Energy efficiency improvements

Adding insulation and draught-proofing can save money and the planet but in traditional buildings this needs to be tackled with care to avoid creating dampness in your home.

Whatever your motive for making your home more energy efficient, whether it’s…

  • saving on fuel bills
  • making your flat more comfortable
  • doing your bit for the environment
  • meeting new private rent regulations

…you need to do this in the right way to avoid making your building damp at the same time.

Doing the right thing in a traditional building

Traditional buildings made of stone and brick work differently to modern construction types, such as timber frame. Walls are usually lined with lath and plaster linings, kept away from the stone or brickwork. They can provide quite reasonable insulation but this is greatly reduced when the stonework is wet. It is important that stone is allowed to breathe as this keeps it dry – and a dry building is a warmer building.

You can keep your building dry by:

  • ensuring gutters and downpipes are kept clear, well-painted, and working well to keep rain from soaking the walls
  • always using permeable materials (such as lime mortar) which allow moisture to evaporate
  • allowing adequate ventilation to dry the air and prevent condensation and mould

It’s estimated that there can be 17 air changes per hour in the average old tenement. If your home is draughty, you will want to heat it to a higher temperature to offset the cold feel of the draught. However, some ventilation is important to stop condensation and damp building up. So, you want to control draughts but not eliminate ventilation completely.

What is an EPC?

An Energy Performance Certificate (EPC) rates your home in terms of how much it will cost to heat and how much carbon dioxide it releases into the atmosphere in use. The ratings use a letter, with A being best. The rating is calculated using a formula based on a number of factors, such as building and wall type, heating and lighting methods, and the amount of insulation provided.

If you are selling or renting your flat, you will need an EPC and this must be made available to potential tenants and to buyers through the Home Report.

Getting an Energy Assessment and EPC

An EPC is required if you plan to let or sell your home. You will also need one to apply for the Home Energy Scotland Loan.

You can check if you have an EPC, download a copy, and find EPC Assessors on the Scottish EPC Register.

An EPC will typically cost between £60 and £120. An assessor will need to visit your home and will check both the inside and outside.

The assessor will look at (and measure) a large number of factors:

  • the age, type, size, and construction of your home
  • it’s location and how exposed it is
  • loft and room in-roof insulation
  • amount of wall insulation added
  • underfloor insulation
  • draught-proofing
  • external door and window types
  • type of ventilation used
  • number of open fireplaces
  • heating and hot water systems (including boilers, heating controls, and room heaters), including the type of fuel and any special tariff (‘white meter’, ‘dual’ or ‘off peak’)
  • lighting type

If you have made energy efficiency improvements, you will need to show the assessor proof of what you have done, materials used, etc.

The EPC Certificate itself will give a grading for your property – A being best and G worst.  You will also be given a typical cost to heat and run the property and a list of recommended improvements.

Private landlords and energy efficiency

This advice is going to be especially important for private landlords as new legislation requires them to ensure that any flats they rent out achieve an Energy Performance Certificate (EPC) rating of C by 2025 where technically feasible and cost-effective, at change of tenancy, with a backstop of 2028 for all remaining existing properties.

For landlords, in most cases, upgrading to a high efficiency gas-fired back boiler will ensure their property meets the minimum EPC rating. However, it is still worth them looking at other measures that will make a flat more affordable to live in and more likely to attract tenants who stay longer and have money to pay the rent.

Important principles

Thermal (cold) bridging

Thermal bridging occurs where one area of the wall is much colder than other parts, perhaps an area that has not been insulated, such as around joist ends or behind pipe boxes. Condensation, damp, and mould can occur on these parts. Thermal bridging is almost impossible to avoid but can be minimised by making sure insulation is taken into even the most difficult corners.


Energy efficiency measures and materials are often rated by u-values. This is a measure of how well the material (or combination of materials) insulates. The U value is given in W/m2/K. The important thing to note in making comparisons is that the less heat lost, the lower the u-value.


It’s important to control, but not totally exclude, ventilation as some air changes are needed to keep the building dry and to keep the internal atmosphere pleasant. Maintaining ventilation in your loft, in chimney flues, and underfloor is important for building health and reducing dampness. Mechanical ventilation can also be used.

Pipes and wiring

Insulation should always be placed so that pipes are kept on the warm side nearest the room. Some forms of insulation react with the coverings of electrical wiring, so insulation should not cover wiring. You might need to get help from an electrician to move wiring.

Energy efficiency improvements to consider
How about replacing windows?

Replacing old sash windows with uPVC ones is one of the least energy efficiency measures recommended. Amongst other disadvantages, the payback period for new double-glazed windows is very long. The Energy Saving Trust estimates that installing new double-gazing will save just £60 and £80 on fuel bills per year in an average flat and they can also reduce the amount of light and passive solar heating that comes into the room.

Other options should be considered first:

  • sash window repair specialists can repair and draught-proof timber windows much more cheaply
  • slimline double-glazing can usually be installed into existing sashes
  • secondary glazing can be added
  • shutters, blinds, and curtains all have a positive impact.

More information on windows

Getting advice and financial help
Home Energy Scotland

You can get free energy advice and support through Home Energy Scotland if you are:

  • a homeowner
  • a tenant
  • a landlord who owns property personally rather than through a company

Home Energy Scotland are funded by the Scottish Government and managed by the Energy Saving Trust. They can provide advice on the measures that are suitable for your home and the funding that is available.

The Technical Team at Home Energy Scotland also offer a free home visit service for householders interested in advice on how to make their homes more energy efficient.

The Home Energy Scotland Loan with Cashback may be available if you are planning:

  • solid wall insulation
  • heating systems
  • gas connection
  • flat roof or room-in-roof insulation
  • loft, floor or cavity wall insulation
  • installing some renewables

A number of rules apply such as:

  • you must get advice first from Home Energy Scotland
  • the energy efficiency improvements must be recommended in an EPC
  • you must apply for the loan yourself – letting agents and installers cannot apply on your behalf
  • you must wait to get the offer of loan in writing to start work

If you are a landlord renting properties through a company, you may be able to get help through the Energy Saving Trust SME Loan scheme.

Further information

Freephone: 0808 808 2282

Common or individual responsibility?

Adding insulation to common areas, such as the loft or close or external walls is treated as maintenance and is therefore generally subject to a majority decision of owners. If you are the top flat owner looking to get the loft insulated above your own flat, and you cannot get a majority decision then you may need to go it alone. It is unlikely that other owners will refuse consent for you to do this.

Insulation and thermal improvements added within your own flat such as under ground floors, to windows, the inside of walls or your flat door is an individual responsibility.

Further reading
2560 1707 Under One Roof

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