When you are looking for a way to reduce the emissions (and the energy bills) from your home, you often look at the usual energy-hog type suspects – like your air conditioning unit, your central heating, hot water heater, and big TV system. It is easy to overlook some of the things that we take for granted and barely think about – such as the dishwasher.
You might think that they just clean your plates with water, and that couldn’t use that much energy up, right? But you’re wrong – their energy consumption is deceptive, and if you’re running it too frequently, it can easily become the leading cause of a high energy bill at the end of the month. Read on to take an eye-opening look at the nation’s forgotten appliance, as we answer your questions about how much energy they use up.
Do dishwashers really use up a lot of energy?
Dishwashers tend to use up a lot more energy than it looks like on initial examination. This is because they don’t actually use up a lot of energy themselves. The simple pump and control electronics involved in the movement of water only use up to around 1200 watts, which is equivalent to the energy consumption of a blow dryer.
This means the energy consumption of the standard dishwasher is pretty low, unless the appliance has its own integrated water heating mechanism, which can raise its electricity demands.
But you will know that dishwashers wash your plates using piping hot water, as they steam when opened, and sometimes have wash options that go up to an incredible 80 degrees Celsius.
Therefore, though the mechanisms in the dishwasher itself do not require extraordinaire amounts of electricity – the act of putting the dishwasher on will use a lot of energy but through your water heater rather than your dishwasher itself. By rights, the gas and electricity consumed by the water heater on behalf of the dishwasher should definitely count towards the dishwasher’s total energy consumption.
The exact amount of hot water that your dishwasher will be using up depends primarily on when (and to a lesser extent, who by) the dishwasher was designed and manufactured:
- Dishwashers that have a manufacture date from before 1994 can use 10 to 15 gallons of water in a single load of dishes.
- Dishwashers that were manufactured in the early stages of the energy star system use around four to six gallons of water in a single load.
- Dishwashers that have been manufactured in the more recent part of the energy star system use less than 4 gallons of water for every load that is run in them.
But how much energy does my dishwasher actually use per load?
Use the water-consumption estimates that we have listed above as a general guideline and rough estimate, rather than set in stone figures. Giving you a truly accurate estimate for your dishwasher’s energy consumption is a little difficult, as a lot of different factors come into play – such as the manufacturer, the model, and the cycles that you run it on.
The dirtiness of your dishes also impacts the energy level that your dishwasher consumes, as there are different settings for the level of dirt on your plates, which changes things such as amount of water, and the water pressure itself. You even have options for the dishwasher to dry your plates with heated air, which can as much as double the base electrical costs of your appliance.
How much is it costing me to run my dishwasher?
The base electrical costs of the dishwasher’s energy consumption (i.e. the pump and control electronics) are quite low, despite what we have been saying about its costs. For a model that runs at a 1200 watt model, and a cycle time of just one hour you will use 1.2 kilowatt hours (kWh) of energy, which adds up to only about 12 cents per load (if you are on a 10 cents per kWh energy plan).
So if you run the dishwasher five days out of every week, then you will only end up adding $2.40 a month for its basic energy consumption. #
Unfortunately, as we have already discussed, the base electricity running requirements are not the only component that affects dishwasher running costs. The hot water, which is usually heated by your main water heating system (the same one that supplies your showers, taps, and baths).
Assuming that we have an inlet temperature of around 68 degrees fahrenheit, and a goal temperature of 120 degrees fahrenheit, the numbers work out about as follows:
- Dishwashers that have a manufacture date from before 1994 that 10 gallons per load of dishes, you are looking at energy use of about 1.27 kWh, equivalent to 12.7 cents per hour, which more than doubles the dishwasher running costs, bringing the total price per load to 24.7 cents, and $4.94 every month.
- Dishwashers that were manufactured in the early stages of the energy star system use five gallons of water in a single load will need an additional 0.64 kWh, or 6.4 cents an hour. Adding the cost of operating the load, each load will cost 18.4 cents per load, or $3.68 a month.
- Dishwashers that have been manufactured in the more recent part of the energy star system use 3.2 gallons of water for every load, the water heating costs will come to 0.38 kWh or 3.8 cents per hour. This comes to 15.8 cents when you add it to the operating cost. If you run 20 loads a month, you’re only looking at $3.26 in expenses.
How to save money, and the environment, when using your dishwasher
You have a few options to reduce the energy consumption and running cost of your dishwasher (and all of your kitchen appliances!). Use our tips to keep electricity use to a minimum:
- Make sure your dishwasher is full so that you can reduce the number of cycles you run every week.
- At the same time, don’t overfill your dishwasher, as this will impede the water from circulating, and the process won’t be efficient.
- Open your dishwasher door as soon as the cycle finishes, which will prevent the heated air dry, which uses a lot of energy.
- Clean your dishwasher often so that no component gets clogged with limescale, soap scum, or bits of food.
- Upgrade your dishwasher to a more energy-saving model.
- Try not to use your dishwasher in the hottest parts of summer, as the additional heat generated from your dishwasher will make your aircon work overtime (and use more energy).