8 Energy saving tips when planning an extension

With energy costs continuing to rise, it’s no surprise that more homeowners are looking for ways to make their homes more efficient when extending or renovating.
Whilst technologies like solar panels and heat pumps often grab the headlines, the foundations of an energy efficient home are actually set much earlier – at the design stage.
If you’re planning an extension or development, here are some of the most effective ways to reduce long-term energy use and save money, from simple design decisions through to more significant investments.

Start with the layout – not the technology

Before considering expensive add-ons, it’s worth looking at how your space is designed. A well thought out layout can dramatically reduce your energy demand. For example:

  • Positioning living spaces where they receive the most natural light
  • Minimising unused or poorly functioning areas
  • Improving the flow of the home so spaces are used efficiently

In many cases, reconfiguring existing space can be more cost effective than building more, and can reduce the amount of energy needed to heat and light your home.

Make the most of natural light

Natural light isn’t just about aesthetics, it has a direct impact on energy consumption. When designing an extension, consider:

  • Larger, well-positioned windows
  • Rooflights or lanterns to bring light deep into the plan
  • Glazing that connects internal spaces with the garden
  • Consider shading and larger overhangs to reduce solar gain

By reducing reliance on artificial lighting during the day, you’ll lower your electricity usage while creating a brighter, more enjoyable space to live in!

Improve insulation beyond the minimum

Building Regulations now set very high standards so three is little point in exceeding these requirements. On older buildings improve the external walls heat loss by insulating first.

Key areas to focus on:

  • Walls, floors and roofs within the new extension
  • Junctions between new and existing structures (to avoid heat loss)
  • High performance glazing
  • Draughtproofing

Better insulation means your home retains heat more effectively, reducing heating demand and energy bills year after year.

Consider orientation and solar gain

The position of your extension on the plot can have a major impact on energy performance.

A well-oriented design can:

  • Capture passive solar heat in winter
  • Reduce overheating in summer with shading strategies
  • Make the most of daylight throughout the year

Taking the time to understand how the sun moves across your site is one of the simplest and most cost-effective ways to improve energy efficiency from the outset.

Invest in high quality windows and doors

Windows and doors are often one of the weakest points in a building’s thermal performance.

Upgrading to:

  • Double or triple glazing
  • Thermally efficient frames
  • Well-sealed installations

… can significantly reduce heat loss and improve comfort! Whilst the upfront cost may be higher, the long-term savings – and improved living environment – make it a worthwhile investment.

Airtightness and ventilation – getting the balance right

Airtight construction helps prevent unwanted heat loss, but it must be paired with effective ventilation.

Consider:

  • Mechanical ventilation with heat recovery (MVHR)
  • Trickle vents or controlled airflow systems
  • Careful detailing during construction

This ensures fresh air without losing valuable heat, improving both efficiency and indoor air quality.

Think long term with renewable technologies

Once the fabric of the building is performing well, renewable systems become far more effective.

  • Air source or ground source heat pumps
  • Solar PV panels
  • Battery storage systems

These can significantly reduce running costs over time, particularly when combined with a well-insulated and airtight building.

Choose materials wisely

The materials you select can also influence energy performance.

  • Thermal mass (such as concrete or brick) can help regulate temperature
  • Sustainable materials can reduce environmental impact
  • Durable materials reduce maintenance and replacement costs over time

These choices may not always be immediately visible, but they contribute to the long-term efficiency and lifespan of your home.
Energy efficient design isn’t about one single feature, it’s about how all the elements of a project work together. From layout and orientation through to insulation and technology, the decisions made at the planning stage will have a lasting impact on how your home performs.
A well-designed extension won’t just give you more space – it will create a home that is more comfortable, more efficient and more cost-effective to run for years to come. If you’d like to discuss options for energy efficiency in your upcoming plans, get in touch with us today.