Cold weather brings more than lower temperatures. It changes how buildings hold heat and moisture.
When heating costs rise, people reduce ventilation and turn to alternative heat sources. Those choices add moisture to the air and make condensation dampness more likely. Surveyors start seeing familiar signs each winter. Water beading on windows. Damp patches along exterior walls. Musty air that points to trapped humidity.
A professional moisture meter confirms what the eye can’t see. It helps surveyors identify where moisture is forming and measure how serious the issue is before it spreads.
The Rise of Condensation Dampness in Winter
While everyone is rightfully worried about affording heat this winter and still keeping warm, they may turn to alternative heating sources such as indoor propane heaters.
However, they may not be aware of the potential dangers of overusing this alternative heating source. Problems arise when unvented propane heaters cause condensation, and condensation causes mold and mildew.
The best offense against condensation is a good defense. Having a professional damp meter on hand is a first step in mitigating condensation problems.
How Propane Heaters Contribute to Indoor Condensation
Supplemental mobile propane, butane, and gas heaters may be viewed as cheaper alternatives to heating homes and apartments. However, these can add high amounts of moisture to the indoor environment.
For every kilogram of propane burnt (about 2.2 pounds), 1.64 kg (roughly 1.6 liters or 0.4 gallons) of water is produced as the carbon in the fuel combines with oxygen in the air.
Without proper ventilation, that moisture remains trapped inside a dwelling – you’ll see condensation dampness clinging on walls, ceilings, windows, and any other surface where it finds purchase.
While indoor propane heaters are safe and effective for briefly heating up a space, it’s also recommended that a window be open for ventilation while they’re in use. This seems counterintuitive for most users, thus they rarely open a window when it’s cold outside.
Dehumidifiers also help pull the excess damp from the air, but it’s fairly safe to guess that people trying to save money on heating costs will not spend more on a dehumidifier.
The Impact of Condensation Dampness on Buildings
First, a primer on condensation.
When you take a cold surface and introduce it to increased humidity (Rh), the water vapor in the air turns from gas to liquid.
It stands to reason then that if customers have let their homes and apartments go cold to save on heating costs… and they start using propane to supplement their heat… and the burning fuel adds more water to the air… That’s right – the warm damp air hits the cold walls and causes condensation. It's usually first noticed as cold weather condensation inside windows.
And if they’re not ventilating their heaters, nor using a dehumidifier, the condensation only gets worse.
This leads to issues inside a home or building, such as:
- Mold
- Mildew
- Water damage
What causes mold and mildew to grow? The same things as other living organisms: food and water. If there’s excess water condensing in a home, the cellulose paper in walls and other building materials become mold's food source.
For homeowners and landlords, properties may sustain permanent and costly damage as the excess damp provides pathways for mold and mildew to spread.
Dampness can make you ill. Mold growth in the living space can cause many ailments that do not always point to mold as being a root cause. This can lead to serious and long term health issues including respiratory infections, allergies, and asthma.
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A note on the difference between mold and mildew: While both are fungi that thrive in humid environments, mildew often visibly appears on surfaces as a powdery substance, but mold is fuzzy or slimy, can grow deep within building materials where it isn’t visible, and poses more health risks. |
Leaving mold and mildew for too long can destroy the materials they’re feeding on, requiring a complete tear-out and replacement of ceilings, walls, window casings, and even floors. Having a dampness meter to spot issues is key.
Measuring Condensation Dampness With Professional Moisture Meters
Professional moisture meters can quickly assess the presence or likelihood of indoor condensation in cold weather and therefore the risk of future mold infestations. They can detect damp at low levels before it can be visually seen or felt.
With the right professional moisture meter, you can assess the potential for condensation by determining the temperature of the air, the air’s humidity, and the surrounding surface (walls, ceilings) temperatures.
When choosing a professional moisture meter look for and single multifunction meter that has:
- Pin & pinless modes
- Measures Rh
- Takes surface temperature readings
Check out the MMS3: With built-in hygrometric capabilities and an infrared (IR) laser thermometer, the MMS3 also assesses indoor air quality conditions.
Condensation Dampness FAQs for Building SurveyorsEven experienced surveyors face questions about condensation dampness. Here are answers to some of the most common ones. Q: How can surveyors differentiate condensation dampness from other forms of damp?A: Condensation dampness appears on cold surfaces like windows, corners, and exterior walls where warm air meets cooler temperatures. It often forms in patches that follow thermal patterns rather than water entry points. Rising damp usually starts at ground level and moves upward, while penetrating damp stems from leaks or structural defects. A professional moisture meter helps confirm the cause by comparing surface and subsurface readings. Condensation tends to show higher moisture near the surface, while deeper readings point to water ingress. Q: What environmental readings or thresholds indicate a condensation risk?A: Condensation risk increases when relative humidity stays around 70% or higher for extended periods. When the surface temperature of walls or ceilings drops close to the dew point, the air releases moisture as condensation. Surveyors should watch for rooms where the air temperature is only a few degrees above the wall temperature. Using a professional moisture meter to log temperature, humidity, and surface readings helps identify when a space is approaching that critical balance. Q: How should surveyors document or report findings from a professional moisture meter?A: Moisture readings should be recorded with context – date, location, and environmental conditions during testing. This helps track changes and compare data between visits. Including photos, temperature, and humidity readings strengthens a report and helps clients understand the findings. Clear language and actionable notes turn raw data into insight, showing how condensation dampness can be prevented before it worsens. |
Reducing Condensation Dampness During Cold Weather
Cold weather always reveals how well a building controls moisture. When ventilation drops and humidity rises from heating, conditions for condensation dampness develop quickly. Once moisture settles on cold surfaces, the damage can spread before it’s visible.
Using professional moisture meters gives surveyors the insight needed to act early. Accurate readings help pinpoint areas most at risk, guide ventilation or insulation improvements, and prevent expensive restoration work. Small readings taken now can stop widespread structural and indoor air quality problems later.
Evaluating Moisture and Dampness Throughout a Building
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