Tjernlund Products says its new UnderAire line of crawlspace ventilation fans offers homeowners a simple, easy and cost-effective way to mechanically circulate fresh, outdoor air underneath homes and porches. These fans are the only crawlspace ventilators currently listed as “suitable for damp conditions.” All three UnderAire models have factory-installed freeze protection thermostats that prevent the units from operating if temperatures are 40°F. The two deluxe models come ready to plug into an electrical outlet and also include a dehumidistat that allows the homeowner to select the humidity level that activates the ventilator. Tjernlund UnderAire fans can be installed in minutes, require no maintenance and are very quiet, the company says.

Tjernlund Products Inc., 1601 Ninth St., White Bear Lake, MN 55110-6794; (800) 255-4208; fax (651) 426-9547;