HYSS - more than a heat pump!

Free Energy’s vision is to provide solar-based energy systems that can deliver all the energy that a building could need. That's why we have developed HYSS - a hybrid heating pump - the most cost-efficient and environmentally friendly heating system on the market.

Fact 1
A typical roof in Norway receives annually 4-5 times more solar energy than the household consumes in a year.

Fact 2
In less than 1 hour, the global solar radiation will be equivalent to Earth's annual energy consumption.

Fact 3
If 2 thousandths of Norway's land area were covered with solar collectors (efficiency 50%) and solar panels (efficiency 12.5%), it'll be equivalent to the country's annual energy consumption.

 HYSS - Hybrid Solar System - an innovative combination solution that utilizes solar heat and heat pump technology in an optimal way. HYSS can easily be configured into a geothermal pump, ground heating pump or watercourse heating pump, all of which can be combined with solar heating. It is also possible to combine an air outlet with a shorter ground loop or a shorter borehole. No matter what type of heating pump you have, performance will improve with solar heat, which means that you get a very efficient operating system. The solar heat provided, drastically decreases  the operating time of the compressor, which causes the heating pump to have a significantly longer service life. With an HYSS system you get 5-7 parts of heat and hot water for each part of electricity that the system uses.


This results in a shorter payback period of the system, because the solar collector's is being used for both hot water production and to increase the efficiency of the heat pump.

With HYSS you will get a complete heating system ensuring both heating and hot water and is suitable both for new buildings and renovation or replacement of existing heating systems.

HYSS is delivered with integrated measuring equipment allowing you to monitor the performance of the system both in real time (COP) and for longer periods of time (SCOP). With internet connection you'll automatically get the latest and best software available. Everything is designed to get the best experience with a modern iPad application leaving you in full control of your system anytime and anywhere.

HYSS - Best at sustainable heating

HYSS combining solar energy and heat pump technology in a unique way. HYSS has a ground source- or geothermal heat pump as basis which provides stable heat and works very well even if it is cold outside. HYSS is suitable for both new buildings, completion, or replacement of existing heating system. The HYSS heat pump is running quiet and has extra long lifespan because it is installed indoors. Installation is exclusively performed by authorised and approved installers. As HYSS utilizes the solar heat, the operating hours of the compressor decrease, which in turn increases the lifespan of the heat pump.

HYSS for larger buildings

HYSS-product range for larger buildings includes three sizes of inverter controlled ground source heat pumps along with a suitable number of solar collectors. All heat pumps are «solar-ready» with inverter controlled compressors which means they will adjust the effect automatically to the house’s heating demands.


HYSS - High Power is available in the following power range:

HYSS 11-45 kW
HYSS 17-60 kW
HYSS 21-87 kW

It’s possible to cover up to maximum 600 kW by cascading 6 units in various configurations. As a professional partner Free Energy provide access for you to an advanced, but easy, calculation program to find the right HYSS-system for any thinkable building. Please apply for partnership here: http://www.free-energy.com/en/become-a-partner#partnership-form

Operated by intelligent supervisor and accessories as well as HYSS unique user interface with online surveillance and control. Automatic software update is included for all heat pumps. HYSS - High Power product sheet can be downloaded here:

Option! If there is a demand for active cooling in addition to passive cooling it is possible to make add ons for all models. ModBus and HYSS Flexible are other possible options. Please contact your installer, or Free Energy, for further information – support.en@free.energy.com

References can be found here: http://www.free-energy.com/en/references

When is HYSS most suitable?

For you who want to replace your heat pump...

For those whom already have a heat pump but need to exchange it for a new heat pump. You might already have an existing borehole or a ground loop which can be reused, thus this investment has already been made. By choosing HYSS you get a heat pump with solar collectors, which beyond giving you free hot water large parts of the year, also provides better operating conditions for the heat pump throughout the year. Instead of investing in the ground you make an effort on the roof this time – an investment for the future. And the best part, solar energy is being received without any costs and the transformation phase to electricity and heat is completely eco- and climate neutral. Summer months sun-surplus may also recharge your energy well or ground loop. This relieves boreholes and ground loops which is too short and thereby loses parts of their energy content.

Those who have had heat pump know how great savings it can provide. Annual heat pump efficiency will approximately be doubled with HYSS (SCOP-Combi***). Pay-back period for solar heat can be decreased with 50% versus conventional systems. And most importantly, the need for supplied energy to the heat pump will decrease drastically.


***SCOP Combi = Seasonal Coefficient of Performance for room-heating and domestic hot water


For you who will build an energy-efficient house...

HYSS has the highest annual efficiency (SCOP Combi***) in the market and has achieved the highest energy rating (A+++) for both heating and hot water. This makes houses with HYSS capable of achieving very good energy performance without extensive isolation in roofs and walls. Even if the house's energy performance relate to current technical building regulations, the energy consumption, due to HYSS, will end at levels comparable to so-called passive houses (20-25 kWh/m2 per year).

If you want to increase the level of ambitions further, it is possible to construct a ground based seasonal storage (ASES*) for heat storage below the concrete slab of the house when building a new house. By storing excess heat from the sun during the summer months (to be utilized during the winter) the annual efficiency (SCOP) of the heat pump may become up to 8. This means for every kWh of energy supplied to the heat pump it will return 8 times in terms of heating and hot water.

*ASES = Active Solar Energy Storage
***SCOP Combi = Seasonal Coefficient of Performance for room-heating and domestic hot water

For you who love solar energy in all forms...

Solar energy is being received without any costs and the transformation phase to electricity and heat is completely eco- and climate neutral. For you who want to utilize solar energy to the maximum, HYSS is the obvious choice. The HYSS-system utilizes solar energy in a very efficient manner. Solar collectors are approximately 4 times as efficient as solar cells. Because solar energy doubles the heat pump efficiency you may achieve an annual efficiency up to 8. This makes the cost for heating- and hot water consumption extremely low. HYSS makes it possible to utilize solar heat in a totally new way in the Nordic climate. Solar heat may handle all heating and hot water consumption during the warmest months (4-6 months), but additionally the HYSS-system will benefit from the solar heat also during the coldest seasons. HYSS is assisted by solar heat to preheat the brine fluid from the solar collectors. As soon as the solar collectors get warmer than the brine circuit they will throughout the year contribute to increase the efficiency of the heat pump. Solar heat also provides a certain return of excess heat to the borehole or ground loop and can also be seasonal stored in a ground storage like ASES *.

*ASES = Active Solar Energy Storage

For you who care about the environment and climate...

Solar energy is the most environment- and climate-friendly carrier of energy available. No added resources are used in the transformation process and therefore it doesn't effect neither the environment nor the climate. A solar collector has considerably better LCC** compared to solar cells due to 4 times higher efficiency and moreover the manufacturing process is significantly less energy intensive.

**LCC = Lifecycle costs

For you who have short borehole or ground loop...

HYSS is especially interesting for you because solar heat will contribute in reducing the energy outtake from the borehole or ground loop. Replacing the heat pump will increase both effect- and energy outtake in many cases. As a result of increased energy outtake it is often necessary to either drill a new borehole or extend the ground loop, with all that implies both practical and cost-wise.

With HYSS this problem is eliminated. Solar heat and the inverter controlled compressor in the HYSS-system will compensate for the increased energy outtake. The solar collector’s additional costs can thus be compared with the cost of drilling a new borehole or extending the ground loop. HYSS has additionally the lowest operating cost in the market and improves the overall operating cost considerably.

For you who want lowest possible operating costs...

Solar energy is free and hard to claim ownership of. All energy provided by solar collectors is consequently free – in principle forever. The sun doesn’t send bills. HYSS utilize solar energy in a completely new way, and in far greater extent than earlier system solutions, and has definitely the lowest operating costs in the market. If you want lowest possible operating costs there are no doubt that you should choose HYSS.

For you who love the latest in technology...

Do you like the latest and most modern technology? Then HYSS is for you. HYSS’ software has the most user-friendly and modern user interface which makes it possible for you as a customer to monitor the performance of the system no matter where you are in the world. When you are at home the HYSS-system will show you all facility data on the provided iPad. If you are traveling, you will get similar information via your Smartphone or computer.

Your installer can remotely monitor and facilitate the performance, perform troubleshooting, calibrate sensors and, if necessary, make changes, adjustments and improvements. The software records, both in real time and over time, the heat factor for heating and hot water (SCOP-Combi***). At any time you can follow the facility's energy consumption, how much money you save and HYSS contribution in reduced CO₂ emissions. Controller functions can be expanded according to individual needs. Software is furthermore automatically and continuously updated. HYSS is simply the most modern and efficient heat pump on the market.

***SCOP Combi = Seasonal Coefficient of Performance for room-heating and domestic hot water

For you who have oil furnaces or paraffin stove...

Do you have oil-based central heating in your house or a paraffin stove in your living room? During a normal heating season a paraffin stove will emit as much CO₂ as a car does in a year. In average, this amounts to nearly three tons of CO₂. An oil-based central heating system emits twice the amount – over six tons of CO₂ per year. The smartest choice, for both environment and climate, is to replace them with HYSS. The benefit for you with oil furnaces is that you probably already have a distribution system for room heating in your house, either via radiators or hot-water heating in floors. Already you will achieve significant financial savings because you don’t have to remove your floors in order to install new water pipes or alternatively a new radiator system. HYSS will heat your house with clean renewable energy and additionally cover your need of hot tap water.

For you who want comfort cooling...

Indoor climate is important to us. As houses become better insulated, contemporaries as the climate seems to give us warmer summers, the need for comfort cooling increases.

All HYSS models offers both passive and active cooling. Passive comfort cooling (free cooling) is in principle free of charge and can benefit the building by supplying a single circuit with an exchanger and circulation pump connected to a separate cooling circuit in the building, e.g. ventilation system. Free cooling cannot be used for greater cooling demands than the naturally extraction from the borehole or ground loop.

At higher cooling demands, the cooling circuit in HYSS can be turned to produce active cooling. The active comfort cooling is energy efficient due to the high heat factor in HYSS. Comfort cooling can thus be used without major operating expenses.

The HYSS software is prepared for managing and distribution of cooling in the building. 

HYSS - a unique heat pump powered by the sun

Utilization of solar energy for heat pump efficiency is designed as an integrated part of the heat pump. That is why you will achieve very good operational economy without excessive investment costs.

Intelligent management of priorities for the use and storage of low, medium and high temperatures from the solar heat results in a higher annual efficiency (SCOP).

To heat and hot water, 7-8 months

High temperatures from the solar collectors are stored directly in the tank. For 7-8 months a year solar heating alone manages to heat the storage tank above 60ºC without supplementary energy from the heat pump. In this way, the solar heating provides virtually free hot water in large parts of the year which improves the annual efficiency (SCOP) for the HYSS-system. During the summer months the solar heating also contributes in decreasing operating hours of the heat pump.


Heat pump efficiency, all year

When the heat pump is operating, the solar heat preheats the brine fluid to increase the efficiency of the heat pump. A specially made inverter controlled compressor makes it possible to apply considerably higher temperatures than normally to the heat pump.

This contributes to a significant increase in heat factor (COP) for the heat pump. Along with free hot water the annual efficiency (SCOP) is being doubled for the HYSS-system compared to a conventional ground source heat pump.


Dumping / re-charging, all year

When the collectors has low working temperature or when the storage tank is fully heated, solar heat is being used to recharge the borehole or ground loop. In this way the temperature recovers in the energy storage faster and results in increased efficiency of the heat pump. High temperatures are simultaneously being avoided in the storage tank because the excess heat from the solar collectors may be dumped in the energy storage in the ground in a simple and secure way.

You can increase the performance in an existing borehole or ground loop with HYSS because the solar heat re-charges (dumps) the excess heat all year around. This means that you can utilize existing collector even if you install a more efficient heat pump with higher power output from the collector. Thus, the use of electric heating element is reduced to a minimum. It also applies if you have extended your house and increased your energy and output needs.

You save more money with solar heating and heat pump

HYSS utilize nature's best resources and here we will explain the interaction between solar heating and the heat pump.

Solar heat preheats the brine fluid* when the heat pump is operating to improve the efficiency of the heat pump. Considerably higher temperatures than normal is being used to the heat pump due to our inverter controlled compressor. This will contribute to a substantially higher annual efficiency (SCOP) for HYSS compared to conventional technology.

Free Energy have verified how much preheating of the brine fluid* constitutes:
Testing at Danish Technological Institute shows when brine temperature is increased by 10 degrees the heat efficiency (COP) of the system increases by 36 percent. If the brine temperature is increased by 20 degrees the heat factor increases by 98 percent.

*Brine is a glycol fluid in the closed system of the heat pump and HYSS-system.

Lower operating costs with highest energy rating A+++

Free Energy's inverter controlled heat pumps in combination with solar collectors has achieved highest energy labeling (A+++), for both heating and hot water according to current eco-design and energy labeling requirements which came into effect on 26 September 2015

Eco-design requirements and energy labeling are common to all EU countries and will facilitate energy labeling of heating products. Market surveillance is now being introduced to ensure that heat pump products meets current legislation within the EU's common market. Market control will protect consumers and ensure fair competition between manufacturers. NVE (The Norwegian Water Resources and Energy Directorate) supervises that eco-design and energy labeling requirements ar met in Norway. Products which doesn't meet the eco-design and energy labeling requirements cannot be traded within the European Economic Area (EEA). NVE may order correction or issue decisions about sales ban if illegal products with incorrect labeling is uncovered.

Free Energy's Hybrid Solar System (HYSS) achieves the highest energy efficiency rating for both heating and hot water in all of its three heat pump's in the villa market. The solar-circuit supplies heat directly to the water heater when the temperature is sufficiently high. The heat from the collectors is also used to raise the temperature of the heat pumps incoming brine for a large part of the year. In some cases heat is returned to borehole or ground loop. By utilizing solar heating where it provides the most benefit, the heat pump's SCOP-combi (heating and hot water) increases to 5-7.

You can monitor the system's instantaneous heat factor (COP) and the efficiency for longer periods (SCOP) through the supplied iPad. Software is automatically updated.

Complete control - anytime and anywhere

Managing your system from your smartphone, pc or the included iPad is one of the major advantages of HYSS.

Being able to monitor the system is not just to see everything working, but also to monitor that the system provides the savings as expected. With our specially developed application you can monitor live data, history and to have complete control of the system

Our application is web-based and you will receive software updates directly to your HYSS-app over the internet.

The application also feature functionality for your installer to perform adjustments and control of your system if necessary.


  Green, orange or red smileys clearly shows if your system is working fine.


The tab Operating displays your system's operating status and if the energy comes from solar collectors, heat pump or a combination of both. Samples of solar heating stored in the tank, solar heating as preheater of brine to the heat pump and solar heating stored in the ground.


You can also see the systems COP right now, SCOP (annual efficiency), split energy between the sun and ground including your savings and reduced CO2 emissions. The tab Compare energy displays the initial stored input of energy consumption and energy prices and more and is the basis for sizing and selection of system.

Click for a closer introduction to the management system.

HYSS-Flexible – extra opportunities included by default

HYSS – Hybrid Solar System offers the most modern software in the market, extendible almost to infinity. Here we present a few unique operating functions, which are pre-programmed and standard in HYSS’s software. Certain functions become available by adding a 3-way valve to the HYSS-System. Easy, reliable, cost efficient and flexible.

Solar collectors in different celestial directions

If the solar collectors are mounted in different celestial directions, there is an integrated controller function to regulate which group the heat is to be delivered from. In the morning the group facing east are prioritised, in the evening it’s the group facing west. At noon, when the sun is at its highest, the heat from both groups can be delivered simultaneously if the temperatures are sufficiently high. This enables maximum utilization of the solar collectors throughout the day. HYSS comes with software that handles this type of management.

Managing an additional heat source

An additional heat source can be connected to the brine circuit if desired. Managing an additional heat source is done via HYSS software. This can be a fireplace with water cap or an extractor module (FLM). Heat can either be lead directly to the storage tank or pre-heat the brine-fluid before it reach the compressor and in this way increase the heat efficiency. Any surplus heat may be returned to the borehole or ground loop.

Air-to-water, outdoor part

The HYSS system is designed to work with an outdoor air-part. The controller function in HYSS is pre-programmed for being able to combine an air-to-water heat pump with a shorter ground loop or bore hole if desired.

Passive and active cooling

Prior for connecting the pipe from the borehole to HYSS, it is possible to install a valve for passive cooling. Cooling is extracted from the borehole and can be distributed in the building by a circulation pump with low energy consumption. Cooling is normally distributed with a conventional ventilation system or via separate fan convectors.

For the smallest heat pump, power range 2.0 - 5.8 kW, it is possible to order an active cooling unit which makes it possible to cover greater requirements of cooling. HYSS 'software is prepared for managing cooling in the building.

Pool heating

It is possible to heat an out- or indoor pool with solar heat during the summer months without any notably operational costs. The solar heat's abundance during summer allows free heating of the pool in 3-4 months. By placing a sensor at the pools inverter, the integrated controller function will regulate the heat supply. The heat pump additionally contributes when the solar heat alone isn't sufficient to maintain the desired temperature level. This type of management is standard in HYSS’s software, also for pools being used all year round.

Floor heating curve in combination with radiators

Through a separate control-valve it is possible to get an additional heating curve. This is especially interesting for houses heated by radiators combined with floor heating in parts of the house. Instead of installing a complete shunt group for the floor heating, it only requires a circulation pump and a control valve for this function. HYSS has ready-made software for this type of management by default.

Managing additional storage tanks

HYSS can connect to several hot water tanks and/or accumulator tank in cases where increased capacity of heat storage and hot water outlet is desired. By using additional storage the compressor will run smoother while more solar heat can be stored and increase the back-up capacity. The HYSS software will monitor and control the storing. It even has a pre-programmed anti-legionella program for the additional hot water tank and also controls to- and decoupling of the peak load in the accumulator tank.

Seasonal storage of solar heat

HYSS can, with its controller functions, optimize the utility of seasonal stored solar heat. In combination with the Swedish invention ASES – Active Solar Energy Storage – solar heat can be stored from summer to winter. By using the pre-programmed controller function in HYSS, stored solar heat is maximally utilized. With this combination it is possible to achieve an annual efficiency of approximately 8, which means that 1 kWh energy will return 8 times more energy as heating and hot water.

Highest quality - best guarantee arrangements

Our choice of components is the result of many years of experience and thorough testing. We offer 10 years warranty on all main components *)

An investment in HYSS - Hybrid Solar System is sensible for both economy and comfort, but also for the value of your property. With 10 year warranty, the investment is often repaid during the warranty period. Solar collectors have a lifespan of more than 30 years and borehole/ground loop may in principle work forever. During this period, when the facility already is repaid, you still have the lowest possible operational costs and thus a good chunk of money to spend on other things in life.

HYSS is tested at Danish Technological Institute in accordance with EN14285. The result of the test shows that all HYSS heat pumps achieved the highest energy rating A+++  for heating. In accordance with the European directive for eco-design and energy labeling requirements HYSS has together with solar collectors achieved the highest energy rating A+++  for both heating and hot water.

Free Energy are members of the Norwegian, Swedish and Danish Solar Energy association. Our solar collectors are approved in accordance with SOLAR KEYMARK. Our heat pumps, storage tanks, circulation pumps (class A) and other accessories are CE certified.

*) applies for the heat pump compressor, 200 liter stainless steel storage tank and solar collectors.


HYSS – get your own zero-energy or plus-energy house

Solar energy enables zero-energy and plus-energy houses for both new buildings and existing buildings being renovated.

Future buildings will meet environmental challenges and there are many good reasons to choose an environmentally friendly housing. Better health (indoor climate), eco (reduced CO2 emissions) and economy (reduced costs of heating and hot water).

In the future all houses will probably be built as passive houses. Depending on how much energy the house consumes, but also produces, will determine whether it is classified as a passive house, zero-energy house or plus-energy house. Passive house means that it is well insulated, but additionally utilizes the heat from humans and technical equipments. A zero-energy house may have solar cells for production of electricity and solar collectors with heat pump for heating and hot tap water. This makes it possible for the house itself to generate the energy needed for household, heating and hot water. Plus-energy houses produces more energy than the household consumes annually by using solar cells and solar collectors  on the roof and (or) facade.



Dreaming of a zero-energy or a plus-energy house?

Then HYSS - Hybrid Solar System is for you. HYSS combine solar energy and heat pump technology, i.e.. a hybrid solution, in a totally unique way. This makes HYSS the most cost- and eco-saving system on the market.

With HYSS as nucleus reduces the need for solar panels by 60%