- Find where the heat escapes
You need to find where warm air is escaping from your home and cold air is coming in. Places that may let in draughts include windows, doors, floorboards, chimneys and loft hatches.
Hold a candle near windows, doors and other areas to see if the flame dances around, suggesting a leak. Alternatively, try a thermal leak detector, such as the Black & Decker TLD100. This flashes blue for cold, green for normal and red for warm, so you know where there are air leakages.
2. Draught-proof your doors
For gaps at the bottom of the front and back doors, the most durable choice is a “brush” draught-excluder. You can make your own draught-excluders for internal doors using rolled-up towels, or tights filled with old clothes, or buy cheap or second-hand draught-excluders on sites such as eBay.
You can buy rubber draught seals from DIY stores and fit these around the sides of your external doors. Install metal keyhole-covers, and fit a letterbox brush to keep the heat in your home.
Read more at: https://www.theguardian.com/money/2022/oct/06/heatproof-your-home-top-tips-for-energy-efficiency