Every once in a while, you've got to question age-old "truths." I find that's especially the case with appliances, which manufacturers are constantly innovating and updating. My new-ish oven heats up quickly, so I don't have to remember to turn it on 30 minutes before I'm ready to bake cookies, like the one I grew up with. Our refrigerator water dispenser works when a door is open, even though I've been trained to wait by my mother-in-law's fridge, which stops the flow when a door opens.
So even though we've heard that running hot water from your kitchen sink before you run the dishwasher can make the appliance more efficient, we thought it was time to revisit the subject and make sure it was still true by consulting the pros: Dirk Sappok, head of product development at Miele, and Travis Robertson, knowledge manager at Sears Home Services.
First, let's start with the basics.
How a Dishwasher Works
Every dishwasher is different, but they all go through the general cycles of getting the dishes wet, adding soap, circulating water, and so on. "The main idea behind the dishwasher process is still the same — the main difference is that advancements in technology allow us to have much more efficient and effective dishwashers," says Sappok. And there are a lot more settings these days: "The settings you choose for each load will affect the amount and duration of cycles. For example, cycles such as sanitize and options like extra dry heat increase the cycle time," says Robertson.
Newer and higher-end dishwashers, like the ones from Miele, can have up to 16 cycles for a single load, depending on the dishwasher model, how dirty the dishes are, and what types of dishes are in there.
How Hot Water Gets into Your Dishwasher
How the water gets hot inside your dishwasher can vary from machine to machine. Some machines connect to both cold and hot water pipes, while others just connect to cold water pipes. The appliance draws water from the pipe(s), then continues to heat it to the appropriate temperature, if necessary. "For the average dishwater, it takes about two minutes to heat the water inside the appliance 1 degree. Most cycles require the temperature to be 135ºF. If the incoming water temperature is only 105ºF, for example, it would take an additional 60 minutes to finish the cycle," says Robertson.
So, Should You Run Hot Water from Your Sink Before You Turn on the Dishwasher?
It depends. Says Robertson: "Especially in the winter, the pipes in our homes can get cold even if the water heater is working. Running hot water will clear out any cold water from the pipes and warm them up, which helps any appliance in your home get hot water faster. This trick works for both older and newer dishwashers, as the problem stems from your water heater and pipes and not the appliance itself."
But Sappok says: "This isn't necessary when using a Miele dishwasher. Some other manufacturer's recommend this, citing that it leads to the best results." But Miele dishwashers are super advanced and this extra step just isn't needed.
If you have an older, less-fancy machine, it's worth it. Even with a newer machine, it won't do any harm, and if you're running that water as you hand-wash other dishes (pots and knives that can't go in the dishwasher), you're not wasting water, either.
So before you start the machine, run the hot water in the sink for two or three minutes, then shut it off. "This will give the dishwasher as hot of water as possible, which minimizes the run time and gives the dishwasher the best cleaning performance it can get," says Robertson.
One note: If you find your dishwasher is taking longer than usual, or it's summertime and you find your dishwasher's performance has decreased, it might be worth having a pro come out to inspect your water heater and pipes.
Do you do run the hot water in your sink before you turn on the dishwasher?