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 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.
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.
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).
If you’re looking to reduce the carbon emissions associated with heating or cooling your building, then a heat pump could be a good option. However, it’s important to understand the different types of heat pumps, their applications, financial aspects, and ongoing operational and maintenance requirements. This knowledge can help you to decide when to choose heat pumps as an option for heating and ensures that the systems are installed and operated efficiently.
A heat pump works by taking heat from one location, raising the heat’s temperature, and moving the heat to another spot. A fridge works in a similar way. It takes heat from inside the fridge, moves it to the grill at the back of the fridge, and eventually releases that heat into the kitchen or room where the fridge is placed. When used to heat a building, the heat pump gathers heat from the outdoor air or ground, then brings it indoors to warm up the rooms using either a system of circulating water or air.
A heat pump uses electricity to collect heat energy, raise its temperature and pump that heat indoors, but the heat energy it supplies is much more than the electrical energy needed to power the system.
This makes heat pumps a more energy efficient way to heat a building than a traditional gas or oil boiler. It also produces far fewer carbon emissions than other heating systems.
There is a wide range of heat pump technology available. An experienced heating, ventilation and air conditioning (HVAC) engineer is best able to advise on what is right for your building following a site survey. However, there are some key questions to answer to help you and your HVAC engineer determine whether a heat pump might be suitable, and if so, which kind.
An air-to-water heat pump transfers heat from the outside air to water.
This heated water can heat water circulating your building via radiators or underfloor heating. It can also heat water stored in a hot water cylinder for showers and hot water taps.
Air-to-air heat pumps transfer heat from the outside air, warming air that enters your building through a series of fan coil units, or ‘blowers’, or via ducted air.
Air-to-air heat pumps are sometimes referred to as air conditioning. While many people think of air conditioning as a way of cooling buildings, it can also be used for heating.
If you have the space, then you can have a ground loop system. The ground will need to be suitable for digging and accessible to machinery from a road entrance.
The area will need to avoid trees, as roots will cause problems when digging trenches.
The length of ground loop and trenches depend on the size of your building and the amount of heat you need.
If space is limited, it may be possible to drill vertical boreholes to gather heat. This is usually more expensive than digging trenches and usually needs a specialist ground (thermogeological) survey. The ground is generally warmer the deeper you dig, so these systems can be more efficient than ground loop systems.
Commercial buildings may require more than one borehole. A borehole is drilled only about 20cm wide, but somewhere between 75 and 200 metres deep. The depth of the borehole depends on your heat demand and the underlying geology.
Duns Swimming Pool in Langtongate, Duns installed two air source heat pumps after receiving funding from the Scottish Borders Council. The new heating system and solar panels supply enough power for its heating and reduce the amount of gas needed to heat the pool’s water. Still, gas may be required to top up water temperatures during the winter months.
St Ninian’s RC Parish Church in Dundee replaced its gas boilers with air source heat pumps alongside other improvements, including LED lighting, cavity wall and underfloor insulation. The savings achieved contribute to running costs for the community café that is open to the local community twice a week and where around 20-25 people attend for a free hot meal.
The Roy Bridge School House is a volunteer run community facility providing a vital space for local youth groups, lunch clubs, meetings and workshops. A new heating system – an air source heat pump – was installed in the schoolhouse building to ensure that the building was well heated and would meet the required standards for public use. This allowed the space to once again be used all year round. The project aimed to install a new air source heat pump system which could be connected to the building’s existing underfloor heating system.
Findon Hall replaced the boiler with an air-to-air heat pump and installed solar PV panels on its south facing roof to generate electricity. These measures were estimated to save the Hall’s management committee £6,628 in energy costs, 45,209 kWhs in energy, and 9.5 tonnes of C02 a year.
When assessing the lighting needs of your building, first consider who is using the space and what activities are being carried out within it. Our requirement for lighting varies depending on the tasks being performed. For instance, if your space accommodates customers or visitors, it's likely you'll want to create a well-lit, inviting atmosphere. Whereas walking down a corridor is a relatively simple visual task and doesn’t require as much light. In an office environment, the amount of light needed to view a computer screen differs from that needed to read a printed report.
It’s also important to understand the occupancy patterns of the space and when lighting is required. Is the building only occupied during typical office hours? Is a particular room only in use for a few hours each day? Are people constantly entering and leaving the room within a short period? Both the bulbs themselves, and their control, play significant roles in the building’s lighting energy use.
Once you know how the building is used, you can then review whether there are any improvements that could be made to reduce your lighting bill. Reviewing your bulb choices can be a useful first step. LEDs are the most common energy efficient bulb on offer.
Light emitting diodes, or LEDs, are efficient, turn on instantly at full brightness, and are available to fit almost every light fitting in a building. An LED works by producing light from the electricity flowing through the bulb.
With traditional bulbs, we used watts to determine the brightness of a bulb, but watts measure power consumption rather than brightness. Energy-efficient bulbs use fewer watts, so it is best to look at lumen output to determine how bright it’s going to be.
This table compares the wattage of traditional bulbs and approximate equivalent lumen values of LEDs.
Low energy light bulbs imitate traditional light bulbs, so if you prefer a particular colour, there should be a close match with the new energy-efficient lighting.
‘Soft white’ or ‘warm white’ bulbs provide a cosy glow that is best for general lighting, while ‘cool white’ or ‘pure white’ are ideal for focussing on tasks, or any area that requires clear vision.
The colour rendering index (CRI) of a bulb shows you how well a bulb will illuminate a chosen colour. Two bulbs can have the same colour, but the bulb with a higher CRI will show colours more accurately than the other.
The bulb’s packaging will indicate the CRI alongside the lumen value. A CRI of 80 or more is appropriate for many tasks.
If there are any incandescent or halogen bulbs in your building, upgrading them to LED can reduce your electricity consumption and your electricity bill. In addition:
• They last longer than conventional light bulbs reducing replacement costs.
• LEDs produce very little waste heat compared to conventional sources, reducing the need for additional cooling on warm days.
Potential savings switching traditional or halogen bulbs for LEDs
Many office and work environments are lit by fluorescent tubes. These vary in efficiency, with modern thin tubes (T5s) being the most efficient and the older, thicker tubes being the least efficient. All fluorescent tubes are more efficient than traditional incandescent bulbs, but even the most efficient tubes are not as efficient LEDs. Compact fluorescent bulbs – designed to fit into domestic style fittings – are not quite as efficient as the best straight tubes.
Modern fluorescent tubes are often fitted in mounts with a reflector to direct more light in the desired direction, and this will improve overall system efficiency. Some also have diffusers over the bulbs, which can improve the look and feel but will tend to reduce efficiency, especially if the diffuser isn’t kept clean.
Replacing a fluorescent lighting system with an LED lighting arrangement can be relatively expensive as you will often need to change the fittings, not just the tubes.
Understanding when and how each area of the building is used will help determine the type of controls needed.
For instance, spaces with varying occupancy throughout the day may benefit from occupancy sensors that automatically adjust lighting levels based on movement detection, reducing energy waste during periods of low activity.
You should also consider the flexibility and ease of use of the lighting controls, especially if you need other people to interact with them. Intuitive controls allow occupants to adjust lighting according to their preferences and tasks.
Advanced controls like daylight sensors can optimise energy savings by automatically dimming or switching off artificial lights in response to available natural light, further reducing energy consumption while maintaining comfortable lighting levels.
Elgin Tennis Club installed modern, energy-saving floodlights at its Cooper Park site after receiving £18,000 from the Scottish Government’s interest-free SME loan with cashback. The site had 18 500w and 750w lights that were used between 350 and 400 hours each year. Only 11 LED improved the experience for players and provided savings to the 150-member club of around £1,000 a year.
Inch Park Community Sports Club received £8,280 to install solar PV and upgrade its lighting units to LED lighting throughout. The aim of the project was to lower energy use and running costs of the facility so that it could offer reduced hire rates for community groups. Lessons learned include ensuring that contractors and suppliers are aware of, and agree to work to, significant dates including start and completion dates and ideally have these written into the contract.
Nairn Community and Arts Centre in Moray upgraded the building’s internal and external lighting, including the theatre’s lighting grid, to energy efficient LEDs expected to reduce the centre’s electricity usage by 75%.
Many buildings are heated by one or more gas boilers, often distributing heat throughout the building via a system of radiators much like a domestic central heating system. Some may use other distribution systems such as warm air distribution, usually as part of a ventilation system (which may also include cooling), or underfloor heating.
Smaller buildings may have a single package boiler, essentially a domestic boiler, where the burner, heat exchanger, flue and other elements are all supplied as a single unit or package. Larger buildings may have a bank of multiple package boilers, or they may have one or more commercial boilers, where the boiler itself, the burner, the flue, and the condensing economiser are all supplied as separate elements and fitted together on site.
If you have a gas boiler for heating then this will often also be providing hot water for taps, showers etc. Generally, the hot water will come from a separate hot water cylinder that is heated by a coil heat exchanger fed from the boiler. If you have a package boiler then this could sometimes be a combination boiler, or combi, in which case the hot water will come straight from the boiler as and when required, with no need for a hot water cylinder.
If you do have a hot water cylinder, then it is important that this is well insulated to avoid wasting energy as the water cools down. Insulation jackets can be applied to existing hot water tanks but often the best performance will be achieved by fitting a new pre-insulated tank. If a tank already has some insulation, then you could still save more by adding further insulation. We recommend at least 80mm of fibreglass insulation jacket or 50mm of pre-sprayed polyurethane foam.
Oil and LPG boilers operate in the same way as gas boilers, with a similar set of options. The main differences are that the fuel needs to be stored on site, with deliveries arranged when necessary, and the fuel is typically more expensive than gas. Oil is also a significantly higher carbon fuel than mains gas and so leads to a higher carbon footprint than an equivalent gas heating system.
Oil and LPG boilers are generally only found in buildings where there is no nearby mains gas supply.
These are not common in the UK due to the big price difference between electricity and other heating fuels. Where they do exist, the hot water produced by the boiler is usually stored in an accumulator tank – a large hot water cylinder used for space heating rather than for hot water supply. This means the boiler can be operated with a variable electricity tariff, heating the accumulator during cheaper off-peak times of day.
This will help to keep operating costs down but is unlikely to make this an attractive option for space heating.
There are a number of technologies that use electricity to heat a room directly, either by heating the air in the room or by radiating energy into the room, or a mixture of both. These include...
University College London has replaced boilers with more efficient models and connected its room booking system with the heating control system to ensure rooms are only heated when they are in use.
Solar water heating systems use panels or tubes, called solar collectors, to gather solar energy. The solar collectors convert the energy in sunlight into heat, which is transferred to liquid made up of water and glycol. This liquid is pumped round a circuit, which passes through the hot water cylinder.
There are three types of solar water heating collectors:
1. Evacuated tubes – a bank of glass tubes mounted on the roof tiles.
2. Flat plate collectors – fixed on the roof tiles or integrated into the roof.
3. Low temperature collectors such as solar matting – often fitted directly on the ground to provide heat for swimming pools.
To tell if solar water heating is right for you, there are a few key questions to consider:
Solar hot water collectors are typically placed on south facing roofs, or somewhere between east to west (but not north facing).
Panels can be mounted on a frame on the ground or on a flat roof, though this will increase the cost. Solar water heating collectors can benefit from being mounted at a steeper angle than solar PV panels because they often over-produce in summer so can be optimised for winter performance without sacrificing annual output. This means they can be attached to walls rather than roofs, though usually on a frame to tilt them upwards slightly.
The amount of space you need depends on the amount of hot water you use. For a domestic scale system you might need around five square metres that receive direct sunlight for the main part of the day.
Energy is transferred from the sun to the water-glycol fluid used to heat water stored in a hot water cylinder. Inside the hot water cylinder, a base coil is connected to the solar collectors.
Typically for small installations, one cylinder is used, with either an immersion heater or another coil connected to your boiler, near the top of the cylinder.
This top immersion heater or coil will heat the water to a higher temperature when needed. If a dedicated solar hot water cylinder is not already installed, then you will usually need to replace the existing cylinder.
Instead of a single hot water cylinder with two coils, some installations use a dedicated cylinder with a solar heating coil in addition to the existing cylinder.
Conventional boilers and hot water cylinder systems are often compatible with solar water heating. However, if you have a combi boiler, this will mean a solar hot water cylinder must be added to the system, so you’ll need to consider where this might be located in your building.
Most small-scale solar water heating systems do not require planning permission. However, exceptions apply, and you should check with your local planning office.
If your building is a listed building, or in a conservation area or national park, you may have more restrictions.
There are a few things you need to consider to get the most out of your solar water heating system.
It’s important to make sure that your back-up heating system is set up to come on at the right time. Before you installed the solar panels, your boiler or immersion heater was probably set to give you a full tank of hot water in the morning.
If you leave it like this, your system will always start the day with a hot tank and there’ll be no water for the solar panels to heat during the day.
Your installer should advise you on how to set your hot water controls to get the most out of your new system, whatever time of day you use hot water.
ISKCON Scotland As part of a significant decarbonisation ISKCON Scotland installed solar thermal panels to supply hot water to a converted old barn used for community functions.
You are likely to save money from installing a battery alongside a renewable generation system as you will be able to use more of the generated energy to operate your appliances rather than exporting it to the grid.
As you usually pay more to import electricity than you can earn from exporting it, this will reduce your bills. You may be able to increase this saving by choosing a variable tariff and changing when you charge and discharge the battery to take advantage of the varying prices offered.
Installing a battery will not directly reduce your carbon dioxide emissions as it will not reduce the total amount of electricity you use.
In fact, as some energy is lost in charging and discharging the battery, your total consumption is likely to increase slightly. However, fitting a battery does have significant indirect benefits by enabling the installation of additional renewable generation systems without putting extra strain on the network.
There is currently no appropriate and accepted methodology for quantifying this benefit and so it cannot be used when calculating your carbon footprint, but it is a very real benefit nonetheless.
The installation time can vary depending on the complexity of the installation and the size of the battery. Typically, for smaller systems, it takes just one day.
No major disruptions are expected during the installation of battery storage systems, apart from disconnection of the electricity supply for a short period.
Energy storage systems are not a technology that you can install by yourself. You will need to talk to an installer who will assess your needs and evaluate your building before proposing which system could be right for you. Click here to learn more about this.
Peedie Kirk United Reformed Church in Kirkwall, Orkney received funding to install solar PV panels and battery storage. The Kirk wanted to use as much of the energy generated by the solar panels as possible and installed battery storage so that they could save excess energy to be used at a different time. The members estimate that they can produce 1750kw each year from a 6kw solar PV system combined with 7.5kwh of battery storage.
Alford and District Men’s Shed (ADMS), a community building in rural Aberdeenshire, installed a whole energy system powered by renewable energy. It includes solar PV, air source heat pumps, a thermal store, batteries and controls. Funding of £14,820 was used for technical assistance for an options appraisal, design specification and procurement to identify the best options, with £84,875 received to cover the actual works. The system enables the members to maximise the on-site use of the energy generated by the solar PV and to optimise the use of each component.
A typical small-scale UK installation of 3.5kWp, mounted on a pitched roof, will cost around £7,000. This cost includes:
• The inverter, generation meter, panel-mounting system and wiring.
• The cost of labour for supplying, installing, connecting and registering the system.
• Scaffolding, which is needed for most pitched roof mounted systems.
Larger systems are usually less expensive per installed kilowatt.
The typical energy bill savings of a solar PV system differ depending on the size of the system you need or can accommodate, how much electricity you need daily, when you use it and what you pay for your electricity.
With the recent increase in the cost of electricity, the payback period for solar PVs has become considerably shorter, which can make installing solar PV a smart long-term financial investment. Payback periods can be less than 10 years in many cases. The PV panels should typically last around 40 years.
Installation can take from one up to several weeks, depending on a number of different factors such as the size of your system, as smaller installations take less time to complete than larger ones, and the type of your roof and its complexity, as installations on flat roofs tend to be quicker than those on pitched roofs.
For the most part, solar PVs can be installed on your building with minimal disruption and your organisation can continue its activities throughout the duration of the installation.
Solar panels are not a technology that you can install by yourself. You will need to talk to an installer who will assess your needs and evaluate your building before proposing which system could be right for you. Click here to learn more about choosing the right installer.
Duns Swimming Pool in Langtongate, Duns received £79,920 to install an array of solar PV panels. Recipients said that the system has generated a cumulative benefit of 50 MW of electricity, which is estimated to have reduced the daytime consumption by approximately 50% while saving 10,000 kg of C02.
Oakwood Tourism and Crafts, a community-owned shop supporting local arts and crafts businesses, has solar PV installed on its premises. The owner of the building, Sunart Community Company, received £11,388 towards the cost of installing a 4kw solar PV system and a 5kw battery storage.
Eaglesham Bowling Club received over £4,000 towards the cost of the solar PV installation, which was 60% of the total costs. The club found an installer on the Microgeneration Certification Scheme register. The solar PV system was estimated to generate around 70,713 kWh and offset around 67,177 kWh over its lifetime (25 years), with carbon savings of 14 tonnes. It is also expected to save the club around £13,261 in energy bills over the same period. Initial savings have paid for increased energy bills.
Loch Ness Hub, a one-stop shop for information, tours and tickets for attractions in the area, installed a 5.2kWp solar PV array on the building’s roof. A 7kW air source heat pump was also installed to provide heating.
Gloucester Cathedral has 150 solar panels on the nave roof, generating around 25% of the cathedral’s energy usage. The cathedral ran a “sponsor a solar panel” scheme, which raised about half the funding for the panels and their installation. Preparation involved the development of an innovative and light touch fixing method by a Cathedral Architect and the gathering of evidence that the solar panels would not be visible from various sites in and around Gloucester.
University College London has installed 600 square metres of solar panels on buildings across its campus to help generate more of its own energy from renewable sources. The panels produce around 120,000 kWh every year, reducing UCL’s carbon emissions by more than 28 tonnes per year.
If you're interested in learning more about the role social investment can play in increasing energy resilience for charities and social enterprises, check out the Energy Resilience Hub. Featuring case studies, blogs, events and more, this hub has been designed to help your organisation explore how repayable finance can and has helped to finance energy saving measures.
