The government must ensure homeowners receive high quality improvements under its new energy efficiency scheme, campaigners and MPs have said.
Under the plan, the government will pay at least two-thirds of the cost of home improvements that save energy in homes.
The Green Homes Grant will be launched in England in September.
But the chair of Parliament's business select committee, Darren Jones MP, has expressed concern about how people will be protected from poor quality work.
Mr Jones warned that under previous government programmes, a number of consumers had work done on their homes by suppliers who failed to meet required standards, with many unable to get the redress they deserve.
He has written to ministers asking what consumer protections will be available.
Meanwhile, campaigner Pauline Saunders, from the Cavity Insulation Victims' Alliance, CIVALLI, has accused some in the industry of bullying people, saying: ''They treat people like idiots''.
The grant will fund improvements such as home insulation and new boilers, with homeowners applying for a voucher of between £5,000 and £10,000 to help with the cost of the work.
More than 13 million homes in the UK have had cavity wall insulation but industry insiders have told the BBC that insulation will have failed in at least 800,000 homes.
Cavity wall insulation is meant to make homes warmer and cut energy bills. The insulation, which can be wool, foam or beads, is injected into the cavity between the exterior brick wall and interior wall by drilling holes in the brick.
Badly installed insulation can lead to damp and mould which can have a detrimental effect on people's health.
Gavin's story: 'I feel like I failed my child'
Gavin Ward had to move out of his home in Bridgend two and a half years ago after the council said it was uninhabitable because of damp, mould and unsafe electrics.
He became emotional as he inspected the mould in his young son's bedroom. "What can be worse than feeling you have failed your child?" he asks.
The problems started after cavity wall insulation was fitted.
Mr Ward went through a claims firm to approach the company that did the work - Miller Pattison - for damages to fix his house in 2017.
Miller Pattison insulated 800,000 homes and it admitted in court that it was receiving between 40 and 50 complaints a month.
Gavin was still in dispute with Miller Pattison when the company went into administration last year. He says he's angry: "These companies know the problems the insulation is causing and yet they are allowing families to live in conditions like this."
Gavin's insulation failed because the installer didn't remove debris from inside the cavity before inserting the mineral wool insulation.
As his surveyor, Kevin Chellew, explains, the debris would have acted as a cold bridge carrying damp into the house. This, he says, is a very common problem. Mr Chellew says it'll cost £60,000 to extract the insulation and repair Gavin's house.
The work was guaranteed by the Cavity Insulation Guarantee Agency (CIGA), which admitted the insulation should never have been installed and has offered to remove it. But because CIGA only became involved late last year it says it cannot assess the damage caused by the faulty insulation rather than damage that's occurred in the meantime and for which it cannot be held responsible. As a result it cannot consider any claim for internal works.
CIGA says Gavin can challenge its decision by taking his case to arbitration.
The Cavity Insulation Guarantee Agency (CIGA) is an industry-funded body and not a regulator. It describes itself as an independent body that provides 25-year guarantees for cavity wall insulation fitted by registered installers in the UK.
But campaigners and some MPs have said it is not fit for purpose.
Ms Saunders from CIVALLI asks how it can claim to be standing up for consumers when its management team is almost entirely made up of people who manufacture or install the insulation, or have done until recently.
She said because much of the work completed under previous programmes was done for homeowners living in fuel poverty, some of the most vulnerable people in society have suffered.
CIGA said it has appointed independent non-executive advisers to its board, including a consumer champion.
It said it's now dealing with 3,000 claims a year and will be carrying out physical inspections on 5% of all future installations.
The government has not yet announced the details of the Green Homes Grant scheme, but has said only accredited installers working to specified standards with robust consumer protection practices will be able to carry out work.
Clarification 25 August 2020: This article has been updated to give more details regarding the background in Gavin Ward's case and his dealings with the Cavity Insulation Guarantee Agency (CIGA)