Skip to main content
Homecodesortmyhouse.co.uk

Problems and symptoms

What should you do about “Gas bill is still high after a new boiler”?

Gas bill is still high after a new boiler | Homecode

Gas bill is still high after a new boiler. UK guidance on the evidence, safety limits and safest next step before you spend. [1]

Do this first

Your safe boundary

DIY covers only listed normal-floor observations and documented occupant controls; unresolved gas-work is ProfessionalOnly, with no casing, pipe, flue, meter, wiring or installer-setting access.

A new boiler does not guarantee a lower bill, but faults, poor heat delivery, missing handover records or unexpectedly high comparable kWh need prompt review.

No verified cost range is available for this page.

Safety warnings

What is known — and what is not

What is known

  • Only the page's recorded observations, documents and stated scope are treated as known.

What remains uncertain

  • Before-and-after bills cannot isolate boiler efficiency from weather, tariff, readings, comfort, hot water, controls, heat distribution and fabric heat loss. [1][6][8]

Possible explanations

  • non-comparable bill periods, tariffs or readings [1][6][8]
  • more comfort or hot-water demand after replacement [1][6][8]
  • a control, compatibility or commissioning issue [1][6][8]
  • an existing heat-distribution limitation [1][6][8]
  • building heat loss unchanged by boiler replacement [1][6][8]

Why the bill may remain high

Replacement changes the boiler, not the tariff, weather, occupants, hot-water demand, emitters or building fabric. A more reliable system may also deliver more comfort, while a commissioning or control issue remains possible and must be assessed rather than assumed. [1][6][8]

What you can safely collect

  • Gather the quote, appliance specification, completed commissioning documents, user-control handover, warranty and relevant installation-notification certificate. [1][2]
  • Compare actual gas kWh per day across similar weather, occupancy, setpoint and hot-water demand rather than pounds alone. [6]
  • Record user-visible schedules, zones, setpoints, achieved room temperatures and any external fault code. [3]
  • Create a timeline of installation, first use, faults, service visits, readings and household changes.

When to stop

This review covers only the stated non-emergency observations. Stop if a fault or safety warning appears, equipment is damaged, wet, leaking or abnormally hot, or the check cannot stay on a normal room floor without opening, detaching, resetting or adjusting anything outside documented occupant controls; the new fact needs its own H3 route. [3]

Who to contact next

Raise a written installation or warranty concern with the original Gas Safe registered installer, providing the evidence pack. Use the supplier when tariff, readings or account data explain the bill; if installation performance is verified but demand remains high, seek independent heating-system and fabric assessment. [1][6][8]

Cost, warranty and bill evidence

Use installer and warranty routes before commissioning duplicate paid work. Require measured findings and separate prices for controls, appliance, distribution and fabric work, with no promised bill saving or payback from a national typical-bill figure. [1][7]

Effect on a sale or letting

A new boiler can provide useful property records but does not guarantee value or lower bills. Keep the Building Regulations Compliance Certificate, commissioning, warranty, service and repair records with the current EPC; landlords still need to respond to heating or hot-water faults. [2][5][8][9]

If you smell gas or a carbon monoxide alarm sounds

  • If you smell gas or suspect a leak, stop this page. HSE says to call 0800 111 999 immediately, open all the doors and windows, and shut off the gas supply at the meter control valve if you know where it is. [4]
  • National Gas says not to smoke or light matches, and not to turn electrical switches on or off. Do not enter a cellar to reach a meter. The National Gas Emergency Service on 0800 111 999 is free and open 24 hours a day in Great Britain. [10]
  • If a carbon monoxide alarm sounds or you suspect carbon monoxide, NHS says to stop using the suspected appliance if you can, go outside, and get medical advice before going back in. Call NHS 111 if you have symptoms. Call 999 if anyone is finding it hard to breathe, has suddenly become confused, has lost consciousness, feels weak, or has chest or muscle pain. [11]
  • If you think a gas appliance is leaking carbon monoxide, NHS says to call the National Gas Helpline on 0800 111 999. That number is for Great Britain. HSENI publishes 0800 002 001 for the Northern Ireland Gas Emergency Service. [11][12]
  • Do not restart or work on a gas appliance, flue or pipework. HSE says anyone employed to work on gas appliances in domestic premises must be a Gas Safe registered engineer. [4]

Evidence checkpoints

  • Gas Safe Register guidance says boiler customers should receive completed commissioning documents and address warranty registration and relevant installation notification. [1]

    Evidence date:

  • Gas Safe Register says a Building Regulations Compliance Certificate belongs to the property and is useful when the home is sold or remortgaged. [2]

    Evidence date:

  • Ofgem states that the total bill still depends on energy used because the price cap limits applicable rates rather than total spend. [7]

    Evidence date:

  • HSE and National Gas publish 0800 111 999 as the free 24-hour gas emergency number for a suspected leak in Great Britain. [4][10]

    Evidence date:

Scope and safety review

This reviewed route applies in England to adult owner-occupiers and private tenants making non-invasive observations from a normal room floor. It excludes a suspected gas escape, carbon-monoxide incident, active electrical danger, leak, abnormal pressure, displayed fault or equipment safety warning; if one appears, this route no longer applies.

Jurisdiction
England
Who this covers
adult owner-occupier, adult private tenant
Tenure
owner-occupied, private rented
Reviewed

Sources

  1. A guide to gas appliance installation and certificatesGas Safe Register. Accessed .
  2. Building Regulations certificatesGas Safe Register. Accessed .
  3. Home Improvement Gas SafetyGas Safe Register. Accessed .
  4. Gas safety - Home ownersHealth and Safety Executive. Accessed .
  5. Be Gas Safe when buying a new homeGas Safe Register. Accessed .
  6. Understand your electricity and gas billsOfgem. Accessed .
  7. Energy price cap and standing charges explainedOfgem. Accessed .
  8. Selling a home: Energy Performance CertificatesGOV.UK. Accessed .
  9. Private renting: RepairsGOV.UK. Accessed .
  10. Emergency ContactsNational Gas. Accessed .
  11. Carbon monoxide poisoningNHS. Accessed .
  12. Carbon monoxideHealth and Safety Executive for Northern Ireland. Accessed .