Delays to the government’s planned consultation on net zero regulations for housebuilding will mean more households being hit with hefty bills for energy, housing experts have said. The future homes standard (FHS), which will stipulate that housebuilders construct new homes to be low carbon, was supposed to be opened for consultation in March, but that slipped to a promise of publication in the summer. At the Tory party conference this week Martin Callanan, the minister for energy efficiency and green finance, told a private gathering that the consultation would not be out until next year. This was later clarified to promise an opening of the consultation by the end of this year. Lord Callanan tweeted: “The government will publish the consultation on the future homes standard for new homes this year. We will implement the FHS in 2025, ensuring new homes are ready for net zero.” The delay would cause further problems for homeowners, said Juliet Phillips, senior policy adviser at the thinktank E3G. “The standard is an essential tool for ensuring all new homes are warm, healthy and highly efficient. Delay to the consultation, which was originally due this spring, had led to concern that the standard had been kicked into the long grass. As a vital policy for ensuring all new homes are green and cheap to run, any further delay to the standard would be costly for homeowners – and the planet.” Louise Hutchins, head of policy at the UK Green Building Council, added: “The best developers have spent years and millions gearing up for modern green building standards. This continued delay and uncertainty on new higher standards only benefits those who took a punt that the government would drag its feet on tackling the climate emergency.” An investigation by the Guardian this week found that housebuilders had benefited by at least £15bn over the last eight years by not having to construct homes to low-carbon standards. Installing heat pumps, solar panels and high-grade insulation on homes while building them is much less expensive than retrofitting them later. But if homes are built to these standards, the costs, which were roughly £5,000 a house before the Covid-19 pandemic and are now about £8,000 a house, are borne by the housebuilder. About 1.5m homes are estimated to have been built without these low-carbon fittings since 2015, when the Conservative government scrapped the zero carbon homes standard. Abandoning the standard has saved housebuilders £15bn by the most conservative estimate. The cost of retrofitting these homes is likely to reach £30bn to £45bn, and will fall on homeowners or taxpayers. Housebuilders and property developers are among the biggest donors to the Tory party. The same Guardian investigation also found that at least 10% of donations to the party since 2010 had come from the sector. Opposition parties called the findings a scandal. Helen Morgan, communities and local government spokesperson for the Liberal Democrats, said: “The Conservatives have proven time and again that they cannot be trusted with protecting our environment. “They have bent over backwards for their developer donors and delayed vital measures to cut bills. All these delays will ensure are higher energy bills for years to come and yet more families having to choose between heating and eating.” Caroline Lucas, the Green party MP, said: “Just as the government slashes vital environmental regulations and kicks low-carbon building measures into the long grass, tens of millions of pounds find their way into Tory coffers. This vicious cycle will destroy nature and frustrate progress on the climate emergency when it’s needed more than ever.” She added: “We know every home has the potential to be its own power station – with mandatory solar panels on all suitable new roofs, insulation and energy efficiency measures providing people with warm homes and cheap energy bills. If the government won’t enforce those regulations, it should make way for one which will.” Hutchins said that seeking further delays to the future homes standard could backfire on the housing industry. “Those who have been secretly lobbying the government behind the scenes for delays, or even scrapping a move to better standards, risk turning public opinion against the industry as the water companies have done so spectacularly,” she said. Phillips, of E3G, called for the new future homes standard to come as soon as possible. “We’ve already had to wait a decade for the government to bring forward a new standard to ensure new buildings are fit for the future. Any further delay would be unacceptable,” she said. The Labour party did not respond to the Guardian’s requests for comment.