When the nights begin to draw in and the temperature drops, a common question pops up: Do air source heat pumps actually work in winter?
Here at Heat Pump Gang, we understand the importance of a warm and comfortable home year-round, especially during those chilly winter months. We also know that you want the most from your heating system and that it must be as efficient as possible.
While it's widely suggested that most heat pumps struggle in cold weather, this doesn’t present a fair or accurate picture.
In this blog post, we'll debunk the myths and explore how ASHPs can be reliable in the winter months, keeping your home cosy even when the frost is on the ground.
Using our expertise, we’ll provide an honest appraisal of these handy devices so you can decide whether it’s a wise investment.
In order to understand the full picture, we need to examine how these devices function, so, here's a brief description...
Unlike traditional gas or oil boilers that burn fossil fuels to generate heat, ASHPs operate on a clever technology similar to your fridge, but in reverse. A refrigerator works by extracting heat from the inside to create a cool environment, while the air source heat pump does precisely the opposite!
The heat pump has an outdoor unit containing a refrigerant liquid that absorbs heat energy from the ambient air, even at surprisingly low temperatures. This captured heat is then concentrated using a compressor, similar to how a bicycle pump creates heat as it increases air pressure (try pressing your finger over the end of a bicycle pump and pushing the plunger down).
The hot fluid is then transferred inside your home through another heat exchanger unit, releasing the captured thermal energy into your central heating system, warming your radiators, or underfloor heating. The beauty of this process is that ASHPs are essentially harnessing renewable energy that's constantly present in the air, even in winter temperatures.
Explore: Can Air Source Heat Pumps Cool?
Heat pumps are rapidly gaining a reputation for being super-efficient. Many contemporary models can work effectively to absorb heat, even in extremely low temperatures, even down to -25°C, making them suitable for most regions in the UK.
However, while they do work in cold temperatures, they need to work harder to produce the same level of heat, which can adversely affect the heat pump's efficiency.
Even so, ASHPs can produce up to three times more heat than the electricity they consume. That translates to a Coefficient of Performance (COP) of 3, meaning for every 1kWh of electricity used, an ASHP can generate 3kWh of heat!
In fact, newer models can be as much as 500% efficient. In comparison, the average gas boiler only has an efficiency rating of about 90% on a good day and in moderate weather!
With this in mind, how much could you save on your energy bills by installing a heat pump?
Let's say your home currently uses a gas boiler and your average annual gas bill is around £1,200. By switching to an ASHP with a COP of 3 and utilising a favourable electricity tariff, your annual electricity cost for heating could potentially be reduced to £800. Even factoring in the cost of electricity, the overall saving could be around £400 per year. That's a significant chunk of change you could put towards other things!
The exact cost savings will vary depending on factors like your home's size and insulation, your current energy usage, and the specific ASHP model you choose. However, the potential for significant reductions in your heating bills due to ASHPs' high efficiency is undeniable.
No, this is virtually impossible. The refrigerant can withstand extremely low temperatures and actually starts boiling at the outside air temperature!
The only effect that cold weather has is a slight drop in efficiency, meaning that it will use more electricity at certain times.
Most of these units also have a defrost mode that kicks in when the temperature drops too low. This is partly where the inefficiency comes from, as the electricity is used to 'defrost' the pump for a while rather than to heat your home. Even so, they only use a relatively small amount of electricity to function, so it balances out in the end in most cases.
Yes, they most certainly do! The facts prove this: Sweden, Norway, Estonia, and Finland are well-known to be cold countries (with average annual temperatures between 3º and 8º and average winter temperatures between -8º and -30º), but more heat pumps are sold here than most other parts of Europe!
However, they do have to be protected from the elements, as there's a risk of damage from strong winds or debris falling on the outdoor units. This can be overcome by installing a heat pump guard that keeps it safe from harm.
If air source heat pumps are so great, why do rumours abound that they don't work in cold climates?
Well, one theory suggests that this is partly due to an ongoing attempt by those with vested interests (mostly in the fossil fuel industry and those associated with it) to use misinformation to undermine the move towards renewable and sustainable energy sources. Sadly, a small minority of the general public is willing to believe this misinformation as they don't accept the reality of climate change, despite the clear signs we see around the globe, with extreme weather causing damage and devastation on an almost daily basis.
Also, older heat pump models may have fared less well in colder temperatures in the past and lacked the efficiency of newer examples.
Whatever the truth of the matter, heat pump technology is constantly being improved and upgraded, offering consumers more efficient models that work in cold weather just as well as they do the rest of the year round!
For now, though, most air source heat pumps work extremely well throughout the year, with a slight dip in efficiency when the outside temperature drops.
Ground source heat pumps work on a similar principle to their air source cousins, but they rely on a system of pipes beneath the ground surface. This 'ground loop system' is laid out horizontally in the garden or vertically, using deep boreholes.
A refrigerant is passed through the loop system, where it absorbs the heat energy from the ground and relays it to the property. It passes through a heat exchanger into the building's heating system, just as with the air source heat pump.
The beauty of this system, however, is that ground temperatures are generally warmer and more stable than the air temperature all year round. This means that your heat pump efficiency will be constant, as it won't need to work harder during cold weather.
But wait! Before you jump in with both feet to buy your ground source heat pump, there are a couple of facts to be aware of...
Ground source heat pumps require a larger initial investment than their air source counterparts.
This is a rough guide to prices to give you an idea:
Explore in-depth: Air Source Heat Pump Cost
Learn more: Ground Source Heat Pump Cost
You'll also need adequate space on your property for the ground loop, which makes ground source heat pumps impractical (but not always impossible!) for those in flats and apartment blocks, or households with only a small yard or garden.
However, if you have the budget and the space, it's worth considering the ground source heat pump as a viable and efficient alternative.
Returning to the subject of cost, several grant schemes are available for property owners who are interested in buying a heat pump. The Boiler Upgrade Scheme provides £7,500 towards the cost, making it an attractive option for most people!
If you opt for an air source heat pump, the grant could cover at least half of the cost if not the entire amount.
As successive governments tackle the climate crisis, you can be sure that further incentive schemes will be rolled out in the future, and Heat Pump Gang will keep you informed as and when these become available.
Take a look: Air Source Heat Pump Grants
As experts in this field, our best advice is to always use a professional heat pump installer. They will set up your system and fine-tune it to your home's needs, making sure it runs efficiently.
Aside from this, here are some tips for minimising any loss of efficiency when running your heat pump in winter...
The outdoor unit is exposed to the elements and can easily be blocked or covered by snow or debris. Make sure to regularly clear a perimeter around the outdoor unit to ensure optimal performance.
Just like any other heating system, ASHPs rely on clean filters for efficient operation. Dirty filters restrict airflow, forcing the unit to work harder and potentially reducing its efficiency. Check and clean your ASHP's filters regularly, typically according to the manufacturer's recommendations.
During colder weather, it's tempting to crank up the thermostat. However, maintaining a consistent and moderate temperature setting is more efficient for your ASHP. Consider lowering the temperature slightly at night or when you're out of the house. Smart thermostats can also be helpful for maintaining a comfortable yet efficient temperature throughout the day.
A well-insulated home is key to maximising ASHP efficiency all year round, but it's especially important in winter. Ensure your loft, walls, and windows are properly insulated to prevent heat from escaping and forcing your ASHP to work harder to maintain your desired temperature.
Schedule Regular Servicing
Regular professional servicing of your ASHP is crucial for maintaining optimal performance. A qualified engineer can inspect the unit, clean internal components, and ensure it's operating efficiently, especially during colder months when the ASHP is working harder.
So, to sum up our findings...
Air source heat pumps work in cold weather, but efficiency may be affected. You can limit the effects by choosing a professional heat pump fitter to handle the installation, selecting a high-quality brand of heat pump, and getting it tuned and serviced.
Heat pump manufacturers have been tirelessly working to produce units that are even more energy efficient and that work in cold weather just as well as they do in summer.
At Heat Pump Gang, we've seen these improvements firsthand, and consider it an honour to be part of this transition to more sustainable resources and lower energy bills!
