Meghan Markle and Prince Harry's new home was renovated with 2.4 million pounds ($4.3 million) of taxpayers' money, Buckingham Palace has revealed.

Key points: Renovations were undertaken to "guarantee the long-term future" of Frogmore Cottage

Renovations were undertaken to "guarantee the long-term future" of Frogmore Cottage The six-month refurbishment included new electrical wiring and heating systems

The six-month refurbishment included new electrical wiring and heating systems Royal officials had already planned to renovate the site before the Duke and Duchess of Sussex moved in

The sum, part of the annual Sovereign Grant, funded the conversion of Frogmore Cottage from several separate homes into a single dwelling for the Royal couple and their son, Archie.

The Duke and Duchess of Sussex paid for the fixtures, fittings and furnishings in the renovation themselves.

"The property had not been subject of work for some years and had already been earmarked for renovation in line with our responsibility to maintain the condition of the occupied royal palaces estate," said Keeper of the Privy Purse Michael Stevens.

"Outdated infrastructure was replaced to guarantee the long-term future of the property."

The 19th century cottage, in the grounds of the Queen's Windsor Castle estate, became the official residence of the Duke and Duchess of Sussex when they moved in shortly before the birth of their first child, Archie, in May.

The building had been previously converted into five separate residences and royal officials had already planned to renovate it before it was agreed that it would become the pair's residence.

The six-month refurbishment included new electrical wiring, replacement of defective ceiling beams and floor joists, new heating systems and the introduction of new gas and water mains.

A palace source, speaking on condition of anonymity, said the taxpayer grant covered the basic cost for kitchens, bathrooms and flooring — with additional outlays for anything more bespoke being met privately by the Royals, who also paid for items such as curtains and furnishings.

Frogmore Cottage is a home on the grounds of the larger Windsor Castle estate. ( Google Maps )

Renovations 'substantially' completed

British newspapers have reported that among the changes, the cottage now has a "floating floor" and a yoga studio.

Work has been "substantially" completed and outstanding renovations would not feature in next year's annual report, meaning the cost would be under the 350,000 pounds threshold to be included in the public report.

Queen Elizabeth was very involved in the decision to allow the couple to use Frogmore Cottage and had been kept informed of the progress of the project throughout, the source said.

The Duke and Duchess of Sussex had previously been living in a residence in the grounds of Kensington Palace, the London home of his elder brother Prince William and his wife Kate.

But since their marriage in May last year, they have been forging their own path, separating their household from the Duke and Duchess of Cambridge and relocating their staff to Buckingham Palace.

Last week, it was announced that they were splitting from the charitable foundation the two couples had shared.

The outlay on Frogmore Cottage formed part of the 82.2 million pound Sovereign Grant, a government handout to the Royal family.

Frogmore Cottage sits inside the grounds of the Queen's Windsor Castle estate. ( Reuters: Toby Melville )

Twenty-five per cent of the fund comes from surplus revenue from the Crown Estate, a property portfolio owned by the monarchy.

But in detailing the costings for the Frogmore project, royal accounts showed taxpayers footed the bill for $4.3 million in renovations.

Reuters