Improve insulation to improve building energy efficiency

Up to 75% of a building’s energy is lost through its ‘fabric’ – the walls, roof, floors, windows and doors.

Improve insulation in your building to reduce energy costs and carbon emissions and improve your energy efficiency.

Contents

  1. Make a plan to upgrade building fabric
  2. Improve insulation and lower air infiltration
  3. Get finance and support

Make a plan to upgrade building fabric

Upgrading building fabric is one of the first things to consider when making a plan to retrofit your premises.

Installing new building fabric:

  • may be required to pass energy efficiency checks
  • reduces the need for heating and cooling
  • can disrupt building activities
  • is required before other upgrades, such as getting a heat pump

Use the Carbon Trust’s Building Fabric Guide for detailed guidance.

Comply with legal deadlines

The quality of building fabric is a major factor in a building’s Energy Performance Certificate (EPC) rating.

As of April 2023, all non-domestic privately rented buildings in England and Wales must be EPC E, or the highest rating under EPC E that installing all cost-effective measures can achieve.

Fines between £500 and £5,000 can apply if you don’t make an EPC available to a prospective buyer or renter.

Check what EPC rating you need for commercial buildings

Become eligible for funding programmes

Funding programmes that help with the cost of new building systems are often dependent on the quality of building fabric and insulation.

Check our finance and support page for a full list of funding opportunities.

Consult building occupants

Consult any tenants you have on plans to make major building fabric upgrades.

Major building fabric upgrades are likely to disrupt business activities.

Find out if there are upcoming occupancy changes or if tenants can change their working hours on site.

Ask your landlord about making changes

As a tenant it’s unlikely you have the authority to make major changes to building fabric.

Ask your landlord about upgrade plans and pass along feedback about building performance and comfort levels.

With landlord permission you might be able to make smaller changes such as draught proofing windows and doors.

Consider ’embodied carbon’

It is also important to consider the ’embodied carbon’ in the materials you use to make improvements.

While new products will reduce operational carbon by increasing energy efficiency, those savings can be negated by how materials are made and disposed of.

Use the Carbon Trust’s Building Fabric Guide to find out levels of embodied carbon in building fabric.

Find out more about how to source products and services from green suppliers.

Improve insulation and lower air infiltration

Preventing outside air from coming in and insulating interior spaces is therefore critical to increasing building efficiency.

Keep in mind that increasing air tightness can affect interior moisture levels. Changes to ventilation may be required to manage condensation.

Increase air tightness around doors

Doors are a major source of energy loss in non-domestic buildings.

Prevent this by increasing air tightness in commonly used areas such as entrance lobbies and goods delivery areas.

Options include fitting:

  • spring-loaded doors that automatically close
  • doors with brush strips
  • a revolving door or entrance lobby partition
  • PVC curtains between spaces with different temperatures
  • airtight seals around vehicular access doors

Find out more in: 

Improve windows

Heat and cold pass through windows more easily than other types of building fabric, so it makes sense to consider them in any improvement plan.

Improve existing windows by installing any or all of the following:

  • draught-proofing around windows that open
  • sealing around window frames
  • curtains and blinds that control temperature and light
  • external shading such as awnings, overhangs or trees

You should also inspect your windows for cracks and moisture. It makes sense to replace sections showing excessive wear or mould.

Replace windows

Compared to other fabric upgrades, replacing windows is expensive and may only be necessary:

  • as part of a major refurbishment project
  • if your existing windows are performing very poorly

Install windows with double glazing to reduce heat loss.

Consider smart windows with low-emissivity (low-E) coatings on glass. 

Smart windows typically cost about 10 to 15% more than regular windows, but they can reduce energy loss by 30 to 50%.

Insulate your tanks, pipes and radiators

Insulating your hot water tank, pipes and radiators is a quick and cheap way to save on your energy bills.

Find out more advice in Energy Saving Trust for insulating tanks, pipes and radiators.

Install roof insulation

Adding loft insulation is one of the most effective ways to lower energy cost if your business has an empty attic space.

According to GOV.UK’s SME Guide to Energy Efficiency (PDF), installing 100-150mm of glass fibre insulation in lofts can reduce these losses by up to 90%.

Loft insulation can pay for itself in as little as two years and remain in place for up to 40 years under dry conditions.

It is more challenging to improve insulation in buildings without attic spaces.

Usually, these are buildings with flat roofs or ‘vaulted’ ceilings without a large empty space that can be filled with insulation.

You should not add insulation to the underside of these roofs as it increases the risk of damp within the roof system.

These roofs are easier to insulate as part of larger refurbishments where the weatherproof layer is exposed.

Install cavity wall insulation

Buildings constructed between 1920 and 1990 often have an empty space between the exterior and interior walls.

Insulation can be injected into these ‘cavity walls’ through exterior holes. It can pay for itself in 3 to 5 years.

Insulating cavity walls can reduce losses from walls by two thirds, according to GOV.UK’s SME Guide to Energy Efficiency (PDF),

Cavity wall insulation may not be suitable for walls that face heavy rain and winds as moisture can get through the filled injection holes.

Find out more in: 

Install external wall insulation

Many non-domestic buildings have ‘solid’ walls with no cavity to insulate.

In these cases, insulation panels or ‘render boards’ can be fixed on the exterior of the building.

Advantages of these systems include:

  • can be installed over different wall surfaces
  • wide variety of styles and finishes
  • improved air tightness in the building ‘envelope’

External insulation:

  • must be installed on walls that do not have moisture penetration issues
  • may not be suitable for listed properties with protected exterior facades

Find out more in Carbon Trust’s Building Fabric Guide.

Insulate floors

Floor insulation can improve comfort and increase energy savings, though major installations are often disruptive.

Sealing gaps around cracks and edges is low cost and should be done on all levels of a building.

During major refurbishments it makes sense to consider adding insulation to suspended timber floors or concrete slabs.

Check:

Get finance and support

Find out about:

Use Trustmark’s guide to help you find insulation installers.

You can also hire a consultant to study your building fabric and make recommendations.

Check how other SMEs have successfully cut their costs and carbon emissions in our case studies.

Related links:

Find out about:

Was this page useful?

Yes
No
Thanks for your feedback!