Why most new homes are still being built to old standards

Few parts of the construction industry have been left untouched by the regulations which have come into force over the past few years. No sector has dealt with more than housing, which has faced an onslaught of new rules since the government’s commitment to the 2050 net zero target was announced in 2019. New building safety regulations introduced since the 2017 Grenfell Tower fire, including requirements for second staircases in tall buildings, have added to the burden for developers. 

Rising build costs have been exacerbated by construction product price inflation and labour shortages, while viability has been hit by a collapse in the housing market since Liz Truss’ 2022 mini-Budget. Chronic planning delays caused by under-resourced councils have added to the woes of the industry, all of this at a time when successive governments have pressed the urgent need to address the country’s housing crisis.

During such a tumultuous period, maybe it should be expected that housebuilders have not all rushed to adopt the new rules as quickly as possible. And, according to new data from energy assessment firm Elmhurst Energy, this very much appears to be the case. The Leicestershire-based firm, which produces Energy Performance Certificates (EPCs), has found that a majority of new homes are still being completed to 2013 housing standards almost three years after the introduction of new rules on carbon reduction.

>> Also read: What the future homes standard means for net zero

>> Also read: The UK is setting the standard for energy-efficient homes but there is still some way to go

In June 2022, the government introduced a requirement for new homes in England to cut carbon emissions by 31%. It came with four new standards, part F covering ventilation, part L for energy efficiency, part O for over-heating and part S for electric vehicle charging.

The so-called “FLOS” rules constituted a significant change for the housing sector, affecting how homes are designed and increasing build costs by at least £5,000 for each home based on average house prices. Part L, which may require thicker walls, has been particularly challenging for builders to accommodate as it has increased the size of individual plots, potentially reducing the number of homes that can be built on a development site.

Housebuilders were given a transition period of 12 months to adjust to the new rules, with the government expecting at least 75% of new homes to be completed to the new standards within two years after the transition. This has proved to be well off the mark, with only around 40% of new homes achieving the new standards as of February 2025, according to Elmhurst.

Because of a new requirement introduced in 2022 for registration of new homes to be done plot by plot, instead of the whole development as had previously been allowed, this means that two newly completed homes on neighbouring plots could be built to standards which are 12 years apart.

The projection by the Ministry of Housing, Communities and Local Government (MHCLG) was “clearly way off”, says Elmhurst’s managing director Stuart Fairlie. An aim for 100% of new homes to be completed to the new part L within four years of the transition period also “looks deeply unrealistic at this stage”, he adds.

“The raft of new regulations introduced in recent years has added huge complexity and cost to the process, inevitably leading to further delays,” a spokesperson for the the Home Builders’ Federation (HBF), which represents private sector housebuilders, said.

So, how did the government get it so wrong? Under the transition arrangements, any homes registered before 15 June 2022 which started construction before 15 June 2023 could continue under the old 2013 regulations. Housebuilders appear to have been taking advantage of the transition period to register homes before the introduction of the rules, start construction before the end of the transition period and then pause those sites until they become viable. 

It’s always more expensive to move to newer regulations because generally they’re more demanding, they’re more onerous, and there’s an element of uncertainty 

Stuart Fairlie, managing director, Elmhurst

“It is likely that many housebuilders would have commenced homes before this transition period ended, owing to the financial considerations associated with the new standards,” Fairlie says. For a housebuilder, it is a no-brainer which saves them the added costs of the significant increases of fabric performance required by part L to improve the performance of walls, roof and floors, as well as the cost of installing low-carbon heating including heat pumps.

It is fair to say that there is nothing unusual about housebuilders – or firms in other sectors for that matter – pushing the legal requirements of transition periods as far as possible in order to mitigate the impact of newly introduced rules. “It’s always more expensive to move to newer regulations because generally they’re more demanding, they’re more onerous, and there’s an element of uncertainty. So it makes sense for developers where they can to try and stay under the previous regulations” says Elmhurst newbuild dwellings manager Jason Hewins.

The difference in this case is how wide of the mark the government’s impact assessment – which came after years of consultations with the sector on feasible timelines – has proved to be. Hewins has worked at Elmhurst for 17 years, with the rules which came into force in 2022 being the third change in part L during his career, the last being in 2013.

“It certainly feels like, this time around, the lag and the drag of building to those new regulations is taking longer than we’ve seen before,” he says. This is partly due to the scale of change introduced, combining four amendments to building regulations and resulting in a much higher cost burden than in 2013.

These changes to the Approved Documents were published in December 2021 and came into force only six months later, including the downtime around Christmas, giving developers a limited time to understand the implications of the changes. “There wasn’t a lot of time for developers to get their heads around what they needed to do to meet these new standards, so that made it quite tricky,” Hewins says.

Statistics published by the National House Building Council (NHBC) in the first quarter of 2022 showed home registrations were 25% higher than for the same quarter in the previous year. In the second quarter, in the weeks before the start of the transition period, registrations spiked at 45% above the level seen a year previously. Registrations then quickly began falling and, by the third quarter of 2023, year-on-year registrations were down by 53%. 

So, what can the government do differently to manage expectations of compliance to the next set of new rules? The Future Homes Standard, which will come into force this year – although the exact date is yet to be confirmed – is the next big change.

It is an even more stringent set of regulations aiming to dramatically increase the energy efficiency of new homes, reducing their carbon emissions by up to 80% compared to current standards. While the industry has been preparing for some time, the slow implementation of the last big change raises the possibility of another slow roll-out.

Fairlie says the slow rate of new homes being built to 2022 standards makes for a “bleak picture” for adoption of the Future Homes Standard. The government is expecting that half of new homes will be built to the standard by 2027 and 95% by 2028, a projection which Fairlie believes is “optimistic at best”.

The HBF has called for clarity and consistency from the government about when the Future Homes Standard will come into effect and what the transition period will be. But there are some measures which the government could put in place beforehand to speed up the adoption of the next wave of standards.

One of these could be putting a strict time limit on how long a home can be built to previous standards after it has started in order to prevent builders starting plots and leaving them idle. While a three-year limit was introduced in 2023, this could be shortened to incentivise faster adoption of new standards.

“That would certainly speed up developers and they wouldn’t be able to just put their foundations down and then walk away,” says Hewins.

Another measure introduced in 2023 is a change in what it means to start a site. Previously defined as commencing the floor slab, builders now have to complete the floor slab, a significant increase in the scope of work required for the site to be recognised as having started.

While this could help with the Future Homes Standard, Hewins suggests it could be strengthened further to require building up to roof level. The implementation period – the time between new regulations being published and the start of the transition period – could also be lengthened to allow builders more time to understand the implications of new rules. The rush to register homes recorded by the NHBC in 2022 was partly a result of builders not having enough time to plan ahead.

Governments will always need to be careful not to stall developments altogether when introducing new regulations and accompanying rules to enforce them. It remains to be seen how effective the current measures will be, or if what has been put in place is already a step too far.