Innovation provider

Green Idea Ltd


Kalle Riepulk
Serva 3
+372 502 4294


The heat exchangers regenerate heat energy from wastewater, e.g. from that of shower, bath and washing machines. Warm wastewater flows over the heat exchanger unit and preheats cold water, which can be fed to the shower or into water heater. Heat is transferred from wastewater to cold water through the wall of heat exchanger unit made of special copper.
HeatEco 60 is able to save up to 60% of warm water (according to tests carried out by the company). It can be installed under the shower bath, regular bathtub, under the ceiling, on the wall or in the floor.
HeatEco 30 suits best in locations, where the water consumption is higher than in small households. Different water supply systems (showers, washing machines) can use the same HeatEco 30 heat exchanger unit simultaneously.  


Since heat is transferred from wastewater to cold water through the wall of heat exchanger unit, the consumption of hot water and energy is reduced up to 60%. The cold water temperature rises from ca 9 °C to 24‐28 °C (15-28 °C depending on the model and installation of the heat exchanger) at the wastewater temperature of 37 °C and flow rate of 9 l/min. It corresponds to the energy saving appr. 9.5 kWh. The water heat recovery system pays off within 3,7 years (in condition the household uses water 30 minutes per day where the heat exchanger is installed).
When taking a shower (30 min) without using the heat exchanger system, 145,1 litres of hot water is used. At the same time, taking shower with the system of heat exchangers, 67,5 litres is needed.

Innovative aspects (ecologic, social and economic)

Environmental aspects
The water heat recovery system reduces hot water and energy consumption up to 60%. Furthermore, it indirectly reduces CO2-emissions. 1-2kg of CO2, which would have been needed for producing electricity, is stopped from being emitting with every shower.

Application examples

HeatEco 60 and HeatEco 30 are both suitable in private houses and commercial application. A number of heat exchangers have already been installed in Germany, Finland, Sweden, Netherlands, Austria and Ireland. 


IImplementation of HeatEco60 and HeatEco30 is low-priced and similarly, their maintenance costs are low. The retail price is approximately 500 EUR.


Current stage of development

Exported to other countries 

Ongoing development and laboratory testing of new innovative models will provide wider usage/installation possibilities and more maintenance-free models.

Intellectual Property Rights

Patent granted
Patent granted in Estonia and Finland, Patent applied for in Germany, Austria, Denmark

Country of origin


Country of application



National Contact Point

Antti Roose
Tartu Ülikooli, Geograafia Osakond
Vanemuise 46
51014 Tartu

Tel: +372 737 6841
Fax: +372 7375825