The Importance of Optimizing Indoor Climate for Both People and Planet

Danny Schleien
Future Proof Cities
5 min readJul 1, 2021


Innovative indoor climate solutions bring a host of positive externalities.

Photo by Annie Spratt on Unsplash

Air quality has always been important, especially as humans have increasingly congregated in urban areas. In modern times, most of the focus was on outdoor air quality. However, the COVID-19 pandemic has put a spotlight on indoor air quality. As cities shut down when the pandemic began over a year ago, outdoor air quality improved noticeably in urban areas like Delhi, Los Angeles, and Venice. Mountains normally obscured by smog were visible in clear daylight. Residents who normally wore masks to protect their lungs now required facial protection for an invisible virus that was both highly transmissible and quite lethal.

Since this coronavirus is transmitted through the air, indoor spaces are much more dangerous than outdoor spaces. This insight wasn’t always clearly understood by governmental bodies and communicated to concerned citizens, but it underlines how routinely we overlook the quality of our indoor spaces in our daily lives, both in pandemic times and in normal times.

People require increased comfort and well-being in the places they live and work. Factors like air quality, thermal well-being, and energy efficiency can be optimized for human health with a suite of indoor climate solutions that reflects a growing understanding of what humans need to be productive, comfortable, and happy in the indoors spaces where we spend the vast majority of our time.

From managing rainwater runoff from hard surfaces to water circulation systems within buildings (meant to deliver efficient space heating and cooling) to systems for water and gas distribution, these indoor climate solutions entail a comprehensive approach centered around plastic pipes to keeping those indoor spaces comfortable for those who use them.

As you’ll see below, the benefits of these solutions are staggering both individually and collectively. They highlight a large opportunity for city dwellers, urban planners, and other constituencies to think differently about how to make the most of indoor spaces.

Indoor Air Quality

Some of the worst factors of indoor air quality include house dust mites, mold, and suspended particles like dust. Indoor climate solutions notably mitigate the effects of each of these factors. Lower humidity prevents the mold growth of feces that causes allergic reactions in humans, and lower humidity prevents other mold growth in indoor spaces.

Underfloor heating increases the temperature of upholstery and mattresses while lowering relative humidity, which can reduce mite populations in indoor spaces by up to 90%. As such, indoor climate solutions would help a lot of people feel better indoors!

Just as lower humidity helps reduce mite populations, it impairs mold growth. Thus, indoor climate solutions help reduce incidence of respiratory illness, allergies, asthma, and immune system issues.

Finally, radiator heating elements need a higher temperature to regulate indoor climate. This makes certain harmful particles in the air more reactive and irritating. Underfloor heating stops this invisible disco party that no one enjoys and sends those annoying air particles home.

Thermal Comfort and Well-Being

To be productive and happy indoors, you usually need some combination of acoustic, visual, and chemical comfort. Most of us don’t like loud noises, distracting sights, and dangerous chemicals.

But there’s another key element to being comfortable indoors: thermal comfort. It’s influenced by personal and ambient factors like human metabolic rates, insulation through clothing, air temperature, air velocity, and air relative humidity.

Indoor climate solutions optimize thermal comfort much more effectively than radiators. They achieve better vertical temperature equilibrium in indoor space thanks to their design, which aligns with what the human body prefers. Plus, the radiant component of an underfloor heating system is higher thanks to its larger surface area and lower water temperature compared to a radiator. All in all, this leads to less variability in temperature, which enhances thermal comfort.

The benefits of increased thermal comfort on productivity and well-being cannot be overstated. Data indicates that indoor climate solutions can increase perceived well-being by 14%, perceived motivation by 16%, productivity by 10%, and children’s educational performance by 8% while decreasing absenteeism due to illness by 2.5%. These figures align with a well-established body of research pointing to the vast benefits of thermal comfort. Children are more sensitive to higher ambient temperatures because of their higher core body temperatures and less developed ability to regulate their body temperatures. A study of over 3,000 U.S. school students showed a 12–13 point increase in math scores for each 1°C decrease in classroom temperature.

Perhaps the biggest benefit of indoor climate solutions is the reduction of CO2 levels, which inhibits health outcomes like drowsiness and cognitive impairment. This CO2 reduction is achieved through improved ventilation.

Energy Efficiency and Emissions Reductions

Research points to greater energy efficiency from underfloor heating/cooling relative to radiator heating/cooling because underfloor heating/cooling allows for low-temperature fluid heat thanks to a lower inflow temperature than radiators.

One study measured the energy consumption of two identical buildings with two different climate solutions. The building with VAV (variable air volume) air-conditioning used 440,000 kWh of energy per year, whereas the building with radiant cooling only consumed 269,000 kWh per year. Per square meter, this translates to 13 kWh of saved energy per year, or 34%, from radiant cooling. Beyond helping the bottom line, underfloor health/cooling is a more sustainable option than traditional radiators.

Occupied Space

Conventional radiators take up a lot of space. An average horizontal radiator requires ~0.14 square meters of displaced area and ~0.07 cubic meters of displaced volume. An average vertical radiator requires ~0.03 square meters of displaced area and ~0.04 cubic meters of displaced volume.

This might not seem like a lot, but when you extrapolate to the amount of heating required in a typical 100 square meter residence, ~1.74 square meters of space can be freed up just by switching from radiators to underfloor heating. And when you account for the average price per square meter of building space in the European Union, underfloor heating can open up about 3,000 euros for a typical homeowner just by freeing up space.

And that figure excludes the cost savings that come from the aforementioned energy efficiency of underfloor heating compared to radiator heating.


Most indoor spaces present a variety of opportunities to improve human productivity and well-being while saving money and space. Compared to some common features of indoor spaces like radiators and traditional air-conditioning systems, indoor climate solutions improve air quality, optimize thermal comfort and well-being, bolster our mental health by diminishing attention theft, make indoor spaces for children and adults, increase energy efficiency and reduce emissions, and increase occupied space.

As we finally claw our way out of the worst pandemic in a century, it’s imperative that we think about how to place health and well-being and human comfort at the center of how we use indoor spaces.

Disclaimer: This content is written for Wavin B.V., a Dutch company which offers connected indoor climate solutions in various European countries.



Danny Schleien
Future Proof Cities

Writer, editor, explorer, lifelong learner. Social distancing expert since 1994, big fan of semicolons and Oxford commas. Think green.