Design Process
10 advantages of living in a passive house
We have realized that in almost all our articles we talk about technical issues regarding passive houses, from design options and construction systems to land appraisal, bio-interior design solutions, or eco-renovations.
So today we are taking it a step further to see how our clients live in their passive houses once we set them in motion; what the 10 advantages of living in a passive house are.
We never tire of repeating to our clients that a passive house is not complex; rather, 90% of its proper climatic performance depends on good design and an accurate demand calculation. If energy demand is reduced to a minimum through bioclimatic architecture strategies (solar gain and accumulation in winter, and protection and ventilation in summer), then you obtain a house that functions passively—meaning nothing needs to be “activated” to achieve a comfortable temperature.
If a house is heated naturally thanks to the sun’s heat or north-south fresh air ventilation, then the indoor environment is more natural and healthy. Furthermore, if this is combined with natural materials free of toxins and pollutants, then my indoor environment becomes the perfect refuge for a family’s life. This is how we aim to carry out all our projects at our studio.
Let us look step-by-step at the advantages of living in this type of home.
10 advantages of living in a passive house
1 Constant ambient temperature without the need to turn on heating or air conditioning
Thanks to the principles of bioclimatic architecture, we can design a zero-consumption house using mechanisms that understand and adapt to the climatic conditions of the location throughout the different seasons of the year.
Therefore, in winter, strategies such as capturing solar radiation, increasing the home’s insulation, and taking advantage of thermal inertia and the greenhouse effect are typically used. In summer, thermal inertia and insulation are also useful, but above all, we need to generate natural ventilation and protect openings from solar radiation using filters, porches, slats, or eaves.
All of these are passive systems, meaning there is no need for the passive house user to “activate” any system that consumes energy for climate control, whether for cooling or heating.
This is an advantage that not only saves energy and management time but is also more natural and pleasant than conventional climate control systems, as the temperature is naturally stable and comfortable without the need for heating systems that can dry out the environment and thus reduce indoor air quality.
At certain times of the year, especially in more northern countries, we may indeed need heating, whether due to a period without sun or very low average temperatures.
In any case, the energy we require will be generated via renewable sources, aiming for a healthy system that does not dry out the environment, as we will describe in the next point of the 10 advantages of living in a passive house.
2 Relative humidity above 40%
As firefighters say, when relative humidity drops below 30%, all alarms go off; the ideal environment for life has a relative humidity of around 40-50%.
Below 40%, our mucous membranes dry out, reducing our natural defenses and leaving the way clear for viruses and bacteria to enter our bodies. This is what we know as the typical summer cold caused by air conditioning.
If we use forced-air heating, the result is the same: we have a very unhealthy indoor environment, and it turns out we spend the winter with colds not because of the cold outside, but because of the heat and dryness generated inside our home.
Having a passive house that is heated naturally by the sun’s heat or through the entry of preheated warm air in a courtyard or a greenhouse-style gallery allows us to enjoy a comfortable temperature without modifying the natural conditions of the air.
Ancient cooling mechanisms, such as the fountains in the middle of a central interior courtyard typical of Arabic architecture, are capable of cooling the environment through water evaporation while respecting and even improving the humidity conditions of the environment. This process is known as adiabatic cooling and converts hot, dry air into cool, humidified air.
3 Reducing heating and cooling costs by 90%
This point is closely related to the first of the 10 advantages of living in a passive house, as passive systems not only save energy but also reduce the maintenance and monthly costs of active heating and cooling systems.
Specifically, it is estimated that energy consumption in a well-conceived and well-built passive house is reduced by up to 90%, with the remaining 10% being the energy needed to heat water for showers and baths, as well as electricity generation for appliances and lighting.
Always with the goal of minimizing our ecological footprint, we will also try to cover the small remaining expenditure with renewable energy.
The extra cost of designing our passive house outside of conventionality will be easily amortized thanks to the reduction in energy consumption, which exempts us from the so-called energy mortgage to which most users are condemned for the rest of their home’s useful life, beyond the bank mortgage.
Furthermore, if we can handle this minimum consumption through renewable energies, we will have the total freedom provided by a house disconnected from the grid.
4 Reduction of CO2 emissions
I always say that most of our clients already come to the studio with a certain ecological awareness, and it is easy to make them understand the advantages of choosing one material over another for ecological reasons or to reduce environmental impact.
But beyond the selection of materials, reducing energy consumption by 90% through home design, as well as ensuring the use of renewable energies, implies the reduction of CO2 emissions throughout the building’s useful life.
However, a building’s energy consumption throughout its useful life goes beyond mere energy expenditure for its operation. Specifically, this is distributed into approximately 30% during construction (extraction, processing, and transport of construction materials to the site), 60% during its useful life, and 10% during its demolition.
If we also use natural materials and insulation for its construction and ensure these are from local producers, we not only reduce CO2 but also our ecological footprint and environmental impact.
In our studio, we have been implementing a system over the last few months to measure the CO2 emissions of our houses throughout the entire construction process and useful life with the help of the Ecómetro program.
5 Better acoustic insulation
One thing leads to another, and the perfect design mechanism is one that solves several problems at once. This is the philosophy of passive design and what happens in the fifth point of the 10 advantages of living in a passive house, where the improvement of thermal insulation resolves the need for acoustic insulation.
The fact of having windows with greater thermal insulation and well-insulated, airtight walls to reduce climate control energy demand also improves acoustic insulation from the outside.
6 Natural ventilation
At our studio, we are not very fond of ventilation via heat recovery units, as we do not consider the inability to open windows and having natural air always pass through a machine that controls it via filters and temperature to be the most appropriate option for living.
We are more in favor of using strategies such as Canadian wells, which preheat the air naturally by passing it through the ground, or using courtyards and greenhouse galleries that preheat the air before it enters the house through vents.
7 Rapid amortization
An important concept for bioclimatic architecture is amortization, as it takes into account many more variables than conventional architecture, which only measures efficiency based on speed and economic cost. A passive house does not compete in economic efficiency at the time of its construction, but in the long run, it can become even more profitable thanks to the savings from the so-called ‘energy mortgage’.
Energy systems
Next, we will analyze the amortization period of different energy systems, whether passive or active, which usually ranges between 5 and 8 years.
Within passive energy systems, we can consider the passive systems of the building envelope, such as high-quality glass and joinery, solar protections like filters or eaves, ventilation systems like Canadian wells and greenhouse galleries… which are amortized in an average of 5 years. Envelope systems such as green or ventilated roofs with high insulation, as well as highly insulated airtight facades or walls with high thermal inertia, are more expensive and are therefore amortized in an average of 8 years.
Active energy systems that run on renewable energies, such as photovoltaic panels for generating electricity, thermal panels for heating water, or others less known like micro-wind, aerothermal, geothermal, and biomass, have an average return on initial investment of 7 years.
Water self-sufficiency systems
Every house disconnected from the grid must also have water self-sufficiency systems, meaning systems for obtaining water naturally, as well as its subsequent reuse.
Normally, water for personal consumption comes from water stored in a tank that collects rainwater, usually through the roof. For this type of collection, green roofs are not the most suitable.
Prior filtering of this resource will be necessary, as the slightest dust or organic residue can lead to the growth of microorganisms. These bulky water collection systems require significant infrastructure and are therefore amortized in an average of 10 to 15 years.
Another option is to dig a private underground well, if the existence of water in the subsoil of our land is known. This is a more costly system than the previous one due to the technical difficulties of excavation, which can be amortized after 20 years.
Water reuse systems allow us to use, for example, the water from the sink or shower to flush the toilet after a simple filtering process. However, we can avoid this latter consumption by installing a dry toilet, which does not require water for its operation and whose waste is transformed into compost for the garden soil. Avoiding the costs of connecting to the sewage network and maintaining a septic tank allows us to further reduce the amortization period to 10 years.
8 Indoor air quality
As we argued in the sixth point of the 10 advantages of living in a passive house, natural ventilation is a crucial pillar in bioclimatic design to ensure optimal indoor air quality in our passive house. The concept of an airtight passive house works at an energy level, but it can be detrimental to our comfort and even health.
The constant renewal of air allows for fresh and clean indoor air with a good balance of CO2 and oxygen, free of pollutants. Furthermore, it prevents humidity problems, which in turn can cause respiratory diseases and be a source of fungal growth.
Conventional architecture, instead of using design strategies to guarantee a minimum air renewal per hour and hygroscopic materials like earth or wood capable of regulating humidity naturally, opts to add biocides harmful to our health and that of our family.
The optimal solution is to live in a passive house built with natural materials and insulation, using natural, toxin-free, and hygroscopic paints.
9 An airtight house
As mentioned in previous points, a balance must be sought between the concept of an airtight house that works by storing heat inside without suffering energy losses and the need and advantages offered by enjoying natural air inside our passive house. This is why the best systems are those that prevent direct entry of outside air in order to control its conditions as much as possible.
However, the need to design a house without energy loss, especially for the winter months, means we must pay absolute attention to possible discontinuities in its insulation. The meeting points of joinery and floor slabs with the facade or the roof itself are often sources of thermal bridges that generate humidity and condensation.
Special attention must be paid to ensuring high thermal insulation, as well as a good solution for the most problematic construction joints and the quality of the joinery and its glass.
10 A conscious house
Returning to the beginning of the article, we analyzed that there are issues beyond technical characteristics when choosing to live in a passive house. It is difficult to put a price on the level of ecological awareness of a family building their dream home; valuing variables that involve paying more to have a lower cost for the planet and ensuring a higher quality of life for ourselves and our loved ones by living in a healthy home are some of the returns that cannot be measured with money.
Currently, buildings are one of the main causes of environmental problems on our planet with an expiration date, accounting for 40% of global energy expenditure. Becoming aware of this and acting accordingly to reduce our ecological footprint is what drives us as a company. Like our clients, we also want to live in a house that shares our slow philosophy and its sustainability criteria.