A quarter of housebuilders admit they don’t know the rules

The Polypipe survey landed with a thud: one in four UK housebuilders admits only a limited grasp of Building Regulations. That means 25% of the people constructing your neighbour’s new home, or possibly your own, are building to standards they don’t fully understand. For the 200,000-plus households moving into new builds each year, this is not an abstract industry problem. It is a direct hit on energy bills, EPC ratings, and the government’s net-zero timeline.

As reported by Housing Today, the survey by Polypipe, a major drainage and plumbing manufacturer, paints a worrying picture of an industry that is supposed to deliver homes fit for a decarbonising Britain. The catch is that Building Regulations, particularly Part L on conservation of fuel and power, are tightening every year. The 2022 update pushed fabric energy efficiency standards up by 31% for new homes. If a quarter of builders are playing catch-up, whose home pays the price?

What this means for your energy bills

The link is direct. A new home built to current Part L standards should use around 30% less energy than one built to 2013 rules. The Energy Saving Trust estimates that a well-insulated, airtight new build can save a typical household £200–£300 a year on heating. But if the builder misinterprets the regulations, uses the wrong insulation thickness, installs a less efficient boiler, or fails to seal the fabric properly, those savings evaporate. You could end up paying £150 more a year than you should, for the life of the mortgage. For a 25-year term, that’s £3,750. Not pocket change.

EPC ratings: the hidden risk

New homes are supposed to come with an EPC rating of B or better. Yet the survey suggests some may fall short. If your new build lands at C instead of B, you face higher running costs and a harder sell when you come to move. The government’s proposed minimum EPC of C for rented homes by 2028 shows how seriously it takes ratings. A builder’s ignorance today becomes your resale penalty tomorrow. Ofgem and the Home Builders Federation have both flagged that compliance checks are inconsistent. The onus, shamefully, often falls on the buyer to spot problems after moving in.

What homeowners can do, and what the industry must

First, if you are buying a new build, demand an independent snagging survey that includes a thermal imaging check. The National House Building Council (NHBC) warranty covers structural defects but rarely energy performance. Second, ask the developer for the Standard Assessment Procedure (SAP) calculation that underpins the EPC. If they cannot produce it, walk away. Third, the government should mandate post-completion testing, blower door tests and thermography, for a random sample of homes. The £1,500 cost per home is trivial next to the £30,000+ price tag of a new build. The Building Safety Act 2022 created a framework for accountability; it should extend to energy performance.

But the deeper fix is cultural. The survey shows that 73% of housebuilders want more training on regulations. That is a demand, not a complaint. The Construction Industry Training Board (CITB) and the Ministry of Housing should fund a mandatory, free online module on Part L and the upcoming Future Homes Standard. No certificate, no sign-off on new projects. The cost to the taxpayer would be a few million pounds. The cost of doing nothing is a generation of homes that lock in higher emissions and higher bills.

For now, the message to UK homeowners is simple: do not assume a new build is energy-efficient just because it is new. Check the EPC, ask for the SAP, and get a snagging survey. The quarter of builders who do not know the rules are not going to tell you. You have to find out yourself.