Passive building: the cheapest energy is the one that we do not consume

Example for gas: heating and hot water in an apartment between 70 and 80 m²

The Energy Regulatory Commission (CRE) estimated, from the Wattissime calculator (cited in the journal Capital), that a couple living in an 80 m² apartment in Lyon would see their gas bill for heating and hot water to increase from € 93,50 per month to € 144,65, i.e. an increase of € 51,15 between January 2021 and October 2021 (+ 54,7%).

In a passive building: The low additional heat required to heat passive apartments is often provided by a collective mini-boiler room supplied with gas. For a passive apartment of 70 m², a recent survey^[1] covering 700 passive housing units built between 2010 and 2018 shows that the average household expenditure for their heating and hot water is only € 20,83 per month. With the same rate of increase, this expense could increase to € 32,30, or an increase of € 11,47 per month ...

Example for heating and hot water in a detached house

The Energy Regulatory Commission (CRE) also estimated that a household with two children living in a 120 m² house in Rennes would see its gas bill for heating and hot water drop from € 136,88 per month to € 217,38, an increase of € 80,50 (+ 58,8%).

The average energy bill for French housing is € 134 per month (source Ministry of Ecological Transition) for an average surface area of ​​101,8 m² (source Eurostat), or € 1 per year, which amounts to € 608 per m² of living space and per year, ie 15,8 times higher than for a passive house!

Indeed, for passive houses: Most passive houses use electricity and do not need gas, which requires an additional subscription since electricity is essential anyway. Also passive houses are heated with an electric back-up sometimes associated with a wood stove.

The average consumption of passive single-family houses is 3 kWh for a surface area of ​​950 m² (sample of 142 passive single-family houses)^[2]. This consumption includes all the uses of the home (including audiovisual devices, computers, household appliances) and represents an expenditure of € 67 per month (€ 52,7 of consumption and € 14,3 of subscription), i.e. 804 € per year, which amounts to 5,7 € per m² of living space and per year.

If we consider only the heating, the real heating expenditure of a passive house of 100 m² is on average 220 € per year and we have met many owners of passive detached houses who only spend 1 euro on heating. per m² and per year, or only 100 € per year !!! (compare to € 15,8 per year for the national average).

Passive buildings: the real price shield for energy, with in addition a guarantee of comfort and indoor air quality

According to the government, the price of electricity should increase by 4% in February 2022. Increases in the price of energy will only impact occupants of passive houses very marginally, less than € 3 per month, all uses included. !!

Passive buildings (apartments, houses but also offices, schools, etc.) are very energy-efficient buildings: they consume two to three times less on average than a recent building and are much less subject to changes in energy prices .

Their energy performance is guaranteed by engineering which designs very well insulated buildings, eliminating almost all thermal bridges and ensuring optimal airtightness (4 to 6 times better than the most recent conventional buildings) while respecting hygienic principles (air renewal)^[3]. Double flow ventilation ensures good indoor air quality (particularly important for good learning in schools).

This is why passive buildings provide comfort (which sometimes surprises visitors) both in housing and in the tertiary sector (school, office, retirement home, etc.) with an absence of cold walls and drafts ( the temperature is almost constant in all areas of the accommodation) and temperature stability, including summer (with good management of solar protection during summer periods). The passive building avoids the need for air conditioning (or greatly reduces them in tertiary buildings).

Its main constraint is that it cannot withstand poor workmanship and design errors, otherwise it loses efficiency and it is then necessary to compensate by additional energy consumption (which is also the lot of conventional buildings!) .

In France, several thousand buildings reach the passive standard (labeled or not) and contribute to the State's commitments to reduce building energy consumption by 50% and greenhouse gas emissions by 84%. greenhouse buildings by 2050.

Passive labeled buildings represent a constructed area of ​​274 m², of which around half are housing and the other half are tertiary buildings, public or private, for a total of 000 operations. 380 m² are in the process of being certified by La Maison Passive France.

If the liability is now well known in new construction, it also has its place in renovation strategies^[4]. Energy renovation operations pursue two major objectives: preservation of the environment and control of energy expenditure (or charges). Passive renovation consists in "exhausting the source", that is to say in optimizing the levels of insulation of the building envelope, in valuing the internal and solar contributions and in guaranteeing a good level of airtightness. building air. And, as the US Passive House puts it so well, “We have the tools. We have the knowhow. We have the passion. We can do this! "

The characteristics of the “classic” Passive Building Label

New labels have recently been put in place to favor the choice of renewable energies for passive buildings (Passive Building Labels PLUS and PREMIUM), with a view to energy transition and the fight against global warming.

[1] Philippe Outrequin, Rental charges for passive social housing, March 2021

[2] Catherine Charlot-Valdieu and Philippe Outrequin, Passive single-family homes, Le Moniteur edition, 2019

[3] As part of the fight against the pandemic, local communities have CO2 sensors placed in schools to warn of ventilation needs. In passive buildings, double flow CMV is frequently associated with a CO2 sensor in order to optimize the quality of the indoor air.

[4] See Catherine Charlot-Valdieu and Philippe Outrequin, Energy rehabilitation of housing, Le Moniteur edition, September 2018, 330 pages