{"product":{"product_id":"B003Z96GR4","title":"Eddy Electronic Water Descaler - Water Softener Alternative - Reduces Limescale","price":"199.99","image_url":"https://m.media-amazon.com/images/I/41CkNrNKY1L._SL500_.jpg","url":"https://www.amazon.com/dp/B003Z96GR4"},"comments":[{"body":"I don't think what you're looking for can exist in an RO system, even if you find filters and membranes that can handle the heat.  Most household RO systems have a pressurized tank as an output buffer which will cause any incoming hot water to lose its heat long before it gets to the tap.  A system without such a tank would have a water flow of barely a trickle, which would also lose all of its heat before getting to the tap.  You'll probably have better luck finding a (non-RO) particulate filter that can handle the temperatures, but even then you're probably still going to have significant heat loss problems due to the additional buffer and surface area, combined with the reduced flow (but not nearly as much as with an RO system).\r\n\r\nAs other commenters are saying, the right way to go is to put a filter before the water heater, which it sounds like you already have.  If the actual issue is that your wife believes there's a water quality issue where none exists, it sounds like a perception problem rather than a technical one; and I understand the problem of not being able to convince someone whose mind has been made up.  Could you just get something like [this](https://www.amazon.com/gp/product/B003Z96GR4) and tell her it'll add the \"extra protection\" she's looking for?  To be clear, I'm pretty sure these things do nothing, and aren't even marketed as a filter - but might be an easy way to fix the perception problem if you can get her to believe.","subreddit_name":"DIY","author":"crispy1989"},{"body":"I just purchased this gadget and will be installing on my incoming main - technically it doesn’t decalcify the water but does prevent the calcium from building up.\r\n\r\n\r\nEddy Electronic Water Descaler - Water Softener Alternative \r\nhttps://www.amazon.com/dp/B003Z96GR4/ref=cm_sw_r_cp_tai_URY2Db6QNSSC1","subreddit_name":"Plumbing","author":"brymc81"},{"body":"https://www.amazon.com/dp/B003Z96GR4","subreddit_name":"SanJose","author":"forhorglingrads"}]}