant to be something to look after my family, to make life easier, and it hasn’t,” he says.

When the work was done, insulation boards were fixed to the outside of the house and render was applied to make it waterproof. But the render has been falling off for years.

Building surveyor Mr Walter, says poor design and poor workmanship has caused the render to disintegrate. He says rainwater will very likely get under the cracked render and behind the insulation and will likely cause dampness inside.

”It’s like a timebomb. It’s going to get worse and worse, affecting the inside of the property,” he says.

Mr Walter says all of the render and insulation will have to come off and will cost tens of thousands of pounds to put right.

Right now the family is stuck with the repair bill because the installer, SPMS Wales, is being liquidated and Mr Proudman says they weren’t given the required guarantee for the work. Trustmark, the organisation responsible for overseeing quality, told Mr Proudman it couldn’t help because the company is no longer accredited.

Mr Proudman says he chose the company ”because it was on a government website and was Trustmark registered. I can’t believe how few rights consumers have.”

Brett Langdon, a director at SPMS Wales says he is ”very sorry the Proudmans have ended up in this situation” and says all works ”were done to the manufactures specification.” He says he gave a guarantee to the Proudmans but has told the BBC he can’t remember who the guarantee is with. He says the delamination of the render was “due to a failure of the system”.

In a statement TrustMark said it was ”very sorry to hear about what’s happened to Mr and Mrs Proudman and Mr and Mrs Wadley and the conditions both families’ homes have been left in. It is totally unacceptable and we are in discussions with the relevant Scheme Providers and guarantee providers to help resolve these situations.”

And it said it underlined ”the need for reform to the current system”.