Blown-in fiberglass insulation is one of the most common and effective insulation materials used today. However, as temperatures drop, humidity levels also fall — often below 30% relative humidity — creating the perfect conditions for static electricity buildup. During installation, that can mean unpleasant (and sometimes painful) shocks for installers.
Although fiberglass insulation is manufactured with an anti-static ingredient, dry air can still lead to static buildup. The good news is that there’s a simple, safe way to minimize it: add a small amount of moisture to the insulation before blowing.
Here's how to do it:
1. Load the machine properly:
Open the fiberglass bags and allow the insulation to expand into the blowing machine hopper.
2. Add moisture carefully:
Using a spray bottle, lightly mist the insulation with a mixture of water and fabric softener.
- - Start by spraying every other bag and adjust as needed.
- - In freezing temperatures, a mix of RV antifreeze and fabric softener works well.
- - Tip: Snow can also be used — just make sure it’s free of debris before adding it to the hopper.
- - ⚠️Safety Note: Always have the SDS (Safety Data Sheet) for any antifreeze used on-site.
3. Avoid adding too much water:
Never pour cups of water directly into the hopper. Excess moisture can cause the fiberglass to clump, reducing coverage and performance.
4. Check your equipment:
Make sure PVC is not used for hose connectors or blow nozzles. PVC builds up static electricity and can make shocks worse. Use grounded or anti-static components instead.
Just a Reminder: Control Static This Winter
As winter temperatures continue to drop, taking a few minutes to control static buildup can make installation safer and far more comfortable for your crew. A small adjustment like this can mean the difference between a long, shocking day — and a smooth, efficient install.