The majority of electricity consumed at home goes into heating and cooling things. Most of this heat is directly disposed into the sewer system after use, my washing machine dumps 40 liters of hot water into the sewer on each run, my dishwasher does the same thing with 13 liters of hot water etc. All these devices heat their own water with a heating element which is on it's own not very efficient. The price of 1kWh in natural gas is €0,09 compared to €0,24 in electricity so natural gas is a factor of 2,5. Most of these devices however do not only consume hot water but also use cold water at specific stages in the cycle so the equation is not 1:1.
Dishwasher
My dishwasher consumes 1,05 kWh of energy and 13 liters of water per cycle at 70 degrees Celsius. It takes 0,83kWh to heat up 13 liters of water from 15°C to 70°C so 79% of the electricity consumed by the dishwasher goes into heating water.
I run my dishwasher approximately 5 times a week which accounts for 4,15 kWh per week or € 1,07 in electricity, with natural gas this would be € 0,37. The heat battery should lower this down further.
Washing machine
My dishwasher consumes 1,05 kWh of energy and 13 liters of water per cycle at 70 degrees Celsius. It takes 0,83kWh to heat up 13 liters of water from 15°C to 70°C so 79% of the electricity consumed by the dishwasher goes into heating water.
I run my dishwasher approximately 5 times a week which accounts for 4,15 kWh per week or € 1,07 in electricity, with natural gas this would be € 0,37. The heat battery should lower this down further.
Dryer
A dryer does not consume water and therefor cannot be hooked