【Detached Houses】About 50% Have Experienced Concerns Over Indoor Air Quality; Around 72% Prioritize Clean Air and Indoor Environment When Choosing a Home

■ Survey on Awareness of Indoor Air and Living Environment

Have you ever noticed the indoor air quality in your daily life?

The lingering smell after cooking, the dampness during the rainy season, the frustration of not being able to open windows during pollen season—these small discomforts may be significant signs affecting the comfort of your home.

Therefore, in collaboration with Trust Home Co., Ltd., we conducted a survey targeting 300 men and women across Japan who previously answered that they live in a detached owner-occupied home, focusing on their awareness of indoor air and living environment and its impact on health.

※ When quoting this press release, please comply with the following:

- Clearly state the source as "Survey by NEXER Corporation and Trust Home Co., Ltd."

- Include a link to Trust Home Co., Ltd. (https://t-trust.co.jp/)

Survey Overview: "Questionnaire on Indoor Air and Living Environment in Homes"

Method: Online questionnaire

Survey Period: June 2, 2026 – June 9, 2026

Respondents: Men and women across Japan who answered "living in a detached owner-occupied home" in a pre-survey

Valid Responses: 300 samples

Survey Questions:

Question 1: Have you ever been concerned about the indoor air quality (cleanliness, ventilation, odor, etc.) in your home?

Question 2: When specifically did you feel concerned?

Question 3: Did you know that homes exist where indoor air remains clean without 24-hour mechanical ventilation?

Question 4: When choosing or building a home, do you want to prioritize clean air and indoor environment?

Question 5: Please explain your reason.

Question 6: How important do you think the indoor air environment is for protecting your family's health?

Question 7: Please explain your reason.

※ Percentages are rounded to the nearest hundredth, so totals may not sum to 100%.

■ 50.0% Responded They Have Been Concerned About Indoor Air Quality

First, we asked whether respondents had ever been concerned about the indoor air quality (cleanliness, ventilation, odor, etc.) in their homes.

The results showed that 11.0% answered "often," 39.0% answered "sometimes," totaling 50.0% who have experienced concern about indoor air quality.

Meanwhile, 28.3% answered "rarely," and 21.7% answered "never."

While not everyone actively thinks about it daily, half of the respondents have experienced concerns about indoor air. Air quality, usually unnoticed, becomes a concern when triggered by odors, humidity, or poor ventilation.

So, in what specific situations did they feel concerned?

We asked about specific moments and present some responses below.

When specifically did you feel concerned?

- During rainy days. (Female, 20s)

- When my pet dog or cat defecates. (Male, 20s)

- During the rainy season when it feels humid. (Female, 20s)

- After cooking garlic or fish dishes. (Female, 30s)

- When I sneeze or have a runny nose. (Female, 30s)

- Smell of raw garbage. (Male, 30s)

Concerns about air quality were often linked to pet odors or cooking smells.

Additionally, many noticed air changes during rainy days or the rainy season when humidity builds up and windows cannot be opened easily.

Some even became aware of air quality due to physical reactions like sneezing or runny nose.

Indoor air is perceived not only by odor but also as a sign of physical well-being.

■ 79.0% Responded They "Did Not Know" About Homes With Clean Indoor Air Without 24-Hour Mechanical Ventilation

Next, we asked whether respondents knew about homes where indoor air remains clean without 24-hour mechanical ventilation.

The results showed that 79.0% answered "did not know," a clear majority.

"Heard the name" accounted for 11.7%, and only 9.3% answered "knew."

It is evident that housing systems capable of maintaining air quality without relying on mechanical ventilation are still not widely known.

When discussing housing performance, attention often focuses on insulation and earthquake resistance.

Information about indoor air environment options may not have reached many people yet.

■ 71.7% Want to Prioritize Clean Air and Indoor Environment When Choosing or Building a Home

Next, we asked whether respondents want to prioritize clean air and indoor environment when choosing or building a home.

The results showed that 19.0% answered "strongly want to prioritize," and 52.7% answered "somewhat want to prioritize," totaling 71.7% who want to prioritize clean air and indoor environment.

Meanwhile, 16.3% answered "do not prioritize much," and 12.0% answered "do not prioritize at all."

In the previous question, about 80% did not know about housing systems that maintain air environment.

Despite this, over 70% want to prioritize air environment when choosing a home.

Even without knowing the specific systems, many people desire to live comfortably in clean air.

So, why do they want to prioritize clean air and indoor environment?

We asked for their reasons and present some responses below.

Reasons for Wanting to Prioritize Clean Air and Indoor Environment

- To avoid sore throat. (Female, 20s)

- It's comfortable not to suffer from odors. (Female, 20s)

- Because people get sick due to poor indoor environment. (Female, 30s)

- I believe air quality affects quality of life. (Female, 30s)

- To possibly prevent health issues. (Male, 30s)

Reasons mainly reflected health considerations.

While some want to avoid throat discomfort or health issues, others emphasized comfort, saying "air quality changes life quality" or "it's comfortable not to suffer from odors."

Although the triggers for concern vary, indoor air environment is clearly seen as directly linked to health and comfort.

■ 82.6% Consider Indoor Air Environment "Important" for Protecting Family Health

Finally, we asked how important respondents think the indoor air environment is for protecting their family's health.

The results showed that 29.3% answered "very important," and 53.3% answered "somewhat important," totaling 82.6% who consider the indoor air environment important.

Meanwhile, 10.0% answered "not very important," and 7.3% answered "not important at all."

It appears that many people recognize indoor air environment as crucial to family health.

Since people spend long hours at home every day, many feel that air quality affects their physical condition and comfort.

So, what specific aspects do they consider important?

We asked why they think the indoor air environment is important and present some responses below.

Reasons for Considering Indoor Air Environment Important

- Poor air causes allergies. (Female, 40s)

- My child has atopic dermatitis, and air quality affects it. (Male, 30s)

- I want to care for my elderly parents' health. (Female, 50s)

- I have respiratory illness, so clean air is essential. (Male, 60s)

- I believe it helps prevent influenza and colds. (Female, 30s)

The importance of air environment is clearly linked to maintaining the health of family members with allergies or chronic illnesses.

Especially in households with children or elderly members, air quality appears to be even more emphasized.