On your next visit to the Manor House at West Horsley Place look out for our new environment monitors. They might be small, but they make a very big difference!

Monitoring the stability of the internal environment is an important part of caring for historic buildings, interiors and collections. Environmental factors that may be taken for granted in a domestic setting need to be monitored closely in the medieval Manor House at West Horsley Place, which is currently on Historic England's 'Heritage At Risk' Register. This can be done manually using hand-held equipment, but ongoing monitoring and data analysis requires a dedicated system. This is a preventive conservation practise, focused on avoiding damage from occurring and reducing the need for future costly repairs. 

As part of a larger project to improve standards of preservation we have installed an environmental monitoring system. This major step forward in how we care for our heritage. 

We would like to thank the Wolfson Foundation for funding this project.

All equipment and software was provided by Meaco, specialists in environmental monitoring and control for museums.

Here is an example of one of our environmental monitoring devices. This one is located in the Drawing Room, and is continuously measuring temperature, relative humidity, and both visible and ultraviolet light intensity. All of these can harm historic materials if present in incorrect amounts. 


Fluctuations in relative humidity are closely linked to outside weather, and also with central heating. Large fluctuations cause change in organic materials leading to accelerated deterioration. We aim to keep humidity between 50% and 65%. Below 50% there is a high risk of damage to organic objects from shrinkage, and above 65% it is likely that mould will grow and damage surfaces. By using heating, humidifiers or dehumidifiers we can help stabilise indoor conditions.


Monitoring and limiting light intensity is important for preserving textiles, such as our damask wall hangings. Unchecked light exposure causes rapid deterioration of pigments and reduction in structural integrity. In rooms such as the Drawing Room, light levels need to be kept low to avoid the bleaching effect of sunlight. This is why we often close shutters on sunny days.


We are still gathering data from our new system, but soon we will be able to build up a pattern of the behaviour of our internal environment. This is highly important as it will dictate our conservation routines and help us protect West Horsley Place for the future.