You’re considering installing an air source heat pump. But you can’t help but wonder: will it blow your electricity bill out? It’s a reasonable question. I mean, going electric seems like it would be extremely expensive.
Here’s the best part. ASHPs are very efficient. They only consume 25–35% of the heat energy they supply in electricity. This is because they don’t produce heat from scratch. They transfer it from outside air into your home. You might even qualify for help through Air Source Heat Pump Grants.
How Do Air Source Heat Pumps Actually Use Electricity?
Before we get to the numbers, let’s learn how these systems operate. ASHPs don’t burn fuel or create heat themselves. They take heat using a refrigeration cycle driven by electricity. It’s like having a fridge operate in reverse.
The sorcery occurs through something known as the Coefficient of Performance, or COP. This determines how well your heat pump operates.
What Is COP and Why Is It Important?
COP is nothing but the ratio of heat delivered to electricity supplied. Present-day ASHPs have a COP rating of between 2.5 and 5.0. The majority of units you’ll see today deliver about 3.0–4.0 in standard conditions.
What does that translate to in real life? If your heat pump has a COP of 3.5, it provides 3.5 kWh of heat for each 1 kWh of electricity consumed. Not bad, huh? You’re receiving over three times the energy that you’re paying for.
How Much Electricity Will Your Heat Pump Actually Use?
Now let’s get detailed. Your electricity consumption relies on a number of factors. System size is one. So is your house’s insulation, your climatic region, and your heating demand.
Daily and Monthly Consumption
An 8 kW ASHP usually draws in the range of 6–10 kWh per day. That means around 180–300 kWh per month under standard conditions. Naturally, you’ll consume more during bitterly cold winter days and less in pleasant weather.
Annual Electricity Use
That’s where it becomes fascinating. The typical UK dwelling requires around 11,500 kWh of warmth per year. With an ASHP operating at a COP of 3.2, that’s roughly 3,600 kWh of electricity.
The majority of UK dwellings employing ASHPs experience between 2,500 and 5,000 kWh of electricity consumption each year for all their heating purposes. That’s across various sizes of dwelling and levels of insulation.
How Does This Compare to Other Heating Systems?
You might be wondering how ASHPs stack up against what you’re using now. Let’s break down the comparison with other common heating systems.
Electric Resistance Heaters
These are 100% efficient at converting electricity to heat. Sounds good, right? Not so fast. They generate heat instead of moving it. That means your annual electricity use can exceed 10,000 kWh. That’s double what an ASHP uses.
Gas Boilers
Gas boilers run at about 90% seasonal efficiency. To get 6,000 kWh of heat, you’ll need roughly 6,500 kWh of gas. At 4p per kWh, that’s around £260 per year.
An ASHP achieving the same heat output at a COP of 3 would use 2,000 kWh of electricity. At 30p per kWh, you’re looking at about £600 annually. Yes, that’s higher. But you’re also cutting carbon emissions significantly. Plus, green energy tariffs can narrow that gap.
Oil and LPG Boilers
These are less efficient than gas and produce more carbon. If you’re currently using oil or LPG, switching to an ASHP becomes even more attractive. The running costs are often comparable, and you’ll slash your carbon footprint.
What Affects How Much Electricity Your Heat Pump Uses?
Several factors determine whether your heat pump sips electricity or guzzles it. Understanding these helps you keep consumption low.
Outdoor Temperature Makes a Big Difference
Here’s something you should know. When it’s colder outside, your heat pump works harder. That reduces the COP and increases electricity use. On really cold days, backup electric heaters might kick in to help out.
Does that mean heat pumps are useless in winter? Not at all. They still outperform traditional electric heating by a wide margin.
Your Home’s Insulation Is Critical
Better insulation means your heat pump runs less often. It’s that simple. If heat escapes quickly, your system must work constantly to maintain comfort.
Pairing underfloor heating with your ASHP is smart. It lets the system operate at lower flow temperatures. That boosts the COP and cuts electricity use.
Proper Sizing and Smart Controls
Is your heat pump the right size for your home? An oversized unit cycles on and off too often. An undersized one runs constantly. Neither is efficient.
Modern ASHPs with variable-speed compressors adjust their output smoothly. Smart thermostats help too. They learn your schedule and optimise heating automatically. Together, these features minimise electricity consumption.
The Bottom Line
So do air source heat pumps use a lot of electricity? Yes and no. They do use electricity. But, thanks to programs like the ECO4 Scheme, they deliver two to four times more heat energy than the electricity they consume. That makes them one of the most efficient electric heating options available.
Annual electricity use of 2,500–5,000 kWh might seem like a lot. But compare it to over 10,000 kWh for direct electric heating. The savings are real. And compared to fossil fuel boilers, you’re making serious carbon reductions.
