Have you ever walked into a space and instantly felt at ease, not just because of the design but because of the air? While air quality and comfort might seem intangible, they significantly impact how we feel indoors. The irony? Many of us can't define what makes air "good" or quantify the line between comfort and discomfort in our homes.
Creating an environment with high-quality air and optimal comfort isn't just about opening a window or turning on a heater—it's about understanding the science behind air quality. Factors like temperature, humidity, CO2 levels, particulates, and even noise play a key role. By measuring and addressing these elements, we can design spaces that feel better and support our health and well-being.
We will break down these factors, highlight why they matter, and explore how thoughtful design and the right tools can help you create spaces where air quality and comfort work in harmony.
First, we need to understand the factors that influence air quality.
There are a few main factors that influence air quality and comfort:
- Temperature: This is an obvious one. Most people's comfort zone is 18-25 degrees C.
- Humidity: This is less obvious but quite noticeable when you get it wrong. High humidity makes the air feel thick and makes us more sensitive to the temperature. The comfort zone is 40-60% RH (relative humidity).
- CO2 level: This is not obvious, but high CO2 concentration can lead to drowsiness. The comfort zone is below 1000 ppm.
- Particulate: This can be self-explanatory in areas with dust/pollen/smoke/etc. There should be as little particulate as possible in the air for maximum comfort/health.
- Noise: This one is very noticeable but not typically considered air quality. The comfort zone is below 30dB for sleeping.
Quantify Comfort in Your Home
The only way to know if you are keeping your house within that comfort zone is by measuring. Many houses overseas have thermostats controlling HVAC (Heating, Ventilation & Air Conditioning), whereas Kiwi houses typically don't. Do you have a thermometer or thermostat in your home? If not, we highly recommend getting one or more. We've listed some of our favourites below:
- Tapo T315 Smart Temperature and Humidity Monitor: This has a screen that displays and records temperature and relative humidity.
- Tether EnviroQ Smart Indoor Environmental Sensor: This pairs with your phone and records the indoor environment, including temp, RH, CO2, Noise, and Light.
- A plug-in thermostat: This allows you to plug in a heater and set it to turn on/off at different temperatures.
Incorporating Air Quality into Your Building Design
Now, with the knowledge of what high-quality, comfortable air means with quantifiable values, we can design indoor spaces that stay within those comfort zones.
Temperature: Since there are very few places on earth where outdoor temperatures and humidities stay within the comfort zone at all (or even most) times, the reality is that the vast majority of indoor spaces need to be temperature controlled with heating or cooling for some parts of the year. It's our job to reduce energy use for temperature regulation through insulation and shading. Heat pumps are typically the most efficient heating/cooling devices.
Ventilation: Additionally, with most of the world's population living in cities over 50,000 people, it's rarely possible to get adequate ventilation to keep CO2 levels down using windows due to noise and particulate entering the windows to reduce comfort. Fans for mechanical ventilation are required and can be installed in different configurations but ideally run continuously with heat recovery.
Humidity: Heat and ventilation, as described above, can heat and dry incoming air while also exhausting airborne moisture from occupants. Dehumidifiers can help, but they are a less desirable choice, as they do not provide heat and comfort to the occupants and do not exchange air to/from the exterior to maintain comfortable CO2 levels.
Dust/noise: While some days/nights may have favourable temperatures for opening doors and windows, noise, dust, bugs, etc., may make this impossible. A "build tight ventilate right" strategy can maintain air quality and comfort indoors without opening windows.
Approaches to Designing for Comfort and Air Quality
Interestingly, the principles behind Passive House design align closely with the criteria we've discussed for achieving optimal air quality and comfort. A passive home is a building standard focused on minimizing energy use while maximizing comfort through airtight design, thermal insulation, and controlled ventilation. This concept has been refined over decades, offering an efficient and holistic approach to creating indoor environments that feel just right.
Of course, there are other ways to design homes and buildings that address some aspects of comfort and air quality, but they may fall short in certain areas. For example:
- Traditional Villas: These homes excel in staying cool and breezy during summer, provided windows and doors remain open. A roaring fire and additional heaters can create a cosy atmosphere in winter. However, this approach can invite noise, bugs, and inconsistent air quality, especially during colder months when windows are closed.
- Historic Stone Buildings: Churches, castles, and similar structures with thick stone walls maintain a stable and dry indoor climate. While effective, this method is cost-prohibitive and impractical for most modern housing.
- Innovative Designs: Earthships and solar-passive homes achieve year-round comfort with minimal energy use. However, their bespoke nature and complexity make them less accessible for widespread adoption.
- North American Standards: Many homes in North America rely on moderately insulated, somewhat airtight designs paired with large ducted gas furnaces and air conditioners. While effective at maintaining consistent temperatures, these systems tend to be energy-intensive.
Each approach offers insights and techniques worth considering, but Passive House design uniquely integrates the key elements of comfort, air quality, and energy efficiency into a unified strategy. By taking inspiration from these principles, we can design spaces that are functional, sustainable, and enjoyable to live in.
The Essential Components of a High-Quality, Comfortable Home
So, to have an efficient, high-quality, comfortable indoor space, you need:
- An enclosure with good insulation for temperature regulation and good shading on windows to mitigate overheating (Modelling for this is recommended).
- Heating/cooling to regulate temperatures on the coldest nights and warmest days (in all rooms).
- Continuous ventilation (ideally with heat recovery) to ensure constant oxygenated, filtered air.
- An airtight enclosure to keep the inside air in and the outside air out to help the ventilation and heating/cooling work as efficiently as possible.
- Sensors/thermostats to verify air quality is staying within comfort zones and to automatically control mechanical systems.
Creating a high-quality indoor space involves finding the right balance between insulation, effective ventilation, and temperature regulation. By carefully integrating these systems, you can ensure that your indoor environment remains comfortable and efficient, regardless of season.
