had a new eco heating system installed at Sandringham House before his death – to ensure the stay warm over .

The renewable energy system, thought to have cost up to £60,000, is fueled by tons of woodchip from trees grown on the 20,000 acre Sandringham estate.

It is said to be proving hugely efficient and has slashed bills for heating and hot water by thousands of pounds.

The savings have been even greater since the crisis as it means the rambling house can be kept warm without having to pay soaring gas or heating oil bills.

Members of the Royal family including King Charles and Queen Consort Camilla will be able to appreciate the warmth as they spend Christmas on the estate in north Norfolk.

This year will be the first time that the extended Royal family has had a festive break at Sandringham since 2019, due to Covid curtailing Christmas celebrations in 2020 and 2021.

A source on the estate revealed the heating system was installed at the behest of Prince Philip during his lifetime as an environmentally-friendly form of heating.

The source said: ‘The old boiler used to have its work cut out, especially at Christmas time with all the Royal family staying over.

‘Everyone would want a bath at the same time, and it would be a struggle to get enough hot water.

‘But now the house is like a furnace in the winter.In case you have any inquiries with regards to where as well as how to employ Kombi Servisi, it is possible to call us from the web site. There is underfloor heating and the biomass boiler is hugely efficient.

‘It provides enough energy to heat a couple of the other buildings on the estate as well as the big house.’

Woodchips for the boiler are created by the estate’s own commercial sawmill, mostly from the offcuts of trees that have been felled for timber.

Biomass experts suggest it could require more than 60 tons of woodchip – the equivalent of 20 to 30 pine trees – to provide heat and hot water at Sandringham House all year round.

But the total amount used is likely to be far less due to the Royal family only occupying the house for kombi servisi a few days a year.

Biomass boilers are said to provide virtually carbon free energy, as they only create carbon dioxide which has previously been taken out of the atmosphere by trees.

The late Queen could have received a cash payout under the Government’s Renewable Heat Incentive scheme to help offset the relatively high cost of installing the system.

But it is not known if the handout was ever claimed on her behalf.

Prince Philip was the first Royal to take an interest in conservation and ‘green energy’ issues, an interest then taken up by his first born son.

For many years Philip used a converted London taxi, powered by liquid petroleum gas, to drive around the capital.

Philip took charge of running Sandringham in 1952.His son Charles who is now King took over a few years before his father died in April, 2021.

Charles has since carried out plans to make the entire estate organic with a herd of cattle to provide manure as a natural fertilser for crops.

Under Philip’s tenure, the estate planted more than two million trees, created 45 new woodlands, planted 40km of new hedges and began recycling food waste, glass, metals, plastic, cardboard and paper.

It also established 160 hectares of wild bird cover, and 200 hectares of uncultivated land to promote wildlife and ten wetlands.

A Buckingham Palace spokesperson refused to comment about the biomass boiler system.

But a leading figure in the biomass boiler industry said: ‘They are the best option for any consumer of heat if you have access to low grade offcuts of wood, especially from your own sawmill.

‘It means that you create your own closed loop supply chain which is absolutely the right thing to do to minimise carbon emissions.

‘Woodland has to be properly managed with trees thinned out to promote new growth.A biomass boiler is a very efficient way of using the offcuts.’