Tighter rules on the carbon footprint of new-build homes in England could likely trigger a fresh boom for residential solar.

New homes will be required to produce 31 percent less carbon dioxide than they do now, according to plans laid out this week, which will require better energy efficiency and being “heat pump ready.” In the vast majority of cases, it is expected that solar will be the most cost-effective way for homebuilders to remain below the carbon threshold.

The new rules are expected to pass into law in the spring of 2021, and they will likely begin to be applied to new building plans starting in the spring of 2022. They are the precursor to a much stricter set of regulations, the Future Homes Standard, to be implemented in 2025 and which will cut permitted emissions by 80 percent.

The changes were overdue because of the strain the coronavirus pandemic has placed on government resources. Fears that the existing rules would remain in place until the Future Homes Standard is implemented turned out to be unfounded.

Building regulations in the U.K. are decided by each of the home nations: England, Northern Ireland, Scotland and Wales.

In 2015, England abandoned plans for a Net Zero Homes standard that would have required houses to generate as much renewable energy as they used; where not possible, developers would make up the shortfall offsite. At around the same time, authorities in Scotland tightened rules, making new-build homes in that country 22 percent lower-carbon than the equivalent in England.

After four years of the new rules, and with no government support or feed-in tariffs on offer for residential solar, 80 percent of new homes in Scotland featured solar.

“[Solar] became a mainstream technology as far as the homebuilding sector and Scotland is concerned,” said Chris Hewett, chief executive of Solar Energy U.K., the country’s solar trade body.

If the same rate of uptake is experienced in England, more than 200,000 new solar homes could be incorporated onto the grid every year. The latest data on solar deployment runs to the end of November 2020. There were 978,751 installs under 4 kilowatts in size across the whole U.K. Of those, just 24,000 were added in 2020, and the majority will have been on new Scottish homes. The new regulations could essentially increase installation volumes tenfold.

Solar to become the norm for new homes

The Scottish rules are far from perfect, however. Carbon dioxide limits are applied across an entire development, not on a house-by-house basis. That means some homes have enough panels for an average family’s usage, some might have none, and others have frustratingly small systems. Lonely-looking pairs of panels set up on a huge roof area are not uncommon.

The new rules in England will be house-by-house. At the same time, the "low-carbon-heating ready" condition means savvier buyers will already be considering the purchase of a heat pump. That might encourage homebuilders to go beyond the minimum required sizes and build more arrays sized to provide greater value.

Hewitt said the entire “solar smart home” concept, including batteries, EV charging and electrified heat, could play its part in larger solar arrays becoming more prevalent.

“I think electric vehicles will probably be more of the driving force [for] customers who are looking at a new-build property,” he said.

Viridian Solar is a U.K. manufacturer of roof-integrated solar panels. Sinking the panels so that they are flush to the roof surface has become practically standard for new builds, CEO Stuart Elmes said. The company works directly with a number of major U.K. homebuilders.

Elmes expects property developers to think differently about how they apply solar as consumer trends change.

“Everyone will expect that new houses come with solar,” he said in an interview. 

There have been concerns that limits set by the Future Homes Standard could be met by the installation of a heat pump alone, meaning that they wouldn’t have to specify solar on each property.

Elmes now believes that it's more likely that consumers will look for the whole package, along with the lower-carbon, lower-cost heating and power that can be attained with the installation of new technologies.

Residential PV sector to ramp back up

The end of the feed-in tariff saw swaths of installers exit the sector. A survey by the Renewable Energy Consumer Code conducted as the subsidy cuts were announced found that 88 percent of installers planned to eliminate jobs, restructure their business or exit the sector entirely. Now U.K. residential solar faces the prospect of a resurgence. 

Generous feed-in tariffs triggered a boom in retrofit PV installs in the U.K. The tariff fell in large increments, creating boom-and-bust cycles on either side of a change. This time, things will likely be very different.

Elmes expects this new rollout to be a more stable and professional endeavor given that it will favor larger contractors. The feed-in tariff boom attracted a patchwork of local installers, not all of which met expectations during the sales and installation processes.  

“They're very different beasts [compared to] the companies that operate in the construction industry,” he said. He expects larger solar installers in the country and other construction contractors to meet the demand. One Scottish roofing contractor, Forster Group, has done a particularly good job of pivoting to solar.

One fear touted around the time that the Net Zero Home regulation was shelved was that if costs rose for homebuilders, they’d build less and put the government’s homebuilding targets at risk.

“House-building didn't fall off a cliff because Scotland went to higher energy regulations,” said Elmes. “Scotland went well ahead of the rest of the U.K. and didn't affect house-building at all.”