Comment by userbinator

My strategy is not to use search engines for product recommendations, but to go to the online shops directly, look for the 1-star and 2-star reviews, and read them carefully. Once narrowed down to a few products, I then research them specifically to find out the details.

For the example of air purifiers, look on Ali if you don't want to DIY one with a box fan and HEPA filter. They're all going to be made by some Chinese OEM anyway, so you'll cut out some middlemen and reduce the price, and at least those listings often have far more technical information, and the reviews can have detailed pictures from buyers of the products' internals.