3 ms·
The article is IMO quite unclear. I tried to understand what's actually going on. From the actual rule in the Federal Register (https://www.federalregister.gov
by amluto 3y ago
The article is IMO quite unclear. I tried to understand what's actually going on. From the actual rule in the Federal Register (https://www.federalregister.gov/documents/2020/10/30/2020-23765/energy-conservation-program-establishment-of-a-new-product-class-for-residential-dishwashers https://www.federalregister.gov/documents/2020/10/30/2020-23...):
> Moreover, the current standard requires standard residential dishwashers to not exceed 307 kWh/year and 5.0 gallons per cycle for the “Normal” cycle. 10 CFR 430.32(f)(1)(i). Consistent with the results of the Department's evaluation of dishwashers offering a 60 to 90 minute “Quick” cycle, DOE's has identified an innovative opportunity for the further development of a dishwasher model offering a “Normal” cycle of one hour or less.
I think the issue is that manufacturers struggle to get good cleaning performance subject to the 307 kWh/year, 5 gallon per cycle rule unless the cycle is very slow, and the DOE has indicated that it will allow more water and/or more energy usage for faster dishwashers.
(Speaking of water usage, I find it odd that dishwashers don't seem to do a final spray with fresh (non-recirculated) water. I would gladly use an extra 1/4 - 1/2 gallon per load to get a freshwater rinse at the end.
P.S. What's up with kWh/year anyway? Surely it should be kWh per cycle with an added restriction on additional power used when not running.
- MichaelZuo 3y ago307 KWh/cycle would be over $30 in electricity costs, per cycle...
- ComputerGuru 3y agoObviously GP means the units should be converted to whatever they actually want usage/cycle to be.
- MichaelZuo 3y agoNo, it's not obvious at all as various models can have different numbers of modes, so even averaging them out for a usage/cycle average number wouldn't yield any meaningful info. e.g. A fancier model with several 'Eco' cycles and only one higher power mode will appear better than simpler models with fewer modes, even though the simpler model might actually use less energy. In fact it would be very counter-intuitive and highly misleading.
- Gibbon1 3y agoI had an old Bosch dishwasher with a pre-heater and a macerator. It heated the water hotter than modern ones. What I noticed was there was no need to prewash dishes. Slob roommate left spaghetti sauce in a pan all week while you were gone. Dishwater would strip that right off. If you compare the energy efficiency of my old one with a new ones where you have to pre-wash your dishes with warm water the old Bosch wins both in energy and water use.
- SoftTalker 3y agoTry a commercial dishwasher if you get the chance, they heat the water to near-boiling and will clean a load of dishes in about 60 seconds. Not exactly friendly for your electric bill though.
- amluto 3y agoAlso not friendly for your delicate dishes.
- sneak 3y agoCommercial dishwashers are only sterilizers. They don't do the cleaning that a residential dishwasher does. They expect as input dishes that are visually "clean", having been scraped and sprayed by hand before going in. The 60 second cycle just cuts remaining grease then kills all the germs with harsh chemicals and then rinses. If you think residential dishwashers are bad at getting plates clean of dried-on gunk, commercial dishwashers are 100x worse, as that's not their job. The pre-washing everyone gripes about shitty residential dishwashers now requiring is an expected and designed-for staple in a commercial dishwashing process.
- davkan 3y agoYeah, you need to pair it with a person who’s entire job is to spray and scrub the dishes before loading them. That said the high pressure sprayer before the dishwasher is enough to get almost everything off dishes except hardened melted cheese. If it didn’t spray everywhere I’d want one for my house.
- gipp 3y agokWh/year is always inane regardless. That's what kW are for
- bryanlarsen 3y agoOnly if you run your dishwasher continuously.
- bee_rider 3y agoI wonder if the kWh/year factors in some information about the size of a typical load.
- eru 3y agoPeople sometimes prefer more convenient units. You probably measure your temperature in something like Kelvin (or Celsius or Fahrenheit), too? Instead of taking the ideal gas law pV = nkT serious and measuring temperature in units that are implied by T = p V / n * k, ie energy per degree of freedom.
- dragonwriter 3y ago> P.S. What's up with kWh/year anyway? I think that now DOE appliance standards, for all appliances, are now in annual consumption terms. They used to use different terms for different appliances that could convert to annual consumption (e.g., for dishwashers, it was "Energy Factor", which was cycles per kWh.) > Surely it should be kWh per cycle with an added restriction on additional power used when not running. That would be strictly more complicated, though I don't think passive draw is a big things for dishwashers.
- gpt5 3y agoTo add to that. kWh/year obviously defines an underlying assumption of the number of cycles. That definition just allows to also account for standby time. Hence it's a better overall number to target.
- Klaus23 3y ago307kWh/a and 5 gallons are a lot. Nowadays there are dishwashers that use 2.2 gallons and 76kWh/a (assuming 0,46 cycles per kWh which I think is the DOE limit) and they clean a full load adequately. Even the cheapest models should be able to meet the DOE limits and clean the dishes completely.
- danw1979 3y agoJust bought a new European made dishwasher which cleans perfectly at 0.55kWh / 2.2 US gallons per “Eco” cycle. But it takes 4 hours. The quick 65C cycle takes an hour but uses 1.1kWh and 10 US gallons.
- Klaus23 3y agoYes, the Eco cycle often takes a very long time. However, modern machines are significantly better than the DOE limits even on a one-hour cycle (I assume your machine uses 10 litres, not gallons).