The Perils of Installing Air Conditioning in English Period Houses

the challenge of integrating modern comforts into historic buildings

Air Conditioning in Period Houses

March. 2024

In recent years there has been a noticeable increase in clients considering the introduction of air conditioning or comfort cooling in to their country house.  This has been driven by the increased availability of the technology, the climate warming up, and the increasing international nature of English country house buyers.  To the latter group, often not used to the delicate nature of the English period houses, the introduction of air conditioning sounds like a breeze (pun intended).  However, its introduction to a period country house comes with many warnings.

Air conditioning in a period house with architectural features such as leaded windows
Air conditioning in a period house with architectural features such as leaded windows


Firstly, period country houses are architectural treasures, encapsulating history and cultural heritage.  From Tudor timber frames to Georgian panelling and Victorian ceilings, the built heritage of Britain’s country houses requires careful handling.

It also requires an acceptance that these houses were not built for modern living in the first place, and when buying a period property, most buyers do with an understanding there may be a few draughty windows and the odd gap in the brick work.

Yet, as we modernise our living and working spaces, the temptation arises for some to integrate modern comforts like air conditioning into their country house.  We have discussed “Improving Energy Efficiency in Period Houses” in a previous article, and while the temptation to retrofit period houses with modern convenience is understandable, it does pose a potential risk to a building’s integrity.  Striking a balance between preservation and practicality is therefore essential.

Air conditioning units can harm the structural integrity of a period house
Air conditioning units can harm the structural integrity of a period house


Period English country houses were mostly built using traditional natural materials with interiors often boasting intricate design, finishes with natural pigments, and structures and decoration made of locally sourced timber and stone.

Retrofitting air conditioning systems through the complex weave of a period house almost always requires intrusive alterations, such as drilling holes for ductwork or installing bulky mechanical units. These alterations can compromise the structural integrity of delicate walls, ceilings, and floors, leading to irreversible damage.  They also diminish the authenticity of the property by simply looking like a poorly considered modern intervention; by simply looking out of place.

However, despite looking highly suspect, it is the unseen risk of upsetting the relative air humidity of the house which poses the biggest risk of all.

Syon House in Brentford well preserved interior
Syon House in Brentford with its well preserved interior


The charm of a period house lies in its distinctive architectural features such as ornate mouldings, handcrafted woodwork, and intricate plasterwork.  Anyone who has visited the magnificent Syon House in Brentford (the London home of the Duke of Northumberland), will know how well preserved the original Robert Adam interior is.  The plasterwork remains crisp and the joinery remains sharp; almost as if it was installed this century, not in 1762.  The incredibly well preserved interior has been put down to the fact that there is no modern heating in the house.  Had there been, the humidity levels would have dropped and the wood, by its nature hydroscopic, would distort.  Ornate plasterwork would also have cracked and dislodged from its lathes.

There are other hidden risks too, and not just to a buildings structure. As air is cooled by an air conditioning system, its moisture content decreases, leading to lower humidity levels indoors. While this can provide relief from muggy or humid conditions, excessively dry air can cause discomfort and potential health issues such as dry skin, irritated respiratory passages, and increased susceptibility to respiratory infections. It can also contribute to issues like static electricity and damage to wooden furniture or musical instruments. Therefore it is important to balance humidity levels to maintain a comfortable and healthy indoor environment. Some modern air conditioning systems now come with humidity control to address this concern.  Others simply open a window.

Condensation from air conditioning units can seep into walls and ceilings
Condensation from air conditioning units can seep into walls and ceilings


Maintaining optimal humidity levels is crucial for preserving the structural integrity of period houses.  Most country houses maintain this balance by being breathable, often via lime courses in the stone work and the natural materials from which they were constructed.

However in periods of extreme temperature the temptation to introduce modern climate control can be strong; air conditioning provides precise temperature control and some might argue improved air quality.  However, air conditioning systems can create microclimates which promote moisture accumulation and mould growth, posing a threat to wooden beams, antique furniture, and archival documents.

Condensation from cooling units can seep into walls and ceilings, fostering hidden mould colonies which jeopardise both the inhabitants’ health and the property’s longevity.  They can also put the building’s very existence at risk.

Andrew Petherick, Guild Anderson’s Business Development Director, recalls one period country house project where a combination of highly effective new windows, a highly efficient air conditioning system, and an owner who rarely opened the windows. caused the house to dry out to such an extent that the original medieval roof structure began to deteriorate to the point where it’s structure nearly collapsed.


Before installing air conditioning, thorough research into building regulations and restrictions is vital.  Period listed buildings are subject to stringent preservation guidelines, limiting the scope of modifications allowed. They require meticulous preservation to safeguard their legacy for future generations.

Local authorities and preservation bodies typically oversee these regulations, ensuring any changes align with the building’s historical significance.  Retrofitting air conditioning complicates heritage conservation efforts, as it involves navigating stringent regulations, obtaining permits, and consulting preservation specialists. Balancing modern comfort with historical authenticity necessitates thoughtful compromise and innovative solutions that respect the integrity of the original architecture.

Seeking guidance from heritage experts and conservation professionals is invaluable when considering air conditioning installations in period listed buildings. Their expertise helps navigate regulatory requirements, select appropriate solutions, and preserve the building’s heritage for future generations.  A casual approach to this modern intervention is therefore ill advised.

Failing that, the traditional approach to ventilation in a period property can also work; open a window!

If you would like to discuss air conditioning in your period house, please contact us


Request a free portfolio or speak with us.

Guild Anderson -


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