Such terms as “zero”, “active” or “passive” houses are becoming more and more common in the information space.
This is a description of housing, the maintenance costs of which tend to zero.
But is it really possible: not to spend money on heating in winter, to provide yourself with electricity, etc.? Maybe it’s just another fashionable chip and fancy marketers? Let’s find out.
In the life cycle of a building, the initial investment in construction is only the tip of the iceberg. Once the house is erected, years of spending on electricity and heat, ongoing repairs, etc.
will follow. Is it possible to do everything “to the max” to pay much less or not pay at all later? Architects all over the world assure that it is possible: more and more energy-efficient houses are built every year.
The criterion: The specific heat consumption for heating during the heating period in kWh/sq.m. is usually considered as a measure of energy efficiency.
But for a house with year-round residence, it is necessary to consider not only the heating period but also the whole year, taking into account the energy consumption for air conditioning/air cooling in the heat.
Energy-saving and energy-efficient – what is the difference
In terms of specific thermal energy consumption, there are houses:
Energy-efficient are buildings with reduced energy use for heating. How low? There is a classification of buildings according to SNiP “Thermal protection of buildings”. A building with an energy efficiency class above a certain level is considered energy efficient.
Passive – buildings whose annual specific energy consumption for heating does not exceed 15 kWh / sq.m.
With ultra-low energy consumption for heating – buildings that consume 16-35 kWh/sq.m for heating per year.
- Active are buildings with different levels of energy efficiency, but with increased comfort due to automatic control of the microclimate using the Smart House system and maximum use of energy from renewable sources (wind, earth, and solar energy). There are examples of active homes that produce more energy than they consume. The surplus can even be sold.
- With a zero energy balance are buildings whose total energy consumption is zero as a result of offsetting losses by using renewable energy sources.
- With positive energy, balance are buildings that produce more energy than they consume.
act: We use the term “energy-efficient houses”, which is not quite correct, although, in fact, only buildings with a positive energy balance conserve energy. The rest of them consume it wisely.
Who sets the standards for home efficiency?
In the mid-1990s the Passive House Institute was founded in Darmstadt, Germany.
Its experts are on the main developments in the construction of energy-efficient buildings.
They also defined the standard, according to which heat losses at such objects should not exceed 15-25 kWh per 1 sq.m. heated area per year. For example, 200-300 kilowatt per hour per “square meter” is a norm for a usual brick house.
It is not possible to achieve indicators of an energy-efficient house just by the quality of insulation.
A passive house is different from an ordinary house in every way – special requirements are imposed on its design, the quality of windows and doors, and its engineering equipment.
For example, instead of the traditional sources of energy supply, it is proposed to use alternative sources – solar panels or systems that draw heat from the ground.
There are many experimental projects in which these ideas have been implemented to a greater or lesser degree.
Five key principles in the passive house concept:
1. Reliable thermal insulation
A well-insulated building envelope keeps the building warm in winter and pleasantly cool in summer.
2. special attention to windows
Windows for an energy-efficient house must fulfill two conditions.
Firstly, they should provide as high a heat transfer resistance as possible.
It is possible with the use of low-emission glasses, “warm” distance frames and filling the space between the panes in the glass with inert gases (argon and krypton), and the use of multi-chamber PVC profiles.
Secondly, the competent arrangement. As windows are channels of both heat loss and gain, it is recommended to put them on the southern facade of the building, and on the north to minimize the area of glazing.
Look at the diagram above: this is how light should fall in a passive house.
Josh Wynne Construction3. Recuperated ventilation
Passive house ventilation systems provide energy efficiency through heat recovery.
Passive houses are designed to be airtight to eliminate air filtration through the exterior envelope.
This increases energy efficiency and minimizes drafts and damage to the building envelope due to excess moisture.
Yes, it is better to forget about “wood breathing” in terms of ventilation in such houses.
5. Designing without thermal bridges
Avoiding thermal bridges, weaknesses in the building envelope promotes even temperature distribution, eliminate moisture damage, and improves energy efficiency.
All five principles can be quantified, and often these numbers are several times higher than the requirements of modern standards for mass construction.
If we talk about the specific values of heat loss per unit area or volume of the building, the best option for the energy-saving house is a ball: it has a minimum ratio of shell area to volume. Moreover, it can be built from quite affordable materials.
Another good option for an energy-efficient house is to build it as a cube. The lack of exterior corners and protrusions on the facade allows you to minimize heat loss even in harsh climates.