Bathroom insulation is important for controlling moisture. Insulating the bathroom keeps the temperature more comfortable when you use the room; remember that the bathroom is one of the most-used rooms in the house. It does need to be approached carefully, however.
The most important part of bathroom insulation is the inclusion of a vapor retarder under the bathroom wall. This prevents the collection of vapor under the insulation, which can cause mold and mildew to form and possibly create health problems for family members.
In many parts of the country, a vapor retarder or vapor barrier is mandated by building codes. Even where it’s not, it’s a very good idea as part of your general home insulation project and an addition should always be carefully considered.
Bathroom insulation is always good, as it is everywhere in the house. It stops heat escaping, which can be especially important given that the bathroom is one of the warmest rooms in the house.
The vapor retarder hinders the escape of heat and also works to control the moisture. These can often be in the form of faced batts of insulation that have the vapor retarder built in and are easier to install than a separate vapor retarder.