Energy efficiency isn't just a buzzword anymore – it's a legal requirement and financial necessity for new build properties in 2026. With rising energy costs and stricter building regulations (see Approved Document L – Conservation of fuel and power), spotting energy efficiency red flags during your snagging survey could save you thousands of pounds in heating bills and costly retrofits.
The sobering reality? Most new build buyers focus on cosmetic issues while missing critical energy efficiency defects that impact their wallet for years to come. Here's what your professional snagging survey should include to ensure your new home performs as efficiently as promised.
1. HVAC System Defects and Poor Installation
Your heating, ventilation, and air conditioning system is the heart of your home's energy efficiency. During inspection, check that all ductwork is properly sealed and free from gaps. Loose connections can waste 20–30% of conditioned air ENERGY STAR – Duct sealing.Look for dirty or missing filters, which reduce airflow and force your system to work harder. The furnace or heat pump should meet current efficiency standards – older or incorrectly sized units consume significantly more energy than necessary. For heat pumps in particular, ensure installation and commissioning follow MCS MIS 3005 (2025).
Pay special attention to radiator functionality using thermal imaging. Cold spots or uneven heating distribution indicate air pockets, faulty valves, or poor installation that will impact your comfort and energy bills.
2. Insulation Quality and Coverage Gaps
Inadequate insulation is one of the most expensive energy efficiency mistakes to fix after moving in. Your snagging survey should verify that loft insulation meets current Building Regulation standards – typically 270mm depth for mineral wool (Energy Saving Trust).Check for compression, gaps, or missing insulation around roof edges, pipes, and electrical fittings. Even small gaps can cause significant heat loss. Wall insulation should be continuous, with no thermal bridging through structural elements.
Don't forget about floor insulation, particularly over unheated spaces like garages or crawl spaces. Missing or damaged floor insulation can account for 10-15% of total heat loss.
3. Air Leakage Around Windows and Doors
Air leaks are invisible energy thieves that can significantly increase heating costs if not addressed (Energy Saving Trust – Draught proofing). During your inspection, check for gaps around all window and door frames, particularly at corners and joints.Test window mechanisms – they should close tightly with proper compression seals. Double-glazed units should show no signs of seal failure or condensation between panes. Poor installation often leaves gaps in the weatherproofing that aren't immediately obvious.
Door thresholds need particular attention. The seal between door and frame should be continuous, and letterboxes or cat flaps should have proper draught excluders fitted.
4. Thermal Bridge Defects
Thermal bridging occurs when heat-conducting materials create a path for heat loss through the insulation layer. Common areas include balcony connections, window lintels, and structural elements that penetrate the building envelope.During inspection, use thermal imaging to identify cold spots that indicate thermal bridging. These defects significantly reduce the effectiveness of insulation and can cause condensation problems leading to mould growth (see BRE guidance on thermal bridges and condensation risk).
Window reveals should be properly insulated, and cavity wall ties should include thermal breaks where required by current building standards.
5. Ventilation System Imbalances
Modern airtight homes require mechanical ventilation to maintain air quality without wasting energy. Check that all extract fans operate at correct speeds and that inlet vents aren't blocked or poorly positioned. See Approved Document F – Ventilation for minimum rates and commissioning requirements.Heat recovery ventilation systems should be properly commissioned with balanced airflow rates (CIBSE Commissioning Code A, 2024). Ductwork should be insulated where it passes through unheated spaces to prevent condensation and energy loss.
Trickle vents in windows should open and close smoothly, providing controlled fresh air without creating draughts. Installers should complete a Part F commissioning sheet (BEAMA).
6. Electrical Installation Inefficiencies
Your electrical installation impacts energy efficiency more than you might think. All circuits should be properly labeled in the consumer unit for efficient system management. LED lighting should be installed throughout the property as standard (Energy Saving Trust – Lighting).Check that all power outlets work correctly and are positioned to minimize extension lead use. Smart home-ready installations with proper wiring for thermostats and energy monitoring systems add significant value.
Look for any electrical work that doesn't comply with current regulations – poor installations can create safety hazards and energy waste.
7. Window and Door Performance Standards
Windows and doors should meet the thermal performance values specified in your home's energy rating documents. Check that U-values and Solar Heat Gain Coefficient (SHGC) ratings match the specification (see Approved Document L and SAP 10.2).Triple glazing should be standard in energy-efficient new builds. Frames should be thermally broken, and glazing units should show manufacturing dates confirming they meet current standards.
Test all opening mechanisms – poorly adjusted windows and doors don't seal properly, creating air leakage paths that waste energy.
8. Roof and External Envelope Defects
The building envelope forms your home's thermal barrier. Inspect roof tiles for damage, displacement, or missing pieces that could allow air infiltration. Guttering systems should be properly sealed and securely fixed.External wall finishes including brickwork, render, or cladding must be continuous with no cracks or gaps. Even small defects can allow moisture penetration and air leakage (see NHBC Standards 2024).
Check that roof-mounted equipment like solar panels or ventilation terminals are properly flashed and sealed to maintain the thermal envelope integrity.
9. Ground Floor and Foundation Issues
Foundation problems don't just affect structural integrity – they impact energy efficiency too. Poor foundation insulation or thermal bridging through ground floor slabs creates cold floors and increases heating demand (see NHBC Standards).Examine the damp-proof course and foundation weatherproofing. Moisture problems in foundations can damage insulation and create thermal performance issues that persist for years.
Check that all service penetrations through the foundation are properly sealed to prevent air infiltration from below.
10. Renewable Energy System Defects
Many new builds include renewable energy systems like solar panels or heat pumps. These systems must be properly installed and commissioned to deliver promised energy savings (see MCS MIS 3005 – Heat pumps).Solar panel installations should be securely mounted with proper roof penetration sealing. Inverters should be correctly positioned and wiring should meet electrical standards.
Heat pump installations require correct refrigerant charges, proper ductwork connections, and appropriate control settings. Poor commissioning and setup can significantly reduce efficiency (Energy Systems Catapult – Electrification of Heat).
Why Professional Energy Efficiency Inspections Matter
Energy efficiency defects often aren't visible during casual property viewings, but they impact your comfort and running costs from day one. Professional snagging surveys use specialized equipment like thermal imaging cameras and air leakage testing to identify problems that untrained eyes miss (air tightness testing is now required under Approved Document L).At Snagit Ltd, our RICS-qualified surveyors understand both traditional building defects and modern energy efficiency requirements. We use the latest technology to provide comprehensive reports that help you achieve the energy performance your new home was designed to deliver.
Getting Your Energy Efficiency Right From Day One
Don't let energy efficiency red flags turn into expensive long-term problems. Under the New Homes Quality Code, developers must address identified defects within 30 days of completion (NHQB), making your snagging inspection the perfect opportunity to ensure energy efficiency standards are met.Our detailed snagging surveys identify both cosmetic issues and critical energy efficiency defects, giving you the complete picture before final sign-off. With energy costs continuing to rise, ensuring your new home performs as efficiently as promised isn't just about comfort – it's about protecting your investment.
Ready to ensure your new build delivers the energy efficiency you're paying for?
Contact Snagit Ltd today to book your comprehensive energy efficiency snagging survey. Our professional team will identify potential problems before they become expensive repairs, giving you peace of mind and guaranteed energy performance.Don't leave energy efficiency to chance – get in touch with our experts and make sure your new home investment pays dividends for years to come.