Karuizawa's climate: Why it's important to take measures against condensation and humidity in both summer and winter
- osaka
- 1 day ago
- 6 min read
── The real fear in Karuizawa and Shinshu is "summer condensation" and humidity control
When you hear the word "condensation," many people probably think of the phenomenon of water droplets forming on window glass in winter. Indeed, measures to prevent condensation in winter have long been considered important in ordinary homes.
but--
In the Shinshu area, including Karuizawa, this alone is not enough. In fact, what you really need to be careful of in this area is "summer condensation" caused by summer humidity !
Key points for preventing condensation and humidity in Karuizawa
To protect your family's health and your home's assets, be sure to understand how to prevent moisture and condensation.
INDEX
What is the commonly known "winter condensation"?
What is the truly scary "summer condensation" in Karuizawa?
The "Air Pass Construction Method" is suited to the Shinshu climate
This can be easily done even in existing vacation homes!!
Summary | The key to building a house in Karuizawa is to deal with summer humidity
What is the commonly known "winter condensation"?
Winter condensation occurs when warm, moist indoor air comes into contact with cold windows and exterior walls .
Main causes of winter condensation
Large temperature difference between indoors and outdoors
Increased water vapor volume indoors due to heating
Insufficient insulation and single-pane glass windows
Risk of winter condensation
Mold and blackening around windows
Deterioration of wallpaper
Health effects such as allergies and asthma
For this reason, the common advice has been to "increase insulation" or "use double-pane glass." This is correct in many areas.
But that's not enough in Karuizawa
Karuizawa is located on a plateau at an altitude of about 1,000m, and while it may seem cool in the summer, the humidity is high throughout the year, and it is said that the relative humidity can exceed 90% in the summer . This can cause stresses on homes, such as dampness, condensation, mold, and wood rot.
In particular, in vacation homes or homes that are only used on weekends, air tends to stagnate and humidity builds up , so it is necessary to take measures to prevent humidity from the design stage.
Karuizawa's climate characteristics
Even in summer, temperatures are low but humidity is high
Large temperature difference between morning and evening
Surrounded by forests, there is a lot of moisture on the ground and in the air.
When these conditions overlap, This is "summer condensation."
What is the truly scary "summer condensation" in Karuizawa?
Summer condensation occurs when humid outside air gets into the cooled interior of a building (under the floor, inside the walls, or in the attic) .
Mechanism of summer condensation
Humid outside air entering the building
The temperature inside the walls and under the floor drops due to shade and geothermal heat.
Moisture in the air reaches the dew point and condenses inside the wall
This is the biggest problem.
Condensation occurs in places you can't see
the result,
Condensation inside walls
Decay of structural materials
Musty odor and sick house syndrome
Shortening the lifespan of homes
This leads to serious problems such as:
In particular, in homes that are used as vacation homes or where people are often away from home, the risk of summer condensation increases because the air does not move and humidity tends to build up .
Summer condensation cannot be prevented by "high insulation and airtightness" alone
In recent years, homes have become more highly insulated and airtight. However, if a house does not allow air and moisture to escape , moisture can end up being trapped inside.
Winter condensation → Easy to prevent with insulation
Summer condensation → Cannot be prevented without ventilation and air flow
This is a very important point when building a house in Shinshu/Karuizawa.
The "Airflow Construction Method" is suited to the Shinshu climate
This is where the airflow method comes in handy.
The airflow method is a method of creating air passages (air paths) within walls, under the floor, and in the attic to control the air flow according to the season.
The essence of the airflow method is to move moisture using natural forces (temperature differences and rising air currents) without relying too much on machinery.
Summer airflow method | A system that prevents moisture accumulation
Summer mode features
Rising air currents expel moisture that has seeped under the floor or into the walls
Allows heat and moisture to escape from the attic
The whole house is like a "shade with a breeze passing through"
This means:
Less likely to cause condensation inside walls
Reduces the risk of mold and rot
The room is also less sticky
This construction method is extremely well suited to combating summer condensation in Karuizawa .
Winter airflow construction method | Dealing with winter condensation Of course, it is also effective against winter condensation.
Winter mode features
Controls ventilation openings to prevent cold air from entering
Air heated by solar heat is circulated under the floor through a circulation duct and circulated within the walls.
Increase the surface temperature of walls and floors
This means:
Prevents condensation caused by temperature differences
Prevents cold under the floor and inside the walls
The strength of the airflow method is that it creates an environment where condensation does not occur, both in winter and summer .
This can be easily done even in existing vacation homes!!
Recommended items and ideas for preventing humidity and condensation
"Isn't it impossible to prevent condensation unless it's a new building?"
That may seem like a common belief, but there are "measures you can take right now" even for existing vacation homes and used homes.
Control humidity with equipment
■ Karaie (Daikin)
A residential dehumidifier that is effective in preventing moisture throughout a building.
It is also suitable for homes with underfloor storage, storage spaces, and the "deadline period" that is unique to vacation homes.
A major advantage is that you can control the humidity even when you are away.
▶ For more details, please visit https://www.ac.daikin.co.jp/karaie
■ Kenta-kun (Rinnai)
Drying laundry indoors is one of the major causes of summer condensation.
If you use the gas clothes dryer "Kantakun",
• Keep moisture out of the room
• Dry your laundry in one go
• Significantly reduces the risk of mold and condensation
This will help you control humidity and improve your housework efficiency at the same time.
▶ For more details, please visit https://rinnai.jp/lp/kanta/
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Review furniture arrangement and air flow
You can reduce the risk of condensation by simply making some adjustments to the way you live without relying on machines.
■ Keep furniture "a little away from the wall"
Do you have dressers, bookshelves, sofas, etc. attached right up against the wall?
👉 Just create a gap of a few centimeters between the wall and
• Air flow
• The wall temperature becomes difficult to decrease.
• Prevents mold growth behind furniture
This has the following effect.
________________________________________
■ Let the air flow (use a circulator)
The key to preventing humidity is to keep the air moving.
• Circulate the air in the room with a circulator
• Ventilates closets and cupboards
• Move stagnant air
This alone can eliminate the conditions for summer condensation to occur.
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The difference between symptomatic treatment and fundamental measures
The items and ideas introduced so far are
✔ Can be done quickly even in existing homes
✔ Cost-effective and effective
It is very effective in that respect.
however,
To fundamentally prevent summer condensation, it is important to create air flow within the building itself.
For more information on the "Airpass Method" that is suited to the Shinshu climate,
Check out this article ⇒
Summary | The key to building a house in Karuizawa is to deal with summer humidity
Generally, people tend to think that "condensation = winter problem", but
In Karuizawa and Shinshu, summer humidity and summer condensation are the biggest risks .
Winter condensation → Visible condensation
Summer condensation → invisible condensation (= really scary)
That's why,
Not only thermal insulation performance
Ventilation, air flow, and moisture escape
It is necessary to build a house that takes this into consideration.
The Airpass method is a "regionally adapted anti-condensation measure" that was developed with an understanding of the climate of Shinshu .
To live comfortably in Karuizawa for a long time, be sure to learn about condensation prevention measures, including in the summer.
We look forward to seeing you at the "Kobo Shinshu no Ie" Karuizawa showroom !
While we are architectural professionals such as designers and construction managers, all of our employees act as "Shinshu concierges" to support a rich life in Shinshu.
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