Is geothermal probe heating the right option for my property?

Need some help finding a cheaper and more energy-efficient way to heat your home? Look no further than geothermal probe heating: the Tesla of heating system solutions. Read on for more details of the basic requirements, costs and how to install systems like this in the following expert article to help you choose.

26.09.20235 min5'

Heating installer explains the new ground source heat pump to the homeowner

Gone are the days of Mars probes; now it’s all about geothermal probes - geothermal probe heating systems to be precise. There are numerous reasons why such systems, also known as brine-water heat pumps, are among the hottest heating solutions of our time. Growing environmental awareness, the climate and energy crisis and - last but not least - scope to boost your household budget a little.

Warming your four walls with a geothermal probe heating system is one of the most eco-friendly and energy-efficient ways to heat a property there is. Systems like this help hedge homeowners against energy market pressures and ease their conscience when it comes to the environment. So as well as saving money, you can also feel good knowing you’re doing your bit to combat climate change.

We explain the context behind the process in this blog article and exactly how it all works. Hrvoje Baric, Head of Heating at MZ Sanitär + Heizung AG, joins us to highlight the pros and cons of geothermal probe heating, the costs involved and how to proceed with your choice of set-up.

How it works

Geothermal probe heating systems are a type of heat pump, which means by nature, they extract heat from the environment. In this particular set-up, the process occurs deep within the Earth, at a depth ranging from 10 to as many as 250 metres below ground, where temperatures remain stable year-round. A geothermal probe installed at the bottom collects thermal energy, which is then conveyed into the property via a water-glycol mixture. This process causes a special refrigerant in the heat pump to evaporate. The resulting refrigerant vapour is then compressed by the heat pump, further boosting the temperature that can be supplied to the home’s heating system and heating up the water heater. And that, more or less, is how you get your toasty-warm home!

This type of heating is not as energy-hungry as you’d think: only the heat pump boosting the temperature extracted from the ground needs power. Conventional electric heaters meanwhile need electricity to heat the water from zero, which consumes far more energy.

Requirements when establishing a geothermal probe heating system

Several factors dictate whether geothermal probe heating is also suitable for you. First and foremost, check out your local area heat map. This simply involves entering your address or plot number to determine whether geothermal probe heating will suit your property. You can usually find the heat map on your local canton or municipal website. Here is the Heat Atlas of the Zurich canton for example.

When it comes to constructing a geothermal probe, most cantons require you to obtain planning permission or drilling permits. Check the specifics with your local council. If planning permission is needed, you’re best off running the project past your neighbours beforehand, as any objections they raise could slow things down. However, if only a drilling permit is required, your neighbours have no say in the matter.

Another key thing to consider is the available space on your property. You can’t just make a hole anywhere - drilling has to be at least four metres from your neighbours’ property lines and the minimum distance between two geothermal probes is eight metres. Placing probes too close together could extract too much energy from the ground. Another thing to make sure of is sufficient basement space to accommodate the heat pump equipment. Boilers, buffer tanks and other components can take up as much as eight to ten square metres. Drilling machinery will also temporarily require space on your property – about 15-20 square metres for the machine, rods and container. If you can’t easily get the machinery needed to the drilling site, crane transport is another option although quite a costly one.

Another thing that can rack up the costs is the depth at which you’re drilling, which, in turn, depends on the property energy requirements. The deeper the geothermal probe, the greater the energy yield. As our expert, Hrvoje Baric, explains: “The exact depth of the drilling depends on the amount of energy needed. For a single-family home with average energy needs, the probes are typically placed at a depth of 180 meters or so.”

The final factor that could hinder efforts to get a geothermal probe installed and ready is the insulation of your home. Poor insulation will mean the heat pump having to generate more energy. Hrvoje Baric advises: “For older buildings with heating systems that require a high flow temperature for radiators, i.e. very hot water at around 55-60 °C, geothermal probe heating isn’t suitable. In cases like these, the amount of electricity required to heat the energy extracted from the ground makes the operation uneconomical.”

Costs

Geothermal probe heating has some financial sustainability advantages over traditional oil or gas heating systems. But despite being relatively affordable to operate, the initial investment for the purchase and installation can be quite hefty.

One of the key cost drivers here is how deep you actually have to drill. As a general rule, the deeper the drilling, the deeper the hole in your wallet. Including permits and assessments, you can expect drilling and installation to cost around CHF 20,000, as well as actual purchase costs. According to our expert, for an average single-family home, initial costs in the region of CHF 50,000 to 70,000 for a geothermal probe heating system are the norm.

This might not seem like a bargain, but cantonal funding programs can make the outlay a little wallet-friendlier. Depending on where you live, you could receive up to CHF 20,000 in grants. But that all depends on you applying for these funds early on, before embarking on the construction phase! So be sure to research which funding programmes are available in your canton as soon as you can.

Once the hole has been drilled and the geothermal probe heating is installed, the savings start. The only post-installation operating costs you have to consider are the costs of powering the heat pump. Precisely how high they are depends on the annual working factor of your selected heating model and your home energy budget. But as a general rule, geothermal probe heating is one of the most efficient ways of warming your home.

Our expert sums it up: ”The long lifespan of geothermal probe heating systems helps put the high initial costs into perspective. A geothermal probe heating system has an average lifespan of 50 to 100 years. Depending on how much energy you consume, a geothermal probe heating system can pay for itself compared to an oil or gas heating system within 15 to 20 years or so. The basic principle is: the lower the flow temperature of your heating system, the faster you amortise the costs.”

Advantages and disadvantages of geothermal probe heating

Here once again are all the key facts at a glance:

Disadvantages

  • High initial investment

  • Installation may be infeasible in certain cases. It depends on available space, distance to neighbouring property and ground conditions

  • Several permits and authorisations required

Advantages

  • Environmentally friendly and low-emission heating

  • High energy efficiency

  • Inexhaustible energy supply

  • After drilling, you can still plant or build on the garden unhindered

  • Low operating costs

  • Noiseless in operation

  • Subsidies obtainable

  • Passive cooling is possible. In summer, you can reverse the set-up, whereupon a portion of the heat in your home will be dissipated into the borehole heat exchanger. However, this cooling capacity cannot be compared with the performance of an air-conditioning system.

Your step-by-step guide to geothermal probe heating

So you’ve decided to take the plunge and go for geothermal probe heating. Here’s your roadmap to get your very own system up and running:

  1. Check the cantonal heat atlas (also known as the geothermal probe map or suitability map for heating). Is geothermal probe heating possible on the land you own?

  2. If necessary, have a geological survey carried out by an environmental consulting firm.

  3. Start planning with your planner and heating company of choice.

  4. Obtain building and drilling permission from the and always inform your neighbours! Note that it can take a few months before the permit is granted.

  5. Apply for the right funding. You may end up drowning in paperwork and possibly also have to fork out. But it’s always worth it in the end, so do allow enough time for this step.

  6. Await confirmation of the building permit and approval of the subsidies, then you are ready to go.

  7. After commissioning, the subsidies will be paid out.

  8. Have your heat pump serviced once a year by a certified heating engineer.