When Is a London Landlord Legally Required to Replace a Boiler?

Landlord Obligations for Heating in Rented Properties

Under Section 11 of the Landlord and Tenant Act 1985, landlords are legally required to keep in repair and proper working order the installations for the supply of heating and hot water. This applies to all assured tenancy agreements of less than seven years. The obligation is absolute — a landlord cannot contract out of it in a tenancy agreement.

The key phrase is "repair and proper working order." This means the boiler must actually provide adequate heating and hot water, not merely exist. A boiler that runs but cannot heat the property adequately, or that breaks down repeatedly, may still give rise to a legal claim.

Repair Versus Replace: The Legal Test

The law does not specify when a landlord must replace rather than repair. Courts apply a reasonableness test based on the principles established in Ravenseft Properties Ltd v Davstone (Holdings) Ltd and subsequent case law. The relevant factors are:

• Age of the boiler: A boiler at or beyond its expected service life (typically 12–15 years) that requires major repair is more likely to warrant replacement.
• Cost of repair relative to replacement: If a repair costs more than 50–60% of replacement cost, replacement is generally the reasonable choice.
• Frequency of breakdown: Repeated breakdowns within a short period indicate the boiler is no longer functioning as designed and may satisfy the "not in proper working order" test.
• Availability of parts: If the boiler is so old that parts are no longer manufactured, repair may be impossible, making replacement necessary.
• Safety: A boiler condemned by a Gas Safe engineer cannot legally be used. Replacement is mandatory.

When Replacement Is Clearly Required

A landlord must replace a boiler when:

• A Gas Safe registered engineer issues a formal notice that the boiler is immediately dangerous (ID) or at risk (AR) and recommends disconnection.
• The heat exchanger has cracked — this is an unrepairable fault on most boilers as new heat exchangers cost more than a replacement boiler.
• The boiler fails repeatedly within a single heating season despite repair.
• Carbon monoxide leakage is detected from the boiler.
• Parts required for repair are no longer available, making repair impossible.

Tenant Rights When a Landlord Fails to Act

If a landlord fails to repair or replace a boiler within a reasonable time, tenants in London have several options:

1. Write formally: Send a letter (keep a copy) setting out the fault and requesting repair within a specific period — 24 hours for total loss of heating in winter, 7–14 days for partial faults are commonly cited reasonable timeframes.
2. Report to the local council: London borough environmental health teams can inspect under the Housing Health and Safety Rating System (HHSRS) and issue improvement notices or prohibition orders where inadequate heating represents a Category 1 hazard.
3. Apply to the First-tier Tribunal: Tenants can apply for a Rent Repayment Order if a landlord ignores an improvement notice, recovering up to 12 months of rent.
4. Sue in the County Court: A claim under Section 11 for breach of the repairing covenant can recover the cost of alternative heating, hotel accommodation if necessary, and compensation for inconvenience.

Boiler Replacement Costs in London (2025)

For landlords budgeting ahead: replacing a standard combi boiler in a London property costs £1,800–£3,500 supply and fit, depending on boiler specification and the extent of associated pipework changes. Upgrading from a heat-only (regular) to a combi system costs £2,500–£5,000 due to the cylinder removal and additional pipework. These costs are an allowable expense for tax purposes against rental income.