Condensation refers to water droplets that form when warm, moist air comes into contact with cold surfaces. It is a common problem in homes during the winter months. Condensation occurs when there is excess moisture in the air and surfaces that are cold enough for the moisture to condense into liquid water. A cold house temperature can certainly contribute to issues with condensation.
What causes condensation in a home?
Condensation in a home is caused by an imbalance between moisture levels and surface temperatures. Here are the main factors that lead to condensation:
- High indoor humidity – From activities like cooking, bathing, laundry, and even breathing, moisture gets added to the indoor air.
- Poor ventilation – If moist air is not properly ventilated and replaced by drier air from outside, it will condense on cold surfaces.
- Cold surfaces – When surfaces like windows, walls, ceilings are colder than the dew point temperature of the indoor air, condensation occurs.
- Poor insulation – Allows cold exterior temperatures to cool the inner surfaces of the home.
- Cold weather – Colder outdoor temperatures mean colder indoor surfaces, resulting in more condensation.
A cold house temperature exacerbates the differences between the temperature of the air and surfaces, making condensation more likely. The colder the home, the colder the inner surface temperatures will be.
What are the optimal temperature and humidity levels to prevent condensation?
To minimize condensation, the optimal temperature and humidity levels are:
- Indoor air temperature between 18-21°C
- Indoor relative humidity 30-50%
Maintaining these levels will prevent excessive moisture in the air and keep inner surface temperatures warm enough to avoid going below the dew point.
The table below shows the recommended maximum relative humidity based on indoor air temperature:
| Indoor Air Temperature | Max Recommended Relative Humidity |
|---|---|
| 70°F / 21°C | 45% |
| 68°F / 20°C | 48% |
| 65°F / 18°C | 50% |
What room temperature should be maintained to avoid condensation?
To avoid excessive condensation, the recommended room temperature to maintain is 18-21°C (64-70°F):
- Bedrooms – 18°C
- Living rooms – 20-21°C
- Kitchen – 18°C
- Bathrooms – Minimum of 18°C
The warmer rooms where people spend more stationary time, like living rooms and bedrooms, should be kept at the higher end of the range. Kitchens and bathrooms can be slightly cooler since people are moving in and out of them. Going below 18°C significantly increases condensation risks.
Which rooms in the house are most susceptible to condensation?
The rooms most prone to condensation issues are:
- Kitchens – From cooking steam and kettles
- Bathrooms – From hot showers producing steam
- Bedrooms – People breathing out moisture overnight
- Common areas – Moisture from people breathing, cooking, washing, etc
- Attics and basements – Cold areas of the home
Kitchens and bathrooms tend to have the most condensation problems due to the high moisture activities occurring regularly in these rooms. Bedrooms and common areas are also common problem spots as they have high occupancy. Uninsulated attics and basements with exposed walls and pipes can easily fall victim to condensation as well due to cold exterior temperatures.
How does poor insulation cause condensation?
Poor insulation leads to condensation by allowing inner surfaces to reach very cold temperatures. Heat is lost through flaws in insulation, allowing exterior cold to come indoors and cool down inner walls, windows, ceilings, and pipes.
When a poorly insulated house is significantly colder inside than regular room temperature, those inner surfaces can reach temperatures below the dew point of the indoor air. This temperature differential causes moisture to condense.
Poor insulation also leads to more moisture generation through increased heating needs. The harder the heating system has to work to compensate for heat loss, the more moisture gets added to the indoor air.
Some ways poor insulation causes condensation:
- Allows cold from outside to reach inner surfaces
- Lowers surface temperatures below dew point
- Increases moisture levels from greater heating needs
- Exposed attics and basements become very cold
Improving insulation keeps the house warmer, reduces heating costs, and minimizes cold surface condensation issues.
How does cold weather increase condensation?
Cold weather increases condensation through:
- Lowering outdoor air temperature – Cools surfaces of poorly insulated homes
- Increasing heating system use – Adds moisture to indoor air
- Lowering temperature of outer walls – Inner wall surfaces become colder
- Wider gap between indoor/outdoor temperatures – Leads to more heat and moisture flow
The colder it is outdoors, the greater the temperature difference between the inside and outside of the home. This increased gradient pulls more heat through flaws in insulation, cooling down inner surfaces. More heat is also pumped out by the heating system, adding extra moisture to the indoor air.
Cold snaps, winter storms, and frosty nights are when condensation problems become most noticeable. Keeping the home properly insulated and ventilated is critical during cold weather.
Which side of the house gets more condensation?
The side of the house most exposed to cold winds and winter weather will typically get the most condensation. This is usually the side that faces the direction of the prevailing winds.
For example, if the prevailing winds come from the North in the winter, the North-facing side of the house will generally have more condensation issues. The wind chill brings colder temperatures that cool down the outer walls and inner surfaces.
Factors causing more condensation on certain sides:
- Exposure to prevailing winter winds – North side in northern hemisphere
- Orientation facing the sun – South in northern hemisphere
- Shaded areas without solar heat – North side
- Poor insulation – Allows cold in on exposed side
- Trees/obstructions blocking sun – Prevents warming
Improving insulation and sealing gaps on the side with the most exposure to winter winds will help balance out the condensation.
What are the dangers of excess condensation?
Excess condensation can cause multiple problems:
- Mold growth – Damp conditions allow mold to grow on walls and ceilings
- Rotting wood – Absorbed moisture rots window frames, sills, and wood structures
- Peeling paint – Trapped moisture bubbles paint and makes it peel
- Dripping water – Condensed water can soak materials and drip from ceilings or windows
- Damage to electronics – Moisture can damage computers, TVs and other devices
- Bacterial growth – Dampness allows bacterial growth that impacts indoor air quality
Chronic excess condensation creates unhealthy living conditions and damages the home. It is important to control moisture levels before problems arise.
How can you fix condensation in a house?
Here are ways to fix condensation in a house:
- Increase ventilation – Use exhaust fans, open windows, install vents
- Raise indoor temperature – Heat home to 18-21°C range
- Use dehumidifiers – Remove excess moisture from the air
- Improve insulation – Fill gaps, upgrade attic and walls, insulate basement
- Increase air circulation – Keep air moving with fans
- Avoid drying clothes indoors – Use vented dryer or drying racks
A combination of improving ventilation, insulation, air circulation, and controlling moisture sources will help reduce condensation. Maintaining proper indoor temperature and humidity levels is also key.
How can you prevent condensation on double glazed windows?
To prevent condensation on double glazed windows:
- Maintain indoor humidity below 50%
- Keep air circulation around windows – Keep curtains open
- Make sure air can flow between window panes – Check for seal failure
- Avoid blocking radiators under windows – Allow heating
- Install higher quality windows – Reduce heat loss at edges
- Apply silicone sealant along edges – Seal gaps
Condensation between double panes indicates a failure of the air seal. This needs professional repair to replace the argon gas fill. Keeping the indoor environment comfortable and air circulation high around windows will help minimize surface condensation.
What is the best way to measure humidity in a home?
The most accurate ways to measure humidity level at home are:
- Digital hygrometer – Provides temperature and humidity readings
- Psychrometer – Measures wet and dry bulb temperatures
- Humidity meter – Probe style or wall-mounted sensor
- Weather station – Combines thermometer and hygrometer
A digital hygrometer is easy to use and provides reliable humidity and temperature data. Place it in a commonly occupied room away from windows and doors. Calibrate annually and replace batteries regularly for best accuracy.
Avoid inaccurate methods like looking for condensation, dry skin, wood swelling or using chemical hygrometers. Digital meters provide the most reliable way to monitor indoor humidity.
What humidity level is too high for indoor air?
The recommended maximum indoor humidity levels are:
- Year-round – Less than 50%
- Winter – 30-45%
- Summer – 35-55%
Indoor relative humidity consistently over 50% is considered too high and likely to cause condensation issues. Ideal humidity is around 30-50% year-round. In winter, a max of 45% prevents condensation and allows proper humidity levels in summer up to 55%.
Humidity levels over 60% provide an ideal environment for mold growth and bacterial propagation. Keeping indoor relative humidity under 50% helps maintain healthy indoor air quality and reduces condensation risks significantly.
Conclusion
In summary, a cold house certainly contributes to issues with condensation by creating cold inner surfaces and raising indoor humidity levels. Condensation forms when warm, moist air meets cold surfaces that drop below the dew point. Maintaining proper indoor temperature (18-21°C) and humidity (30-50% RH) provides the best prevention against problematic condensation. Improving insulation, sealing gaps, and increasing ventilation can all help control unwanted moisture settling inside the home during colder weather.
