Quick wins you can do yourself

1. Lower the flow temperature (combi boilers only)

• Why it works: Condensing boilers only reach peak efficiency when return water is below 54°C. Lowering the flow temperature makes this happen far more often.
• Savings: 5–9% gas
• How to do it: Set the boiler to 50–60°C (lower in milder months).

2. Switch off pre-heat (combis only)

• Why it works: Some combis keep a small amount of hot water heated 24/7, firing unnecessarily.
• Savings: 3–5% gas
• How to do it: Activate eco mode or disable pre-heat in the boiler menu.

3. Check your boiler’s age before replacing

• Why it matters: Most boilers last 18–22 years with servicing, so replacing at 10–12 years wastes money and locks you into gas longer.
• Savings: Avoiding premature replacement saves £2,500–£4,000.
• How to check: The serial number usually includes the manufacture date.

Efficiencies tweaks that need a heating engineer

1. Down-rate the boiler

• Why it works: Most boilers are oversized and run inefficiently. Down-rating improves modulation and reduces cycling.
• Savings: 6–9% gas
• Ask for: Reduced maximum output matched to your home’s heat demand.

2. Adjust the pump speed

• Why it works: If water circulates too quickly, it returns too hot for efficient condensing.
• Benefit: Lower return temperatures = higher efficiency.
• Ask for: Pump speed set to match your radiator circuit (NB not all boilers have an adjustable pump)

3. Balance the radiators

• Why it works: Balancing ensures each radiator gets the right heat flow, improving comfort and condensing performance.
• Ask for: Lockshield valves adjusted based on radiator temperatures.

4. Fit load or weather compensation

• Why it works: These controls let your boiler modulate rather than constantly firing at maximum.
• Savings: Up to 12% gas
• Ask for: Simple manufacturer-approved compensation controls.