Air leaks and poor insulation can waste 20–30% of your heating and cooling energy. A thorough home audit and targeted improvements can dramatically reduce your electricity bill. This guide walks you through identifying problem areas and fixing them.
Why Air Sealing Matters
Conditioned air escapes through gaps around windows, doors, electrical outlets, and penetrations in the building envelope. Cold or hot outdoor air enters in return. Your HVAC system must work harder to maintain comfort, driving up energy use and costs.
Conducting a DIY Air Leak Audit
On a windy day, walk through your home and feel for drafts. Use a lit incense stick or thin tissue—movement indicates airflow. Check these common leak locations:
- Window and door frames (especially corners and sills)
- Electrical outlets and light switches on exterior walls
- Baseboards and where walls meet floors
- Attic hatches and pull-down stairs
- Plumbing and wiring penetrations
- Recessed lighting (can lights) in ceilings
- Fireplace dampers and flues
Types of Weatherstripping
Door Sweeps and Thresholds
Gaps under doors are among the largest sources of air leakage. Install door sweeps (attached to the bottom of the door) or replace worn thresholds. Ensure a snug fit without scraping the floor.
V-Strip and Foam Tape
V-strip (tension seal) works well for door and window jambs. Foam tape is inexpensive and easy to apply but may need replacement every few years. Choose the right thickness—too thick and doors won't close properly.
Caulk for Stationary Gaps
Use silicone or acrylic latex caulk for cracks and gaps that don't move: window frames, baseboards, and trim. Clean and dry surfaces before applying. For gaps larger than ¼ inch, use foam backer rod first, then caulk.
Insulation Basics
Insulation slows heat transfer. R-value indicates resistance to heat flow—higher is better. Recommended levels vary by climate and location in the home. Attics are often the most cost-effective place to add or upgrade insulation.
"Seal before you insulate. Air leaks can bypass insulation and undermine its effectiveness. Fix the leaks first, then add or upgrade insulation."
Attic Insulation Checklist
- Check current R-value (many attics have R-19 or less; R-38 to R-60 is recommended in most climates)
- Seal around pipes, wires, and recessed lights before adding insulation
- Don't block soffit vents—use baffles to maintain airflow
- Consider blown-in insulation for irregular spaces; batts for accessible areas
Outlet and Switch Gaskets
Exterior wall outlets and switches can leak significant air. Foam gaskets behind cover plates are an easy, low-cost fix. Install them on all outlets and switches on outside walls.
When to Call a Professional
For comprehensive audits, consider a professional energy assessment. They use blower doors and thermal imaging to find hidden leaks. If you have an older home, asbestos, or complex attic access, professional help is safer and more thorough.
After sealing and insulating, use ElectriBill's calculator to estimate your reduced energy use and compare with previous bills.