Watch the video; it makes a huge difference even though the hot water input is not as hot as the water can get when the dishwasher runs its heating element.
Also the size of the heating element is irrelevant. What matters is the power dissipated. Most dishwashers in the US will use only about 900 watts of power even when plugged into a circuit that supports 1500 watts. In the EU they often hit 3000 watts. Even when just heating up a gallon or two of water that makes a huge difference.
Bosch dishwashers are NOT heat pump dishwashers! They have a pump that also heats the water. They call it a “heat pump” but I find that terminology a bit strange, as its clearly not a heat pump (which is a term of art in appliances and HVAC). It’s just a resistive heater that is no more efficient than any other dishwasher heating element.
Crystal dry uses a heat exchanger for drying, so I guess that is what they are referring to. I guess you could try to claim that only the way HVAC's move heat around qualifies for being called a heat pump, not any other way of moving it should count right?
Here is what I got from Gemini:
Bosch does not refer to their dishwashers as having a "heat pump" in the same way the term is used for HVAC systems; rather, the part is often called a circulation motor and heating assembly or a combined "heater/pump" unit by users and repair sites. Bosch dishwashers use a flow-through water heater (a type of resistive element) to heat the water and a different, non-refrigerant-based system for drying.
How the Bosch System Works
Water Heating: All Bosch dishwashers use a flow-through water heater, which is a heating element integrated with the circulation pump. This system rapidly increases the water temperature to the required level. It uses electrical resistance, not the reverse-refrigeration cycle of a true heat pump.
Drying: Bosch dishwashers (especially the higher-end models with features like CrystalDry) typically do not use a separate heating element for drying. Instead, they rely on a process involving a stainless steel tub and a heat exchanger or a mineral-based drying technology (like Zeolith for CrystalDry) to condense moisture and wick it away from the dishes. This is an energy-efficient method of moisture removal, not active heat generation for drying.
> I guess you could try to claim that only the way HVAC's move heat around qualifies for being called a heat pump, not any other way of moving it should count right?
Anything that moves heat from one area to another, not just evening them out but actually forcing the heat to move, counts as a heat pump. HVAC style, or peltier style, or other methods with tension or chemical reactions all count.
A combination heater and circulator does not do that. It is not a heat pump.
CrystalDry is an “upsell” feature on the high end versions of their dishwashers for more efficient drying. It’s not the thing that they’re calling a heat pump, that’s the water pump that also does resistive heating. Bottom line is, Bosch (nor anyone else afaik) does not make dishwashers that are more efficient due to using “heat pump” technology.
Sure, but most people don’t have a modern dishwasher. It’s an appliance that lasts 20 to 30 years ergo most people have old dishwashers that were manufactured decades ago.
Ya, but eventually the new tech will take over and we will be talking about very different things. Even if you just consider new builds, or hundreds of millions of Chinese buying their first dishwasher ever. Also, lots of utility districts offer incentives to upgrade to more efficient appliances.
Also the size of the heating element is irrelevant. What matters is the power dissipated. Most dishwashers in the US will use only about 900 watts of power even when plugged into a circuit that supports 1500 watts. In the EU they often hit 3000 watts. Even when just heating up a gallon or two of water that makes a huge difference.