​One of the UK's flagship government schemes to boost low-carbon heat in British homes has failed to miss its year 1 target.

The Boiler Upgrade Scheme offers grants of £5,000 to help eligible homes to switch their heating to heat pumps, which burn far less carbon and create far lower emissions than traditional boilers. The government said it would issue 30,000 grants every year across England and Wales, but it only achieved 50% of the goal in the first year of the scheme.

The finger of blame has been pointed at the cost of insulating homes to make them heat-pump ready and a lack of available installers. A third factor is related to the high cost of heat pumps.

Heat pumps form a central part of the UK's strategy to hit net zero carbon emissions by 2050. This would ensure that no additional greenhouse gases were pumped into the atmosphere. Currently, domestic heating represents around 14% of Britain's total emissions.

The new boiler grants scheme began in May last year, but the disappointing data published this week comes hot on the heels of criticism from the UK's climate watchdog, which warned the government that it was already significantly off track with its work to hit net zero. The scheme was originally planned to run until 2028. The terms of the scheme mean that the £70 million in grants that were left unclaimed will now return to the Treasury, rather than being rolled over to next year.

The responsible department for the scheme, the Department of Energy Security and Net Zero said that the industry had seen higher volumes of enquiries as time went on, and claimed that they were 'confident' that more heat pumps would be installed over time.