When selecting a heating system for the bathroom, keep in mind the following:
• Even if the bathroom is part of the central heating system duct network, consider adding supplemental heat, especially if the bathroom is at the end of the duct run, or the client tends to keep the house cooler than they would like in the bathroom. Bathroom Planning Guideline 27 recommends a supplemental heat source and the IRC code (IRC R 303.8) states that all bathrooms should have an appropriate heat source to maintain a minimum room temperature of 68 degrees Fahrenheit (20 degrees Celsius).
• When ducting a central heating system into the bathroom, consider installing either a ceiling vent or a baseboard vent. Keeping the register off of the floor, especially in small bathrooms, will prevent users from stepping on the sharp vent with their bare feet.
• If converting a previously unheated area into a bathroom, or expanding a bathroom into an unheated area like a closet, be sure the central heating system can handle the additional load. If the new space is too far from a central heating system, a supplemental heater may be needed to deliver adequate heat.
• When multiple rooms need to be heated, use a zonal system that allows the flexibility to control the heating levels in each area separately.
• Strongly discourage the use of portable heaters as an option for supplemental heating. They are dangerous to use near water and can be a tripping hazard.
• If the shower is oversized or designed with a walk-in entry, additional heat may be necessary for comfortable use.
• If a tub/shower with a door is used, this enclosed area will also benefit from added heat.