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Choosing the right heating system can be a crucial decision for the heating requirements and energy costs of your home for the next several years. Once you choose between a boiler system and a heat pump, the next decision is whether an air source heat pump will save you more or a ground source heat pump would be a preferred choice as per your heating requirements.
Well, choosing a heat pump depends on multiple factors, including heating needs, space available, and budget constraints. In this article, we will consider all the factors which can influence your decision and help you find a suitable choice for your home. We will not be telling any stories today though.
By making an informed decision, you will not be shocked by energy costs anymore.
What are Heat Pumps?
Heat pumps are the energy efficient heating counterparts of heating boilers. Heat pumps provide heating for central heating and hot water for domestic use. Heat pumps have two major types:
- Air Source Heat Pumps (ASHPs)
- Ground Source Heat Pumps (GSHPs)
- Water Source Heat Pumps (less common, won’t be discussing today)
Both air source and ground source heating systems promote green energy and produce less greenhouse gas emissions (for real). Besides providing green energy, they also save massively on energy costs for UK households.
Air Source vs Ground Source Heat Pumps
Let us make this very clear, both ground-source and air source heat pumps have the same work process. They both extract the heating from renewable sources, compress it, and provide heating and hot water to the main supply. However, these systems have many points of difference; we will be exploring all of them in this article.
1. Air Source Heat Pumps (ASHPs)
As the name suggests, an air source heat pump extracts heat from outside air to provide heating for the central heating system. ASHPs’ energy-efficiency changes throughout the year across different seasons.
Because this heating system pulls heat from the air, when it’s extremely chilled outside, the heat pump requires more electricity to provide heating (seems like a person with iron deficiency).
So, when you are in more need of heating, these heat pumps can be problematic (a little toxic). You might experience higher energy costs than usual.
Air source heat pumps are usually tested in an inlet temperature of 7°C, so if you are living in a region with comparatively moderate temperatures, you can go for air source heat pumps by all means.
Types of Air Source Heat Pumps
There are two major types of air source heat pumps based on their functionality (Aghh! More types!).
- Ducted Systems: Air source heat pumps with ductwork systems distribute the air through air ducts or heat exchangers throughout the building.
- Ductless Systems: Air source heat pumps with ductless systems work as wall mound split systems with zoned heating and multiple indoor units.
Efficiency & Performance
As compared to ground source heat pumps, the air source systems are susceptible to seasonal environmental changes.
The performance and energy efficiency of the air source heat pump might be dropped in extremely cold weather conditions. However, they provide 2.5-4.0 COP (coefficient of performance) in mild weather conditions up to 5°C.
Installation Process & Costs
Unlike ground source heat pumps, these systems do not require trenching or drilling (fortunately). Instead, it includes a wall or ground-mounted outdoor unit to extract heat from the air.
The installation costs of air source heat pumps usually range from £7,000–to £15,000. Air source heat pumps are typically cheaper than ground source heat pumps. However, if you choose Monobloc systems, they are usually cheaper and easy to install.
Pros & Cons
Here are some advantages and disadvantages of choosing a ground source heat pump vs an air source heat pump.
Pros:
- Lower Upfront Costs
- Less Space Required for Heat Pump Installation
Cons:
- Reduces energy efficiency and performance in colder weather conditions.
2. Ground Source Heat Pumps (GSHPs)
Ground source heat pumps pull out the heat from the ground, compress it, raise its temperature, and provide heating and hot water for central heating systems and domestic use. That’s why they are also known as geothermal heat pump systems.
As the ground has a more stable temperature throughout the year, ground source heat pumps can maintain a temperature between 10-12°C across seasons. You know what? GSHPs are tested at a 0°C inlet temperature, which makes them more reliable in winter.
Types of Ground Source Heat Pumps
Ground source heat pumps pull heat via underground loops of pipes buried in different ways. Based on configuration, GSHPs have two major types:
- Closed-loop vs. open-loop systems
- Horizontal vs. vertical loops
Whatever the names are, this choice depends on the available space, the temperature in your area, and the budget for the installations, rather than how fancy a name is or whether you do not want to dig deeper (till you see groundwater). Your installer can help you choose the best one as per the requirements.
Efficiency & Performance
Let us tell you an interesting fact, the energy efficiency of heat pumps is measured by COP, while the seasonal performance factor is considered a measure of heat pump performance.
The COP of ground source heat pumps is around 4-5 COP, which means it produces 4-5 units of energy with 1 unit of electricity used. SPF is also higher for these heat pumps across seasons.
Installation Process & Costs
Do you know? Before actually installing the heat pump, your property is assessed to define suitability. After the site assessment, the decision of open loops or closed loops is made.
Plus, whether to bury them horizontally (3-6 feet) or vertically (100-400 feet) also depends on the space availability.
The installation costs for ground source heat pumps range from £18,000–£35,000 (pretty costly yeah?). However, if you have space available for horizontal loops, you might save significantly on installation costs.
Pros & Cons
Here are some of the advantages and disadvantages you might experience with ground source heat pumps. Discussing the cons is our favourite thing as spoiler alerts often help making good decisions.
Pros:
- High Energy Efficiency: transfers 3 to 5 times more heat than electricity consumed.
- Stable Heating & Hot Water: Ground source heat pumps provide stable heating throughout the year do not drop performance and have higher efficiency all year round.
- Low Running Costs: GSHPs use 25% to 50% less energy as compared to their counterparts.
Cons:
Higher Upfront Costs: The only disadvantage associated with installing ground source heat pumps is its expensive to install at your property.
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Comparative Analysis Table of Ground Source vs Air Source Heat Pumps
We have summarized all the features of both heat pumps in comparison to each other in the below comparison table. Have a detailed look at them to make an informed decision.
| Feature | Ground Source Heat Pumps | Air Source Heat Pumps |
|---|---|---|
| Efficiency & Performance | COP 4-5 (Provides Constant Performance | COP 3-4 (drops performance after 5° |
| Installation Costs | £18,000–£35,000 | £7,000–£15,000 |
| Running Costs | Lower energy costs | Higher then GSHPs |
| Annual Maintenance Cost | £150–£200 | £100–£150 |
| Lifespan | 20-25 years | 15-20 years |
| Government Grants | Boiler Upgrade Scheme (Partially Funded) | ECO4 (fully funded) & BUS Scheme (partially funded) |
Final Thoughts
To wrap up the guide, ground source heat pumps are far better choices if you do not have budget constraints and if you are living in cold weather conditions. However, if are living in a mild climate, air source heat pumps should be enough for your heating requirements.
In this article, we have provided detailed information you might require to make an informed decision. From types, energy efficiency, costs, pros, and cons, everything has been covered.
FAQs
Well, it depends on unique user requirements. In terms of energy efficiency and performance in cold weather, ground source heat pumps are better. While considering the upfront costs, performance in moderate weather, and hassle of installation, air source heat pumps can be a better choice. It’s better to get your property assessed to make a final decision as per your needs.
While there are various advantages, here are some downsides of ground source heat pumps:
- Expensive Upfront system and installation costs.
- Disruptive Installation and massive digging were involved.
- Not a suitable choice for a small garden.
So, the choice totally depends on your household requirements, so it’s better to get it assessed.
It depends on how well you maintain your heating system. The typical lifespan ranges from 15 years to 25 years for modern systems. If you do annual and seasonal servicing and keep it safe from physical damage, it might last longer. Of course, it will not stop working as soon as it completes its lifespan, it will show signs of aging and start being inefficient.
