An historic mansion housing one of the world's finest collections of antique miniatures is reaping the benefits of being heated by the latest in 21st Century green technology.

Northumberland (UK)-based re:heat has installed two wood pellet fired biomass boilers to supply renewable heat to keep visitors, staff and the valuable collections in Nunnington Hall, near York, at the optimal temperature.

Owners the National Trust appointed re:heat after a competitive tender process to deliver the project.

re:heat, of Alnwick, fitted two 50kw biomass boilers to replace an old, inefficient oil powered heating system, giving the hall clean, renewable heat and helping preserve its stunning Carlisle Collection of dolls house-style rooms and miniature figures.

The complex project was completed to time and specification by re:heat's expert engineers as part of the National Trust's environmental commitment to substantially reduce carbon emissions at its properties by switching to more renewable energy sources and deliver 50 per cent of its energy from renewable sources by 2020.

An oil-powered boiler, storage tanks and pipe network running from a garage under a courtyard to the stately home were removed, allowing re:heat to install the new biomass boilers which run on sustainable wood pellets.

"There were a lot of challenges to overcome with this project but it has worked very well," said National Trust project manager Edward Wood.

"It was essential that the new system was installed quickly so that the impact on our conservation heating was minimised.

"We have to maintain our environmental conditions at the right level so our listed buildings and collections don't deteriorate. We also need to supply comfort heating for our staff and volunteers.

"Most of this work was being done while the site was open so it had to be managed around visitors and daily deliveries. re:heat managed these challenges very well.

"It was a complex project but well worth the effort. In addition to reducing our impact on the environment, going to biomass gives us a level of security in no longer responding to fluctuating oil prices, and we qualify for the Government's Renewable Heat Incentive scheme. Even better, the money we save can be put back into the conservation of the property."

Nunnington Hall can be traced back to Tudor times and working in its old buildings presented its own unique challenges to the re:heat team.

"This was a very sensitive site and the spec that we were given was quite challenging in that a very old heating system was in place which needed to be replaced to meet the Hall's present day and future needs," said re:heat director Ben Tansey.

"Cost was one of the key drivers for the National Trust but there was also a requirement to remove potentially hazardous materials from the site such as oils.

"We had a restricted timeline of eight weeks to fit the boilers to minimise impact on the general public. We were only allowed to drill in certain places and had to work alongside conservation builders when installing the system.

"Nunnington Hall now has a much more efficient and modern heating system to meet their requirements."