# Energy and cost calculator for heating water

With this calculator you can calculate the energy you will need to heat water with a certain flow. You can specify starting temperature and desired end temperature of the water It also calculates the cost of heating when using electricity or natural gas heating for the water.

 Flow in liters per hour: l/h For converting to and from US/UK units click here Begin temperature: in °C For converting to and from US/UK units click here Tempeatrure you want: °C K °F (must be °C for further calculations). . Needed energy: kWh(1) Electric cost (per kWh)(2): € per kWh. The total cost with electicity is € Cost of gas(2): € per m3 Natural gas. Energiy of one m3 natural gas(3) MJ/m3 (In Holland ca 32 MJ)(3). Gas heater efficiency: %. Total costs for natural gas heating are € /* optional */ The density of water is g/cm3 kg/m3 sp. gr. lb/ft3 lb/gal with the temperature of above. (has to be kg/m3 for further calculations)

J = kWh =  cal

## Example: The cost of taking a bath with an electrical boiler or a gasheater.

Assume a bath with a volume of 120 liters. The incoming tap water is ca. 13 degrees Celsius. This water will be heated to for example 36 degrees Celsius. The efficiency of a gas-heater is usually between 85% and 90%. The cost of electricity is for example 7.15 €ct per kWh and for natural gas is 28 €ct per m3 of gas. This means that you will have to pay 23 €ct to heat the bathwater with electricity and and 12 €ct to heath with gas if you take a bath (exlusive watercosts).

1to heath one liter of water it will cost one kcal, what equals 4.18 kJ. This is also The value of the specefic heat of water.

2source: Eneco consumens The Hague/Voorburg/Leidschendam/Rijswijk. This can also be another value (outside the Netheralnds). Ask your energy company to the costs or look at your bills.

3source: ECN

4the currency may also be another one (the one of your country, like \$ and ¥ and £ etc.)