Your Home Climate
Energy · The problem library

Why are my energy bills so high, and what should I look at first?

Recently reviewed·Reviewed June 2026, next review December 2026

The largest single line in most UK energy bills is heating, followed by hot water, then the always-on electrical load that runs in the background. Reducing the bill almost always starts with where the heat is going rather than how it is being produced. Generation and storage become much more powerful once consumption has been understood.

Editorial confidence
High confidence. Multiple regulator, government or academic sources agree.
Evidence status
Recently reviewed · reviewed June 2026 · next review December 2026
Monitoring
Every three months, in line with Ofgem price-cap reviews and DESNZ household consumption updates.
Evidence drawn fromGovernment guidance: DESNZ, Ofgem, ECO4Professional bodies: EST, Loughborough DEFACTO

Typical UK household gas use

≈11,500 kWh / year

Source: Department for Energy Security and Net Zero · DESNZ's Typical Domestic Consumption Values place a medium-use household at roughly 11,500 kWh of gas per year; a bill well above this suggests fabric or system losses worth investigating.

Typical UK household electricity use

≈2,700 kWh / year

Source: Department for Energy Security and Net Zero · DESNZ medium-use TDCV for electricity; always-on background load often accounts for a third or more of this number.

Who this advice is for

Applies to

  • Owner-occupied or long-let homes on standard domestic tariffs
  • Households with one or more years of bill history
  • Properties where heating dominates the annual cost
  • Anyone weighing fabric, generation, storage or controls against each other

Not intended for

  • Off-grid homes or properties on bespoke commercial tariffs
  • Households on prepayment meters with no annual statement
  • Diagnosing a specific appliance fault rather than overall consumption
  • Short-term holiday lets where occupancy patterns dominate

What it usually looks like

These are the symptoms readers describe most often. None of them alone is diagnostic, but together they build a picture.

  • Bills noticeably higher than neighbours in similar homes
  • Heating dominant in the annual cost
  • Standing charges feel disproportionate
  • Unsure where the kilowatt-hours are actually going

Most common in: Postwar semi (1945–1980) · Interwar semi (1920s–1930s) · Modern detached (post-2000) · Victorian terrace

Before you buy anything

Watch the house respond as you scroll.

These checks are listed in the order we would work through them. The illustration on the left changes with each one, so you can see what each check is actually addressing before deciding whether it is worth doing.

Heat leaves through every uninsulated surface. The room cools faster than the boiler can refill it.

01

Look at twelve months of statements together

A single quarter tells you very little. The annual shape reveals how much is heating, how much is constant load and how much is summer use.

02

Spend an evening tracing the always-on load

A smart plug on the fridge, the broadband router, the TV and the chargers in the kitchen will usually identify several hundred kilowatt-hours of avoidable use per year.

03

Check the loft and the walls

Fabric improvements reduce the bill every year for the lifetime of the house. They are unglamorous and they work.

04

Review your tariff

A time-of-use tariff suits some households dramatically better than a flat one, especially with a heat pump, an EV or solar. Comparing once a year is worth the half-hour.

05

Decide where the money is meant to come back from

Solar reduces the import bill but does not change heat loss. Insulation reduces consumption but generates nothing. Understanding which one your home actually needs is the only way to spend well.

Before you spend money

The cheapest answer is usually the one nobody sold you.

  1. 01

    Read the meter on the same day and time each week for a month

    Four real numbers replace a vague worry with a baseline. Every later decision (tariff, insulation, kit) gets cheaper because you stop guessing.

    Free
  2. 02

    Walk the house at 7pm with everything supposedly off

    Standby loads commonly run at 100-300W in UK homes. That is £100-300 a year before any other change.

    Free
  3. 03

    Check the boiler flow temperature and the immersion timer

    A boiler at 80°C and an immersion left on for hot water it never reaches usually accounts for more saving in an afternoon than any product purchase.

    Free
  4. 04

    Compare your tariff against the cheapest fixed deal available today

    Switching tariff costs nothing and resolves in days; insulating a wall costs thousands and resolves in years. Do the free thing first.

    Free

What we recommend, and why

Every recommendation explains why it comes first, the evidence behind it, how confident we are, and when it would not apply.

01

Read twelve months of bills before changing anything

Why this comes first

Without an annual shape, every other decision is a guess. The split between heating, hot water and always-on load determines whether fabric, generation or behaviour will return the most, and it is almost impossible to read from a single quarter.

Evidence

DESNZ Typical Domestic Consumption Values give the benchmarks; Ofgem publishes the unit-rate and standing-charge components needed to translate kWh into pounds.

DESNZ · Ofgem

Confidence

High confidence. Multiple independent sources agree on the direction and the order.

Exceptions
  • Households that have moved in within the last six months
  • Recent major changes (new heating system, EV, baby) that invalidate the historic shape
Next step
Open the energy domain
02

Reduce heat loss before adding generation

Why this comes first

A kilowatt-hour saved through insulation costs the household nothing once installed, recurs every year, and lowers the size of any future heat pump or solar system. A kilowatt-hour generated by solar still has a capital cost and a degradation curve. Insulation also reduces winter bills, when solar produces least.

Evidence

EST consumer guidance, ECO4 delivery data and Loughborough's DEFACTO monitoring all show fabric improvements outperform generation on whole-life pence-per-kWh for typical pre-2000 UK homes.

EST · ECO4 · Loughborough DEFACTO

Confidence

High confidence.

Exceptions
  • Homes already at EPC B or above where fabric returns diminish
  • Properties with confirmed planning constraints on external fabric work
Next step
Plan it on the Home Planner
03

Review the tariff once a year, especially with an EV, heat pump or battery

Why this comes first

A time-of-use tariff can shift a sizeable share of consumption to overnight unit rates that are often a fraction of the day-time price. Households with flexible loads typically see the largest gains from a tariff review, and it requires no capital spend.

Evidence

Ofgem publishes regulated tariff data; EST guidance recommends an annual tariff review for any household with shiftable load.

Ofgem · EST

Confidence

Reasonable confidence.

Exceptions
  • Households with no shiftable load and no smart meter
  • Vulnerable customers on specific protected tariffs
Next step
See the energy hub

The trade-offs

Every choice gives you something and asks for something back.

  • Behavioural and tariff changes only

    You get

    A measurable bill drop within a billing cycle at near-zero cost, and a clean baseline before any capital work.

    You give up

    The ceiling on how much you can save (usually 10-20%) and the satisfaction of buying something visible.

  • Targeted fabric upgrades (loft top-up, draught-proofing, hot water cylinder jacket)

    You get

    Permanent reduction in heat demand, payback often inside five years, and a more comfortable house alongside the saving.

    You give up

    Several hundred to a few thousand pounds, time spent choosing installers and a winter of disruption in places.

  • Major kit (heat pump, solar, battery)

    You get

    A step change in running cost when paired with the right tariff, and a path off gas entirely.

    You give up

    Five-figure capital, a year of decisions, and the need to do fabric and controls first or the kit underperforms.

Real homes that faced this

Publicly documented UK projects that ran into the same problem and reported what happened.

We did not run these projects. Each links back to the original publisher so you can read the figures in context and judge for yourself what carries over to your home.

How we'd approach this

Cheapest, fastest, most boring first; capital decisions last.

If our bills had jumped we would spend a fortnight measuring, not shopping. A clamp meter on the consumer unit and a notebook by the meter beats any survey we could buy. The data tells you which third of the bill is heating, which third is hot water and which third is everything else; without it you are guessing.

We would do the free and the cheap work next, in that order. Tariff, flow temperature, immersion schedule, standby loads, loft top-up. None of that is glamorous and most of it pays back inside a year. Skipping it to buy something visible is how most households end up disappointed by their solar.

And we would size capital kit against the house we will have after the cheap work is done, not the one we have today. A heat pump sized for a draughty house with 80°C radiators is the wrong heat pump. Doing it in the right order saves more than any single product can.

Evidence behind this page

Every recommendation on this page is traceable to its source. Click a publication to read the original.

Products that may help

Only consider these once the checks above have been ruled out. A product fitted into the wrong cause is rarely satisfying.

House Summary

The cheapest answer to energy bills feel too high is usually the one that addresses the cause rather than the symptom. The list above is in the order we would work through it, because the checks at the top tend to rule out the most expensive mistakes further down.

Related decisions
Next Best Step

Solar; is it worth it in the UK?

Take the next step