It can seem like an age for the paint to dry between coats. If you’re a busy tradesperson or just an impatient DIYer, you might wonder if using a dehumidifier helps paint to dry faster.
While it seems that a dehumidifier is a useful tool when preparing a room for painting, a fan heater is probably better for speeding up the drying process after the paint is applied.
A dehumidifier is best used to create the optimum humidity level in a room before any painting begins. When applying paint at the ideal temperature and humidity, drying times automatically reduce.
Ideal paint drying conditions
There are 4-components involved in paint drying properly; additives, binder, filler, and solvent.
The effectiveness of each one depends on the temperature and humidity of the room.
If the room is too cold, the paint will have difficulty bonding to the surface; if it is too warm, it might crack or have a sub-standard finish.
Rooms where humidity is high and temperatures are low, create longer paint-drying times.
Ideal painting conditions
| Paint type | Temperature °c | Humidity % |
| Oil-based | 4.4 – 10° | 40-70 |
| Latex | 29.4 – 32.2 | 40-70 |
Will using a dehumidifier harm drying paint?
Humidity is the enemy of drying paint, causing defects in the film as it dries.
To guarantee the best finish; paint should be allowed to dry at its own pace, as per the manufacturer’s instructions.
However, if it is necessary to speed up the process, a combination of moving air and heat is the safest method.
The best way to achieve this is by having a heater in the room and doors and windows open to circulate the air.
On particularly hot days, the combination of an electric heater and the climate will increase the humidity.
In this instance, running a dehumidifier in the room might help prevent the build-up of damaging condensation.
Finally
Paint needs time to cure between layers; this is the final process when the paint reaches maximum hardness and lustre.
Rushing drying time interferes with the process, leaving imperfections in the finish.
The best way to combat it is by using a dehumidifier to draw out any unwanted water vapour from the air – before any painting occurs.
Just as too much humidity affects the appearance of paintwork, so does air that is too dry.
Follow the guidelines for ideal humidity levels; your paint job will be perfect.
A dehumidifier does help to dry paint faster but at the expense of the finish. Use your machine to achieve the best painting environment and switch it off.