When Boris Afinogenov moved to Liverpool from Lithuania in 2011, he knew that most Britons preferred to live in houses rather than the Soviet-era tower block he had left behind. But in a rambling Georgian property, he quickly found himself missing his cosy old flat.

The idea of every home having its own boiler was also alien to him: in his town there were two municipal boilers for the entire population.

“It was much more comfortable than the draughty, mouldy and cold terraces here,” he said, recalling his surprise at the UK’s antiquated infrastructure – “Telephone poles! That’s like the stone age.” So much of Lithuania was flattened in the second world war that the country was essentially rebuilt from scratch, meaning that wires and pipes are all hidden under the ground and homes are much better insulated, he explained.

Ten years on, Afinogenov is now making a living warming up draughty homes in his adopted homeland after leaving his sales job and retraining as a retrofitter, specialising in flooring insulation.

He was trained by Manchester’s Carbon Co-op as part of its People Powered Retrofit (PPR) project, which retrofits homes and trains contractors to do the work.

It has an increasingly long waiting list, with 60 retrofits currently under way. They plan to scale up to 500 a year, funded by community share issue, launching in September, which will allow supporters to buy a share for GBP250 for a return of 5% on their investment.

PPR’s courses are aimed at existing trades people and DIY enthusiasts keen on carbon-reducing construction, with about 14% of the UK’s greenhouse gas emissions coming from heating the UK’s draughty housing stock.

There are seminars in ventilation, workshops in making a building airtight and masterclasses in using hemp and lime for insulation.

With the government looking to phase out gas boilers in the coming decades there is also a five-week course in heat pumps for beginners. More than 1,000 people attended one of PPR’s webinars during the pandemic last year and 220 people completed their “eco-renovation for builders” course.

Retrofitting is going to become a huge business. In the north of England alone, more than 270,000 homes must be upgraded every year between now and 2035 to meet government targets and to contribute towards the UK’s net zero ambition, according to the Northern Housing Commission.

But so far any attempt to scale up retrofitting has failed because of a lack of qualified trades people and because of the costs involved. The government scrapped the green homes grant, its programme to install insulation and low-carbon heating, after only six months, during which a fraction of the homes targeted were insulated, and there were widespread complaints of poor service.

Demand is already outstripping supply for PPR, which provides detailed home assessments for GBP550 and then guides owners through the often daunting progress of retrofitting in their home.

“We’re like the householders’ advocate. We’re there to advise, hand-hold, offer specific services like the assessments, the design and the procurement, and then they contract a contractor,” said Jonathan Atkinson, an environmental scientist who set up the Carbon Co-op in 2008. “We don’t do the work but we make sure it is done to a certain quality. We’re not here to exploit people or make a quick buck. The organisation’s main mission is fighting the climate crisis . That’s why we exist.”

Without grants, retrofitting a home is expensive. Afinogenov says it is still a challenge to persuade clients to spend GBP3,500 insulating wooden floorboards.

Nonetheless, demand is already outstripping supply in Greater Manchester, where the mayor, Andy Burnham, recently set up a retrofitting taskforce. In May, Burnham also announced GBP1.1m funding to train at least 1,140 people in retrofitting at the new Retrofit Skills Hub, hailing it as “the first step in moving towards a greener and low carbon city-region”.

But with over a million homes in Greater Manchester alone likely to require work, thousands more tradespeople will need to get into the retrofitting game if Burnham is to reach his target of the region being carbon neutral by 2038.

There is little incentive for builders to branch out into the often fiddly and unglamorous work of retrofitting, which Atkinson admits can be “a pain in the arse” – particularly now they are experiencing a pandemic-related bonanza with homeowners spending their savings on extensions rather than exotic holidays.

With many people taking up trades aged 16 and working on them in the same way for decades, “it can be hard to teach an old dog new tricks”, said Afinogenov. “But it will be worth it. You will be at the sharp end, ahead of the game.”