Air source heat pumps pay for themselves at least 5 times over their lifetime and can reduce heating and hot water bills by up to 80%

Incredible efficiency and savings

Installing an air source heat pump is one of the best routes to savings with amazing returns for home and building owners. For every 1kWh of energy consumed the heat pump can produce up to 5kWh of thermal energy. Our heat pumps typically pay for themselves within 3.5 years or even less if you receive government subsidies or a grant for the system.

Unit Combinations

The TermoPlus® air-source heat pumps require a combination of two units – an indoor unit and an outdoor unit. The indoor unit can either be a Hydrobox, which provides heating only, or a Hydrotank which produces both heating and domestic hot water (for showering, dishwashing etc.). The TermoPlus® air source heat pump range is designed to work with Mitsubishi outdoor units that provide both heating and cooling: either a Power Inverter unit or a Zubadan unit. The main difference between the two is that the Zubadan can operate in colder environments than the Power Inverter.

Why Mitsubishi Zubadan or Eco/Power Inverter?

Mitsubishi’s Zubadan series is the market leader for outdoor air-source heat pump units due to their outstanding efficiency and reliability. The Power Inverter is one of the most established outdoor units for newer homes and the Eco Inverter series is extremely efficient. For that reason TermoPlus® created indoor units that can make the Zubadan, Power Inverter or Eco Inverter an even better investment for homeowners. Our Hydrobox and Hydrotank ranges are fully compatible with the outdoor units but also fully customisable for a higher-performing installation. A Termoplus indoor unit with a Zubadan, Eco Inverter or Power Inverter outdoor unit make an unbeatable combination of efficiency and reliability.

The split series is the only one in the market with a heating power up to 14kW using R32 refrigerant also providing extreme protection against freezing. Some of the latest features include reversible functionality (which can be used for heating and cooling) and support for longer piping lengths (which makes them more flexible to place). The latest units are also ultra quiet and extremely efficient.

Guaranteed to last

TermoPlus’s very first heat pump built in 1984 is still fully operational. The minimum life expectancy of all our heat pumps is 25 years and they are covered by a 3+3 year warranty. This means that with a quick check-up every year you are guaranteed 6 years of absolute peace of mind. We’ll support our products for their entire lifetime and guarantee spare part availability. Find out more about the TermoPlus promise.

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Incredible efficiency and savings

With a heaterless design there is no power requirement for an electric heater. You will enjoy the same comfort without a heating element which would use more energy. The TermoPlus – Mitsubishi combination with energy efficient inverter technology delivers significant efficiency and unmatched real savings.

Flexible and compatible

The combination is suitable for floor, radiator and fan coil heating in new buildings or as a renovation of existing heating systems. The units can also work in conjunction with an external heat source such as a biomass, a boiler or a woodstove and take up very little space.

Optimized performance

Performance is boosted in our indoor units but not at the expense of compatibility – the original Mitsubishi weather compensated control is retained along with all features (see in detail below*). Switching between water and space heating is automatic and adequate capacity is ensured so that a storage tank is not required.

Constant availability

You will have uninterrupted hot water with our hydrotank as it uses an external large-surface condenser that  heats water up faster due to its larger heat transfer surface.

All-season use

The outdoor units can function at temperatures as low as -20°c for the Power Inverters and -28°c for Zubadans (with full heating capacity even at -15°c for the Zubadan).

Function-packed but easy to use

A multi-functional controller provides optimal management with programmes such as automatic anti- legionella, floor drying, holiday mode and a weekly timer.  Web control via app is optionally available and includes an efficiency monitoring feature. Two-zone heating is also available as an option.

Reliable and durable

TermoPlus units can operate  longer than others in harsher conditions due to their larger evaporator and optimized fin spacing and the Mitsubishi outdoor units have a proven record of reliability in tough conditions.

Long lasting and easy to maintain

Maintenance is easy to perform since all components are easily accessible. TermoPlus hydrotanks also feature complete anti-corrosion protection through the use of a top quality enamelled water tank with a build-in MG anode.

Quiet and unobtrusive

Both the indoor and outdoor units are both extremely quiet and compact. Using a TermoPlus hydrotank to replace a hydrobox / hot water heater also saves space and makes for a seamless, out-of-sight solution.

Maximum safety

All units run an automated anti-legionella programme even without an additional electric heater and by design the hydrotank uses an indirect heating condenser to prevent the risk of refrigerant leakage into sanitary hot water.

All original Mitsubishi control features are retained: Auto-defrost, automatic switching between DHW and heating / cooling, automatic anti-legionella program, control of external heating source , DHW and heating timers *, 2 zone control *, floor dry function*, monitoring of consumed and produced energy (COP)* , access via web and mobile app* , master for cascade connection*   (Features followed by * are optional)


Split heat pumps

Split heat pump systems consist of two separate units: an indoor unit and an outdoor unit.

The indoor unit contains the heat exchanger and the internal hydraulic system components while the outdoor unit contains the compressor, aircooled heat exchanger, inverter and the expansion valve. The two units are connected by refrigerant lines that transport the refrigerant between them.

Some advantages of our Split units:

  • Longer piping lengths allow for more flexible
  • Greater protection against the freezing
    temperatures. Due to the refrigerant
    connection, there is no chance of the system
    freezing, even in the event of a power cut.
  • The use of anti-freeze is not necessary, nor is
    the installation of additional heat exchangers.

Monobloc heat pumps

Monobloc heat pump systems house all the key components in the external unit and transfer the heat indoors without the use of a refrigerant line.The heated or cooled water is pumped directly into the internal unit which handles distribution.

Our Monobloc heat pumps are Fully Hydronic, which means they circulate refrigerant only within the external unit and use water to transfer heat inside. As a result, they offer distinct advantages:

  • Use of standard heating pipes between exterior
    and interior.
  • The system offers greater protection against
    refrigerant leaks and can be installed without a
    refrigerant-qualified engineer.
  • More flexible placement options for the
    outdoor unit due to the lack of refrigerant


Wi-Fi module

With the wireless adapter installed. the heat pump can be operated with the MELCIoud app even when you are not at home. The application enables control of the basic settings of the heat pump’s operation. Optionally, the amounts of heat and power can be monitored along with the efficiency of the heat pump.

Cascade operation

The cascade operation allows the connection and operation of up to six heat pumps into one heating system. Doing this can achieve a maximum heating power of up to 138 kW. This large amount of heating power is ideally suited for multi- apartment buildings, hotels, industrial plants and other business facilities.

Remote Control

The wireless remote control makes it easy to operate the heat pump from the comfort of your armchair. The device is portable and can be operated from any space without the need for wiring. The built-in sensor tracks the room temperature, constantly ensuring comfort.

Air Source Heat Pumps Web Control


The TermoPlus Hydrobox and Hydrotank units are compatible with specific Mitsubishi external units from the Ecodan, EcoInverter and Zubadan ranges. The corresponding Mitsubishi external units come paired as a standard bundle with the purchase of any TermoPlus air-source heat pump.

These unit combinations offer exceptional reliability, silent operation and great efficiency.


  • Housing: Vile Brtonigla

    In the small village of Brtonigla in the northwestern part of the Istrian peninsula, a series of eight properties was constructed by the developer, Tehnogradnje. Surrounded by olive groves and vineyards each villa is a premium realestate project with 4 en-suite bathrooms and a 40m² heated swimming pool.

  • Hospitality: Frui Diem

    In the quiet village of Draguzeti in Croatia, two-villas were developed as rental properties. Each villa has four bedrooms with en-suite facilities and their own outdoor swimming pool and heating system. The project’s goals were to offer great comfort levels while at the same time to reduce heating cots through a very efficient system. With the new system the estimated running costs per year are only between €500 - €700.

  • Retrofit: Šmarje Church

    The picturesque church in the small village of Šmarje in Slovenia required a subtle, unobtrusive heating system. Economy and reliability were a must so as to maintain a low running cost. More importantly, the heating system had to blend in with the interior of the restored church, maintaining the feel and atmosphere of the original structure.

  • Office Space and Residences: BB Investicije

    A building housing three residences and a consultancy office in Ljubljana needed a completely new heating and cooling system installed. Due to the different needs of each space and an underlying requirement for efficiency a more complex system was designed and installed. The required objective was to achieve optimal comfort with low running costs (between €1.500- €2.000 annually for all thee residences and the office together).

  • Hospitality: Villas Adagio

    Located in the heart of the Istrian peninsula between Pula, Rovinj and Rabac, Villas Adagio is a 9-house villa rental complex. Client comfort was of paramount importance to the property owners.

  • Heat Pump in Hotel Kovač

    Hotel: Kovač B&B

    B&B Kovač is a 20-room hotel with a restaurant located in Portorož, Slovenia. The hotel used to be heated by an oilfired boiler and radiators. Domestic hot water (DHW) was prepared in two 300 litre DHW heaters (V= 2x300=600 litres).

  • Hospitality: Villas Bonada

    Situated in a small picturesque Istrian village Ruzici, a few kilometres from the Istrian coast, Villas Bonadais a settlement comprising of 3 rental villas with independent swimming pools. The facility owners initially planned to heat the new villas solely through air conditioning units. Due to the shortcomings that this would entail in comfort levels and long-term economy they opted for a hybrid heat pump system instead.


Your savings depend on many factors such as your local fuel cost, how much heating you require and what other systems are in place. Let’s consider an example of a 200m² house with average insulation and underfloor heating. With the existing heating system an estimated annual requirement of 2700lts of heating diesel at a current estimated cost of €0,9 per litre would result in a yearly cost of €2.430. If this same house switched to a TermoPlus Hydrobox / Zubadan combo with an annual consumption of 5450kWh, the annual cost would be €709 assuming a rate of 0,13 EUR/kWh. That would be an annual saving of €1721 which over the 25 year life of the product would amount to €43.025 and that isn’t even taking into account the expected rise of fuel costs.

Besides the above savings from the use of our air-source heat pump installation you would also have the additional savings from lower domestic hot water heating costs.

Your hot water savings depend on many factors such as your local cost per kWh, how much hot water usage you require, and what other systems are in place. Let’s consider a conservative example of a 5 inhabitant home with a local kWh average cost of €0.13 With an average power consumption using a standard electric hot water boiler, the annual consumed power of 4500 kWhs would cost €585. With a TermoPlus Hydrotank the consumption would drop to 1100 kWhs annually costing €143. That would be an annual saving of €442 which over the 25 year life of the product would amount to €11.025, and that isn’t even taking into account the rising cost of electricity. If the cost per kWh was €0.29 as it was for an average household in Germany in 2016, the annual savings would be €986 and the lifetime savings would amount to €24.650.

Our air source and domestic hot water heat pumps are extremely easy to maintain and have very low maintenance costs. Our units only require a single annual quick service where we ensure everything is working correctly and efficiently.

Our heat pumps can installed in both new buildings and older buildings . The units can work with underfloor heating, radiators and fan coils alike. The hydrotank can replace or upgrade existing hot water facilities.

Our air-source products can be combined with an existing heating boiler, biomass or woodstove.