Union leaders have accused the Scottish Government of trying to “bully and intimidate homeowners” into installing heat pumps after statistics revealed less than 200 installations were completed under a key funding scheme in the space of seven months.

Patrick Harvie launched a public consultation on his proposed legislation to require Scots to replace polluting gas boilers with renewable heating systems such as heat pumps.

Under the proposals, modernised energy efficiency standards, which could take the type of heating system into account, as well as the insulation and fabric of the building, will need to be met from 2028.

The draft plans sets out that privately rented homes will be required to meet a minimum energy efficiency standard no later than 2028, while owner-occupied homes will need to meet those same standards by the end of 2033.

Mr Harvie said that all homes and non-domestic buildings will be required to end their use of polluting heating by the end of 2045.

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But the GMB union has issued a warning about the strategy after statistics revealed under Freedom of Information showed that only 164 heat pumps that received funding under the Home Energy Scotland grant and loans scheme were signed off as completed in the first seven months of the initiative after it launched in December last year.

Scottish Government statistics show that Home Energy Scotland received more than 6,000 applications since launching last December until the end of August 2023, with more than 1,900 funding offers issued for heat pump installations in this period.

Applicants have nine months from receiving a funding award to carrying out the work.

But the union has warned the low completion number shows a reluctance from the public to switch from fossil fuel boilers to renewable heating systems, largely due to costs.

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The total costs of the move to net zero heating systems in Scotland is estimated to be at least £33 billion, with only £1.8 billion pledged by the Scottish Government so far.

But the Scottish Government has stressed that this is not the full picture – with an annual increase of 22% for the grants and loans scheme and more than 5,000 households a year in Scotland already moving to clean heating systems.

Claire Greer, GMB Scotland’s organiser in energy, claimed the small number of grants being completed in the first six months of the scheme, shows a widespread reluctance to instal the expensive heating systems.

She said: “These figures only confirm what everyone, including the Scottish Government, knows already, Scots simply cannot afford to fit heat pumps and to insist they must is a fantasy.

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“Given that reluctance, the official determination to bully and intimidate homeowners into adopting heat pumps is both misguided and a missed opportunity.”

She added: “All that energy and resource should instead be used to investigate and implement better, quicker and more practical ways of driving towards net zero.

“They are refusing to even discuss practical measures which could cut emissions in the short to medium term while trying to bully Scots into spending a fortune on heat pumps.”

The Scottish Government is encouraging landlords and homeowners to replace gas boilers with electric heat pumps to speed the drive to net zero.

Scots can apply for a grant of up to £7,500 or £9,000 in rural areas, to replace boilers with heat pumps and other renewable heating systems, and can also be eligible for an interest-free loan of up to £7,500 to cover remaining costs.

Statistics show Home Energy Scotland show applications for grants and loans relating to 112 heat pumps and 52 hybrid heat pumps were completed in the seven months to June.

Scottish Labour’s climate spokesperson, Sarah Boyack, said: “People need more than warm words from the SNP Green Government which appears to be all over the place on how the people of Scotland heat our homes.

“Last week it was clear that Patrick Harvie had no solutions for homeowners or landlords on getting the financial support they need during a cost of living crisis to make their homes warm and affordable to heat.”

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Zero Carbon Buildings Minister, Patrick Harvie, said: “Scotland has the most generous funding package of grants and loans across the UK for households seeking to switch to clean heating systems.

“Between December 2022 and August 2023, over 1,900 funding offers were issued under the Home Energy Scotland Grant and Loan scheme for heat pump installations - a 22% increase on the previous year.

“Across Europe there has been a dramatic increase in demand for clean heating. More than 5,000 households a year in Scotland are already moving to clean heating systems.

“Heat pumps are much more efficient than gas boilers, and we believe that they and other clean heating options will save money on energy bills over time – liberating people from exposure to volatile fossil fuel prices.”

He added: “However, different types of buildings in different areas will need different solutions. We are looking for views on proposals that before the end of 2045 everyone will need to have switched to clean heating, of which heat pumps are only one option alongside other forms of electric heating and heat networks.”

“We believe that our proposals will send a vital signal to Scotland’s supply chain and installers about the value and opportunities of this transition. The journey towards net zero will offer a tremendous chance to increase the number of jobs in the sector as existing businesses diversify and new ones seek to take advantage.”