Household retrofit guidance for private properties Insulating your property

The importance of ventilation

Ventilation is key for improving the following areas:

  • indoor air quality
  • removing pollutants
  • controlling moisture from cooking and washing
  • preventing your home from overheating

Ventilation is especially important in kitchens and bathrooms to stop moisture from building up and causing dampness. 

Extractor fans and open windows can help manage this. Bedrooms and other less humid areas also require ventilation. 

If your windows have trickle vents, keep them open to allow fresh air circulation.

For better efficiency, single-room mechanical ventilation with heat recovery MVHR systems can reuse heat from extracted air. 

For larger retrofit projects, a whole-house MVHR system may be a better option.

Heat recovery ventilation system with metallic boxes, blue connectors, and black ducts on wooden framework in a partially constructed home.

Loft insulation

Before insulating your loft, ensure the space is dry and in good condition to prevent moisture or mould issues. 

Loft insulation will keep your home warmer but will also make your loft colder. This may result in draughts through the loft hatch. 

To keep your loft warm, you can carry out the following work:

  • install an insulated loft hatch and add draught-excluding strips around the edges
  • attach a piece of rigid foam insulation to the back of the hatch and use draught strips around the edges

Standard loft insulation

Most homes use standard loft insulation, which usually comes in rolls of mineral wool. This can be easily laid between or over the floor joists. This is a simple job that can be done with materials sourced from DIY stores or builder's merchants.

If you use your loft for storage, you can install joist extenders to raise the loft boards above the insulation. To make this installation, carry out the following tasks:

  • leave a gap for ventilation between the insulation and the boards to prevent condensation
  • do not squash the mineral wool, as this will reduce its effectiveness

The Centre for Sustainable Energy has easy to follow advice about insulating your home to improve energy efficiency. 

The Energy Saving Trust provides a comprehensive guide to roof and loft insulation from installation to saving money on your energy bills.