Keeping Warm in a Period Property
- Iain Collins
- Jul 1, 2024
- 4 min read
Improving thermal efficiency in heritage properties is a very big topic and one which is of particular interest to listed property owners. I thought it might be helpful to provide a taste of some of the practical improvements you can make, together with links to some additional resources on the topic.
Traditional properties need not be the draughty, cold and damp places they are sometimes portrayed as being. Whilst traditional properties will not achieve the same thermal efficiency as a modern property, there are plenty of improvements you can make to warm your house up. As listed property owners, we are constrained by the requirement to retain our home’s special historical or architectural significance and so Listed Building Consent may not be granted for some measures.
Taking a 'whole house' approach is considered to be the best way to improve your home's thermal efficiency. Rather than focusing on isolated areas or components, this approach considers your home as a system, addressing all potential sources of energy loss or inefficiency, including walls, roofs, windows, doors and insulation.
Insulation
It is possible to make thermal improvements to both the walls and roof of your property but in practice, unless this can be incorporated into other planned works, the easiest way to make improvements is in your roof. A key consideration for older properties when considering upgrading insulation is maintaining 'breathability', which refers to how moisture can move in, around and out of the building.
Having the right coverage and thickness of insulation in your roof can make a significant difference to the thermal efficiency of your home. There is an enforced minimum thickness of 270mm in new build properties, regardless of the insulation materials used. This rule came into place in 2003, meaning that if your home was insulated before that year the total thickness of insulation installed is likely to be lower (e.g. in 1985 it was just 100mm).
Historic England have published some guidance notes on insulating traditional properties here -Roofs, Walls and Floors.
Windows
Traditional windows were originally single-glazed and there is a lot of opinion around the relationship between the effectiveness, economic cost and impact on a property's historical significance when making upgrades to windows to improve thermal efficiency. From a conservation point of view, replacing historic windows is the least desirable option as it can significantly alter the historic significance of your home.
Taking a 'whole house' approach may mean that a simple and inexpensive draught-proofing exercise may achieve as good a result when taken collectively with other measures as an expensive replacement or retrofit. Draught proofing strips can be easily fitted around window openings and special brushes can be installed on sash windows to allow them to continue to be opened smoothly.
Secondary glazing is quite a common solution to achieving the benefits of double glazing without impacting the integrity of the original window or having to pay anywhere near the cost.
Ventilation
Adequate ventilation is important to all properties as a control against damp. In older properties, care needs to be taken when dealing with ventilation as the way they are constructed means they respond differently to modern homes when levels of ventilation are changed.
Activities such as cooking, showering, bathing, drying clothes and the very act of breathing all produce moisture, which circulates in the air in your home. If the level of moisture in the air is not managed properly, it can condense on cold walls, window panes and timber potentially causing damp issues and make heating your home more expensive. In kitchens and bathrooms this is often managed using extractor fans, but this may not be enough for your whole house.
Conversely, homeowners don't want an excessively ventilated home either - draughty homes can be cold and also expensive to heat. So there's a balance to be struck.
There are some inexpensive measures that can be taken to reduce obvious sources of draught - e.g. external doors, windows (see above), panel infill gaps. Fitting draught strips to doors and window openings is easy and inexpensive. If you need to seal small gaps around a wooden window externally, there are traditional products that can be used to do this (try to avoid mastics). Sealing gaps in shrunken external daubed panel infills means simply applying more daub or haired lime putty into the gaps.
Some advocate sealing unused chimneys but it's important to note that chimney stacks need adequate ventilation too so, if it's not coming from inside your home, it will need to come from an open chimney pot, chimney vent cap or sufficient air bricks. Also, open chimneys are often a key source of ventilation for an older property, and so if you notice the appearance of excessive condensation in your home (e.g. on windows) after blocking it, you may need to reconsider.
Energy Efficiency and Historic Buildings - A general guide produced by Historic England for anyone looking to improve energy efficiency in an historic building.
Energy Efficiency and Old Buildings - Highlights the issues of energy efficiency in old buildings and what upgrades can be made.
The Easy Wins - Cheaper, less invasive improvements often yield comparable benefits to more complex, expensive, or harder-to-implement measures.
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