Use cold water.
Heating water for a 20-second hand wash is like starting your car to drive to the mailbox.It's energy spent on a destination never reached.
Why Cold Water?
The Planet
Heating water accounts for about 15-20% of home energy use. Switching to cold reduces your carbon footprint instantly.
The Wardrobe
Hot water breaks down fibers and fades dyes. Cold water keeps your favorite shirt looking new for years.
The Body
Cold exposure improves circulation, boosts dopamine, and helps with muscle recovery.
Interactive Labs
Explore the science of thermal lag and see how small decisions add up to massive savings.
The Pipe Problem
When you turn on the hot tap, you're not just heating water—you're heating meters of copper pipe inside your walls.
For short tasks, the warm water often arrives after you're done. Test it with your home setup:
🏁 The Great Pipe Race
💰 Savings Calculator
Potential Savings
Equivalent to 101x driving an EV for 20 km 🚗
Calculate Your Impact
It's not just pennies. Switching laundry from hot to cold saves enough energy to power your entire digital life.
Tap Decision
Washing hands before dinner
⏱ 20 seconds
🤔 Guess the Waste
If you run the hot tap for just 20 seconds, how much energy is wasted?
The Science of Cold
Evidence-based reasons why switching to cold water is better for your hygiene, your clothes, and your biology.
Hygiene & Handwashing
A landmark study by Rutgers University found no difference in bacteria reduction between water at 15.5°C (60°F) and 38°C (100°F). Detergent and friction do the cleaning, not the heat.
Read the Rutgers Study ↗
Carbon Footprint
Heating water accounts for 75% to 90% of a washing machine's energy. Shifting from 40°C to 30°C washes can reduce global warming potential by 20-25% per cycle.
ACI Laundry Research ↗
The Dopamine Rush
Immersion in 14°C (57°F) water has been shown to increase dopamine levels by up to 250%. This provides a sustained mental boost without the crash of artificial stimulants.
PubMed: Cold & Dopamine ↗The Plumbing Reality Check
Most people don't realize that in typical copper piping, hot water cools down at a rate of 1°C every few minutes once the tap is off. When you turn on the "warm" tap for a quick rinse, you often pay for the energy to heat the pipe, while using only the cold water that was already sitting in it.