Efficient homes: Passive house and Sunthalpy

Passive house

The concept of Passive house emerged in the late 1980s in Germany. A few years later, in September 1996, the Passivhaus Institut (IPHA) was founded with the aim of promoting and regulating this standard of energy certification in efficient homes.

The main criteria when certifying a construction as a passive house are:

  1. Maximum effective thermal insulation.
  2. Watertightness, to prevent heat leakage.
  3. Absence of thermal bridges.
  4. Appropriate guidance.
  5. Controlled Ventilation System (SVC)

Sunthalpy follows these criteria for the design and construction to which it adds its own patented technology, which allows the capture and active management of energy from 100% solar origin. We cover all the energy needs of homes, even in an Atlantic climate, being able to create self-sufficient and disconnected buildings.

Main differences: Sunthalpy house versus passive house

Although with low consumption, a passive house still needs an external heating contribution (cald or similar) and be connected to the electricity grid.

Sunthalpy designs each of the elements so that they work in a coordinated way (as is done in the automotive industry) since our technology allows us to turn the building’s own structure (or even a pool) into a free thermal battery. Thus, the result is excellent energy efficiency, 100% solar and sustainable.

Fewer CO2 emissions

Next, we compare CO2 emissions between two 200m2 houses, a Sunthalpy and a Passive wooden house.

The Sunthalpy house has more initial emissions due to the construction materials used but then in its daily operation it does not have any emissions while the Passive house has emissions due to its heating and electricity energy consumption.

Sunthalpy has fewer accumulated CO2 emissions than a Passive House at the age of 12. In 50 years, useful life of a typical home, the emissions of a Sunthalpy house are half that of a Passive house.
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Greater uptake of solar energy and less need for electric batteries

A passive house with photovoltaic panels captures approximately 20% of solar energy (conversion of solar energy to electricity in photovoltaic panels), while a Sunthalpy is capable of capturing 80% of solar energy (20% equal with photovoltaics and the remaining 60% as solar-thermal energy that we store in the structure of the building and/or pool). That extra 60% of energy captured and stored in thermal form reduces the need for electrical storage (necessary to meet subsequent thermal demand)

Patented Sunthalpy solar thermal sensors

Sunthalpy technology captures more energy from the Sun thanks to our patented solar thermal collectors. That thermal energy is used to heat the house and domestic hot water (ACS). Passive house houses have to meet that thermal need of the house with photovoltaics, so they need to install more panels, and many more electric batteries for storage.

The cost of photovoltaic panels and additional electric batteries is much higher than Sunthalpy solar thermal collectors and storage in the mass of the building or in the pool water.

solar house
solar house

Better energy efficiency

A Sunthalpy house is much more efficient than a Passive Premium house (Which is the lowest energy consumption classification of Passive house and uses photovoltaic and aerothermal energy) because Sunthalpy uses a Low enthalpy emitter system (enhanced radiant floor) That allows the house to be heated to 21oC having the temperature of the radiant circuit water between 20oC and 22oC, in any outdoor weather situation (Cold, heat, rain, high humidity, sudden changes in temperature, etc.).

In addition, we also use the same emitter system to capture excess radiation and accumulate energy efficiently.

Thanks to these two patented innovations, for each unit of electrical energy Sunthalpy is capable of obtaining more than 9.5 units of thermal energy, while a Premium Passive house is capable of obtaining only 3 units of thermal energy for each unit of electrical energy (photovoltaic directly or battery)

Sunthalpy is, therefore, 3 times more efficient converting electricity to heat or cold, so it needs 3 times less electrical energy (directly from panels in hours of Sunshine or stored in batteries) than the best Passive houses.

No need for additional cooling

Passive houses need to manage overheating, which can happen even in winter, since they are designed to maximize the capture and maintenance of thermal energy. Sunthalpy carries out energy management optimized for all weather conditions and substantially improves the comfort of air conditioning by dispensing with air conditioning and heating.

The Sunthalpy low enthalpy emitter (enhanced radiant soil) can refrigerate in a much more comfortable and uniform way using water at 20oC without any risk of condensation. Our system prevents drafts, environmental dryness and health problems generated by air conditioning.


A totally disconnected Passive house is only possible in very sunny climates and using a larger area of photovoltaic panels with many electric batteries. This implies a much higher cost than a Sunthalpy house.

Sunthalpy allows you to live 100% disconnected from the electricity grid more efficiently and at a much lower cost by needing fewer photovoltaic panels and fewer electric batteries.

In addition, Sunthalpy technology has achieved something so far impossible even for the best Passivhaus (premium certificate): self-sufficient houses at reasonable prices in climates such as oceanic/Atlantic and continental in Europe, even in southern Sweden (lateness 60ºN).

Sunthalpy technology allows passive homes to be converted into the technological home of the future, where previously passive elements become active but efficiently integrated from an operational and architectural point of view.

In short, Sunthalpy is an evolution of the best Passive House technology.

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