70% of People Considered Seismic Performance for Custom-Built Homes; What Makes Comparing Seismic Performance Among Companies Difficult?

■ How much is seismic performance considered when purchasing a custom-built home?

Japan is known as an earthquake-prone country.

While custom-built homes offer high degrees of freedom in layout and design, buyers are also required to make their own judgments regarding structural and seismic performance.

So, to what extent did people who actually purchased custom-built homes consider seismic performance?

To answer this, we collaborated with Panasonic Archiskelton Design Co., Ltd. to conduct a survey on "House Builder/Contractor Selection and Seismic Resistance" targeting 146 men and women nationwide who had previously responded that they "have purchased a custom-built home."

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"Survey on House Builder/Contractor Selection and Seismic Resistance" Overview

Survey method: Internet questionnaire

Survey period: March 5, 2026 - March 13, 2026

Target respondents: Men and women nationwide who responded in a preliminary survey that they "have purchased a custom-built home."

Valid responses: 146 samples

Questions:

Question 1: Did you consider seismic performance when purchasing?

Question 2: Please tell us the reason.

Question 3: Did you compare seismic performance when choosing a house builder or contractor?

Question 4: Please tell us the reason.

Question 5: Was it clear to you how the seismic performance of each company differed?

Question 6: What points did you find difficult to compare? (Multiple selections allowed)

Question 7: What was the deciding factor regarding seismic resistance for the house builder you ultimately contracted with?

*As a general rule, figures are rounded to one decimal place, so the total may not always be 100%.

■ 70.6% responded that they "considered" seismic performance when purchasing a custom-built home

First, we asked if they considered seismic performance when purchasing a custom-built home.

"Considered very much" was 32.9%, and "considered somewhat" was 37.7%, totaling 70.6% of people who were aware of seismic performance. On the other hand, "did not consider much" was 20.5%, and "did not consider at all" was 8.9%.

The result of over 70% is a trend unique to earthquake-prone Japan.

However, it is also noteworthy that about 30% did not place much importance on seismic performance.

We asked for the reasons behind each response, and here are some of them:

Reasons for considering seismic performance:

・Because I experienced the Great Hanshin-Awaji Earthquake. (60s, male)

・I thought it was important as preparation for future earthquakes and disasters. (40s, male)

・Because I live in an area where the Nankai Trough earthquake is expected. (30s, female)

・Because if it collapses, I will lose everything. (60s, male)

・Because Japan is an earthquake-prone country, seismic resistance is important. (40s, female)

Reasons for not considering seismic performance:

・I thought it would naturally be included in the builder's design. (80s, male)

・Because the standard seismic performance was high. (50s, male)

・I thought it would be fine if it met building codes. (70s, male)

・Because I built it within budget, paying attention to the layout. (60s, male)

・At that time, I didn't consider seismic performance. (60s, male)

Heartfelt voices were received from those who had experienced major earthquakes or were aware of future earthquake risks. On the other hand, voices from those who purchased decades ago, stating "interest in seismic resistance was low at that time," were also prominent, suggesting that awareness has changed over time.

■ 71.9% responded that they "did not compare" seismic performance

Next, we asked if they compared seismic performance when choosing a house builder or contractor.

Only 28.1% responded "yes," while 71.9% constituted the majority who "did not compare."

Despite approximately 70% responding "considered" seismic performance in the previous question, less than 30% actually compared companies.

We asked for the reasons behind each response, and here are some of them:

Reasons for comparing seismic performance:

・Because it's a once-in-a-lifetime purchase, I wanted a house that would be safe in case of an emergency. (40s, female)

・Because I built it after the Great East Japan Earthquake, I wanted to choose the building with the best seismic resistance. (70s, male)

・To learn what method is best. (80s, male)

・Because I want to live in a safe house. (30s, female)