I feel compelled to point out this important bit of context for anyone who doesn't read the paper:

Overall, based on the four environmental indicators used in this study, home-washed reusable nappies have the potential for the least environmental impact if washed in a water-efficient front￾loading washing machine in cold water, and line-dried.

The UK study similarly found that colder water and line-drying would sufficiently reduce the carbon footprint to a lower level than disposables.

But seriously? Who does that?

For regular clothing, where you can use a more powerful detergent? Sure.

But for something that goes directly against your child's most sensitive skin, which will need to be laundered with gentle detergent?

Maybe we can find a paper on how to do all that without heat but with proper sanitation? Remember, laundry detergent is designed to clean, but not necessarily to sanitize.