Insulation
If you occupy premises that need to be heated, then improving the insulation levels can help to reduce the heating demand, which in turn will cut your energy bills and emissions. Insulation levels can be improved by adding layers of insulation to existing building elements such as walls, roofs and floors, and by replacing poorly insulated elements such as doors and windows with better insulated alternatives.
Heat loss can also be cut by reducing the amount of unwanted and uncontrolled draughts. Technically speaking this is not insulation, but it often goes hand in hand as part of a building upgrade, and ideally both need to be done to effectively minimise the heating requirement.
This page will explore everything you need to know about Insulation to better understand whether it's an energy saving measure that could work for your organisation. Scroll to learn more, or click the button below to download the guide in PDF format.
Cavity wall insulation
If you occupy a building that is made of brick or concrete blocks, which was built between 1920 and 1980, then there is a good chance that it has cavity walls. This means the external walls were built as two separate walls with a gap or cavity in between. It is often possible to fill this gap with insulation sprayed through holes drilled in the outer wall. The insulation material is usually either mineral wool or polystyrene beads, but polyurethane foam may sometimes be used instead.
Where possible, cavity wall insulation is one of the most cost-effective ways to upgrade the thermal performance of a building.
Internal wall insulation
Internal wall insulation may involve fitting rigid insulation boards to the inside surface of the wall, building an additional stud wall filled in with insulation material such as mineral wool fibre, or sometimes by spraying foam insulation directly onto the inside surface of the wall.
Internal insulation:
• Is generally cheaper to install than external wall insulation.
• Will slightly reduce the floor area of any rooms in which it is applied (the thickness of the insulation is typically around 100mm).
• Can be quite disruptive but can be done room by room.
• Requires internal fittings to be removed and reattached and may require modifications to window and door frames.
• Can make it hard to fix heavy items to inside walls – although special fixings are available.
• Cannot be done before fixing any problems with penetrating or rising damp.
External wall insulation
External wall insulation involves fixing a layer of insulation material to the wall, then covering it with a special type of render (plasterwork) or cladding.
The finish can be adapted to fit in with the general look of the building, or with other nearby buildings.
External insulation:
• Can be applied without disruption to your organisation.
• Will not reduce the floor area of your workplace.
• Will renew the appearance of outer walls.
• Will improve weatherproofing and sound resistance.
• Reduces the risk of condensation on internal walls.
• Best installed at the same time as external refurbishment work to reduce the cost.
• May need planning permission – check with your local council.
• Requires good access to the outer walls.
• Not recommended if the outer walls are structurally unsound and cannot be repaired.
Insulation options
If you have an accessible loft space that is easy to access and has no damp or condensation problems, it should be easy to insulate. You can lay rolls of insulation, usually mineral wool, between the joists and then another layer at right angles to achieve the desired thickness – 300mm is usually the recommended depth for mineral wool loft insulation. It is important to make sure the loft space is well ventilated to avoid condensation in the now colder loft, and to make sure any water pipes or tanks that sit above the new insulation are well insulated to avoid freezing.
If you have a flat roof, or a pitched roof with a room directly beneath, or a loft that cannot easily be accessed, then you will need professional installers to suggest the best solution. This will usually involve applying a layer of rigid foam board insulation, and often requires the replacement of some of the existing internal or external finishing layers.
A detailed moisture risk analysis is usually required so an appropriate vapour control strategy can be applied to minimise the risk of internal condensation.
Indicative costs and savings
Straightforward loft insulation can be one of the cheapest insulation options available, maybe as low as £10 per square metre, plus any costs for increasing ventilation, draught-proofing access hatches etc. All other roof insulation options will be considerably more expensive and will require installers to visit before they can estimate costs for you.
Savings can be significant for a building that is heated regularly throughout the day, but will be very dependent on occupancy, heating system and building geometry.
The thermal performance of windows and doors cannot be improved by adding a layer of insulation, but you can often make considerable saving by replacing old, single glazed windows and insubstantial external doors with newer, more efficient alternatives. The cost is generally higher than other insulation options, so the expenditure is often not recovered through energy bill savings alone. However, the additional benefits of comfort, improved appearance and reduced maintenance may make the investment worthwhile. If replacement is not allowed due to planning restrictions, or is too costly to justify the expenditure, then secondary glazing may be an alternative. This involves adding an additional layer of glass or polycarbonate to the inside of an existing window, trapping an insulating layer of air without the need to replace the window.
When considering modification or replacement of glazing it is worth remembering that, in an office environment, glare and overheating are often just as significant issues as heat loss. Adding shading, blinds and anti-glare coatings may be of more benefit to the occupants or may be useful additional measures to consider as well as any actions you take to reduce heat loss.
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Alongside the installation an air source heat pump and renewables, the Acharacle Community Centre installed loft insulation and insulation in one of the largest rooms (lowering the ceiling and adding insulation above the panel boards).
