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Most dishwashers are connected to hot water. Some higher end dishwashers can work with cold water, but the cheaper ones don’t. Does this mean using a dishwasher

Most dishwashers are connected to hot water. Some higher end dishwashers can work with cold water, but the cheaper ones don’t. Does this mean using a dishwasher is a problem as well?

15457345234 3y ago
This must be a US-centric thing, having had many dishwashers in my time and having never seen one with anything other than a cold water inlet. I assume this is related to the availability of 230v/15A for the heater element.
- wkipling 3y ago
  Must be. I'd say most dishwashers are connected to the mains supply and not pre heated.
- crazygringo 3y ago
  If you have hot water, why wouldn't you use that for the water connection? My dishwasher has a heating element, but the colder the water is, the more it has to work. So if it's cheaper to use gas-powered hot water from the boiler than to heat it electrically, why wouldn't you? And it's there in the kitchen right next to the sink which has hot water available anyways, so it's kind of a no-brainer. Yes, I'm in the US -- you can see on a kind of average dishwasher installation manual [1], it specifically instructs you to connect it to a hot water line. [1] https://www.whirlpool.com/content/dam/global/documents/201012/installation-instructions-W10282559-RevA.pdf https://www.whirlpool.com/content/dam/global/documents/20101...
  - adrianN 3y ago
    My dishwasher uses sufficiently little water that it would get mostly cold water from the hot water pipe.
    - crazygringo 3y ago
      Yeah, the standard advice is actually to run your kitchen faucet on hot until you get hot water, before you start the dishwasher. I'm always rinsing off the bigger gunks of food with hot water anyways as I load the dishwasher, so it's hot already. At the end of the day it doesn't matter that much. The main point is just, if you have hot water available, it's hard to see why you wouldn't take advantage of that.
      - adrianN 3y ago
        I’d assume that wasting a lot of hot water before running the dishwasher negates any price benefits from heating the water with gas instead of electricity. Not to mention the CO2.
  - nemetroid 3y ago
    > If you have hot water, why wouldn't you use that for the water connection? Two protein related reasons: hot water can denature detergent enzymes making them less effective, and hot water can cause food proteins on the dishes to harden and set. European manufacturers claim that detergents work better when starting the program with cold water, and recommend doing so. The situation might be different in the US, where using the hot water seems to be the norm.
SoftTalker 3y ago
Probably not. Most of the water runs off the dishes. A very thin film remains that evaporates in the dry cycle, and even at that a lot of it will bead up and run off completely.
- brnt 3y ago
  I have found that new dishwashers with good eco ratings leave easily detectable amounts of soap on the dishes. Even apart from any health impact, I make it a point to never use them on their default eco programming, but switch to sth that uses more water. I want my dishes clean, that includes soap residue. I got rid of a perfectly fine 35 yo dishwasher that cleaned fine even without soap, due to heat and water use. I got rid of it because it was loud, but I always wondered if running it without soap was perhaps not as eco friendly as a modern washine using less heat and water.
  - stjohnswarts 3y ago
    Use less soap. I use about half as much and the dishes come out fine. I've had better luck with liquid based soaps too as they mix immediately with the water.
    - brnt 3y ago
      You cut those tablets up?
      - stjohnswarts 3y ago
        I don't use those, I use liquid dishwashing gel.
  - astura 3y ago
    Sounds like you're probably using too much detergent.
    - brnt 3y ago

Most dishwashers are connected to hot water. Some higher end dishwashers can work with cold water, but the cheaper ones don’t. Does this mean using a dishwasher is a problem as well?

15457345234 3y ago

This must be a US-centric thing, having had many dishwashers in my time and having never seen one with anything other than a cold water inlet. I assume this is related to the availability of 230v/15A for the heater element.

wkipling 3y ago
Must be. I'd say most dishwashers are connected to the mains supply and not pre heated.
crazygringo 3y ago
If you have hot water, why wouldn't you use that for the water connection? My dishwasher has a heating element, but the colder the water is, the more it has to work. So if it's cheaper to use gas-powered hot water from the boiler than to heat it electrically, why wouldn't you? And it's there in the kitchen right next to the sink which has hot water available anyways, so it's kind of a no-brainer. Yes, I'm in the US -- you can see on a kind of average dishwasher installation manual [1], it specifically instructs you to connect it to a hot water line. [1] https://www.whirlpool.com/content/dam/global/documents/201012/installation-instructions-W10282559-RevA.pdf https://www.whirlpool.com/content/dam/global/documents/20101...
- adrianN 3y ago
  My dishwasher uses sufficiently little water that it would get mostly cold water from the hot water pipe.
  - crazygringo 3y ago
    Yeah, the standard advice is actually to run your kitchen faucet on hot until you get hot water, before you start the dishwasher. I'm always rinsing off the bigger gunks of food with hot water anyways as I load the dishwasher, so it's hot already. At the end of the day it doesn't matter that much. The main point is just, if you have hot water available, it's hard to see why you wouldn't take advantage of that.
    - adrianN 3y ago
      I’d assume that wasting a lot of hot water before running the dishwasher negates any price benefits from heating the water with gas instead of electricity. Not to mention the CO2.
- nemetroid 3y ago
  > If you have hot water, why wouldn't you use that for the water connection? Two protein related reasons: hot water can denature detergent enzymes making them less effective, and hot water can cause food proteins on the dishes to harden and set. European manufacturers claim that detergents work better when starting the program with cold water, and recommend doing so. The situation might be different in the US, where using the hot water seems to be the norm.

SoftTalker 3y ago

Probably not. Most of the water runs off the dishes. A very thin film remains that evaporates in the dry cycle, and even at that a lot of it will bead up and run off completely.

brnt 3y ago
I have found that new dishwashers with good eco ratings leave easily detectable amounts of soap on the dishes. Even apart from any health impact, I make it a point to never use them on their default eco programming, but switch to sth that uses more water. I want my dishes clean, that includes soap residue. I got rid of a perfectly fine 35 yo dishwasher that cleaned fine even without soap, due to heat and water use. I got rid of it because it was loud, but I always wondered if running it without soap was perhaps not as eco friendly as a modern washine using less heat and water.
- stjohnswarts 3y ago
  Use less soap. I use about half as much and the dishes come out fine. I've had better luck with liquid based soaps too as they mix immediately with the water.
  - brnt 3y ago
    You cut those tablets up?
    - stjohnswarts 3y ago
      I don't use those, I use liquid dishwashing gel.
- astura 3y ago
  Sounds like you're probably using too much detergent.
  - brnt 3y ago