Does our home directly affect our well-being?

Humans have evolved living outdoors with natural light, clean air, cool temperatures, and slightly humid relative humidity, and it is under these conditions that our health is guaranteed.

Currently, we spend about 90% of our time indoors, and due to increasing remote work dynamics, this time is even more concentrated in our homes.

What conditions must a space meet to ensure our health?

Having solar gain and natural lighting, good ventilation, and achieving a comfortable temperature without excessively drying out the environment are some of the basic guidelines that define the quality of our indoor environment and directly affect our well-being, not only physically but also psychologically or emotionally.

The design of efficient, sustainable, and healthy spaces

It is important to distinguish between the terms efficiency, sustainability, and health of a space.

An efficient space is one that manages to reduce energy demand through natural means, such as bioclimatic strategies:

In winter, we capture heat from the sun, store it in walls, and prevent it from escaping thanks to good insulation and airtightness.

In summer, we avoid sun exposure through natural protections such as louvers, porches, overhangs, or green pergolas, and we generate cross-ventilation to naturally cool the environment.

Once we have reduced demand to a minimum, we generate the rest using renewable energies, and we can then affirm that we have an efficient space.

However, if all these strategies are not carried out with natural materials, with reduced impact and ecological footprint, and with minimal carbon emissions, then we may have an efficient space, but it will not be sustainable because it will have a high ecological impact.

Furthermore, if we want to guarantee the health of an efficient and sustainable space, we must consider a series of factors, starting with the use of natural and healthy materials, but also a design that ensures indoor environmental conditions that preserve our health, comfort, and well-being.

What is a healthy space?

Let’s look at each of the factors that define health and well-being in a space.

It is important to remember that the sole purpose of a built space is to house life, and therefore, ensuring the health and well-being of the people who occupy them should be one of the main challenges in any design process.

But what do we mean by the health of a space?

Health is defined by the WHO as a state of complete physical, mental, and social well-being.

We have identified the 10 key factors in designing a healthy space for life that influence physical, mental, and social health. These are:

10 FACTORS THAT DEFINE A HEALTHY SPACE

1. TEMPERATURE

Seek a comfort temperature between 17 and 27 degrees Celsius.

The sensation of comfort is determined by multiple factors, including age, gender (studies show that, in general, women have a thermal sensation 30% lower than men), but also our own physiology (sweating and perspiration capacity) or the activity we are performing.

Excessive heat. Reduces concentration and performance, increases pulse, and causes drowsiness and discomfort.

Conversely, the sensation of cold also reduces concentration by causing nervousness and a desire to move.

In general, the temperature range considered to produce a “pleasant” sensation is between 17 and 27 degrees Celsius.

Comfort temperature varies depending on the use of the space; a study or work area is not the same as an activity zone like the kitchen, a bathroom, or a resting area.

Having an adequate temperature is especially important during the night when we sleep, which is when our body regenerates. A low comfort temperature around 18 degrees Celsius promotes deep breathing and allows for good rest.

The design of spaces that allow for solar heat gain, good wall insulation, the use of materials with heat storage capacity, control of air currents, and the use of healthy radiant heating systems are basic aspects to ensure the thermal well-being of our home.

2. HUMIDITY

Maintain relative humidity around 50%.

Optimal relative humidity values for our health range between 40-60%.

When the environment is too dry, below 30%, our mucous membranes dry out, reducing our defenses and exposing our body to viruses and bacteria. Additionally, dry environments promote the appearance of static electricity and airborne dust, associated with the onset of allergies.

Conversely, excessive humidity makes breathing difficult, causes fatigue, and hinders the natural evaporation of our body. Furthermore, excessive humidity promotes the growth of mold and bacteria associated with multiple respiratory diseases such as asthma, pneumonia, and allergies.

The reality is that our environments tend to be excessively dry due to the overuse of heating or air conditioning, especially air or convection systems (radiators) that excessively reduce the relative humidity of the space.

A relative humidity above 40% has been shown to promote deep rest as it reduces apnea and improves sleep quality.

To ensure adequate humidity, it is necessary to have good constant ventilation, either by natural or mechanical means.

3. AIR RENEWAL

Ensure good ventilation that renews air and improves well-being.

Ventilation is also directly related to thermal comfort and is especially desirable in summer, as our sensation of comfort improves in the presence of an air current.

Ventilation is also important to ensure indoor air renewal and prevent the accumulation of CO₂ that we emit when breathing, as well as other pollutants and toxins present in the home.

New building regulations increasingly demand more airtight and sealed spaces to ensure energy efficiency, but airtightness is linked to the new requirements of ensuring constant ventilation by mechanical means. That is, if we forget to open windows, there are devices that activate ventilation above certain CO₂ levels.

The Technical Building Code (CTE), in its Basic Document on Health and Hygiene (DB-HS), includes the requirements established by current legislation related to indoor air quality.

In older homes, it is up to us to ventilate sufficiently to ensure indoor air quality. A simple measure is to have a CO₂ detector, whose use has become widespread since the COVID-19 pandemic, and which allows us to easily detect when indoor air is stale.

If we take outdoor air as a reference, which in 2022 already has a concentration of 413 ppm of CO₂, we consider indoor air stale above 800 ppm, which would be the maximum to ensure our comfort and health in indoor spaces.

4. AIR QUALITY

Ensure adequate air quality free of toxins and pollutants.

Sources of air pollution in an environment can come from:

Indoors:

• Accumulation of CO₂ due to poor ventilation.
• Humidity and mold.
• Building materials, finishes, and furniture or fabrics that incorporate and emit toxins into the environment (VOCs).
• Cleaning products.
• Combustion byproducts (fireplaces, stoves, kitchens).

Outdoors:

• From the ground itself (radon).
• Combustion byproducts (smoke, carbon monoxide, nitrogen dioxide, hydrocarbons (PAHs), etc.).

It is important to ensure constant air renewal, either manually, by generating cross-ventilation by opening windows on opposite facades of our home, or by mechanical means such as air extractors, forced ventilation, or, in exceptional cases where ventilation is not possible, by air purifiers.

5. WATER QUALITY

Control water quality, free of biological or chemical contaminants.

If we live in the global North, we can rest assured that the water reaching our homes has passed quality controls regarding microbiological and chemical parameters.

However, water can become contaminated inside our buildings.

• Biological contaminants (bacteria) – There is also a risk in water heating systems or private wells, environments where bacteria such as Legionella can proliferate, posing a risk when vapor can be inhaled, such as during showering or sprinkler irrigation. The most common are Legionella and E. coli.

• Chemical contaminants. During its passage through installations, among many others, one of the most common cases is when we find old lead installations, which is toxic to humans and especially to children.

Finally, there are different water hardness levels related to the calcium and magnesium content. The WHO has not found sufficient evidence to link high hardness with an increased health risk.

6. NOISE LEVELS

Maintain reduced noise levels.

Noise reaching our homes can come from external sources (traffic, commercial activities, neighbors, weather phenomena, etc.) or internal sources such as machinery, ventilation systems, or appliances.

Constant exposure to noise not only causes disturbances in rest and sleep but is also linked to an increased risk of cardiovascular disease and the weakening of the immune system, which is constantly on alert, especially relevant in children where there is a risk of behavioral alteration derived from noise pollution.

Our built environment can be better or worse prepared to dampen these noises, which we divide into airborne noise or impact noise.

• When we talk about airborne noise, we refer to noise transmitted through the air due to insufficient acoustic insulation. It is caused by air disturbance from sound sources whose sound level is higher than that of the dwelling. An example of airborne noise can be hearing traffic, neighbors, television, appliances, etc. To protect ourselves from airborne noise, we use materials that absorb and reduce it, such as dense insulation or double-glazed windows.
• Impact noise, on the other hand, refers to noise caused by a blow to a solid medium that propagates through the structure, usually the floor slab. The most common impact noises are footsteps from the upper floor. These noises are dampened with joints in structures or with flexible materials.

Getting used to noise does not mean that it does not negatively affect our health. In the design of a healthy space, it is essential to propose a good acoustic insulation system that considers airborne and impact noises to be able to silence them or, at least, attenuate them.

In Spain, the Basic Document on Protection against Noise (DB-HR) of the CTE, as well as UNE ISO, UNE EN, and UNE Standards, are recommended as regulatory complements.

7. LIGHTING

Ensure healthy natural and artificial lighting.

Sunlight is the natural source of heat, light, and energy, so good sun exposure means energy savings in lighting and heating, but it also guarantees the healthiness of the space by reducing humidity and preventing the appearance of fungi and bacteria.

For this reason, unaltered natural light will always be preferable to artificial light, which should act as a complement to natural light, trying to resemble it as much as possible.

Thus, the choice of artificial light must ensure correct luminous and visual conditions, capable of contributing to the physical and mental well-being of people according to the following criteria:

Light tone or temperature

Light temperature affects mood and has a direct relationship with body activation. Depending on the use of the room to be artificially lit, a warm or cooler tone is chosen:

• Rooms related to rest (bedrooms or living rooms) should emit warm tones, with a color temperature equal to or below 3000ºK, and low intensity.
• In rooms where activities requiring greater concentration will be carried out (work areas), the best option will be to opt for whiter and higher intensity lights approaching 4000ºK.

Color Rendering Index

The Color Rendering Index (CRI) is the measure used to indicate the ability of a light source to reproduce colors in relation to natural sunlight, whose reference index is 100.

Thus, the CRI range goes from 0 to 100, with 100 being the color reproduction of the sun. Currently, LED lighting technology has progressed greatly and is capable of offering the highest CRIs, ranging between 80-89 and 90-100.