You suspect your home is losing heat, but you are not sure where to start fixing it. A professional retrofit assessment can cost several hundred pounds. You can identify the biggest problems yourself, for free, before you decide whether to call in an expert.
A DIY home energy audit costs nothing except time and requires no special tools beyond a torch, a notepad, and a phone with a camera. The single most important finding is the location and severity of draughts, which the Energy Saving Trust says can account for 20–30% of heat loss in an average UK home (Energy Saving Trust, 2026).
A DIY energy audit checklist follows seven rooms and four building-envelope checks
The checklist covers your loft, living areas, kitchen, bedrooms, bathroom, hallways and stairs, plus four building-envelope checks for walls, the floor, windows, and doors. For each room, you record visible gaps, cold surfaces, condensation patches, and how the room feels relative to the rest of the house. The envelope checks require you to inspect the loft hatch, skirting boards, external wall junctions, and window frames for gaps wider than 1 mm. This structure is modelled on the EST home energy check methodology (Energy Saving Trust, 2026).
The audit produces a ranked list of quick fixes under £50, such as draught strips and radiator reflector foil, versus capital measures such as loft insulation, cavity-wall fill, or a boiler upgrade. You do not need a retrofit assessor or an Energy Performance Certificate (EPC) to start. A DIY audit is the first step before commissioning any professional survey.
Quick numbers – what a DIY audit typically finds in a pre-2000 UK home
| Item | Typical Finding | Annual Cost Impact if Unaddressed |
|---|---|---|
| Loft insulation depth | Less than 270 mm | Up to £135 lost per year (Energy Saving Trust, 2026) |
| Cavity-wall insulation | Unfilled cavity | Up to £160 lost per year (Energy Saving Trust, 2026) |
| Single-glazed windows | Single pane or old double-glazing | Up to £110 lost per year (Energy Saving Trust, 2026) |
| Draughts around doors/windows | Visible gaps | Up to £45 lost per year (Energy Saving Trust, 2026) |
| Boiler age and type | Over 15 years, non-condensing | Up to £205 lost per year (Energy Saving Trust, 2026) |
All figures are 2026 averages for a typical gas-heated semi-detached home in England, Scotland, or Wales. Your actual savings will depend on your home size, your energy tariff, and your usage patterns.
The most important thing a DIY audit reveals is the location and size of draughts
This is the direct answer to the keyword query “home energy audit checklist”. You systematically check every external junction for air leakage. Use a damp hand or a lit incense stick on a still day. Movement indicates a draught that can be sealed with foam strip or mastic. Common draught locations include the loft hatch rim, the letterbox, the keyhole, pipe penetrations through external walls, and the gap between floorboards and skirting. The Energy Saving Trust states that sealing draughts can save £45 to £90 per year, depending on home size (Energy Saving Trust, 2026).
If you find a draught, buy a basic draught-excluding kit for under £20. You do not need a specialist for this work. If you find a draught around a gas pipe or flue, contact a Gas Safe Register engineer rather than sealing it yourself (Gas Safe Register, 2026).
A DIY audit must check loft insulation depth against the current 270 mm standard
The current 2026 minimum recommended depth for mineral-wool loft insulation is 270 mm, which is 10.6 inches, per the Building Regulations Approved Document L (2021 edition, as amended) (GOV.UK, 2026). Measure from the joist top to the insulation surface. If the insulation is below the joist line, it is below 100 mm and will be performing at less than half its potential. A top-up from 100 mm to 270 mm typically costs £200 to £350 for a three-bed semi-detached home and can save up to £135 per year (Energy Saving Trust, 2026).
If your loft has a boarded floor, you cannot simply lay rolls on top. You may need to lift boards and install insulation between the joists, then add rigid insulation board on top. This is more expensive and may require a professional installer. How to insulate a boarded loft without losing storage space
A DIY audit should include a boiler-age check and a radiator-balance test
Locate the boiler data badge. If the boiler was installed before 2005, it is almost certainly a non-condensing model with efficiency below 78% (Ofgem, 2026). A condensing boiler installed after 2005 should have a SEDBUK rating of 90% or higher. If the rating is below 86%, replacement may be cost-effective. SEDBUK stands for Seasonal Efficiency of Domestic Boilers in the UK. It is the standard measure of boiler efficiency.
For the radiator-balance test, turn off all radiators. Then turn on each one individually. If any radiator remains cold at the bottom when the top is hot, it needs bleeding. If one room heats much faster than others, the system needs balancing. The Energy Saving Trust provides a step-by-step guide to bleeding and balancing radiators (Energy Saving Trust, 2026).
If your boiler is over 15 years old and your DIY audit shows high heating costs, you may be eligible for a grant under the Boiler Upgrade Scheme in England and Wales, or the Home Energy Scotland scheme. Check the latest eligibility criteria on the GOV.UK website (GOV.UK, 2026).
A DIY audit is not a substitute for an EPC or an MCS-certified survey, but it tells you when to call one
An Energy Performance Certificate (EPC) is a legal requirement when selling or renting a property. A DIY audit cannot replace it. For fabric upgrades such as cavity-wall insulation, external wall insulation, or solid-wall insulation, you must use an installer certified by MCS or TrustMark and registered with the relevant scheme. Cavity-wall insulation must be installed by a CIGA-registered installer. Solid-wall insulation must be installed by a SWIGA-registered installer (MCS, 2026; TrustMark, 2026).
If your DIY audit finds persistent condensation or mould in a specific area, you need a professional damp survey, not just sealing gaps. Mould can be a sign of rising damp, penetrating damp, or inadequate ventilation. A surveyor will use a moisture meter and may take core samples. When to call a damp surveyor instead of sealing gaps yourself
Your DIY audit gives you a ranked list of problems and estimated savings. You can use that list to decide which professional survey to commission and to compare quotes from installers. Without the audit, you are commissioning a survey blind. With it, you know what you are asking for.
