New homes could be built without solar panels, heat pumps and high-grade insulation, leading to higher household bills if the Conservative party wins the next general election.

Kemi Badenoch made scrapping the future homes standard (FHS) one of the central planks of her bid to become the next prime minister at the Tory party conference this week.

The announcement gained little attention compared to her inheritance tax bombshell, but it would have more far-reaching impacts on a greater number of people. The UK is in need of approximately 6m new homes and failing to equip them with efficient and low-carbon energy sources would doom households to higher bills for decades to come.

The Tories quoted estimates of £30,000 for new-build houses, but the real cost is likely to be much less. Installing heat pumps, solar panels, batteries and insulation costs about £5,000 to £8,000 at the point of building – a figure estimated in 2024 when energy prices were much lower – to save more than £1,300 a year on bills, a saving likely to be substantially higher now. To retrofit homes after building would cost more than £20,000.

Jan Rosenow, a professor of climate and energy policy at the University of Oxford, said: “Every home constructed today that runs on fossil fuels is a liability for the occupants. It also results in investor uncertainty and disrupts the supply chain that has been gearing up for this. What we need is less political point scoring and more long-term clarity.”Housebuilders have been among the biggest donors to the Conservative party, though this has fallen off in recent years. And according to the UK Green Building Council (UKGBC), the construction industry is well prepared for the FHS and will have to implement the policy before the next general election, so scrapping it is of little benefit.

Simon McWhirter, the chief executive of UKGBC, said: “The housebuilding industry has spent years preparing for the introduction of the FHS, investing in skills, supply chains and new products. Reversing course would … risk slowing progress towards building the homes that people want and need.”Badenoch’s housebuilding plans are only part of a torching of the Tories’ green policies. Despite the crisis of sewage and farm pollution in the UK’s rivers and beaches, and the dramatic drop in wildlife, the party would abolish the Environment Agency and Natural England.

The party’s U-turn on environmental issues and net zero was contrary to what voters wanted, said Robbie MacPherson, Kennedy scholar at Harvard University and the former head of the UK’s all-party parliamentary group on climate. “No winning political strategy, after years of fossil fuel-driven energy price spikes and a summer of climate breakdown, can include environmental regression.

“Voters won’t reward politicians who want to kill employment opportunities, spurn economic growth and fail to keep Britain safe.”While the Conservatives spent their party conference burning their green credentials, an equally unexpected U-turn came from the Green party, which resolved last weekend to abandon its long-held opposition to nuclear power.

Although the party would still prioritise renewable energy, Green MPs could now support new reactors, in recognition of their potential role in low-carbon generation.

Paul Dorfman, Bennett scholar at the University of Sussex and the chair of the Nuclear Consulting Group thinktank, said: “The Green party has taken a wrong turn on nuclear and this will lose them significant grassroot support and votes.

“With 20-plus-year construction times, repeated delays and huge cost overruns, new nuclear diverts scarce resources from faster options. Renewables, storage, efficiency and stronger grids can deliver much more for every pound spent.”The battle between the Green party and the Labour party in this week’s Holborn and St Pancras byelection is likely to be repeated during the general election, where the Greens could be the main challengers in urban Labour strongholds.

Responding to Sagal Abdi-Wali’s win for Labour, Greenpeace UK’s head of politics, Ami McCarthy, said: “Abdi-Wali has shown that voters are putting their trust in Labour, but the Green party increased its share of the vote and remains a serious challenger. As extreme heat becomes a regular threat and droughts extend for much of the year, concern about climate change is on the rise and cannot be ignored.”At Labour’s conference, Andy Burnham made only passing references to the climate, pollution crises and nature.

He announced a publicly owned body to invest in the energy grid, alongside the privatised National Grid, which has been criticised for slow progress on upgrades. There was also a nod towards localised support for nature with a community fund for planting 500,000 trees across England.

McCarthy said: “Voters will be comparing Labour with other parties that have a clear plan to lower energy bills and tackle the climate crisis rather than with the fantasies of the Conservatives and Reform. Labour has a clear plan but needs to deliver it – starting with a full-throated rejection of any scramble for fossil fuels in the North Sea.”The decision on the future of the Rosebank and Jackdaw drilling sites was reportedly postponed for the byelection, and McCarthy said it would “truly define this government’s legacy on climate”.

Failure to recognise and tackle the damage caused to the UK by a summer of record heat and drought would prove costly, campaigners warned. A record El Niño weather system is brewing, super-charged by global heating and likely to bring heatwaves, droughts and floods to key agricultural areas, pushing millions into hunger and raising food prices globally.

Rosie Downes, the head of campaigns at Friends of the Earth, said: “With El Niño bringing a wetter and stormier winter season to the UK, we desperately need to see some parties getting back in touch with reality. The government must translate its words into action that delivers for people and the planet.”