Replies

1. 
   charlie_sullivan | Jan 06, 2016 08:04pm | #1

   A humidifier is pretty much never a good idea in CT. Unless your envelope is leaky, you'll be able to maintain high enough humidity in the winter without it--in fact you'll need deliberate outside-air ventilation to avoid building up excessive humidity. Any halfway competent builder using open-cell spray foam can achieve a tight enough envelope that low humidity will not be a problem.

   In a leaky house, the humidity can be uncomfortably low, but the moisture that a humidifier introduces goes into the walls through those leaks and causes mold, decay and other problems. So a humidifier is a bad solution to that problem.

   Open cell spray foam works well, but there are more cost effective ways to achieve the same or better air tightness and insulation levels.

2. 
   justinmurphy | Jan 06, 2016 09:41pm | #2

   Charlie, thanks for you thorough answer! I'm GC'ing my own home so I have "halfway competent builder" covered. haha

   I've already installed open cell in this case, but I'd be curious to hear your thoughts on other "cost effective ways..." for future reference. Thanks again!

3. GBA Editor
   Martin Holladay | Jan 07, 2016 06:55am | #3

   Justin,
   Charlie gave you good advice. Humidifiers are dangerous devices that can cause condensation in hidden areas of your home, and have been known to cause sheathing rot. Don't install a humidifier.

   A humidifier is a last-ditch effort to solve a fundamental construction error: namely, not making the building tight enough. If your building is leaky, the indoor air will be dry in winter. Sloppy builders make leaky buildings, and then try to solve the problem of dry air with a humidifier. This is nuts.

   So pay attention to airtightness at all phases of construction. Before you install your drywall, hire a home performance contractor to perform a blower door test. You want to achieve 1.5 air changes per hour at 50 pascals if you can -- 1 ach50 is even better. If you take this advice, you won't have dry air.

   You don't need spray foam to get a tight house. In many cases, all you need is caulk, high quality tape, and some gaskets. If you spend some time researching these issues on the GBA site -- use the GBA search box -- you'll find lots of articles to help you.