<h2>Start with evidence</h2><p>Walk through the house while heating or cooling is running. Note drafts, rooms that lag behind and equipment cycling unusually often.</p><h2>Check the easy signals</h2><ul><li>Look for gaps around doors and loft hatches.</li><li>Read one month of bills in energy units, not only currency.</li><li>Photograph thermostat and boiler settings before changing them.</li></ul><p>Low-cost sealing can help, but never block purpose-built ventilation or combustion-air openings.</p>