Keep the Warmth You Have Already Paid For

Every winter, the same conversation happens in homes across the UK. The thermostat creeps up, the boiler works harder, and the bill arrives looking considerably healthier than the occupants. Before you reach for the dial again, it is worth asking a simple question: how much of the heat you are paying for is actually staying in the house?

Insulation is not glamorous, and it will never be as satisfying as a new boiler. But it is the single most reliable way to reduce what you spend on gas, because it lets your existing heating system do less work for the same comfort. Think of it as plugging the holes in a bucket before you turn the tap on harder.

Draught Proofing: The Cheapest Win in the House

Draughts are the low-hanging fruit. A cold trickle of air around a door or window can make a room feel several degrees chillier than it actually is, encouraging you to overheat the whole house to compensate.

• Doors and windows: brush or rubber seals around frames, and a good quality draught excluder on the bottom of external doors, cost very little and take an afternoon to fit.
• Keyholes, letterboxes and cat flaps: often overlooked, always leaky. Purpose-made covers cost a few pounds.
• Chimneys: an open flue is an open window. A chimney balloon or sheep-wool draught excluder is effective, provided the fireplace is not in use.
• Floorboards and skirting: silicone sealant or flexible filler along gaps will quieten both draughts and rattles.

One caution: never draught proof a room that contains an open-flued gas appliance, or that relies on permanent ventilation for combustion air. We will come back to that.

Loft Insulation: Still the Best Value Measure

Heat rises, and an uninsulated loft is effectively a hole in your roof through which your money disappears. Current guidance recommends around 270mm of mineral wool for a typical UK loft, laid evenly across the joists.

Many homes have some insulation already, perhaps 100mm from an older installation. Topping it up to the recommended depth is straightforward and can be done as a DIY job with rolls from a builders' merchant, or by a professional installer if access is awkward.

• Lay insulation between the joists first, then a second layer across them at right angles to avoid cold bridges.
• Keep it clear of the eaves so ventilation paths remain open — blocking them invites condensation and rot.
• Do not insulate directly over recessed downlights unless they are rated for it, and keep the loft hatch insulated and draught-proofed too.
• Lag any pipes and the cold water tank in the loft before insulating around them, so you do not accidentally warm them.

Cavity and Solid Walls

In a typical UK home, walls account for a substantial share of heat loss. If your property was built after the 1920s, it may have a cavity that can be filled with injected insulation material. This is not a DIY task: it needs assessment, and it should only be carried out by an installer covered by a proper guarantee, because incorrect work can lead to damp and bridging.

Homes with solid walls — common in older terraces and period properties — have fewer easy options. Internal or external wall insulation can transform comfort and running costs, but both are disruptive and best planned alongside other renovation work. It is worth speaking to your local authority or energy supplier about support schemes before committing, as grant funding for insulation measures changes regularly.

Pipes, Tanks and Radiators

A surprising amount of heat is lost from the pipework that carries hot water around your home. Foam pipe lagging is cheap, simple to fit and pays for itself quickly, particularly on runs through cold spaces such as lofts, garages and under floors.

• Lag all accessible hot water pipes, and the cold tank and its pipework in the loft to reduce freezing risk.
• Fit a thermostatic radiator valve to each radiator where possible, so unused rooms are not heated to the same temperature as the living room.
• Radiator reflector panels behind external-wall radiators push warmth back into the room rather than into the brickwork.
• Lag external condensate pipe runs from the boiler, as these are a common cause of winter breakdowns when they freeze.

Once your home holds heat better, a lower flow temperature on the boiler and a thermostat set one degree lower can make a real difference — often around ten per cent of heating costs.

Insulation and Gas Safety: What Not to Cover Up

This is the part that matters most, and it is where a qualified engineer's advice is worth every penny.

• Never block permanent ventilation. Air bricks, vents and grilles exist to supply combustion air to gas appliances. Covering them with insulation can create a serious risk of carbon monoxide.
• Keep flue terminals clear. Insulation, boarding or stored items must not obstruct a flue outlet or restrict the free flow of air around it.
• Do not box in appliances. Boilers and gas fires need the clearances specified in their instructions.
• Fit an audible carbon monoxide alarm meeting the relevant British Standard, and have every gas appliance serviced annually by a Gas Safe registered engineer.
• If you seal up a room, think about the boiler first. A draught-proofing project can inadvertently remove the only air supply an open-flued appliance has.

Insulation and gas safety go hand in hand: a warmer, tighter home is a cheaper home to run, but only if it is also a safe one. Do the easy measures yourself, bring in specialists for the walls and the gas work, and you will spend the winter comfortable rather than simply paying for warmth your neighbours never feel.