How to Heat Your Home: Heat Pumps 101

by Brian Flax | Jan 05, 2023

A consistent, comfortable indoor environment is one of the main benefits of a properly insulated home. A building with high levels of insulation requires less energy demand to heat and cool and can keep temperatures relatively level regardless of the outdoor air temperature. Combined with industry best practices, like paying attention to air tightness and thermal bridging, insulation reduces strain on heating systems, allowing it to run more efficiently and for shorter periods of time.

Without considering a building’s thermal envelope, even the most efficient heating system on the market can only do so much if its battling constant heat loss. While we believe in a “fabric first approach“, once the home is ready the next logical step is introducing a high efficiency heating system, like a heat pump.

In our latest post on the KORE Blog, let’s explore the different types of renewable heating systems available on the market today.

What are heat pumps?

When combined with proper levels of insulation, heat pumps are efficient heating systems designed to replace the traditional gas or oil-fired boilers found in most homes throughout Ireland and the UK. A heat pump system work much like a refrigerator. Heat pumps are mechanical compression cycle refrigeration systems that move heat from outside in, or inside out depending on the time of year. It accomplishes this with the use of refrigerant, which absorbs heat and redirects it the same way an air conditioner would. A compressor moves this refrigerant around, either heating the indoor air space if it’s cold outside, or absorbing heat from the indoor environment and releasing it outside during the summer. Most heat pump systems, with the exception of air to air heat pumps, can provide both space heating and hot water.

Heat pumps work using electricity, so they are best for temperate climates. In colder climates back up heating systems may be required. There are different types of heat pumps available:

Air Source Heat Pumps

Air source heat pumps extract heat from the air. This heat is evaporated and transferred using refrigerant to a coil inside the home where this gas is turned back into a liquid. This heated liquid then feeds your heating system inside the home and is distributed to the desired locations. During the summer, the heat pumps extracts heat from the air inside your home and transfers it using refrigerant to a coil outside the home, helping to keep the indoor temperature cool.

Ground Source Heat Pumps

Ground source heat pumps are considered to be more efficient as the heat found underground is more consistent. In fact, heat removed from the home during summer months can actually be stored underground for use during the colder winter months. Ground source heat pumps can be installed horizontally (in a loop of pipe), underneath a garden for example, or they can be installed vertically at depths of up to 100 metres. Horizontal systems are normally installed two metres deep and can require a fair bit of space depending on the size of the ground loop. Vertical systems require less space but can be more expensive to install as they require the drilling of bore holes. The image below shows a typical ground loop installed underneath a garden.

Water Source Heat Pumps

Like air and ground source heat pumps, water source heat pumps work in the same way, but they extract heat from rivers, lakes and ponds. In reality, and body of water that is heated by the sun can be used for a water source heat pump system. Water based systems are even more efficient than ground based systems as the rate of heat transfer is faster, meaning less electricity is used to extract heat. If you’re lucky enough to live near a moving body of water it can be even more efficient as the water that’s already had its heat extracted is continually replaced. Water source heat pumps are efficient during the winter unless the body of water freezes completely. Installation is usually less complicated compared to ground based systems that require digging or bore holes. For every 1kW of energy used by a water source heat pump, the system can extract 4-5kW of usable heat!

Funding for heat pump systems

SEAI offers grants towards the purchase of air, ground or water-source heat pumps. Homes built before 2021 are eligible. The home must also be well-insulated and have low heat loss. If not, the heat pump will not perform efficiently and you may see an increase on your energy bill. A technical assessment is required to ensure the home meets the requirements for a heat pump system and can be arranged with an independent SEAI Registered Technical Advisor. The technical assessment will outline any steps that must be taken before a heat pump can be installed, such as new insulation.

Heat pump grants are available under SEAI’s Individual Energy Upgrade Grant Scheme, or can be combined with a whole-home energy upgrade under the One Stop Shop Grant Scheme.


Heat Pump System Grant Amount (House)
Air to Water €6,500
Ground Source to Water €6,500
Exhaust Air to Water €6,500
Water to Water €6,500
Air to Air €3,500
Technical Assessment €200


Reduced grant amounts are also available for apartments. More information can be found on the SEAI website.

For those who wish to apply for a whole-home energy upgrade under the One Stop Shop Scheme, please visit the KORE Retrofit website for more information and to apply.