Passive house

The Passivhaus concept 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 energy certification standard.

The main criteria for certifying a building as passive house are:

  1. optimal high-efficiency thermal insulation.
  2. airtight construction, to prevent heat loss.
  3. absence of thermal bridges.
  4. optimal orientation.
  5. Controlled Ventilation System (CVS).

Sunthalpy follows these criteria for the design and construction of buildings adding its patented technology to capture and to actively manage solar energy. It covers then all the energy needs of houses, even in an Atlantic climate, enabling to make 100% solar and disconnected buildings.

Main differences: Sunthalpy house versus passive house

Passive houses have low energy consumptions but still need an additional heating source (boiler or similar) and they also require electricity power supply.

Sunthalpy designs each element of the building to work in a coordinated way (as is done in the automotive industry) enabling to use the building structure (or a swimming pool) as a free thermal battery. The result is an excellent energy performance, 100% solar power and fully sustainable.

Lower CO2 emissions

We compare below the CO2 emissions of two houses with 200m2, a Sunthalpy and a wooden Passivhaus.

A Sunthalpy house has more initial emissions due to the building materials used during construction but then in its daily operation generates zero emissions whereas the passive house has emissions due to its energy consumption for heating and electricity.

A Sunthalpy house generates less cumulative CO2 emissions than a wooden passive house after 12 years. After 50 years, typical average useful life of a house, the emissions of a Sunthalpy house are half that of a wooden passive house.

Chart by Visualizer

More solar energy collection and less need for electric batteries.

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

Patented Sunthalpy solar thermal collectors

Sunthalpy technology captures more energy from the sun using our patented solar thermal collectors. This thermal energy is used to heat the house and for domestic hot water (DHW). Passivhaus houses cover the thermal needs of the house with photovoltaics, so they need to install more panels, and many more electric batteries for storage.

The cost of these additional PV panels and electric batteries is much higher than Sunthalpy solar thermal collectors and the storage we achieve in the mass of the building or in the water of a swimming pool.

sunthalpy efficiency home

Better energy efficiency

A Sunthalpy house is much more efficient than a Passivhaus Premium (which is the passive house with the lowest energy consumption using photovoltaics energy and aerothermal heating) because Sunthalpy uses a low enthalpy emitter system (i.e. improved underfloor heating) to keep the house at 21ºC in all weather conditions (cold, heat, rain, high humidity, sudden changes in temperature, etc) with water in the radiant circuit between 20ºC and 22ºC

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

As a result of these two patented innovations, for each unit of electrical energy Sunthalpy delivers more than 9.5 units of thermal energy, whereas a Passivhaus with an aerothermal system and a standard radiant heating system can achieve only 3 units of thermal energy for each unit of electrical energy (from photovoltaic directly or from a battery).

Sunthalpy is therefore 3 times more efficient at converting electricity to heat or cooling therefore we need 3 times less electrical energy (directly from panels during sunshine hours or stored in batteries) than the best Passivhaus.

No need for additional cooling

Passive houses need to manage overheating, which can occur even in winter, as they are designed to maximise the capture and storage of thermal energy. Sunthalpy optimizes the energy management for all weather conditions significantly improving comfort by eliminating air conditioning and heating radiators.

Sunthalpy’s low enthalpy emitter (i.e improved underfloor heating) provides a uniform and more comfortable cooling using water at 20°C without any risk of condensation. Our system removes the draughts, dryness and health problems caused by air conditioning.


A fully disconnected Passivhaus is only possible in very sunny climates and using a large surface of photovoltaic panels with a lot of electric batteries. This implies a much higher cost than a Sunthalpy house.

Sunthalpy delivers 100% off-grid living that is more efficient and at a much lower cost by requiring fewer photovoltaic panels and electric batteries.

In addition, Sunthalpy technology has achieved something that was previously impossible even for the best Passivhaus (e.g premium): self-sufficient houses at reasonable prices in climates such as the oceanic/Atlantic and continental climates in Europe, as far south as Sweden (latitude 60ºN).

Sunthalpy technology transforms passive houses into the technological home of the future converting passive elements into active components that are integrated efficiently from an operational and architectural points of view.

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