The Short Answer
A bungalow takes a heat pump like any other house, but we'd start with the loft. It's the cheaper job, and in DESNZ's measured figures for one year's installs it cut gas use by a median 7.8% in bungalows. A bungalow tends to need more heat for its size: DESNZ found bungalows use more gas per square metre than any other type of house, and only around a third of those with an EPC are rated A to C, against almost half of other houses.
On our model a 70 sq m 1960s bungalow with an unfilled cavity and 100mm in the loft needs a 7kW heat pump, or 5kW with the cavity filled and the loft topped up. The DESNZ medians for those sizes are £12,200 and £11,500, before the £7,500 Boiler Upgrade Scheme grant in England and Wales.
Estimate the Saving for a Bungalow
Pre-set for a bungalow on gas, using the median gas use of bungalows in England and Wales (£920 bill). Put your own bill in if you know it.
1. What heats your home today?
Pick whichever your main heating uses.
Add up last year's bills, or use the typical figure for your home below.
3. What size is your home?
We use this to estimate the size of heat pump you'd need.
4. Do you have solar panels?
Free electricity from your roof cuts what the heat pump costs to run.
5. Your options
Both are on to start with. Leave them on unless you know they don't apply.
Your estimated saving
£396a year
Over 15 years that's around £5,940 off your heating bills.
Now: Gas boiler
£920 / year
With heat pump
£524 / year
You save
£396 / year
What about the upfront cost?
- Heat pump install (DESNZ median for this size)
- £12,200
- Less government grant
- -£7,500
- You pay
- £4,700
- A new gas boiler would cost
- ~£2,750
If your boiler needs replacing anyway, the heat pump costs about £1,950 more upfront (before any radiator upgrades), earned back in roughly 4.9 years from running cost savings. That assumes you have the gas supply disconnected, so you stop paying its standing charge (about £108 a year). Keep gas for cooking and it takes longer. It leaves out a heat pump's dearer servicing.
Like the look of £396 a year?
These are estimates. The only way to know your real saving is a free quote from an MCS-certified installer. Takes about 60 seconds, no obligation.
How we worked this out
Energy prices: Ofgem price cap for 1 October to 31 December 2026 (Direct Debit, GB average): gas 7.97p/kWh, electricity 26.32p/kWh. There is no VAT on domestic electricity from 1 October 2026 to 31 March 2027; the gas figure includes 5% VAT. Heat pump tariff blended at 20p/kWh (an estimate for Cosy Octopus, E.ON Next Pumped or EDF Heat Pump Tracker on a heat pump load profile, not a quoted rate). Heating oil 11.31p/kWh (111.52p/litre plus 5% VAT, over 10.35 kWh/litre; BoilerJuice UK average, 23 October 2026). LPG at the price you enter (we start from 75p a litre, our estimate: there's no published average).
Heat pump efficiency: a seasonal efficiency of 3.5. That sits between two measured figures: a median of 2.80 across 291 air source heat pumps in the government's Electrification of Heat trial (installed in 2020 and 2021, whole system), and an average of 4.01 across the 307 systems on heatpumpmonitor.org with a full year of data when we checked in October 2026, a self-selected group of air and ground source systems, mostly high temperature capable R290 units. The break-even with a 90% gas boiler on a standard tariff is a SCOP of about 2.97.
Typical bill ranges: for a 3-bed using 9,500 to 10,300 kWh of heat a year (DESNZ's median and mean gas use for 3 bedrooms in England and Wales, through a 90% boiler): gas £950 to £1,000 (with the standing charge, which the saving assumes you stop paying by having the gas supply disconnected), oil £1,250 to £1,350, LPG £1,200 to £1,300 on our LPG price, direct electric heating £2,500 to £2,700. At these prices a unit of heat from oil costs about 1.5 times as much as from gas, and from LPG about 1.4 times, which is why the saving from switching is bigger.
Solar: A 4kW system in central England generates around 3,800 kWh a year on our estimate (950kWh per kW). On the government's SAP 10.2 self-use formula, a typical 3-bed's heat pump uses about 350 kWh of that a year without a battery, and about 510 kWh with one (8 kWh usable). Most of its demand falls in winter, when panels make least, and the calculator works it out for your bill.
Install costs: DESNZ Boiler Upgrade Scheme statistics (August 2026), median cost of real installs by size: about £11,500 (4-6kW), £12,200 (6-8kW) and £13,900 (10-12kW). New gas boiler about £2,750 (our estimate). The £7,500 grant is the Boiler Upgrade Scheme (gov.uk) for England and Wales; £9,000 for oil or LPG heating with no mains gas connection until March 2027, which this calculator applies when you choose oil or LPG (if you also have a mains gas connection, take that extra off).
Estimates only. Your actual saving depends on the installer, flow temperatures, your home's heat loss and your electricity tariff. Always get a heat loss survey from an MCS installer for an accurate quote.
Heat Pumps in Bungalows: What the Data Says
DESNZ's National Energy Efficiency Data-Framework puts the median bungalow's gas use at 10,229 kWh a year, against 10,574 kWh for a semi and 13,771 kWh for a detached house. Those are weather-corrected figures for mid-May 2024 to mid-May 2025, with cooking and hot water included.
Per square metre it's a different picture. DESNZ says bungalows have "a notably higher gas consumption per square metre than other types of houses", which suggests they are "the least energy efficient type of house".
Through a 90% boiler, 10,229 kWh of gas is about 9,200 kWh of heat a year, a little high because some of that gas goes on cooking. That's our estimate for a bungalow, and the figure the calculator above starts from. Your own bills are a better guide: a year's gas in kWh, times 0.9, is roughly your heat.
Why Bungalows Lose More Heat
On one storey, every square metre of floor sits on the ground and under the roof. For the same floor area, a bungalow has about twice the roof and twice the ground floor of a two-storey house, and both lose heat, which fits DESNZ's finding on gas use per square metre. In our model the 70 sq m bungalow loses about 91W per square metre on the coldest day, against about 74W for our 90 sq m 1930s semi.
In the example, the walls lose the most (2.6kW), then the floor (1.2kW) and the windows and doors (1.1kW), with the roof at 0.7kW once it has 100mm of insulation. A bare loft would lose a lot more.
Typical Heat Loss and System Size
We ran our example bungalows through the same heat loss model as our size calculator (standard RdSAP assumptions, a -5.1C design day in the Midlands, double glazing fitted before 2002):
| The bungalow (1960s) | Heat loss on the coldest day | Heat pump size | DESNZ median for that size band |
|---|---|---|---|
| 70 sq m, cavity not filled, 100mm in the loft | 6.4kW | 7kW | £12,200 |
| The same, loft topped up to 270mm | 6.0kW | 6kW | £12,200 |
| The same, cavity filled | 5.01kW | 6kW | £12,200 |
| The same, cavity filled and loft to 270mm | 4.6kW | 5kW | £11,500 |
| 100 sq m, cavity not filled, 100mm in the loft | 8.1kW | 8.5kW | £12,700 |
| 100 sq m, cavity filled and loft to 270mm | 5.8kW | 6kW | £12,200 |
Only a room-by-room heat loss calculation settles it for your house, and an MCS installer has to do one to size the heat pump. Put your own home in here. It starts as a different house from our example, so choose "Detached bungalow" and set the floor area, age, walls and loft to match yours:
What Size Heat Pump Do I Need?
Describe your home and we'll estimate its heat loss on the coldest design day, using the same default values an EPC assessor uses and the design temperatures MCS installers must use.
Estimated peak heat loss
6.3kW
At -5.1C outside, 20C inside
Heat pump size to look at
7kW
Smallest common size at or above your heat loss
Heat loss per sq m
70W
Lower is easier for a heat pump
What air source heat pumps of 6kW to 8kW actually cost
£12,164
median installed price, before the grant
£4,664
after the £7,500 Boiler Upgrade Scheme grant
Median of 8,054 real installations in that size band in 2025/26. Source: DESNZ Boiler Upgrade Scheme statistics, August 2026 (installations with a paid voucher, England and Wales). The grant applies in England and Wales.
Where the heat goes
What would shrink the heat pump
- Fill the cavity walls: -1.5kW
- Replace the windows with modern double glazing: -0.6kW
- Top the loft up to 270mm: -0.3kW
An estimate, not a design. MCS installers must size a heat pump to cover at least 100% of a room-by-room heat load calculation to BS EN 12831-1:2017 (MCS standard MIS 3005-D), and that survey replaces this number. Our defaults: U-values from BRE's RdSAP 10 specification (June 2026), window area from RdSAP 2012 Table S4, design outdoor temperatures from MIS 3005-D Table 2 column B, a whole-house 20C indoors, a rectangular plan with 2.5m storeys, no thermal bridging allowance, and air leakage from SAP 10.2 with a minimum of 0.5 air changes an hour. Solid floors use the design temperature rather than the annual average MCS specifies, so that part errs high. Flats and homes with extensions or room-in-roof conversions will be less accurate.
Insulation: Start With the Loft
The loft
The Energy Saving Trust puts insulating an empty loft to 270mm at £750 for a typical home in Great Britain, and topping up from 120mm at £600. It doesn't publish a bungalow figure, and a bungalow's loft is bigger for its floor area, so a quote may come in above the typical one.
DESNZ compares homes that had one measure fitted with similar homes that had no measure recorded. For lofts insulated mid-May 2023 to mid-May 2024, the median first-year saving in bungalows was 7.8% (748 kWh) across 207 homes. Treat that as one year's figure rather than proof that lofts save more in bungalows. The spread is wide, and in at least a quarter of bungalows gas use rose against the comparison homes. DESNZ cautions that its savings by property type vary a lot between years, likely because the samples are small, and show no systematic differences between types.
At the median that's about £60 a year on gas, so a £600 top-up (the Energy Saving Trust's price from 120mm) pays back in about 10 years. With a heat pump on a standard tariff it's worth £50 a year, so about 12 years. It takes longer if your quote is higher or you're on a cheaper heat pump tariff. In our model, topping the loft up from 100mm to 270mm takes the heat loss from 6.4kW to 6.0kW.
Cavity walls
The Energy Saving Trust says a house built after the 1920s probably has cavity walls, and puts filling them at around £2,200 for a typical home in Great Britain (around £1,000 in Northern Ireland). It may not suit a home that's exposed to extreme weather or flooding, in poor condition, at risk of rooms overheating, or with cavities narrower than 50mm. DESNZ's measured median saving in bungalows was 10.7% (1,074 kWh), more than the loft, but the job costs more. At the median it would take about 26 years to pay back £2,200 on gas, against about 10 for the loft. In our model it takes the example from 6.4kW to 5.01kW. That's just over 5kW, so on its own it still needs a 6kW heat pump.
The floor
The floor is the second-biggest loss in our example, because the whole bungalow sits on it. DESNZ doesn't publish a measured saving for floor insulation, and lifting floors is disruptive, so we'd look at it only if you're replacing floors anyway. Our floor insulation guide covers the options.
The Heat Pump + Solar Combination
The same geometry that costs a bungalow heat gives it a big roof for its size, so there may be room for more solar panels than on a two-storey house with the same floor area. Our solar panels and heat pump guide works through how much of a solar system's output a heat pump can use.
What It Costs
Heat pump costs are the DESNZ median for the size our example needs (Boiler Upgrade Scheme statistics, 2025/26 installs by capacity). Insulation is the Energy Saving Trust's typical home, and radiators are our estimate. Treat the radiators as a possible extra: DESNZ's costs are installers' own reported figures for the system, labour and VAT, and DESNZ doesn't say whether radiator work is in them. It also notes installers may differ on whether the figure includes the grant.
| The job (70 sq m example) | Before grant | After the £7,500 grant |
|---|---|---|
| Heat pump as the bungalow is (7kW) | £12,200 | £4,700 |
| Fill the cavity and do the loft first, then a 5kW heat pump | £14,300 to £14,450 | £6,800 to £6,950 |
| Radiator upgrades, if needed (our estimate) | £750 to £2,800 | £750 to £2,800 |
Heat pumps run at lower flow temperatures than gas boilers (35C to 55C, against the 70C to 80C a gas boiler supplies), so some radiators may be too small. Your installer works it out room by room. A bigger bungalow costs more: our 100 sq m example needs 8.5kW as it is (£12,700) and 6kW insulated (£12,200).
Help with the cost: the Boiler Upgrade Scheme gives £7,500 in England and Wales if you own the home and are replacing gas, oil, electric or LPG heating, with no insulation condition. Until March 2027 it's £9,000 if you heat with oil or LPG and have no mains gas connection. In Great Britain, ECO4 can help with insulation if you get certain benefits, until 31 December 2026, and in England the Warm Homes: Local Grant can pay for insulation and a heat pump for eligible low-income households. Our 1930s semi guide sets out who qualifies for each.
Running Costs
At the 1 October to 31 December 2026 cap (26.32p a kWh for electricity, 7.97p for gas) and a SCOP of 3.5, on our 9,200 kWh of heat:
- 90% gas boiler: about £810 a year
- Heat pump, standard tariff: about £690 a year
- Heat pump, heat pump tariff: about £530 a year, at our estimate of a 20p blended rate
Those are fuel costs only; if you have the gas supply disconnected altogether, you also stop paying about £108 a year of gas standing charge, which the savings calculator above counts. If you heat with oil or LPG the saving is bigger; our running costs guide compares every fuel.
Planning: One Unit or Two
In England a heat pump on a bungalow is permitted development, so you won't need a planning application, if it meets the same rules as any house:
- the outdoor unit is no bigger than 1.5 cubic metres
- it meets the 37 dB noise limit 1 metre outside a neighbour's habitable-room window or door (on the MCS 020 a) calculation)
- it isn't on a pitched roof, or above the ground floor on a wall facing the road
- it isn't on a listed building
In a conservation area or World Heritage Site it can't go on a wall or roof facing the road at all. On a detached bungalow you can have up to two air source heat pumps; on one that isn't detached, one. Wales has similar rules, and Scotland and Northern Ireland their own. Our semi-detached house guide goes through siting.
Getting Started
- Check the loft first. If there's less than 270mm, top it up: it's the cheaper job and pays back sooner.
- Find out whether you have cavity walls, and whether they're filled.
- Get quotes when the boiler is due. If yours is more than 10 years old, start now, and ask each installer for the heat loss calculation and which radiators they'd change.
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More: Heat pumps in 1930s semis | Heat pumps in detached houses | How the £7,500 heat pump grant works
Frequently Asked Questions
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Ask each installer for the heat loss calculation behind the size they quote, and whether they'd top up the loft first. Free quotes from MCS-certified installers.