Downing Street has an ‘F’ rating for energy efficiency during the Net Zero drive

Downing Street has been given a poor ‘F’ rating for energy efficiency as the government urges Britons to be more careful.

Historic buildings on 10-12 – including the offices and apartments it occupies Rishi Sunak and Jeremy Hunt – received a score of 130 on this month’s assessment.

This compares to a typical number for public buildings of 100. Higher numbers mean emissions are worse. Experts made a number of suggestions to improve performance, including eliminating drafts and installing a heat pump.

The changes to Downing Street’s energy use have no effect on Mr Sunak and Mr Hunt, who only pay a taxable allowance for running costs in Grace and Benefit housing – capped at 10 per cent of their ministerial salaries.

No10 previously said it was impossible to separate these costs from the wider costs of running offices and kitchens.

The historic building at 10-12 Downing Street – including the offices and flats occupied by Rishi Sunak (pictured) and Jeremy Hunt – received a score of 130 in this month’s assessment.

Downing Street has been given a poor ‘F’ grade for energy efficiency as the government urges Britons to be more careful

Energy certificates are mandatory for all public buildings.

Downing Street’s score of 130 is a slight improvement on last year’s 150, but still on the edge of a ‘red’ rating on the efficiency scale.

In the year to June 2021, it increased from 106.

Separate energy report reiterated some of the advice the government has been giving households amid the cost of living crisis.

No10 said it had taken advice on smart meters and more loft and wall insulation and was “looking into the viability” of using heat pumps.

Among the recommendations in the energy report, carried out last May, was: “Consider how the airtightness of building fabrics could be improved, for example sealing, removing drafts and closing unused ventilation openings, chimneys.”

Building managers were also instructed to consider “the installation of secondary glazing and/or under-glazing lighting where appropriate”.

Another attractive suggestion was to “install photovoltaic panels to generate electricity installed in the building” – something that could be difficult given Downing Street’s heritage status.

This would have a “large” impact on efficiency, but would take more than seven years to recoup the investment, according to the document.

Existing ‘modular’ boilers were said to be ‘nearing the end of their useful life’, with the assessor discussing the idea of ​​replacing them with ‘an air source heat pump as the main source of heat or switching back to district heating’.

A UK Government spokesman said: “The buildings at 10 to 12 Downing Street were originally built in the 1680s and are now Grade 1 listed.”

“The estate has adopted a number of environmentally friendly measures, such as a full rainwater harvesting system for the gardens and low-energy and motion-sensing lighting, while protecting the integrity of this heritage site despite significant challenges.”

“The UK continues to lead the world in clean, green technology and sustainable living and we will continue to build on these actions in Issue 10 going forward.”

Downing Street’s score of 130 is a slight improvement on last year’s 150, but still on the edge of a ‘red’ rating on the efficiency scale. In the year to June 2021, it increased from 106.