Frequently Asked Questions

A geothermal system uses the thermal energy stored in the earth instead of creating heat from fossil fuels to condition your home. Geothermal energy is a free and renewable resource just below the earth’s surface. Temperatures remain stable at between 15°C and 19°C all year round. This stored energy is absorbed by fluid circulating through a series of underground pipes (ground loop) to a heat pump inside the building. A small amount of electricity is needed to exchange this energy to a higher temperature and distribute it as heat throughout the home. In summer, the system reverses, pulling heat from the home and returning it to the cooler earth.

By installing a geothermal system, the average homeowner can reduce greenhouse gas emissions by up to 7 tonnes per year and even more for bigger homes or commercial projects. This is the environmental equivalent of taking two cars off the road each year or planting an acre of trees.

Some homeowners are reluctant to consider a geothermal solution due to the high perceived capital cost of installation. As each home is unique, the system cost depends on several factors including the size of the home, available land for a ground loop, comfort levels and the insulation qualities of the building. Highlands GeoExchange can recommend a system (geothermal, aerothermal or hybrid) that will cater to almost every budget, while offering superior comfort and long-term energy savings.

The payback period varies for each project and is calculated during the design phase. We conduct thermal modelling of each home to determine peak heating and cooling loads. From this, we can estimate the running costs of each system and recommend the most cost-effective heating and cooling system for your unique requirements.

Our heat pumps are usually installed inside the home or in a garage and will produce some noise. However, it is very minimal as the units are well insulated and operate at lower speeds than traditional boilers or air-conditioning systems.

A geothermal system extracts heat from the earth or water using a ground loop and delivers it to a ground source heat pump in the home. The heat pump exchanges this energy to a higher temperature and delivers it as warm water to a radiator, fan coil unit or an underfloor heating loop system. The thermal energy can also be used to supply domestic hot water and to heat a swimming pool or spa. This process is reversible for cooling in warmer months.

A geothermal system can be designed to supply a dedicated supply of hot water for all the home’s domestic uses. Excess energy can be diverted to heat a swimming pool or spa. We can also condition a cool room or wine cellar to a desired temperature all year round.

Yes, provided the existing heating and/or cooling system is in good working condition, Highlands GeoExchange can advise on the best geothermal or hybrid solution to suit your situation. As our systems operate at lower temperatures, extra radiators or ducting may need to be installed to run the system more efficiently.

Geothermal systems do not burn fossil fuels to make heat and are up to five times more efficient than a conventional system. This is a 400-500% annual efficiency rating, while the most efficient gas furnace operates at 98%. A ground source heat pump requires about 1kW of electrical power to produce 4-5kW of heat. An average air-sourced heat pump requires about 1kW of electrical power to produce 2-3kW of heat. However, these efficiencies can be significantly reduced if your home is not properly insulated.

There are several loop options that can be used for heat exchange depending on the availability of resources. A closed ground loop is the most common and can be installed either vertically or horizontally. A horizontal loop is used when there is adequate land available and a series of trenches are dug using an excavator. Pipes are laid in the trench and then backfilled. When space is limited, a vertical loop can be used. This involves drilling a series of bore holes, inserting two pipes into each hole and grouting them up. Pipes can also be submerged into a water source such as a dam or pond provided it is more than 3 metres deep and replenished all year round. Where there is an abundant supply of water via a bore, river or the ocean, an open loop can be installed. The water used is pumped back into the ground or water source or can be used for irrigation.

A geothermal system has smaller power supply needs than a traditional air conditioning system as it uses on average 50% less power. However, supply is dependent on the total kilowatt demand required to heat and cool the home and the number of machines needed to achieve this.

Minimising energy loss from a building will reduce the run hours of the heating and cooling equipment and cut down energy consumption. Energy can be lost through the roof, windows, walls and doors of a home. An example is a double-glazed aluminium window that is not thermally broken can be less efficient than a timber single glazed window. A properly insulated home can save up to 30-40% on energy consumption which means smaller utility bills. Combined with a solar system and battery storage, some consumers can reduce their power supply costs to zero.

If a heat pump is replacing an existing gas boiler or air conditioning system (retrofit), the installation can take a few weeks. New home builds can extend over one or two years depending on the builder’s schedule. Highlands GeoExchange is involved at the beginning of a new build when ground loops and underfloor heating pipes are installed right up until the equipment is commissioned prior to the homeowner moving in.