VSi ground source heat pumps

Certified quality from Scandinavia

Trouble-free operation and increased self-reliance


VSi is compact, quiet heat pump solution that fits neatly into a utility room or similar space. The heat pumps have been awarded the best A+++ energy classification and carry the EHPA QL quality label. Part of the Oilon and Lämpöässä ground source heat pump range, VSi units offer the largest storage tank (230 l) in their size class. Combined with our unique superheat technology, the large tank ensures that you’ll have plenty of hot water even for long showers more self-sufficiently than ever. The heat pump comes with an exceptional array of accessories preinstalled, saving you from unexpected extra costs and making installation quick and easy.



  • An EHPA Quality Label product: The first range of heat pumps in Finland to receive the EHPA Quality Label (EHPA QL), a quality label provided by the European Heat Pump Association.
  • Safe choice: Long factory warranty combined with excellent Finnish craftsmanship.
  • Maximize your savings with unique technology: The heat pump uses only geothermal energy for space heating and domestic hot water production all year round.
  • Compact: Dimensions based on Finnish modular design guidelines ensure that the unit will fit and blend in well with cabinets, for example.
  • Control for three heating circuits: Split different areas (such as wet areas) into their own zones for temperature control, or control your domestic hot water circuit. Optional accessory.
  • Easy-to-use and clear control system: Developed in Finland, the ÄssäControl system provides a clear interface for controlling your home’s heating anywhere.
  • Extensive scope of delivery: Thanks to the extensive scope of delivery, there will be no unexpected extra costs and installation is quick and easy.


Applications: buildings up to 300 m²


VSi ground source heat pumps are easy to use


The ÄssäControl system used in VSi heat pumps has a clear touch screen with versatile function shortcuts, making it easy to control your heat pump. If required, you can even monitor and control your heat pump with a mobile device. Remote control for the geothermal heating system is provided as an option.

To read more about ÄssäControl, download our brochure:



Or watch the video:


The most economical cooling solution


All Oilon and Lämpöässä ground source heat pumps can be equipped with ÄssäCooling units, allowing you to cool your home during the summer months at a lower cost than any other system.


Unique superheat technology


Fine-tuned over several decades, our superheat technology enables your heat pump to produce domestic hot water as a side product of heating, making your system exceptionally self-sufficient. Thanks to our advanced superheat technology, domestic hot water is heated up to the required level 100% with geothermal heat. Consequently, if you select the heat pump’s heating capacity based on the coldest winter day, the heat pump’s electric immersion heater will never be used in normal operation. Your heat pump will be able to provide space heating and produce domestic hot water at the same time, meaning that your home’s heating won’t be shut off even if you take a warm bath.



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Heat pumps are dimensioned and priced individually according to the installation site.
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Sales contact information

Aarnio Markus

Markus Aarnio

Sales Manager
p. 044 7576 411

Laaksonen Mikko

Mikko Laaksonen

Sales Manager
p. 044 7576 288

Petri Virta

Export Director,
Ground Source Heat Pumps
p. 044 7576 259