Over 80% Feel Uncomfortable Even with Air Conditioning On! The Blind Spot of Tropical Nights: Only 1.5% Aware of "Bed Climate"

With severe heatwaves and tropical nights expected in the summer of 2026, many people are struggling with the problem of feeling uncomfortable at night even when their air conditioner is on. Moonmoon Co., Ltd., which operates "Kaimin Land," a website introducing sleep-enhancing goods, conducted a "Survey on the Actual Conditions of Mattress Environments during Tropical Nights" targeting 200 men and women nationwide aged 20-60 who currently use a mattress and use air conditioning during sleep. The results revealed that a staggering 81.5% of respondents felt uncomfortable at night despite using air conditioning. A major cause of this is the deterioration of the "bed climate" – the temperature and humidity between the body and bedding that affects sleep quality (e.g., heat buildup in the back and waist). However, only 1.5% of people are aware of this term and its implications, highlighting a significant "blind spot in awareness."

Background of the Survey

In recent years, summers in Japan have become increasingly extreme, with the number of tropical nights steadily increasing. While using air conditioning during sleep has become common practice for heatstroke prevention and comfortable sleep, many voices express discomfort that cannot be solved by air conditioning alone, such as "waking up in the middle of the night despite the air conditioner being on" or "feeling cold overall but hot in the back." To maintain comfortable sleep, it is essential not only to regulate the room temperature but also to maintain an appropriate "bed climate" (ideally around 33°C and 50% humidity) between the body and bedding. This survey aimed to shed light on the challenges of summer sleep environments that modern people tend to overlook and the actual needs for reviewing bedding in the future.

Survey Summary

Over 80% (81.5%) experience "discomfort" even when using air conditioning. This highlights sleep challenges during tropical nights that cannot be solved by temperature control alone.

The top complaints regarding bedding are "heat buildup in the back and waist (18.6%)" and "dampness from sweat (17.8%)." Discomfort is concentrated in the areas of contact between the body and bedding.

Awareness of "bed climate," which holds the key to comfortable summer sleep, is only 1.5%. 98.5% responded "don't know/don't know in detail," revealing the biggest blind spot.

Summer discomfort directly impacts the next day. "Decreased concentration/efficiency" and "headaches/body fatigue" (19.7% each) indicate serious negative effects on daytime performance.

Regarding sleep environments to review most in the future, "bedding, including sheets and the mattress itself" accounted for a total of 51.5%, representing over half of the respondents.

* When quoting the results of this survey, please include the URL of "Kaimin Land" (https://intiinti.com/goodsleep/).

Detailed Data

Q1. During summer nights, do you feel uncomfortable even when using air conditioning?

Feel uncomfortable sometimes: 40.0%

Feel uncomfortable about half the week: 25.0%

Rarely feel uncomfortable: 18.5%

Feel uncomfortable every night: 16.5%

→ Combining "every night," "about half the week," and "sometimes," a total of 81.5% feel uncomfortable despite using air conditioning. This suggests that sleep challenges that cannot be solved by lowering the room temperature are lurking in many households.

Q2. In the summer, what concerns you about your mattress or bedding while sleeping?

Heat buildup in the back and waist: 18.6%

Bedding feels damp from sweat: 17.8%

Waking up from heat in the early morning: 13.0%

Moving around in sleep to find a cool spot: 12.0%

Feeling poor breathability of bedding: 11.8%

Other: 26.8% (Feel like I'm tossing and turning more: 8.5%, Feel like the mattress is retaining heat: 7.2%, Feel like the pillow is hot: 6.0%, etc.)

→ The top two concerns were "heat buildup in the back and waist" and "dampness from sweat." The data confirms that discomfort is concentrated in the "contact surfaces between the body and the mattress," where air conditioning's cool air struggles to reach.

Q3. Do you know that "bed climate" – the temperature and humidity between your body and bedding – affects sleep quality?

Did not know: 82.5%

Have heard of it but don't know the details: 16.0%

Know the term and its meaning: 1.5%

→ Despite being a crucial factor in determining sleep quality, only 1.5% of people correctly understand the term and meaning of "bed climate." The fact that the cause of feeling hot even with air conditioning on is the "microclimate between bedding and the body" can be considered the biggest "blind spot" in current tropical night countermeasures.

Q4. What measures do you take regarding your mattress and bedding to cope with summer discomfort?

Use cool-touch mattress pads/sheets: 29.4%

Use a circulator/fan to blow air onto the bedding: 25.9%

Frequently air out/dry bedding: 12.5%

Switched to a mattress/topper with good breathability: 8.1%

Use ice packs/ice pillows: 7.6%

Other: 16.5% (Do nothing in particular: 7.5%, Use dehumidifying sheets/slatted bases: 6.2%, Switched to pillows made of cool materials like linen or buckwheat hulls: 1.9%, etc.)

→ "Using cool-touch bedding" and "blowing air" were the most common measures, indicating that easy-to-implement solutions are prevalent. However, measures that lead to a fundamental solution, such as "switching to a highly breathable mattress," are still less than 10%, and the current approach largely focuses on superficial cooling.

Q5. How does summer discomfort affect your daytime activities the following day?

Decreased concentration/efficiency in work and chores: 19.7%

Headaches/body fatigue: 19.7%

Strong daytime sleepiness: 19.2%

Loss of appetite/summer fatigue: 16.9%

Irritability/low mood: 14.0%

Other: 10.5%

→ "Decreased work/chore efficiency," "headaches/fatigue," and "strong sleepiness" were ranked almost equally at the top. Sleep deprivation during tropical nights is not just a sleep issue but directly leads to reduced productivity and health problems the next day, revealing a serious reality.

Q6. What aspect of your summer sleep environment do you most want to review in the future?

Air conditioning such as air conditioners and fans: 31.0%

Bedding such as mattress pads and sheets: 30.0%

Mattress itself: 16.5%

Bedroom insulation/light blocking: 12.0%

Do not intend to review anything in particular: 5.0%

Other: 5.5%

→ While "reviewing air conditioning (31.0%)" was the most frequent single answer, when combined with "mattress pads/sheets (30.0%)" as the second most frequent, "mattress itself (16.5%)" as third, and "pillows (5.0%)" as fifth, a total of 51.5% of respondents expressed a desire to improve their bedding environment. This indicates a shift in consumer consciousness from relying solely on air conditioning for summer対策 to investing in the "quality of bedding," including mattresses.

Summary of Survey Results

This survey suggests that the reason for feeling "uncomfortable even with air conditioning on" during tropical nights is the deterioration of the "bed climate," where heat and humidity build up between the body and the mattress. However, awareness of this concept itself is very low at only 1.5%, leaving many people struggling with reduced daytime performance and physical discomfort without identifying the cause.

On the other hand, regarding future sleep environment improvements, the desire to improve "bedding, such as mattress pads, sheets, and the mattress itself (total 51.5%)" exceeded half of the respondents, surpassing the desire for improved air conditioning. To solve the "back heat buildup" that superficial cooling measures cannot resolve, fundamentally reviewing the sleep environment by introducing mattresses or toppers with excellent breathability and heat dissipation is likely to become the new standard for overcoming the severe heat of summer 2026.

Comment from Kaimin Land Operator

Operator: Koichi Takeda's Comment

"The reason behind the problem of 'not being able to sleep soundly despite the air conditioner being on' is precisely the miscontrol of the 'bed climate' that this survey has highlighted. The human body enters deep sleep as its core body temperature drops. However, if the mattress has poor breathability and heat builds up in the back and waist, the body temperature won't decrease, and the brain remains awake. This is the true cause of the phenomenon where 'the room is cool, but you wake up because your back is hot.'

Many people try to cope with measures like cool-touch sheets, but these are temporary. If the mattress itself has low heat dissipation and breathability, heat will accumulate over time. For heatwave countermeasures going forward, a double approach is needed: 'air conditioning' to cool the room, and 'bedding (mattress)' to release body heat and moisture. At Kaimin Land, we will continue to propose 'creating a non-stuffy sleep environment' based on scientific evidence, not just cooling.

Survey Overview

Survey Period: July 5, 2026 - July 6, 2026

Target Audience: 200 men and women nationwide aged 20-60 who currently use a mattress and use air conditioning during sleep.

Survey Method: Internet survey

Implementing Organization: Kaimin Land (Moonmoon Co., Ltd.)

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