I have been looking for answers on Google but it looks like they are mostly personal and different opinions....

From my knowledge and experience, I agree that sunlight will have bleaching effect on clothes and garments but not dryer, but how about strength of the clothes? Does sunlight or heat from dryer weaken clothes more easily? It's said clothes dried by sunlight will last longer because they do not experience heat from dryer, however, I think the energy from sunlight is more damaging to the bonding of the textile of the clothes, isn't it? Which is correct?

Last but not least, will clothes of the same textile but with white color last longer or break less easily because they do not absorb sunlight (white color) than that of the dark color (e.g. black absorbs heat)

Edited August 16, 20223 yr by kenny1999

The ultra-violet part of the spectrum does damage cloth, in a similar way that bleach does, weakening the fabric making it easy to tear, like paper. But it's likely to be negligible for clothes on a washing line. 

I have a set of nice curtains, that have a white liner that hangs as an outer layer, and the liner has suffered, but the curtains have been hanging for years, and the window does get strong sunlight. You can easily rip the liner with your fingers, if you pull the curtains roughly, but the inner decorative curtain is in perfect condition. To replicate that kind of fabric weakening, I think you would have to leave the clothes on the washing line for years. 

The curtain liner is white, so that hasn't protected it from damage. 

53 minutes ago, kenny1999 said:

I have been looking for answers on Google but it looks like they are mostly personal and different opinions....

From my knowledge and experience, I agree that sunlight will have bleaching effect on clothes and garments but not dryer, but how about strength of the clothes? Does sunlight or heat from dryer weaken clothes more easily? It's said clothes dried by sunlight will last longer because they do not experience heat from dryer, however, I think the energy from sunlight is more damaging to the bonding of the textile of the clothes, isn't it? Which is correct?

Last but not least, will clothes of the same textile but with white color last longer or break less easily because they do not absorb sunlight (white color) than that of the dark color (e.g. black absorbs heat)

While it is true that UV does eventually weaken fabrics, this is usually noticeable only for things such as curtains and sofas that may be exposed to a lot of direct sunlight for hours every day, for years on end. For clothes and bed linen, i.e. the items on your washing line, you can usually ignore this, as the exposure time is a few hours per week at most. Most clothes wear out for other reasons.

Regarding dryers, it is noticeable that a significant amount of fluff collects on the filter of a dryer every time you run it. This is no doubt partly human skin cells, but a lot is fibres from the fabric. My guess would be this will have more of a weakening effect than sunlight on a clothes line. 

In my opinion, clothes dried outside smell fresher - and of course it is more environmentally friendly as well. So personally I always dry clothes outside, when the weather permits. I make an exception for towels, which are much softer if dried in a dryer.

 

Sunlight could affect fabric differently depending on it being organic or synthetic fibers.

While UV light could cause fabric dyes to fade and fabric to incrementally weaken.

It will also break down and destroy fragments of DNA and RNA providing disinfection.

On 8/16/2022 at 2:42 AM, exchemist said:

While it is true that UV does eventually weaken fabrics, this is usually noticeable only for things such as curtains and sofas that may be exposed to a lot of direct sunlight for hours every day, for years on end. For clothes and bed linen, i.e. the items on your washing line, you can usually ignore this, as the exposure time is a few hours per week at most. Most clothes wear out for other reasons.

Regarding dryers, it is noticeable that a significant amount of fluff collects on the filter of a dryer every time you run it. This is no doubt partly human skin cells, but a lot is fibres from the fabric. My guess would be this will have more of a weakening effect than sunlight on a clothes line. 

In my opinion, clothes dried outside smell fresher - and of course it is more environmentally friendly as well. So personally I always dry clothes outside, when the weather permits. I make an exception for towels, which are much softer if dried in a dryer.

 

I think uv does not make clothes week but they will make them shrink a lot. For rayon i have seen this a lot.

6 hours ago, timcok8 said:

I think uv does not make clothes week but they will make them shrink a lot. For rayon i have seen this a lot.

You're wrong about that: https://www.researchgate.net/publication/230076355_The_Effect_of_Light_on_Textiles