Are Ground Source Heat Pumps Suitable for My Home?
The first step in assessing the design of ground source heat pumps is to research on the ways of minimising the hot water demand and space heating. It requires accurate energy efficiency measurements, which can be done through Domestic Energy Efficiency Primer. It helps to find the heat pumps of the right sizing that will decrease the energy consumption, heat loss and hot water needs.
There are two different types of loop systems for ground source heat pumps, the open loop system and the closed loop system. The open loop system extracts groundwater which passes through a heat pump where heat is extracted. The closed loop system draws the heat from the ground itself and uses a continuous loop of piping connected to the indoor heat pump. There are several types of closed loop systems:
Horizontal Ground Source Heat Pump
The ground source heating system is laid in horizontal trenches that are approximately 1-2 metres deep. It is more common in rural areas where there is more land available. To install the horizontal system, the area required depends on the heating and cooling loads of your home, the depth at which your loop is going to be buried, your soil and its moisture, the climate, and the efficiency of the heat pump. The average 150 m2 home needs an area of between 300 and 700 m2.
Vertical Ground Source Heat Pump
The ground source heat pump borehole cost can vary. Vertical boreholes are a more expensive alternativewhen there is not enough area to lay the pipes horizontally. It is more often the appropriate choice for suburban homes where space is restricted. A hole is dug at least 6m into the ground for insulation and thetotal piping will be 50-150 m deep depending on the composition of the ground and the heat requirement of your home.
Closed Loop System for Pond/Lake
Although less common than horizontal or vertical systems, a closed pond loop is also an option. It is uncommon because it requires proximity to a body of water, so an open loop system is usually preferable. It may be advantageous when poor water quality prevents the use of an open loop.
Other types of Closed Loop Systems
Due to the fact that water availability is limited, this guide considers only the closed loop (ground sealed) system. There are two other criteria when choosing the right ground source heat pumps:
Direct expansion (DX)
It relies on a cyclical process when the refrigerant changes its position back and forth between a gas and a liquid. When the refrigerator absorbs the heat, the compressors start pulling the vapour from suction lines and the process is launched.
It is commonly used in freezer applications with carbon dioxide when changing secondary working media. In other words, during antifreeze solution/water circulation the energy is relocated from or to the refrigerant circuit through ground heat exchange pipework.
Price of Ground Source Heat Pumps
Which are the prices of ground source heat pumps? Setup costs are higher than more traditional systems, but the difference is usually compensated by energy savings. The Energy Saving Trust (EST) estimates it can cost between $13,000 and $20,000 to install a ground source heat pumps in your home. Running costs depend on the size of your home and how well insulated it is.
The price of ground source heat pump also depends on whether any new radiators or a fully new underfloor heating system is required, therefore the price estimations below doesn’t include any wet system upgrade.
Groundwork Costs of Vertical vs. Horizontal Systems
Costs vary whether you set up a vertical or a horizontal system. There is a significant difference in groundwork costs between horizontal and vertical systems. Although the horizontal installation is cheaper, it requires a minimum of ½ an acre of land.
|Number of Rooms||Heat Pump and Installation Cost||Horizontal Groundwork Cost||Vertical Groundwork Cost|
The costs depend on each individual case and numbers do not represent actual offers. They are merely for general reference.
How Much Money Can You Save with Ground Source Heat Pump?
The following is a table based on figures from the Energy Saving Trust, outlining the carbon dioxide and energy bill savings when using a ground source heat pump in England, Scotland and Wales. The existing systems listed are all non-condensing systems, which are likely the systems users are looking to replace.
| Current System ||Savings on Energy Bill ($/year)|| Carbon Dioxide Savings (kgCO2/year)|
| Gas|| $440-660|| 2100-3300 kg|
| Electric|| $790-1425|| 6700-11700 kg|
| Oil|| $130-220|| 3000-4700 kg|
| LPG|| $960-1500|| 2800-4500 kg|
| Coal|| $590-990|| 7600-12100 kg|
Ground Source Heat Pump Efficiency
GSHP systems save energy by using the constant temperature of the ground to increase the seasonal efficiency of home heating. The source of heat used for ground source heat pumps is the sun, as it heats up the ground water resulting in the stable temperature of the Earth’s floor.
For every kW of electricity consumed by the heat pump, around 4 kW’s of heat is generated in return, meaning you have a 400% cost-effectiveness ratio.
What do the COP and SCOP tell us about efficiency?
Ground pump systems reach rather high-performance coefficients, with the average between 3 and 4. The Coefficient of Performance is found by dividing the useful heat output by the electrical energy input.
A ground source heat pump that transfers 4 kilowatts of heat from the ground for 1 kilowatt of electricity has a COP of 4. We recommend you check out the seasonal coefficient of performance (SCOP), as it is a more accurate representation of the efficiency during different times of the year, compared to the COP.
While the COP is the performance delivered at a specific moment, the SCOP will provide an average for the whole year, giving a more trustworthy figure.
What brands sell GSHP’s?
Ground source heat pumps differ in efficiency, price, and brands. Certain brands may have similar efficiencies and prices, yet some brands are available at higher costs than others.
There are many brands of ground source heat pumps available in the Canada market, some of the most known brands include Baxi, Calorex, Bosch and Mitsubishi. Due to the large variety of brands available, it is important to compare supplier quotes to help make your decision easier when buying the best ground source heat pump. Ground source heat pump efficiency is improved by utilising solar recharge of the ground.
Advantages and Disadvantages of GSHP
Contrary to popular belief, you don’t need several acres of land to install a heat pump. Even a modest garden can be used to benefit from the Earth’s heat.
Ground Source Heat Pumps Explained
Ground source heat pump systems have three components:
- The heat pump
- The underground heat exchanger
- The distribution system
A mixture of water and antifreeze or refrigerant is pumped into the ground via the heat pump, and the antifreeze mixture is continuously warmed up by the constant temperature of the ground.
The liquid is fed into a heat exchanger and energy absorbed from the ground is transferred into a refrigerant which boils at a low temperature and turns it into gas.
The gas is fed into a compressor and the compressing process makes the temperature of the gas rise. The water is heated in the hydronic distribution system, where water is distributed to either radiators or floor heating.
Finally, the gas is transferred into a condenser, from which it delivers heat to serve the household’s space heating needs.
Installation of Ground Source Heat Pumps
House size and building requirements will determine whether a vertical or horizontal loop system is needed. The first step is the excavation of the loop fields.
To install a vertical ground source heat pump, the loop is placed in the drilled well that is dug deep into the ground. The heat exchanger is then installed in order to capture the heat from the ground.
For horizontal installation, a large area of land is dug up so that the loops can be placed on the land without having to dig deep into the earth.
Underfloor Heating System vs. Radiators
For maximum performance of your ground source heat pump, underfloor heating is ideal. The underfloor heating system performs better than radiators because the heat is transferred equally across the whole surface, whereas radiators need to spread the heat from one corner to the entire room.
However, due to the higher cost of underfloor heating, radiators are also a good choice that results in high performance. The SCOP is higher for underfloor heating compared to radiators because heat distribution is well designed with underfloor heating and therefore the floor system will likely have a lower output temperature than a radiator, meaning a higher coefficient of performance.
Heat Pumps Combined with Renewable Energy
Since electricity is required to run the heat pump, if you’re not using renewable energy, it is not an entire carbon neutral system. However, when heat pumps are combined with solar panels it is possible to reach a full carbon neutral system.
It is important to note that special planning permissions are required in Wales and Northern Ireland, and in England and Scotland permissions depend on your location and the size of your property.
Does the Government Provide Grants for GSHP?
With incentives available from the Canada government, saving money on heat pumps has never been easier. Currently, the Renewable Heating Incentive pays 19.33 p/kWh of energy generated by ground source heat pumps. This is one of the highest tariffs you can get and after solar thermal panels at 19.74 p/kWh.
Payments are made on a quarterly basis over seven years. A number of funds you receive will depend on a number of factors – including the technology you install, the latest tariffs available for each heating solution and, in some cases, metering.
The Non-Domestic Renewable Heat Incentive (RHI) aims to compensate the costs of ground source heat pumps installations in commercial applications. The business owners and social housing providers benefit from a quick payback and long-term rate of return. In addition, the Canada Government financial support gives an opportunity for retrofit installations and new houses to get modernised.
The third type of grants is the Energy Company Obligation (ECO), which is relatively new and imposes legal obligations on energy suppliers to carry on energy efficiency measures. The main focus is on three different areas: Home Heating Cost Reduction Obligation, Community Obligation and Carbon Emissions Reduction Obligation.
If you are interested in buying the best ground source heat pump, we are here to help you. Simply fill in the contact form with your details and preferences and we will get back to you with customised, free, and no-obligation quotes!