How to Save on Gas Heating Costs in the UK

(What Temperature to Set, What to Adjust, and What Actually Works)

Gas heating costs in the UK are high because most homes waste heat, not because boilers are inefficient.
Savings come from control, consistency, and flow efficiency — not from constantly touching the thermostat.

The Single Most Important Rule (Read This First)

Do NOT keep turning the heating up and down.

Gas boilers work most efficiently when:

• They run longer at lower output

• Water temperature is stable

• Heat demand is predictable

Constantly changing temperatures causes:

• Short cycling

• Higher flow temperatures

• More gas burned per hour

Best Thermostat Temperature for Gas Heating (UK Homes)

Recommended Settings

• Daytime (occupied): 18–19°C

• Evening comfort: 19–20°C

• Night / sleeping: 16–17°C

• Away from home: 14–15°C

Reality Check

• Every 1°C increase = ~10% more gas usage

• 22°C vs 19°C = ~30% higher bill

If your house feels cold at 19°C, the issue is heat loss or circulation, not temperature.

Should You Keep Heating On All Day or Turn It Off?

Answer:
➡️ Low and steady beats off-and-on

Why Turning It Off Costs More

• Cold walls absorb heat when reheating

• Boiler fires at maximum output

• Flow temperature spikes

• More gas burned in short time

Smarter Approach

• Keep heating on at low temperature

• Use timers, not manual changes

• Avoid full cooldowns in winter

Boiler Flow Temperature (Huge Savings Most People Miss)

Set Your Boiler Flow Temperature To:

• Radiators: 55–60°C

• Older systems: max 65°C

Most boilers are set at 75–80°C — pure waste.

Why Lower Flow Saves Gas

• Boiler condenses properly

• Less heat lost through flue

• Longer, efficient burn cycles

• Radiators emit steady heat

This alone can cut gas usage by 10–15%.

Radiator Control = Direct Gas Savings

Use TRVs Properly

• Living rooms: TRV 3–4

• Bedrooms: TRV 2–3

• Hallways: TRV 1–2

• Unused rooms: TRV 1 or off

Heating unused rooms = burning gas for nothing.

Balance Your Radiators (Underrated, Powerful)

Unbalanced systems:

• Some rooms overheat

• Others stay cold

• Boiler runs longer to compensate

Balanced systems:

• Even heat

• Faster warm-up

• Lower gas consumption

Result: less runtime = lower bill.

Bleeding & Cleaning = Efficiency, Not Comfort

What Dirty Systems Do

• Restrict flow

• Trap heat in boiler

• Force higher gas burn

• Cause uneven heating

Action

• Bleed radiators yearly

• Clean system every 5–7 years

• Add inhibitor after any drain

Dirty water = higher gas cost.

Insulation Beats Temperature Changes

Fast wins:

• Loft insulation (biggest ROI)

• Draught-proof doors & windows

• Curtains closed at night

• Reflective foil behind radiators (external walls)

Insulation saves gas every hour, forever.

What Does NOT Save Gas (Common Myths)

❌ Turning heating off completely daily
❌ Cranking thermostat to heat faster
❌ Heating unused rooms
❌ Running boiler at max temperature
❌ Constant manual thermostat changes

These increase gas usage.

Simple Gas-Saving Formula (UK Homes)

• Stable thermostat (18–19°C)

• Lower boiler flow temp (55–60°C)

• TRVs set correctly

• Balanced, clean system

• Insulated envelope

Expected saving:
➡️ 20–35% on gas bills without discomfort

Bottom Line

Gas savings don’t come from suffering in the cold.
They come from system efficiency and discipline.

Control the flow temperature, stop temperature swings, heat only what you use — and the gas bill drops automatically.