Key Takeaways:
- A heat pump delivers 3–4 units of heat for every unit of electricity. A gas boiler converts roughly 90% of each unit of gas into heat. The efficiency gap is significant.
- On a standard electricity tariff, a gas boiler currently costs around £175 less per year to run than a heat pump. That gap reverses on a smart tariff.
- Smart tariffs like Octopus Cosy or Intelligent Go drop heat pump running costs to £600–675/year, beating gas by £75–150/year. This is the single biggest factor in the comparison right now.
- Upfront cost is higher for a heat pump, but grants of up to £7,500 through Home Energy Scotland (£9,000 for rural homes) close the gap substantially.
- Oil boiler and electric boiler households almost always benefit from switching.
- The real variable is not the technology. It is insulation, system design, radiator sizing, and flow temperature. These determine whether a heat pump saves you money or costs you more.
Table of Contents
The question most Scottish homeowners arrive at is simple: should I stick with my gas boiler, or switch to a heat pump?
The honest answer is that it depends on your home. Not on headlines, not on national averages, and not on what worked for a neighbour. A heat pump vs gas boiler comparison only means something when it accounts for how your property actually loses heat and what electricity tariff you are on.
This guide compares running costs, upfront costs, and efficiency between heat pumps and boilers using current Scottish energy prices as of April 2026. It also explains what actually determines whether a heat pump will save you money, because that part gets left out of most comparisons.
How a Heat Pump and a Gas Boiler Actually Work Differently
A gas boiler burns fuel to create heat. Natural gas enters the boiler, combustion happens, and hot water is sent to your radiators or hot water cylinder. Most modern gas boilers are condensing boilers, which recover some of the heat from exhaust gases. A condensing boiler vs heat pump comparison starts here: even the best condensing boiler operates at around 90–94% efficiency. For every £1 of gas burned, roughly 90–94p becomes useful heat.
A heat pump does not burn anything. It moves heat from the outside air into your home using electricity. The measure of its efficiency is the Coefficient of Performance (COP). A COP of 3.5 means the heat pump produces 3.5 units of heat for every 1 unit of electricity consumed. That is 350% efficiency.
COP is not fixed. It changes with outdoor temperature and flow temperature. On a mild autumn day, a well-designed system might achieve a COP of 4.5 or higher. On the coldest night in January, it may drop to 2.5–3.0. Across a full Scottish heating season, a properly installed system typically achieves a Seasonal Performance Factor (SPF) of 3.0–3.5.
That seasonal average is what matters for running cost calculations.
Running Costs: Heat Pump vs Gas Boiler in Scotland
This is the section most people are looking for. Here is how the heat pump vs gas boiler running cost comparison works in practice, using the current Ofgem price cap for April–June 2026.
Under the current cap, Scottish electricity costs approximately 24.71p per kWh and gas costs approximately 5.64p per kWh. Electricity is roughly 4.4 times more expensive than gas per unit.
But a heat pump uses far fewer units.
A typical Scottish home needs around 12,000 kWh of heat output per year for space heating and hot water. Here is what that looks like for each system on a standard tariff:
Gas boiler (90% efficiency): 12,000 kWh ÷ 0.90 = 13,333 kWh of gas consumed 13,333 × £0.0564 = approximately £752 per year
Air source heat pump on a standard tariff (SPF of 3.2): 12,000 kWh ÷ 3.2 = 3,750 kWh of electricity consumed 3,750 × £0.2471 = approximately £927 per year
On a standard electricity tariff, the gas boiler is cheaper to run by approximately £175 per year. That is the honest starting point.
But that is not where the comparison ends. Three factors change the equation.
1.Smart tariffs close the gap and reverse it.
Tariffs like Octopus Cosy and Intelligent Octopus Go offer significantly cheaper overnight and off-peak electricity rates. Heat pumps are well suited to these tariffs because they can pre-heat your home and hot water cylinder during cheaper periods, then coast through peak hours.
A realistic blended rate on a smart tariff sits around 16–18p per kWh.
Air source heat pump on a smart tariff (SPF 3.2, blended rate 17p/kWh): 3,750 × £0.17 = approximately £638 per year
That is £114 less than the gas boiler. On a smart tariff, the heat pump wins.
2. Eliminating the gas standing charge.
If you switch fully to a heat pump and remove your gas supply, you no longer pay the gas standing charge of approximately £107 per year. This alone closes the standard tariff gap from £175 down to roughly £68.
On a smart tariff with no gas standing charge, the heat pump costs around £220 less per year than gas.
3. Solar pairing changes the maths entirely.
A heat pump powered partly by solar PV and battery storage uses less grid electricity. This is where the economics become one-sided. Christine, one of our customers in Gartcosh, went from £600/month electricity bills to £24.79 after we installed solar, battery, and optimised her existing heat pump.
Bottom line: On a standard electricity tariff, a gas boiler is currently cheaper to run by around £175 per year. That gap closes to roughly £68 when you factor in eliminating the gas standing charge. Switch to a smart tariff like Octopus Cosy or Intelligent Go, and the heat pump becomes the cheaper option by £75–150 per year. Add solar, and the comparison is no longer close.
The direction matters too. Energy policy is shifting levies from electricity to gas, which will narrow the price ratio further over time. The numbers today favour gas on standard tariffs. The trajectory favours heat pumps.
Want to know what a heat pump would actually cost to run in your home, on your tariff?
Heat Geek Mastery | MCS Certified | Trusted Across Central Scotland
“When the team came to install the system, the entire process was incredibly streamlined and completed in just three days. The guys made sure to cover all our carpets and left the place spotless. Our heat pump is now up and running, and even on the coldest days, our energy usage is nearly half compared to gas.”
Heat Pump vs Oil Boiler Running Costs
For off-grid Scottish homes, the air source heat pump vs oil boiler comparison follows a similar pattern. Heating oil currently sits around 58–62p per litre, which works out to approximately 5.8p per kWh. Oil boilers run at around 85–90% efficiency.
Using the same 12,000 kWh heat demand:
Oil boiler (87% efficiency, oil at 5.8p/kWh): 12,000 ÷ 0.87 = 13,793 kWh of oil consumed 13,793 × £0.058 = approximately £800 per year
Air source heat pump on standard tariff (SPF 3.2): 3,750 × £0.2471 = approximately £927 per year
Air source heat pump on smart tariff (SPF 3.2, 17p blended): 3,750 × £0.17 = approximately £638 per year
At today’s stable oil prices on a standard electricity tariff, oil is cheaper. On a smart tariff, the heat pump wins by roughly £160 per year.
But oil prices are volatile. In 2022, many Scottish households saw oil costs spike to 8–10p per kWh, which would push annual costs above £1,100–£1,400. A heat pump removes that volatility entirely. Electricity prices are capped and more predictable.
Oil boiler replacement also eliminates the oil tank, frees up space, and removes delivery logistics. Home Energy Scotland grants apply to oil boiler replacements. Rural and island homes can access up to £9,000 in grant funding, making these among the strongest financial cases for switching.
Heat Pump vs Combi Boiler: What Changes
A combi boiler heats water on demand. No cylinder, no stored hot water. It is compact and convenient. Many Scottish homes run on them.
A heat pump works differently. It heats water slowly and stores it in a hot water cylinder. This means replacing a combi boiler with a heat pump requires adding a cylinder, which needs physical space in your property.
The running cost comparison between a heat pump vs combi boiler follows the same maths as above. The practical difference is the hot water delivery method, not the efficiency.
Cylinder sizing matters. A 200–250 litre cylinder suits most households. Larger families may need more. The cylinder is typically fitted in an airing cupboard, utility room, or loft space.
This applies to both combi and system boilers. A system boiler vs heat pump swap is simpler because a cylinder already exists.
The combi boiler vs heat pump decision is not about whether the heat pump can deliver hot water. It can. The question is whether you have space for the cylinder and whether the system is designed to reheat efficiently.
Heat Pump vs Electric Boiler
This is the clearest comparison. An electric boiler converts electricity to heat at close to 100% efficiency, which sounds good until you compare it with a heat pump.
An electric boiler vs heat pump comparison on the same 12,000 kWh demand:
Electric boiler (100% efficiency): 12,000 × £0.2471 = £2,965 per year
Air source heat pump (SPF 3.2): 3,750 × £0.2471 = £927 per year
The heat pump uses roughly a third of the electricity for the same heat output. That is a saving of over £2,000 per year. If you currently heat with an electric boiler, switching to a heat pump is one of the strongest financial decisions you can make.
Upfront Cost: Heat Pump vs Boiler
A new gas boiler installation in Scotland typically costs £2,500–£4,500. A new boiler vs heat pump comparison on upfront cost alone will always favour the boiler.
An air source heat pump installation typically costs £7,000–£13,000 before grants, depending on property size, radiator upgrades, cylinder, and electrical work.
Home Energy Scotland offers grants of up to £7,500 towards heat pump installation. Rural and island properties in Scotland can access up to £9,000, effectively covering the entire cost of many installations. Interest-free loans are also available to cover any remaining balance.
After grants, the heat pump cost vs gas boiler cost gap narrows significantly. A £10,000 installation becomes £2,500 after the full grant. That is less than a mid-range boiler installation, with 20+ years of lower or comparable running costs ahead.
The heat pump vs combi boiler cost comparison is similar, with the additional cost of a hot water cylinder factored in.
The heat pump also lasts longer. A well-maintained heat pump has a lifespan of 20–25 years. A gas boiler typically lasts 10–15 years. Over a 20-year period, you may need two boilers but only one heat pump.
Find out how much grant funding your home qualifies for and what the net cost of a heat pump would be after support.
Heat Geek Mastery | MCS Certified | Trusted Across Central Scotland
“Neat install, great communication, and they made the grant process easy. Aventus Eco combine technical know-how with genuine customer care, and I'd happily recommend them. Thanks. Genuinely. ”
What Actually Determines Whether a Heat Pump Is Cheaper
This is the section that matters more than any of the numbers above. Every comparison you read online uses national averages. Your home is not an average.
The real answer to “is a heat pump cheaper to run than a gas boiler” depends on decisions made before and during installation. These are the factors that separate a heat pump that saves money from one that costs more.
Flow temperature is the single biggest lever.
A heat pump’s efficiency drops as flow temperature rises. At 35°C, a well-designed system achieves a COP of 4.0 or higher. At 55°C, that drops to around 2.5. The difference between those two numbers is hundreds of pounds per year in running costs.
At a COP of 4.0, the same 12,000 kWh of heat demand requires only 3,000 kWh of electricity. On a smart tariff at 17p, that is £510 per year. On a standard tariff, it is £741. Even on standard rates, a high-efficiency installation nearly matches gas.
Many poor installations run at high flow temperatures because radiators were never checked against heat loss at lower temperatures. The installer treated the heat pump like a boiler, set the flow temperature high to compensate, and efficiency collapsed. That is not a heat pump problem. It is a design problem.
Radiator sizing determines what flow temperature you can run.
If your radiators are large enough to deliver sufficient heat at 35–45°C, you can run low flow temperatures and achieve high efficiency. If they are undersized for the room’s heat loss, the system has to push hotter water to compensate.
This is why radiator sizing is assessed room by room during a proper survey. Some rooms need upgrades. Many do not. Blanket radiator replacement is unnecessary in most Scottish homes, but targeted upgrades in specific rooms can dramatically improve system performance.
Heat loss calculations set the foundation.
A room-by-room heat loss calculation tells you exactly how much heat the building needs. Without this, the system is guessed. Oversized systems short-cycle and waste electricity. Undersized systems cannot keep up in winter and get forced to high flow temperatures.
Every system Aventus Eco installs begins with a full heat loss calculation. This is the step that most failing installations skip.
Insulation helps, but is not a prerequisite.
The common advice that you must fully insulate before installing a heat pump is misleading. Insulation lowers heat demand, which helps. But a properly sized system in an older Scottish home can perform well without wall insulation, provided the system design accounts for actual heat loss.
Simple measures like loft insulation and draught-proofing make a meaningful difference. Full external wall insulation is expensive and may not be the best use of your budget compared to correct system design.
Weather compensation keeps efficiency high automatically.
Weather compensation adjusts the heat pump’s flow temperature based on outdoor temperature. On a mild day, the system runs cooler and more efficiently. On a cold day, it increases output. This automatic adjustment keeps the COP optimised throughout the year without manual intervention.
Any properly commissioned heat pump should have weather compensation enabled. Many do not, because the installer did not configure it.
Solar PV changes the maths entirely.
Electricity is the heat pump’s fuel. If you generate your own electricity, you reduce or eliminate the main running cost. A heat pump paired with solar and battery storage can achieve near-zero heating costs for large parts of the year. This is the combination that makes the heat pump vs gas boiler running cost comparison one-sided.
Your electricity tariff matters as much as your system design.
This is the new reality of the heat pump vs boiler comparison. At current prices, the electricity-to-gas ratio is roughly 4.4:1. A heat pump with an SPF of 3.2 on a standard tariff cannot overcome that ratio. But a smart tariff at 16–18p blended brings the effective ratio closer to 3:1, where the heat pump’s efficiency advantage translates directly into savings.
Choosing the right tariff is not optional. It is part of the system design. Any installer who does not discuss tariff optimisation as part of the handover is leaving money on the table for you.
The takeaway: Two identical homes on the same street can have completely different heat pump running costs based on system design and tariff choice. The technology is not the variable. The installation and setup are.
Get a heat loss assessment and system design that shows exactly what efficiency your home can achieve, not a national average.
Heat Geek Mastery | MCS Certified | Trusted Across Central Scotland
“What really stood out was the additional guidance Sean provided about how we could improve our home's insulation and reduce drafts. He explained how making these simple DIY improvements would help lower the heat loss in our home, ultimately reducing our energy bills in the long run. ”
The Long-Term Picture: Why the Gap Is Closing
Even where gas currently holds a running cost advantage on standard tariffs, the long-term direction favours heat pumps.
The UK government has signalled intent to rebalance the electricity-to-gas price ratio. Environmental levies currently loaded onto electricity bills are expected to shift towards gas. This would make electricity cheaper relative to gas and improve the heat pump running cost position further.
Carbon costs on gas are likely to increase over time. The Scottish Government’s Heat in Buildings Strategy commits to phasing out fossil fuel heating in homes. New-build properties in Scotland already cannot install gas boilers.
Hydrogen boilers are sometimes raised as an alternative. A zero emission boiler vs heat pump comparison is largely theoretical at this point. Hydrogen heating networks do not exist at scale, and the UK’s hydrogen strategy remains uncertain. Heat pumps are available, proven, and grant-supported now.
The direction is clear. Gas boilers face long-term restrictions. Oil boilers face even stronger pressure. A heat pump is an investment that aligns with where energy policy is heading, not against it.
Frequently Asked Questions
Is a heat pump cheaper to run than a gas boiler?
On a standard electricity tariff at current prices, a gas boiler costs roughly £175 less per year. On a smart tariff like Octopus Cosy, a heat pump costs £75–150 less per year. The answer depends on your tariff, your system’s efficiency, and whether you pair the heat pump with solar. In a well-designed system on the right tariff, the heat pump wins.
How much does a heat pump cost to run compared to a gas boiler?
A typical Scottish home needing 12,000 kWh of heat per year will spend approximately £752 on gas or £927 on a heat pump at standard rates. On a smart tariff, the heat pump drops to around £638. With solar generation, it drops further still. Removing the gas standing charge (£107/year) also narrows the gap.
Are heat pumps cheaper to run than oil boilers?
At stable oil prices (around 5.8p/kWh), oil costs approximately £800 per year for 12,000 kWh of heat. A heat pump on a standard tariff costs around £927. On a smart tariff, the heat pump drops to £638, comfortably beating oil. Oil prices are also volatile and can spike significantly, while electricity is price-capped. With grants of up to £9,000 for rural homes, oil boiler replacement is one of the strongest financial cases for switching.
How much does a heat pump cost compared to a new boiler?
A new gas boiler costs £2,500–£4,500 installed. A heat pump costs £7,000–£13,000 before grants. After the Home Energy Scotland grant of up to £7,500 (or £9,000 for rural homes), the net cost of a heat pump can drop to as low as £1,000–£5,500. The heat pump also lasts 20–25 years compared to 10–15 for a boiler.
Are there grants to help with the cost of a heat pump?
Yes. Home Energy Scotland offers grants of up to £7,500 towards heat pump installation in Scotland. Rural and island properties can access up to £9,000. Interest-free loans are also available. Aventus Eco handles the full grant application process.
Can a heat pump replace a combi boiler?
Yes. A heat pump replaces both the heating and hot water functions of a combi boiler. The main practical change is the addition of a hot water cylinder, since heat pumps store hot water rather than heating it on demand. A survey confirms whether you have suitable space and what changes are needed.
Is a heat pump worth it if I already have a new boiler?
If your boiler is less than 2–3 years old and working well, immediate replacement may not make financial sense on running costs alone. However, grant and loan support available now may not be available indefinitely, and a heat pump lasts significantly longer than a boiler. If you are considering solar or planning longer-term, it is still worth getting a survey to understand your options. For older or inefficient boilers, the case for switching is stronger.
Will a heat pump work in an older Scottish home?
Yes. Older Scottish homes including Victorian, sandstone, and stone-built properties can work well with a heat pump when the system is designed around the building’s actual heat loss. The key is accurate sizing, correct radiator assessment, and proper commissioning. Age alone does not disqualify a property.
How efficient is a heat pump compared to a gas boiler?
A gas boiler operates at around 90–94% efficiency. An air source heat pump typically achieves a Seasonal Performance Factor of 3.0–3.5, meaning 300–350% efficiency across the year. On milder days, efficiency can exceed 400%. The heat pump produces significantly more heat per unit of energy consumed.
Get a Running Cost Comparison Based on Your Home
Online comparisons use national averages. Your home is not an average.
Aventus Eco carries out full heat loss calculations, radiator assessments, and system design for Scottish homes. We can show you what a heat pump would actually cost to run in your property, what tariff makes the most sense, and whether solar changes the equation for you.
If you want real numbers before making a decision, start with the right data.
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