Q: Jason, I’ve been thinking of various ways to insulate my whole house fan for the winter and happened to your product. I was thinking of removing the shutter and placing the Chimney Balloon in the plenum space just as you would a chimney. Have you ever had anyone inquire about this application? Any idea what level of R-value it may offer? Thanks for your time! – RF

A: You are bringing up a little known, but much used, application of the Chimney Balloon. HVAC contractors use the Chimney Balloon all the time to seal off ducts like you are referring to with your whole house fan systems or HVAC duct systems. The Chimney Balloon is quite effective in air sealing this way.

Unfortunately, we cannot have an R-value assigned to our product since that rating system applies to insulation building materials like fiberglass batting and windows. The Chimney Balloon is an air sealing product that the R system measurement does not apply to (much like Tyvek wrap is not R system rated). However, in a vent environment air sealing is key since it is the unwanted cold air currents through the vent system that you want to stop.

Keep in mind that the Chimney Balloon will take up about 9″ to 12″ in depth space (top to bottom of the balloon) when inflated in a vent or duct. The Chimney Balloon handle/valve can also be shortened if necessary, so it will only require about another 4″.

If you have any questions about your application give us a call at 608-467-0229 and we can walk you through getting a properly fitted Chimney Balloon to plug your whole house fan vent. – Jason