Window Sealing: How to Stop Drafts & Save on Heating Costs
Leaky windows are energy guzzlers! Whether it's cold drafts in winter or high heating costs – poorly sealed windows can be expensive. In this guide, we show you which methods you can use to professionally seal windows, which sealing materials last best, and how you can save energy in the long term.
✅ What you will learn in this article:
✔ What types of seals are available (rubber, foam, silicone & more)
✔ Step-by-step DIY guide
✔ The best tips for old buildings & modern windows
✔ Cost comparison:
Is DIY or professional installation worth it?
1. Why seal windows? The benefits at a glance Leaky windows lead to:
❌ High heating costs (up to 20% more energy consumption!)
❌ Mold growth due to moisture
❌ Drafts & uncomfortable cold spots
Good sealing not only saves money but also increases living comfort.
2. What sealing materials are available?
|
Material |
Advantages |
Disadvantages |
Ideal for |
|
Rubber Seal (EPDM) |
Durable, flexible, weather-resistant |
More expensive |
Window frames, outdoor areas |
|
Foam Sealing Tape |
Inexpensive, easy to apply |
Doesn't last forever |
Rental apartments, temporary solutions |
|
Silicone Seal |
Waterproof, elastic |
Difficult to remove |
Bathrooms, humid rooms |
|
Window Fleece (FiberGuard) |
Invisible, good insulation |
Not for strong drafts |
Minor leaks |
|
Insulation |
|
Not for strong drafts |
Minor leaks |
➡ Tip for old building windows: Combine rubber seal + compression tape for maximum sealing effect!
3. Sealing windows – step by step🛠️ Materials:
- Sealing tape (e.g., EPDM or foam)
- Scissors / utility knife
- Cleaning alcohol (for grease-free surface)
- Measuring tape
🔧 Instructions:
1. Clean windows (remove dust & grease, otherwise the seal won't stick).
2. Cut sealing tape to size (slightly overlapping at the corners).
3. Press on seal (apply slowly and evenly).
4. Close and test windows (draft test with lighter/light).
➡ Pro tip: Use self-adhesive seals for easy installation!
4. When is a professional worth it?
✔ If several windows are leaky (free check by energy consultant possible)
✔ For historic windows (special solutions needed)
✔ If mold is present (sealing alone is not enough then)
💡 Cost example:
- DIY sealing: €5–20 per window
- Professional installation: €50–150 per window
5. Conclusion:
Well-sealed is half-heated! With the right seal, you save hundreds of euros in heating costs annually and prevent mold. For old buildings, combination solutions (EPDM + compression tape) are suitable; for modern windows, foam sealing tape is often sufficient.