Home energy assessment

Understanding how your home uses energy is the first step in planning any energy-efficient upgrades. An assessment helps you identify where heat is escaping and which improvements will give you the best return on investment.

Types of professional assessment

Depending on your goals, you may need a different type of assessment.

Energy Performance Certificate (EPC)

An EPC is a legal requirement whenever a property is built, sold, or rented. It provides an energy efficiency rating from A (most efficient) to G (least efficient) and is valid for 10 years.

  • Best for: A quick overview of your home’s performance and seeing how it compares to similar properties.
  • Cost: Usually between £60 and £120.

Retrofit Assessment (PAS 2035)

If you are planning significant upgrades or applying for government grants like ECO4, you will likely need a formal Retrofit Assessment. This is much more detailed than an EPC.

  • Best for: Deep retrofits (e.g., heat pumps, external wall insulation) and grant applications.
  • Covers: An in-depth survey of the property’s condition, occupancy patterns, and ventilation requirements to ensure upgrades don’t cause issues like damp or mould.

Many government grant schemes require a Retrofit Assessment carried out by a qualified professional to ensure the proposed measures are suitable for your specific home.

DIY energy checks

Before booking a professional, there are several things you can check yourself to understand your home’s baseline.

1. Check your loft insulation

Carefully check the thickness of the insulation in your loft. The recommended depth for mineral wool is 270mm. If yours is thinner, topping it up is one of the most cost-effective upgrades you can make.

2. Identify your wall type

  • Cavity walls: Usually found in homes built after 1930. The brickwork has a regular pattern with all bricks laid lengthwise.
  • Solid walls: Common in pre-1930s homes. The brickwork usually has an alternating pattern of long and short brick ends.

3. Inspect your windows and doors

Look for gaps in frames, perishing seals, or condensation between panes of double glazing. These are key areas for heat loss and draughts.

4. Locate your boiler and meters

Note the make, model, and age of your boiler. Check your energy meters to see if they are “smart” meters, which can help you track real-time usage.

Preparing for an assessment

To get the most out of a professional survey, you should:

  • Gather your energy bills: Have 12 months of electricity and gas usage data ready.
  • Provide clear access: The assessor will need to access your loft, boiler, hot water cylinder, and all rooms in the house.
  • Prepare a list of issues: Note any specific cold spots, persistent damp, or draughty areas you’ve noticed.

After the assessment

Once you receive your report, you will have a list of recommended improvements. It is usually best to follow a “Fabric First” approach:

  1. Insulate: Fix the walls, loft, and floors first to keep heat in.
  2. Ventilate: Ensure the house can “breathe” to prevent damp.
  3. Modernise heating: Only once the house is insulated should you consider a heat pump or other low-carbon heating.