Ground source heat pumps

Using heat from the ground  

Looking for alternatives to a gas boiler? You’ve likely heard the term ‘heat pumps’ used when researching alternative heating appliances, and you may be intrigued as to what a heat pump is and whether you should get one for your home. Well, Viessmann’s ground source heat pumps are a great way to heat your home in a more sustainable, green way.  

What is a ground source heat pump?

A ground source heat pump is a more renewable, eco-friendly way of heating your home. Using geothermal collectors or geothermal probes and an electricity supply, they gather natural heat from the ground surrounding your property and use it to provide your home with heating and hot water. As ground temperatures stay fairly constant throughout summer and winter, they can work year round and even provide cooling in summer.

For most ground source heat pumps, there are two ways the natural heat can be accessed - either from open loop or closed loop circuits.

Within the closed loop category, there are two further variants - horizontal ground loops and vertical boreholes. All of Viessmann’s ground source heat pumps can be used in both open and closed circuits .

Ground source heating and cooling systems are becoming increasingly popular as people look for more environmentally friendly energy solutions for their homes. By harnessing natural, renewable resources, ground source heat pumps and cooling systems can help you cut your carbon footprint and bring your energy bills down. You could further reduce your home’s emissions by choosing a setup that allows the pump to be powered by other renewable energy sources, such as photovoltaic solar panels.

What are the benefits of ground source heat pumps?

So many people are choosing to switch to heat pumps because of the benefits of this type of system. You can find some of these listed below.

• Environmentally friendly
  

Heat pumps can harness the natural heat in the ground to heat your home, using electricity to help them along a bit. This makes them more environmentally friendly than their gas counterparts, but it should still be noted that electricity can be created through burning fossil fuels. You can make your heat pump even more friendly to the environment by using it alongside solar panels or energy generated from other renewable sources.

• Energy efficient
  

Heat pumps are more efficient than gas boilers. In fact, it’s thought that whereas gas boilers are around 95 per cent efficient, heat pumps can be over 400 per cent efficient because for every unit of electricity used, around four units of heat are generated and used.

• Provide cooling as well as heating

Unlike a boiler, which only has the ability to heat your home, a heat pump system can cool your home, too, by working in reverse.

• Eligible for grants
  

Homes that have a heat pump installed are eligible for the  boiler upgrade scheme (BUS).

• Reduce energy bills
  

While electricity does cost more than gas, we’ve previously calculated that a heat pump could actually cost less to run each year than a gas boiler, so you can reduce your annual heating bill.

• Come with a warranty

All Viessmann’s heat pumps come with a standard warranty of two years, however this can also be extended if installed by a registered Viessmann installer.

• Work even at low temperatures

If you’re concerned that a heat pump can’t generate enough heat when outside temperatures dip below zero, don’t worry. They can gather heat even when it’s as low as -20 ℃ outside, so more than adequate for the UK climate.

• Low maintenance
  

Heat pumps are easy to run, don’t rely on any fuel deliveries and just require an annual service to ensure they’re working safely and efficiently.

Given these advantages, it’s not hard to understand why this technology continues to grow in popularity across the UK.

How does a ground source heat pump work?

As mentioned, a ground source heat pump gathers heat from outside and brings it into your home. It does this via pipes that are filled with a heat transfer fluid and laid in the ground. This heat is then transferred to a refrigerant which boils at a low temperature evaporating to a gas.

The gas can now be compressed to increase its temperature even more, raising it to a level where it can be used to heat your home. This is done in the condenser heat exchanger. As the gas heats the water, it cools down, causing it to condense back into a liquid refrigerant. The whole process then starts again.

Viessmann’s heat pumps and geothermal cooling systems use the most advanced technology to make the appliance work as quietly as possible, while also optimising its lifespan.

You can find our video on how a heat pump works here, as well as additional information. 

How efficient are ground source heat pumps?

Viessmann’s ground source heat pumps have a Coefficient of Performance of between four and five, making them more efficient than a gas boiler. 

What is Coefficient of Performance (COP)?

COP is a way of measuring the efficiency of a ground source heat pump. In simple terms, it tells us the amount of energy that needs to be input in order to obtain a set amount of energy that comes out. For example, a heat pump with a COP of four would tell us that for every one kilowatt (kW) of electrical energy used, we would get the equivalent of four kW of heat out.

What size ground source heat pump do I need?

As with any heating system, it’s important that you get the size of the system right for maximum heat transfer without using too much energy.

Heat pumps come in a range of sizes from around 4 kW to 15 kW for residential use, and the size you need will depend on the potential heat loss of your home as opposed to the size of your existing gas boiler.

An expert will need to come to your property to work out how much heat is lost from your home. This is because the heating installation will be sized to counter the loss of warmth from your property and to ensure that the heating needs of your home are met comfortably even on a cold day in winter.

Heat pumps are best located in homes that have excellent insulation and minimal heat loss. A competent MCS accredited heating installer will be able to assess this for you.

How much noise do ground source heat pumps produce?

One of the main worries about heat pumps is the amount of noise they make, but with adaptations in technology, they’re actually not that loud.

Ground source heat pumps are slightly quieter than air source heat pumps, which is good as they’re located indoors. They’re thought to reach around 40 to 50db. This is relatively quiet when you consider the average dishwasher is around 50 to 60bd and a vacuum cleaner around 70db.

Our compact, floor-standing heat pumps take up little space and are particularly quiet when in operation, making them suitable for installation in a range of places, including near living spaces.

How to install a ground source heat pump

When installing a ground source heat pump, there are some things to consider, including:

• Whether you will use bore holes or a horizontal ground loop
• Whether the system will be connected to solar panels
• Where the indoor unit will go
  
  

Once an installer has conducted an on-site survey (including an evaluation of the hydrology and geology of the soil on your land), they will be able to advise you on the best system for your property. This may include a horizontal or a vertical ground loop, depending on how much space is available. Boreholes are better for homes that don’t have a lot of surrounding land. The installer will also advise on the best heat pump and energy distribution system for your home.

The installation itself usually begins with the ground loop, and the pipes and connections will be tested once in place. Then, the installer will begin modifying the pipework. If necessary, they may recommend replacing or upgrading your existing radiators or underfloor heating. The heat pump will then be installed and connected.

When the whole system is in place, it will be flushed and tested to ensure everything is operating correctly. If the installer is happy with the results, they will hand the system over to you, demonstrating how to operate it and check its health. It’s important to make sure you take all this information on board as this will help you to get the most out of your new eco-friendly heating solution.

Who should I get to install a ground source heat pump?

When looking for an installer to fit your heat pump, it’s important that you use a properly accredited professional who is Microgeneration Certification Scheme (MSC) approved. This is vital if you want to qualify for the RHI grant.

It’s also recommended that you get a number of quotes before making a final decision, and you may want to read customer reviews or ask for references from owners of systems that are a number of years old.