New boiler cost for a 2 bed flat
The short answer
- £1,800 to £3,000 installed on Heatable's example of an old combi replaced in the same place; national average for 2 bedrooms about £3,200
- 7,100 kWh of gas a year in a typical 2 bed flat, about £674 with the standing charge
- £90 to £170 a year saved replacing an old non-condensing boiler, a payback of about 11 to 39 years; a condensing one saves about £13
A new gas boiler for a 2 bed flat typically costs £1,800 to £3,000 installed, on the installer Heatable's example of an old combi replaced in the same place. A typical 2 bed flat burns about 7,100 kWh of gas a year, £674 with the standing charge, and replacing an old non-condensing boiler saves about £90 to £170 a year, so it pays back in about 11 to 39 years. Replacing a boiler that is already condensing saves about £13 a year and does not pay back.
What a new boiler costs for a 2 bed flat
£1,800 to £3,000 installed, on Heatable's example of an old combi replaced in the same place. The national average for a 2 bedroom home is about £3,200.
| Job | Typical installed cost |
|---|---|
| Heatable's example for a 2 bed flat: an old combi replaced in the same place | £1,800 to £3,000 |
| Combi boiler, like-for-like swap | £1,800 to £3,500 |
| System boiler, like-for-like swap | £1,800 to £3,500 |
| Regular or system boiler converted to a combi | £3,000 to £5,700 |
| National average new gas boiler for a 2 bedroom home | about £3,200 |
Read the detail
Heatable, an online boiler installer, gives £1,800 to £3,000 as its guide price for a 2 bed flat, for an old combi replaced in the same place. Across every kind of home, its like-for-like combi and system swaps were quoted at £1,800 to £3,500 from January to June 2026, with a median of £2,300 for a standard combi.
Typical installed prices from 2,000 Heatable quotes, January to June 2026, and its example estimates (updated 25 September 2026). Heatable sells and fits boilers itself, so these are one firm's prices, and a local installer can quote more or less. The national average is the DESNZ figure of about £3,500 for a new gas boiler, scaled by home size in our model, which is our assumption.
The national average for a 2 bedroom home is about £3,200: the Department for Energy Security and Net Zero (DESNZ) puts a new gas boiler at about £3,500 including VAT, and our model scales that by home size. The new boiler cost calculator works the cost, saving and payback out for your own home and boiler, and our new boiler cost guide covers what a quote should include and the extras that push a price up.
What a 2 bed flat uses and pays for gas
About 7,100 kWh of gas a year, £674 with the standing charge, in a typical 2 bed flat.
| Home | Gas a year | Gas, energy only | Gas with standing charge | Whole energy bill |
|---|---|---|---|---|
| Typical insulation, around EPC band D | 7,100 kWh | £566 | £674 | £1,437 |
| Well insulated, around EPC band C | 6,035 kWh | £481 | £589 | £1,352 |
| Poorly insulated, around EPC band E | 7,881 kWh | £628 | £736 | £1,499 |
Read the detail
A typical 2 bed flat on mains gas uses about 7,100 kWh of gas a year for heating, hot water and any gas cooking. At the price cap of 7.97p per kWh that is £566, or £674 a year with the gas standing charge. It is about the same as a 2 bed mid-terrace house (7,000 kWh).
Median gas use for a gas heated home of this type and size, from the DESNZ National Energy Efficiency Data-Framework 2026, as held in our heat model, with the measured difference between EPC bands. Priced at the Ofgem cap for October to December 2026: gas 7.97p per kWh and a standing charge of £108.33 a year by direct debit. The whole bill adds the electricity a 2 bedroom home typically uses.
A new boiler works on the gas column only: it cannot cut the standing charge or the electricity bill, so its saving is limited by how much gas the home burns. Our guide to energy bills for a 2 bed home has the full bill.
What a new boiler saves in a 2 bed flat
£90 to £170 a year replacing an old non-condensing boiler; about £13 if it is already condensing.
| Old boiler rating | Saving with a new A-rated boiler and controls |
|---|---|
| G (under 70% efficient) | £170 a year |
| F (70 to 74% efficient) | £120 a year |
| E (74 to 78% efficient) | £100 a year |
| D (78 to 82% efficient) | £90 a year |
Read the detail
Replacing an old gas boiler with a new A-rated condensing one and better controls saves about £90 to £170 a year in a mid-floor flat, according to the Energy Saving Trust, depending on how inefficient the old boiler is.
Energy Saving Trust estimates at July 2026 fuel prices, for a gas heated home fitting an A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator valves in place of an older boiler with a programmer and room thermostat. The Trust's flat is a mid-floor one, with heated homes above and below. A top floor or ground floor flat loses more heat, and the Trust publishes no figure for those, or for flats by number of bedrooms. These are modelled savings, and they include the new controls.
Measured savings are smaller. Across homes that had a new condensing boiler fitted, whatever it replaced, gas use fell by a median 2.3%: on the 7,100 kWh a typical 2 bed flat uses, about £13 a year. That is the figure to expect if the boiler being replaced is already a condensing one. Our guide to whether it is worth replacing an old boiler explains the gap between the two.
How long it takes to pay back
About 11 to 39 years for an old non-condensing boiler. A working condensing boiler does not pay back on fuel.
| Old boiler rating | On a £1,800 swap | On a £3,500 swap |
|---|---|---|
| G (under 70% efficient) | about 11 years | about 21 years |
| F (70 to 74% efficient) | about 15 years | about 29 years |
| E (74 to 78% efficient) | about 18 years | about 35 years |
| D (78 to 82% efficient) | about 20 years | about 39 years |
Read the detail
On a like-for-like swap at £1,800 to £3,500, a new boiler in a mid-floor flat pays for itself in about 11 to 39 years: the short end is a low quote replacing a G-rated boiler, the long end a high quote replacing a D-rated one.
The cost of the swap divided by the Energy Saving Trust's yearly saving for a mid-floor flat, the same sum our new boiler cost calculator does. The saving is modelled and includes new controls, so real paybacks tend to be longer.
Viessmann, a boiler maker, says a regularly serviced boiler should last up to around 15 years, which is a fair test of whether the saving comes back in time. Replacing a boiler rated G or F pays for itself inside 15 years only towards the cheaper end of the price range. One rated E or D does not: even a £1,800 swap takes longer than that, so on fuel alone it does not pay. On Heatable's £1,800 to £3,000 example for this home, a G-rated boiler pays back in 11 to 18 years and a D-rated one in 20 to 33 years.
A working condensing boiler is not worth replacing for the fuel saving. At the measured £13 a year, a £1,800 to £3,500 swap would take over 100 years to pay back. If the boiler has failed, the sum is different: you are paying for heating anyway, and the saving is a bonus. If it can be repaired, our boiler repair or replace calculator sets the repair quote against a replacement.
Which boiler type suits a 2 bed flat
One bathroom and good mains pressure: usually a combi boiler. Bathrooms, water pressure and heat pump plans decide the rest.
| Your home | Usually suits | Typical output | Why |
|---|---|---|---|
| One bathroom and good mains pressure | Combi | 24 to 27 kW | No cylinder or tanks to find room for, and hot water on demand |
| A hot water cylinder you want to keep | System | 9 to 18 kW | Stored hot water, and the cylinder a heat pump would use later |
| A regular boiler with tanks | Rarely suits a flat | Not applicable | The tanks have to sit higher than the highest hot tap or radiator |
Read the detail
Most of the choice in a flat is about space. A combi needs no cylinder cupboard and no tanks, and the Energy Saving Trust calls it an efficient choice for smaller households. It says a regular boiler is unlikely to suit a flat. If the flat already has a cylinder and you may want a heat pump one day, a system boiler keeps it.
Which type suits which home is the Energy Saving Trust's advice. Outputs are the general guides Vaillant and Viessmann publish by bedrooms, bathrooms and radiators, not a specification: the installer's heat loss calculation and your hot water use set the real size.
The output on the label is not the heat the home needs. Our heat model puts the heating load of a typical 2 bed flat at about 6 kW, the size of heat pump it would need. A combi is rated far higher because it has to heat water the moment a tap opens. See what size boiler you need and combi vs system boiler.
How a heat pump compares in a 2 bed flat
A median £11,800 installed, about £4,300 after the grant, so more upfront; cheaper to run only on a heat pump tariff.
| Cost | New gas boiler | Air source heat pump |
|---|---|---|
| Installed | £1,800 to £3,500 for a like-for-like swap | £10,000 to £14,500, median £11,800 |
| After the grant | No grant for a gas boiler | £2,500 to £7,000, median £4,300 |
| Energy a year | £566 of gas | £430 on a heat pump tariff, £605 on a standard tariff |
Read the detail
A heat pump for a typical 2 bed flat costs a median £11,800 installed, about £4,300 after the £7,500 Boiler Upgrade Scheme grant, against £1,800 to £3,500 for a like-for-like boiler swap. It costs more upfront. On a heat pump tariff it then costs about £136 a year less to run than gas; on a standard electricity tariff it costs about £39 a year more.
Heat pump prices are the median and the middle half of what installers recorded under the Boiler Upgrade Scheme for a heat pump of the 6 kW this home needs (DESNZ statistics, August 2026). Running costs use the median efficiency measured in the government's Electrification of Heat trial, at the Ofgem cap for October to December 2026. Gas also carries a standing charge of £108.33 a year, which stops if the gas supply is removed.
In a flat the bigger hurdle is permission, not price: the freeholder usually has to agree to an outdoor unit, and the planning rules allow only one heat pump per block of flats without permission. Our guide to a heat pump for a flat covers both.
Our boiler vs heat pump calculator compares the two over 15 years for a home like this one.
New boiler figures for other homes
The swap costs much the same in any home; the saving follows the gas the home burns.
| Home | National average new boiler | Gas a year | Gas bill with standing charge | Old boiler replaced, saving a year |
|---|---|---|---|---|
| 2 bed flat | about £3,200 | 7,100 kWh | £674 | £90 to £170 |
| 2 bed terrace | about £3,200 | 7,000 kWh | £666 | £140 to £270 |
| 3 bed semi | about £3,500 | 11,000 kWh | £985 | £190 to £350 |
| 4 bed detached house | about £3,800 | 14,600 kWh | £1,272 | £220 to £500 |
| 2 bed bungalow | about £3,200 | 9,200 kWh | £842 | £170 to £320 |
Read the detail
The price of the swap changes little from one home to the next. What changes is the gas the home burns, and so what a new boiler can save.
National average: the DESNZ figure of about £3,500 scaled by home size in our model. Gas use and bills from our heat model at the price cap. Savings from the Energy Saving Trust for that type of home, replacing a boiler rated D to G.
Frequently asked questions
How much does a new boiler cost for a 2 bed flat?
Heatable's guide price for this home is £1,800 to £3,000, for an old combi replaced in the same place. A like-for-like combi or system boiler swap typically costs £1,800 to £3,500 installed, and the national average for a 2 bedroom home is about £3,200.
How much gas does a 2 bed flat use?
About 7,100 kWh a year in a typical gas heated 2 bed flat, which costs about £674 a year with the standing charge at the October to December 2026 price cap.
How much would a new boiler save in a 2 bed flat?
About £90 to £170 a year replacing an old non-condensing gas boiler in a mid-floor flat, according to the Energy Saving Trust. Replacing a boiler that is already condensing saves far less: about £13 a year at the measured median.
What size boiler does a 2 bed flat need?
One bathroom and good mains pressure: usually a combi boiler of 24 to 27 kW, on the manufacturers' general guides. The installer's heat loss calculation sets the real size. See what size boiler you need.
Is a heat pump worth considering for a 2 bed flat?
It costs more upfront: a median £11,800 installed, about £4,300 after the £7,500 grant. On a heat pump tariff it costs about £136 a year less to run than gas. Our boiler vs heat pump calculator compares the two over 15 years.
Data sources
Heatable quotes and DESNZ for prices, the Energy Saving Trust for savings, our heat model for gas use.
Show every source
- Heatable, New boiler installation costs 2026 (updated 25 September 2026): typical installed prices from 2,000 of its own quotes, January to June 2026, its example estimates by home and its price ranges by brand. Heatable is an online boiler installer, so these are one firm's prices. Checked 5 October 2026.
- Department for Energy Security and Net Zero, Boiler Upgrade Scheme 2026 to 2030 summary business case, footnote 8: a new gas boiler costs about £3,500 including VAT. Other home sizes are scaled from it by our model, which is our assumption.
- Energy Saving Trust, Boiler types explained (last updated 20 May 2026): yearly savings for a gas heated home fitting an A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator valves in place of an older boiler, by the old boiler's rating, at July 2026 fuel prices; £3,500 typical cost of replacing a G-rated gas boiler. Checked 5 October 2026.
- Department for Energy Security and Net Zero, NEED impact of measures data tables 2026: the median fall in gas use in homes that had a new condensing boiler fitted, with and without new heating controls, priced at the Ofgem cap gas rate of 7.97p per kWh.
- Gas use, heating load and energy bills from our heat model, js/heat-model.js, and bill model, js/bills.js: median gas use by type of home and bedrooms from the DESNZ National Energy Efficiency Data-Framework 2026, priced at the Ofgem cap. See our methodology.
- Ofgem, energy price cap for 1 October to 31 December 2026: gas 7.97p per kWh by direct debit.
- Vaillant, What size boiler do I need? (not dated): recommended combi, system and regular boiler output by bedrooms, radiators and bathrooms, given as general guidelines. Read 5 October 2026.
- Viessmann, What size of boiler do I need for my home? (22 March 2022): boiler size by radiators and bedrooms, the heat load of an average home, why an oversized boiler is not recommended, and that a regularly serviced boiler should last up to around 15 years. Read 5 October 2026.
- Heat pump cost from our heat model, js/heat-model.js: the median installed price under the Boiler Upgrade Scheme for a heat pump of the size the home needs (DESNZ statistics, August 2026). EPC points from our EPC calculator model.