Can an Electric Space Heater Cause Moisture in Plaster Walls?

The question of whether an electric space heater can cause moisture in plaster walls is a complex one, as heaters can have both drying and moistening effects on the air. This comprehensive guide will provide a detailed analysis of the issue, along with technical specifications and a DIY approach to address the problem.

Understanding Heater Types and Their Effects on Moisture

Firstly, it’s essential to understand the difference between heaters that add moisture to the air and those that do not. Propane or kerosene space heaters, for example, release water vapor as a byproduct of combustion, effectively adding moisture to the air. In contrast, electric space heaters generally do not introduce additional moisture into the environment.

However, the presence of moisture in plaster walls is not solely determined by the type of heater used. Other factors, such as insulation, air exchange, and the source of moisture, also play a significant role in the overall moisture levels.

Drying Plaster Walls with Electric Space Heaters

can an electric space heater cause moisture in plaster walls

In the context of plaster walls, moisture can be a concern during the drying process of joint compound or when dealing with wet drywall from leaks. A combination of heat and air movement is recommended for drying plaster surfaces, as moving the moisture to other places helps the compound dry quicker. Electric space heaters, in particular, can make the environment warmer and suck moisture out of the air, making them a suitable option for drying plaster walls.

Maintaining the Ideal Temperature Range

When using heaters to dry plaster walls, maintaining the right temperature range is crucial. A temperature range of 65 degrees to 80 degrees Fahrenheit (18 to 27 degrees Celsius) is ideal for drying joint compound. If the temperature is too high, it can negatively affect the ability of the joint tape to bond to the face of the gypsum board, cause joint compound to shrink excessively, and form cracks at the edge of the tape. Therefore, it is essential to maintain the room temperature within this range to avoid these issues.

Technical Specifications for Effective Drying

In terms of technical specifications, every electric heater is 100% efficient, meaning all the electrical energy is converted into heat. However, a convection heater is preferred when drying plaster, as it ensures even heat spread throughout the room. For large areas, multiple heaters or a dehumidifier might be necessary to maintain the desired temperature and humidity levels.

A DIY Approach to Monitoring Moisture Levels

To address the question of moisture in plaster walls specifically, a DIY approach can be taken by monitoring the temperature and humidity levels in the room. A hygrometer, which measures relative humidity, and a thermometer can be used to track these variables.

Measuring Relative Humidity

Relative humidity is a crucial factor in determining the moisture content in the air. Ideally, the relative humidity in the room should be between 30% and 50% for optimal drying conditions. A hygrometer can be used to measure the relative humidity and ensure that it remains within this range.

Maintaining the Ideal Temperature

In addition to monitoring humidity, maintaining the ideal temperature range of 65 to 80 degrees Fahrenheit (18 to 27 degrees Celsius) is essential. This can be achieved by carefully adjusting the settings on the electric space heater and monitoring the room temperature with a thermometer.


While electric space heaters can contribute to drying plaster walls by providing warmth and reducing humidity, it is essential to consider other factors such as insulation, air exchange, and the source of moisture. By maintaining the right temperature range, ensuring adequate air movement, and monitoring the temperature and humidity levels, the risk of moisture buildup in plaster walls can be minimized.

Reddit Discussion on Using Space Heaters to Speed Evaporation
Plasterers Forum Thread on Heater or Dehumidifier Recommendations
Heating Help Forum Discussion on Sweaty Walls and Steam Heaters
The Answer Bank Question on Moisture in Plaster Walls
King Electric Guide on Using Portable Electric Heaters to Dry Joint Compound