Renewable Energy Project at Osterley Park

View of the front of Osterley House

As part of the National Trust Renewable Energy Investment Programme, Osterley is installing a water-source heat pump in the Middle Lake.

A new water-source heat pump will provide reliable and energy efficient heating to the house and stable block at Osterley.

How will it work?

An array of coils will be installed in the Middle Lake which extract the natural heat produced in the water through heat transfer. Underground pipes bring this heat from the lake to the heat pumps in the basement of the house, which bring the water temperature up to suitable temperatures for conservation heating from the show rooms, and comfort heating for the cafe, shops and offices. Once installed, the parkland will be restored to its original state.

What are the benefits?

  • Reduction of Osterley’s dependence on fossil fuels by removing five gas-fuelled boilers.
  • Increase of oxygen production in the Middle Lake, with positive impacts on biodiversity.
  • Upgrade of an aging and costly system
  • Gain of Renewable Incentive Income from the government, as well as the reduction of overall cost, allowing for more funds being allocated to conservation work.

For more information on heat pumps visit Baystar Energy, with whom we are working on this project.

Latest updates

12 Feb 20

Week 6

Storm Ciara tried its best but hasn’t put us off this week! Trenching in front of the portico steps is nearly finished and we will spend the next week back-filling and restoring the normal access to the front of the House. This area should be looking back to normal very soon! Work down by the lake is continuing well: the heat collectors, some of which you may have seen floating on the lake, are being connected to their manifolds, which are essentially waterbutts which collect the warmed water before it is funnelled through pipes up to the House.

Work continuing to restore normal access to the Portico steps

06 Feb 20

Week 5

This week we discovered something really special! In the trench that has been dug along the front of the portico steps we found this tile fragment showing half of a grasshopper, the symbol connected to the Gresham Family. Sir Thomas Gresham, who founded the Royal Exchange in 1565, built the original Tudor Osterley House in the 1570s, two centuries before it was transformed into the neo-classical mansion we see today. We have another example of this tile on site, found some years ago in a flowerbed in the walled garden. We think that the design was hand-painted, with a turquoise grasshopper surrounded by a dark blue and yellow border. This tile fragment therefore likely dates between 1570 and 1580.

Tile fragment found at Osterley

29 Jan 20

Week 4

The heat collectors are nearly finished, with the first one ready and waiting on the lake surface. These will float for the next few weeks while we install the underground manifold. They will then be filled with a non-toxic anti-freeze which makes them sink – it is this liquid which extracts the heat and circulate it to the heat pumps, known as a closed-loop system. Make sure you go and have a look before they disappear under the water!

Floating heat coils on Middle Lake