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Cranbrook Museum - Energy Audits for Kent & Medway Museums

Project Background

Kent Museums Group invited Sustainable Business Partnership CIC to outline their audit process and highlight the very large savings made by Rochester Guildhall Museum after an audit and the execution of resulting recommendations.  Following an interested response from its members, Kent Museums Group applied successfully for a Development Grant to pay for three museums to undergo the same audit to guide them to substantial reductions in their utility bills.

This Case Study is from Cranbrook Museum, the first to apply for the grant support via Kent Museums Group.


Museum Background

Cranbrook Museum is a Grade II Listed, 15th Century, timber framed building in the heart of the Kentish Weald. The oldest part was probably used to house the bailiff of the Rectory Farm, belonging to the Archbishops of Canterbury.

In the 1620s the old medieval hall was rebuilt with two new brick chimney stacks whose inglenook fireplaces can still be seen today. During the 17th century the building was in use as the Rectory and the brick facing to the north and west walls was added by Charles Buck, vicar of Cranbrook, in 1683. Evidence of the date of this transformation is recorded in the external plasterwork.

In the 19th century the building was divided into four cottages, which in 1889 were bought by a local solicitor, W T Neve. More external renovations were made and a further date was added. Later, the cottages came into the possession of Cranbrook Rural District Council and, in 1971, one cottage was made available to the Cranbrook & District Local History Society for its museum. As other cottage tenants left, the museum gradually expanded into the vacant properties. After 1995 the whole building was conserved and refurbished by Tunbridge Wells Borough Council and adapted to house the much increased and expanding museum collections, displays and archives.

Clearly, older buildings like this can have substantial problems with environmental control and often use more energy to maintain conditions; any savings are welcome!


Project Aims

The aims of the project were to conduct a professional energy audit in order to identify cost savings from new energy tariffs and/or suppliers where possible, rationalisation of supplies, reduction of waste disposal costs, and investigation of lighting usage and equipment leading to replacement with more modern, cost effective equipment.  Overall, the aim was to find year on year savings and a reduction of UV exposure to artefacts.


Recommendations and Actions

Cranbrook made contact with Rowan Wallis of Sustainable Business Partnership and supplied two year's energy bills for him to analyze.  A site visit was arranged for 4th August 2015 and Rowan spent a couple of hours reviewing the museum's lighting arrangements, gas usage, water supply and waste disposal.

A full report was supplied by Rowan within two weeks which detailed actions necessary to create cost savings and benefits to light exposure to artefacts.

  • Replacement of the existing (now obsolete) lighting track together with low voltage spots and 50w lamps with new track and fittings with LED lamps.
  • Replace all fluorescent fittings with LEDs, including linear tungsten cabinet lights.
  • Replace all emergency lights with equivalent LED fittings.
  • Change energy tariff and take advantage of un-advertised charity savings
  • Minimize water usage by removing one particular supply
  • Rowan to provide information on available grants to complete works

This resulted in an annual saving of around 1681 kWh or £350 with a carbon saving of 80 tonnes a year although payback of the cost of new equipment would be about 10 years it was still worth the expense plus the benefit of the added life of LEDs and a sizeable reduction in UV radiation.

Energy tariff was changed to a new contract and weekly gas and electricty meter readings are taken to monitor usage.

Radiator thermostats have been re-set and are monitored to make sure nobody turns them up too much. And water heaters have been turned off when not in use - though care should be taken to ensure water is heated enough to avoid bacterial growth.

The conversion of water and sewage supplies from four cottages to museum usage in 1972 left two water mains coming in to the building.  This has now been streamlined into one supply at a one-off cost of £220 whilst halving the water and sewage charges year on year.

Rowan helped the museum draft a new Sustainability Policy incorporating refreshed perspectives on energy use.

Rowan directed Cranbrook to a British Gas Energy Efficiency Fund for financial assistance but British Gas took from 27th July to 9th October to deal with the museum's application. Despite several calls and emails for additional information during that time, the Fund had run out of money by 9th October.


Final Outcomes

Though it may take time to recoup the cost of replacing equipment and streamlining the water supply Cranbrook Museum will make substantial savings every year now, whilst also reducing aretfact's exposure to unnecessary UV light, and creating a more positive and constructive Sustainability Policy for future management.

The Museum highly recommended Rowan's expertise and professionalism to Kent Museum Group members; even without a grant to pay for the audit, the savings made by Cranbrook Museum and Rochester Guildhall Museum make an audit cost-effective.

Anyone wishing to use Sustainable Business Partnership CIC should contact Rowan Wallis