Home experts and DIY enthusiasts are sharing a simple, low-cost method to improve indoor comfort during winter months: placing a bowl of salt water near a sunny window. Surprisingly, this technique can mimic the insulating or reflective effects that aluminum foil provides in warmer seasons.
How It Works
The principle relies on thermal absorption and reflection:
- Salt water absorbs sunlight and releases gentle heat into the room
- Positioning it near a window allows it to capture maximum sunlight
- The water also helps regulate humidity, creating a slightly warmer and more comfortable environment
While aluminum foil in summer reflects heat away, salt water in winter essentially stores and radiates heat indoors.
Benefits
Homeowners have reported several advantages:
- Reduced reliance on heaters for small spaces
- Improved ambient warmth near windows
- Minimal cost and easy setup
This method is safe, eco-friendly, and requires no special equipment beyond a simple bowl and salt.
Tips for Best Results
To maximize effectiveness:
- Use a wide, shallow bowl to increase surface area
- Place it where sunlight directly hits the water
- Replace water every few days to prevent stagnation
Optional: a small layer of clear plastic or glass over the bowl can enhance heat retention without reducing sunlight exposure.
Why It Works Like Aluminum Foil in Summer
Aluminum foil blocks and reflects heat during hot months, preventing interiors from overheating. The salt water trick, by contrast, absorbs and slowly releases heat in colder months, creating a passive, energy-efficient warming effect.
Final Takeaway
This simple winter hack — a bowl of salt water by a sunny window — offers a surprisingly effective way to boost warmth indoors, functioning similarly to aluminum foil’s reflective properties in summer but in reverse. It’s a practical, low-effort trick for anyone looking to make their home cozier without extra energy costs.








