For most off-grid homes in Kent and the South East, an air source heat pump can offer better long-term value than an oil boiler. Heat pumps are around three to four times more efficient, can significantly reduce heating-related carbon emissions and may qualify for the £7,500 Boiler Upgrade Scheme grant, subject to eligibility.
They also remove the need for oil deliveries and reduce exposure to fluctuating heating oil prices. However, oil boilers have lower upfront replacement costs and may still be a practical option for larger, poorly insulated properties where a short-term solution is needed.
More than a million homes in England still rely on heating oil, particularly in rural areas such as the Weald, Romney Marsh, the North Downs and East Sussex. If your existing oil boiler is approaching the end of its lifespan, it is worth considering whether replacing it with another oil system or switching to a heat pump makes more financial and practical sense.
At Guscott Heating, we help homeowners and landlords across Kent and the wider South East explore the benefits of switching from oil boilers to air source heat pumps. Whether you are in Tenterden, Cranbrook, Faversham, Sevenoaks, Ashford or a surrounding village, this guide compares both heating options to help you make an informed decision.
Air Source Heat Pump vs Oil Boiler: Key Facts
Air source heat pumps have several advantages over oil boilers, particularly when it comes to efficiency, carbon emissions, available grants and protection from fluctuating fuel prices. Oil boilers, however, are generally cheaper to install or replace upfront. The table below summarises the key differences to help you compare both heating systems at a glance.
| Factor | Air source heat pump | Oil boiler |
| How it works | Moves heat from the outside air into your home using electricity | Burns heating oil (kerosene) to heat water |
| Efficiency | Around 300% to 400% (SCOP 3 to 4) | Around 90% to 93% for a new condensing boiler |
| Performance | Gentle, steady heat; works down to around minus 20°C | Fast, high temperature heat on demand |
| Unit cost | £4,000 to £8,000 | £1,500 to £3,000 |
| Total installed cost | £10,000 to £15,000 | £3,000 to £5,000 (plus £2,000 to £4,000 if the tank needs replacing) |
| Cost after grants | £2,500 to £7,500 after the £7,500 grant | No grant available |
| Running costs (3 bed home) | Around £780 to £900 a year, or £550 to £650 on a heat pump tariff | Around £850 to £1,050 a year, depending on oil prices |
| Price stability | Electricity prices capped by Ofgem and reviewed quarterly | Oil prices are not capped and can swing sharply |
| Carbon emissions | Around 70% lower than oil | High; heating oil is one of the most carbon intensive home fuels |
| Reliability | Few moving parts, no fuel to run out | Reliable, but you can run out of oil or suffer tank leaks or theft |
| Lifespan | 15 to 20 years or more | 15 to 20 years |
| Servicing and maintenance | Annual service, around £100 to £200 | Annual OFTEC service, around £100 to £200, plus tank checks |
| Space needed | Outdoor unit plus hot water cylinder | Boiler plus a large outdoor oil tank |
| Safety | No flame, no fumes, no carbon monoxide | Combustion appliance, needs a carbon monoxide alarm |
| Best for | Most homes, especially reasonably insulated ones | Short term fixes in large, poorly insulated homes |
Running cost figures are estimates for a typical three bed home needing about 12,000kWh of heat a year, with heating oil at 65p to 80p a litre and electricity at about 26p per kWh. Your own costs depend on your home and prices at the time.
Thinking of replacing your oil boiler? Guscott Heating provides air source heat pump installation across Kent and the wider South East of England, including Ashford, Maidstone, Canterbury, Tonbridge, Sevenoaks, Horsham and Lewes. Get in touch today for a free estimate tailored to your location.
Air Source Heat Pump vs Oil Boiler: Which Should You Choose?
Whether you should choose an air source heat pump or an oil boiler depends on your budget, your home’s insulation and how long you plan to stay. Use these checklists to see which suits you.
Choose an air source heat pump if…
- Your oil boiler is 10 to 15 years old or needs replacing soon
- You want to stop relying on oil deliveries and unpredictable oil prices
- You want to claim the £7,500 Boiler Upgrade Scheme grant
- Your home has reasonable loft and wall insulation
- You plan to stay in your home for several years
- You want to cut your carbon footprint or improve your EPC rating
- You have, or plan to add, solar panels
Don’t choose an air source heat pump if…
- Your home is very poorly insulated and you cannot improve it at all
- You need the cheapest possible fix today and plan to move within a year or two
- There is truly no outside space for the unit or indoor space for a hot water cylinder
Choose an oil boiler if…
- Your current boiler has failed and you cannot afford even the reduced cost of a heat pump right now
- Your home loses heat very quickly and needs high temperature heating that cannot be improved
- You already have a newer oil tank in good condition and want a short term replacement
Don’t choose an oil boiler if…
- You want lower, more stable running costs over the long term
- You want to access government grants
- You are worried about future rules on fossil fuel heating
- You are a landlord planning for tighter EPC rules on rented homes
Air Source Heat Pump vs Oil Boiler: What Are the Pros & Cons?
The pros and cons of an air source heat pump vs oil boiler come down to long term savings and lower emissions versus a lower upfront price. Here is how each one stacks up.
Pros & Cons of Air Source Heat Pumps
| Pros | Cons |
| Three to four times more efficient than an oil boiler | Higher upfront cost before the grant |
| £7,500 Boiler Upgrade Scheme grant available | Some radiators may need upgrading |
| No oil deliveries, tank or price spikes | Needs space for a hot water cylinder |
| Around 70% lower carbon emissions | Heats more gently, so it runs for longer periods |
| No flame, fumes or carbon monoxide risk | Works best in reasonably insulated homes |
| Pairs well with solar panels and batteries | Installation takes 2 to 5 days |
| Helps improve EPC ratings | Requires an MCS certified installer |
Pros & Cons of Oil Boilers
| Pros | Cons |
| Lower upfront cost | No government grants available |
| Fast, high temperature heat | Oil prices are uncapped and can spike |
| Works with existing radiators | You can run out of oil in a cold snap |
| Familiar technology | Tank leaks can cost thousands to clean up |
| Quick like for like replacement | Oil theft is a known risk in rural areas |
| No hot water cylinder needed with a combi model | High carbon emissions |
| Combustion means a carbon monoxide risk |
Air Source Heat Pump vs Oil Boiler: How Do They Compare Head to Head?
An air source heat pump vs oil boiler head to head shows the heat pump winning most rounds. The oil boiler keeps the edge on upfront cost and heat up speed. Here is each factor in turn.
How They Work
An oil boiler burns kerosene stored in a tank in your garden to heat water for your radiators and taps. An air source heat pump uses electricity to draw heat from the outside air, even in winter, and moves it into your heating system. It moves heat rather than making it by burning fuel, and that is why it is so efficient.
Winner: Air source heat pump, for its cleaner, fuel free design.
Efficiency
A new condensing oil boiler turns around 90% to 93% of its fuel into heat. A well designed air source heat pump delivers around 3 to 4 units of heat for every unit of electricity, which is an efficiency of 300% to 400%.
Winner: Air source heat pump
Performance
An oil boiler heats water to high temperatures quickly, which suits homes with small radiators and people used to a fast warm up. A heat pump works at lower temperatures for longer, keeping your home at an even, comfortable warmth. Modern heat pumps keep working in temperatures as low as minus 20°C, far colder than a Kent winter usually gets.
Winner: Draw. Oil warms up faster, while a heat pump gives steadier comfort.
Unit Cost
An oil boiler costs around £1,500 to £3,000 to buy. An air source heat pump costs around £4,000 to £8,000, depending on size and brand.
Winner: Oil boiler
Installation Cost
Replacing an oil boiler usually costs £3,000 to £5,000, or more if the tank needs replacing at £2,000 to £4,000. A heat pump typically costs £10,000 to £15,000 installed. After the £7,500 Boiler Upgrade Scheme grant, that falls to around £2,500 to £7,500, which brings the two much closer, especially when an old oil tank also needs replacing.
Winner: Oil boiler, though the grant narrows the gap a lot.
Running Costs
For a typical three bed home, an oil boiler costs around £850 to £1,050 a year with oil at 65p to 80p a litre. A heat pump costs around £780 to £900 on a standard tariff, or £550 to £650 on a heat pump tariff. Add solar panels and the savings grow further.
Winner: Air source heat pump
Price Stability
Heating oil is not covered by the Ofgem price cap. In 2022, prices climbed above £1 a litre, more than double the level of a year earlier. Electricity prices are capped and reviewed every three months, which makes bills easier to plan.
Winner: Air source heat pump
Carbon Emissions
Heating oil is one of the most carbon intensive ways to heat a home. Switching to a heat pump typically cuts heating emissions by around 70%, and the saving grows every year as the UK grid adds more wind and solar power.
Winner: Air source heat pump
Reliability
Modern oil boilers are generally reliable, but the fuel supply is not. Running out of oil during a cold snap, delivery delays in snow and tank theft are common worries in rural Kent and Sussex. A leaking tank can also lead to clean up bills running into thousands of pounds. A heat pump has no fuel to run out of and fewer things to go wrong.
Winner: Air source heat pump
Lifespan
Both typically last 15 to 20 years with regular servicing. Many heat pumps run for longer, and they have no burner or flue parts to wear out.
Winner: Draw
Servicing and Maintenance
An oil boiler needs an annual service by an OFTEC registered technician, usually £100 to £200, plus regular checks on the tank, pipes and fuel filters. A heat pump also needs an annual service at a similar cost, but there is no tank, flue or burner to look after.
Winner: Air source heat pump
Space Needed
An oil boiler needs a large oil tank in the garden, typically holding 1,000 to 2,500 litres. A heat pump needs an outdoor unit, roughly the size of a large suitcase or small fridge, plus a hot water cylinder indoors. Removing an oil tank often frees up more garden space than the heat pump takes.
Winner: Air source heat pump
Safety
Oil boilers burn fuel, so they need a flue and a carbon monoxide alarm. A heat pump has no flame, no combustion and no fumes, so there is no risk of carbon monoxide.
Winner: Air source heat pump
Best Suited Properties
A heat pump suits most homes, from bungalows in Romney Marsh to farmhouses near Tenterden, especially once loft insulation is topped up and a few radiators are upgraded. An oil boiler is mainly suited to very large, poorly insulated homes where the owner wants a short term, low cost replacement.
Winner: Air source heat pump, for most homes.
The Overall Winner
The air source heat pump wins most rounds. It is cheaper to run, cleaner, safer and backed by a £7,500 grant. An oil boiler only wins on upfront price. For most homeowners and landlords in Kent and the South East, a heat pump is the smarter long term investment.
Replace Your Oil Boiler With an Air Source Heat Pump From Guscott Heating
Moving away from oil heating involves more than choosing a new boiler replacement. You’ll need to consider your property’s heat loss, the right heat pump capacity and what happens to your existing oil tank. Guscott Heating can manage the process, helping homeowners and landlords across Kent and the wider South East make the transition to air source heating.
Our MCS certified engineers will help you with:
- A detailed home survey: we’ll assess your property’s heating requirements and calculate the heat pump size needed.
- A tailored installation quote: receive a clear, fixed price based on your home and the work involved.
- £7,500 grant assistance: we’ll handle your Boiler Upgrade Scheme application, subject to eligibility.
- Oil tank removal: we can arrange the removal of your existing oil tank as part of the switch.
- Professional installation: our experienced team will guide you through the process from initial assessment to completed installation.
We provide air source heat pump installations across Kent and the wider South East of England, with advice tailored to your property’s individual requirements.
If you’re ready to move away from oil deliveries and explore a different way to heat your home, request your free air source heat pump estimate today and find out what the switch would involve and cost.
Frequently Asked Questions
There is more to know about switching from an oil boiler to a heat pump, from removing your oil tank to checking your electricity supply. Here are the questions Kent homeowners and landlords ask us most often.
What Happens to My Old Oil Tank?
Your old oil tank is usually drained, cleaned and removed by a specialist when you switch to a heat pump. It is best to run your oil down before the installation date, so you are not paying for fuel you will not use. Removal typically costs a few hundred pounds, depending on the tank’s size and access.
Are Oil Boilers Being Banned?
No, oil boilers are not currently banned, and you can still replace an existing oil boiler with a new one. The government has said it wants to phase out new fossil fuel heating over time, so it is worth checking the latest rules before committing to a new oil boiler that may need to last 15 years or more.
Can I Combine a Heat Pump With My Oil Boiler?
Yes, you can combine a heat pump with an oil boiler in a hybrid system, but it will not qualify for the £7,500 Boiler Upgrade Scheme grant. The grant requires the heat pump to fully replace your fossil fuel heating. For most homes, a correctly sized heat pump on its own is the better value option.
Do I Need to Upgrade My Electricity Supply for a Heat Pump?
Most homes do not need to upgrade their electricity supply for a heat pump. Your installer will check your main fuse and let the local network operator know about the new system, which in Kent and much of the South East is UK Power Networks. In a small number of cases, the main fuse may need upgrading, usually at no cost to you.
Will a Heat Pump Add Value to My Home?
A heat pump can add value to your home by improving its EPC rating and lowering its running costs, both of which appeal to buyers. Many buyers now look closely at energy efficiency, and a modern, low carbon heating system can help a rural Kent property stand out against homes still running on oil.