Energy bills are one of the biggest household expenses — and many people don’t understand why theirs are so high. This guide explains the main reasons for expensive energy bills and how to reduce them.
Understanding Your Energy Bill
Your bill consists of:
| Component | What It Is |
|---|---|
| Unit rate (p/kWh) | Cost per unit of gas or electricity used |
| Standing charge (p/day) | Daily fixed charge regardless of usage |
| Usage (kWh) | How much energy you actually consumed |
| VAT (5%) | Tax on domestic energy |
Your bill = (Unit rate × kWh used) + (Standing charge × days) + VAT
Top Reasons Your Bill Is High
1. You Use More Energy Than Average
The “typical” household figures used by Ofgem are:
- Electricity: 2,700 kWh/year
- Gas: 11,500 kWh/year
If you exceed these, your bill exceeds the typical amount.
High usage factors:
- Larger home with more rooms to heat
- Older, poorly insulated property
- More people living at home
- Working from home
- Electric heating (no gas)
- Electric vehicles charging
- Energy-hungry appliances (old fridge, tumble dryer)
- Higher thermostat setting
2. Your Property Is Poorly Insulated
Heat escapes through:
- Walls (up to 35% of heat loss)
- Roof (25%)
- Windows and doors (15-20%)
- Floors (10%)
- Draughts (15%)
An EPC rating of E, F, or G means your home is very inefficient. You could be paying £500-1,500 more per year than a well-insulated property.
3. Estimated Bills Were Wrong
If your supplier has been estimating:
- They may have underestimated your usage
- Now actual readings show the truth
- You owe a “catch-up” amount
Check if your bills show “E” (estimated) or “A” (actual).
4. Unit Rates Have Increased
Energy prices change when:
- Ofgem updates the price cap (quarterly)
- Your fixed deal expires (moved to expensive SVR)
- Wholesale energy markets rise
Compare your current unit rates to previous bills to see if rates increased.
5. Your Fixed Deal Ended
Fixed tariffs eventually expire. When they do:
- You move to Standard Variable Tariff (SVT)
- SVT is usually more expensive
- You should switch to a new deal before expiry
Check your bill for tariff name — is it what you signed up for?
6. Standing Charges Have Risen
Standing charges increased significantly in recent years:
- Now ~50-60p/day electricity
- ~30-35p/day gas
- Combined: ~£300/year before using any energy
You pay this even if you use zero energy.
7. Heating to Higher Temperatures
Every degree higher on your thermostat increases heating costs by ~10%.
| Thermostat Setting | Relative Cost |
|---|---|
| 18°C | Baseline |
| 19°C | +10% |
| 20°C | +20% |
| 21°C | +30% |
| 22°C | +40% |
The recommended temperature is 18-21°C.
8. Inefficient Appliances
Old appliances use more electricity:
| Appliance | Old Model | Modern Efficient |
|---|---|---|
| Fridge-freezer | £80/year | £35/year |
| Washing machine | £45/year | £25/year |
| Tumble dryer | £120/year | £50/year |
| TV (plasma) | £50/year | £15/year (LED) |
Appliances rated A or higher cost less to run.
9. You’re on a Poor Tariff
Not all tariffs are equal. Check:
- Are you on standard variable (usually most expensive)?
- Are there cheaper fixed deals available?
- Does your tariff reward gas/electric combo?
Compare deals on Uswitch, Compare the Market, or Money Supermarket.
10. Your Boiler Is Inefficient
Boilers rated below A waste gas:
- G-rated boiler: 70% efficient (30% wasted)
- A-rated boiler: 90%+ efficient
Replacing an old boiler could save £300-500/year.
How to Check Your Bill
Step 1: Understand What You’re Paying
Find on your bill:
- Unit rate (electricity): Currently ~22-25p/kWh under price cap
- Unit rate (gas): Currently ~6-7p/kWh under price cap
- Standing charge: Electricity ~53p/day, Gas ~31p/day
- Total kWh used this period
Step 2: Compare to Average Usage
| Household Size | Electric (kWh/year) | Gas (kWh/year) |
|---|---|---|
| 1-bed flat | 1,800 | 7,500 |
| 2-bed flat | 2,500 | 9,500 |
| 3-bed house | 3,000 | 12,500 |
| 4-bed house | 4,000 | 15,000 |
| 5-bed house | 4,500 | 18,000 |
If your usage is much higher, investigate why.
Step 3: Check for Estimates
Look for “E” (estimated) vs “A” (actual) readings. If all estimated, submit actual readings now.
Step 4: Get a Smart Meter
Smart meters:
- Send readings automatically
- No more estimates
- Show real-time usage
- Help identify waste
Request free installation from your supplier.
How to Reduce Your Energy Bill
Quick Wins (Free)
- Lower thermostat by 1°C — Saves ~10%
- Submit actual meter readings — Stop overpaying estimates
- Switch off standby — Saves £55/year average
- Only boil water you need — Kettles waste energy
- Wash at 30°C — Modern detergents work fine
- Draught-proof doors — DIY foam strips cost £10
- Close curtains at dusk — Reduces heat loss
Medium Investments (£50-500)
- LED bulbs throughout — 80% less than incandescent
- Smart thermostat — Optimise heating schedule
- Radiator reflector panels — £20-30, saves heat escaping through walls
- Draught-proofing — Windows, doors, letterbox
- Cylinder insulation jacket — £15-25, pays back in months
Bigger Investments (£500+)
- Loft insulation — £300-500, saves £200-300/year
- Cavity wall insulation — £500-1,500, saves £150-300/year
- New boiler — £2,000-4,000, saves £300-500/year
- Double/triple glazing — £4,000-10,000, saves £100-200/year
- Solar panels — £5,000-10,000, saves £300-500/year
Government Grants
Check if you qualify for:
- ECO4 scheme — Free insulation for eligible households
- Warm Home Discount — £150 off electricity bill
- Boiler Upgrade Scheme — £7,500 grant towards heat pump
- Great British Insulation Scheme — Free/subsidised insulation
Switching Supplier
When to Switch
- Fixed deal about to end
- On expensive standard variable tariff
- Better deals available elsewhere
- Moving home
How to Compare
- Go to comparison site (Uswitch, MSE, Compare the Market)
- Enter postcode and current usage
- Compare annual costs
- Check exit fees from current tariff
- Switch online — takes 17-21 days
Fixed vs Variable in 2026
| Factor | Fixed | Variable (Capped) |
|---|---|---|
| Price certainty | Yes, locked in | Changes quarterly |
| Exit fees | Usually yes | No |
| Better when prices fall? | No, locked higher | Yes, follows cap down |
| Better when prices rise? | Yes, protected | No, rises with cap |
If You Can’t Afford Your Bills
Payment Support
- Warm Home Discount: £150 off (apply Sept-March)
- Cold Weather Payments: £25/week in very cold weather
- Winter Fuel Payment: £200-300 for pensioners
- Household Support Fund: Council discretionary help
Payment Plans
Contact your supplier if struggling:
- Request payment plan
- Ask about hardship funds
- Discuss prepayment meter options
- Avoid debt — priority bill
Priority Services Register
Free extra support if:
- Elderly
- Disabled
- Chronically ill
- On medical equipment
Register with your supplier for priority help during outages.
Related Guides
- Complete UK Energy Guide — All about energy
- Help Paying Energy Bills — Financial support
- Energy Price Cap Explained — How the cap works
- Warm Home Discount Guide — £150 off
- Should I Fix My Energy? — Tariff decisions
High energy bills are often fixable. Check your usage, submit real meter readings, improve insulation where possible, and switch to a better tariff. If you’re struggling to pay, contact your supplier immediately — they must offer support.