Air Source Heat Pump vs Oil Boiler: Which Is Better?

Last Updated on June 19, 2025

If you’re a UK homeowner or landlord exploring alternatives to traditional heating systems, you’re likely weighing up the choice between an air source heat pump vs oil boiler. 

With rising energy costs and increasing pressure to reduce carbon footprints, many are now considering switching to heat pumps. 

In this guide, we’ll provide a detailed, side-by-side comparison to help you decide which system is better suited to your property, considering factors such as cost, efficiency, lifespan, and more.

Air Source Heat Pump vs Oil Boiler: A Quick Overview

Before we dig deeper, here’s a quick comparison table to give you a snapshot of how these systems measure up:

Air Source Heat Pump vs Oil Boiler: Which Is Better?

Air Source Heat Pumps

Air source heat pumps (ASHPs) absorb heat from the outside air, even in temperatures as low as -15°C and use electricity to compress and amplify it, providing hot water and heating for your home. 

Instead of generating heat like a boiler, they move existing ambient heat using a refrigerant cycle making them far more efficient in terms of energy output versus input.

This efficiency (often 300% to 400%) means that for every unit of electricity used, you receive 3–4 units of heat. They work particularly well in well-insulated homes and are highly compatible with underfloor heating or low-flow radiators. 

If you’re unsure about sizing, our guide on what size air source heat pump you will need can help.

Best suited for:

• Modern or newly built homes with good insulation
  
• Renovated older properties where insulation has been upgraded. Read our article on whether air source heat pumps work in older houses for more insights.
  
• Urban or suburban homes where space is available for the outdoor unit
  
• Landlords looking to futureproof properties and meet upcoming energy efficiency regulations

Tip: It’s crucial to know if your house is suitable for a heat pump because factors like insulation levels, available outdoor space, and your existing heating system will directly impact how efficiently the system performs.

Pros and Cons of Air Source Heat Pumps

Pros

• Exceptionally energy-efficient (up to 400% efficiency)
  
• Long lifespan with low maintenance
  
• Eligible for generous heat pump grants
  
• No fuel storage required
  
• Very low emissions
  

Cons

• Higher upfront cost
  
• Performance relies on good insulation
  
• May require radiator upgrades (do heat pumps work with radiators?)
  
• Less effective in poorly insulated or extremely cold homes (although heat pumps do work in cold weather)

Oil Boilers

Oil boilers work by burning heating oil, typically kerosene, which is stored in a tank outside your home. The combustion process heats water, which is then distributed via radiators and taps. 

While oil boilers are effective at generating high heat output quickly, they rely on a finite fossil fuel and can be subject to volatile market prices and delivery delays.

Oil heating systems can be suitable in very specific scenarios particularly in remote or rural areas where the property is off the gas grid, and upgrading insulation or radiators may not be practical or financially viable in the short term.

Pros and Cons of Oil Boilers

Pros

• Lower initial installation cost
  
• Suitable for homes off the gas grid
  
• Can produce high heat output quickly
  

Cons

• High carbon emissions
  
• Fuel storage tank required
  
• Subject to oil price volatility
  
• Shorter lifespan and more frequent servicing

Which Is Better Based on Property Type and Energy Needs?

Here’s how the two systems compare when matched to real-world property scenarios in the UK:

Air Source Heat Pump vs Oil Boilers: Key Differences

When comparing air source heat pumps vs oil boilers, the most important differences come down to how each system performs in terms of efficiency, lifespan, installation and running costs, carbon emissions, and maintenance requirements. 

These factors can significantly influence which heating solution is right for your property.

Efficiency

Air source heat pumps are significantly more efficient, with a Coefficient of Performance (COP) between 3 and 4. That means for every 1kW of electricity consumed, 3–4kW of heat is produced.

In contrast, oil boilers typically operate at 85%–95% efficiency, meaning you lose a portion of energy during combustion. If you’re considering switching, read about the cost to replace a gas boiler with a heat pump as a helpful point of comparison.

Air Source Heat Pump Running Cost vs Oil Boiler

Tip: Running costs for heat pumps are significantly reduced when your home is well insulated. If you live in an older property, insulation upgrades can dramatically enhance heat pump performance and reduce your energy bills.

Maintenance

Heat pumps have fewer moving parts and don’t burn fuel, so their maintenance requirements are minimal, usually a quick annual check-up. 

Oil boilers require regular servicing, filter changes, and monitoring for fuel leaks or soot buildup.

Installation Costs

The upfront cost of an air source heat pump may seem high, but homeowners in England and Wales can access funding through the Boiler Upgrade Scheme. 

This government-backed initiative offers a grant of £7,500 towards the installation of an air source heat pump, significantly reducing the cost barrier. Additionally, check out our guide on heat pump grants for more funding options.

Carbon Emissions

When it comes to reducing your carbon footprint, air source heat pumps are significantly more environmentally friendly than oil boilers. The key difference lies in how each system produces heat.

Air source heat pumps use electricity to extract heat from the outside air, rather than burning fuel. If powered by a renewable electricity source, their carbon emissions can be close to zero. 

Even when using electricity from the national grid, modern heat pumps can reduce household carbon emissions by up to 65% compared to oil heating. For more insights, read our guide on how much electricity air source heat pumps use.

In contrast, oil boilers burn kerosene, a fossil fuel that emits high levels of CO₂ and other pollutants such as nitrogen oxides. A typical oil-heated home in the UK emits more than 3,000 kg of CO₂ per year, making it one of the highest-polluting domestic heating options.

Which Is Better for You: Air Source Heat Pump or Oil Boiler?

If you want to reduce energy bills, cut carbon emissions, and futureproof your property, a heat pump is the better long-term investment. 

Oil boilers may still suit remote, off-grid homes where upgrades are not possible, but for most modern UK properties, heat pumps lead in efficiency, sustainability, and comfort.

Request a Free Air Source Heat Pump Quote Today!

Eco Happy can help you take the next step. Our accredited team will assess your property, insulation, and heating needs to recommend the best system and help you access funding through the Boiler Upgrade Scheme or other grants.

Don’t wait for oil prices to rise again. Get your free, no-obligation air source heat pump quote today. Save money, reduce emissions, and heat your home smarter.