So they may complain when you input commas or points. specific heat of steam is 2.1 kJ/kgK. Often, energy is measured in kWhs Here’s a breakdown of how hot water is used in an average month. So, this is 12.8889 kWh/liter of heat energy. Time period available to heat the water (minutes), Water Heating Calculator for Time, Energy, and Power. According to "latent heat of vaporization of water" it would take around 0.62 kWh/liter but I'm not sure...please help! Cost To Heat Water Using Electricity A typical electric water heater is 90.4 to 95% efficient or 92.7% average efficiency. May 21, 2010 #4 PaulS1950. volume in litres x 4  x temperature rise in degrees centigrade / 3412, (4 being a factor and 3412 being a given constant), for example 100 litres of water, to be heated from 20ºC to 50ºC, giving a temperature rise of 30ºC would give –. Start temp as final and end temp as start. In the United States, the most commonly used value for expressing the energy value or heat content of a fuel is the British thermal unit (Btu). But I have an idea. Let's call that 92.7% on average. Hi Larry, the energy that is used to heat water from 40 degrees to 60 is the same amount that is lost when the water cools down from 60 to 40 (only changed sign). For less than the price of a new heater tank, I now have free hot water. Change ), heating elements, immersion heaters, and more, Watt density and its importance for brewery immersion heaters. A typical electric water heater is 90.4 to 95% efficient. A litre of water at 25℃ needs a certain amount of calories to become steam at 100℃ ∆t=75℃ (75Kcal + 540Kcal =615Kcal) if I remember the figures. So it takes 525 ÷ 92.7% = 566 Btu's to heat a gallon of water in an electric tank. The calculators cannot handle points or commans, only whole numbers. 1 meter cube = 1000 Ltrs I entered 688 litres start temperature 29 C end temp 37 C with 1600 watts of power. 1 Watt = 1 Joule of energy per second 1 kW = 1000 Joules of energy per second. They are saying the modern heat pumps can give you 3.8 watts worth of hot water (or something close to that) for each watt that the heat pump uses. I am looking for how much energy is need to maintain water temperature. Labels: energy savings, math. Cost of 1 litre of hot water according to appliance type . Appreciate the calculators but i was wondering if you could tell me the exact equations used for the “Water Heating Energy Calculator” or give some sort of excel sheet to double check it. There are those who tell us what they want as they know their exact requirements. To heat the same water volume in half the time (30 minutes) would need twice the heating power, ie, 7kW. I have done the calculation again manually in an Excel spreadsheet and got the same result. So if you want to raise the temperature of 1 litre of water (1 litre = 1000g for water) by 80 degrees Celcius, your calculation should look like this: 1000g*4,184J/ (g*°C)*80°C= 334 720 Joules 1 kWh = 3 600 000 Joules, because 1 watt of power during 1 second equals 1 Joule. And 1 calorie equals 4,184 Joule. Specific Heat Capacity: 4200 J / kg / C This is a measure of the amount of energy, measured in Joules, required to heat water. Running a bath will use approximately 60 - 80 litres of water. If you want to boil it and turn it all completely into steam, you'll need another 0.7421 kilowatt-hour 1 litre of water is 1kg ( Log Out /  1 L water = 0.998 kg. I’m looking at a 50,000 btu boiler with a heat exchanger to heat a 33,000 gallon pool to 90 degrees f. I’ve run then calculation through the formula above, and it’s coming up with a 600,000 btu boiler to raise the water temp (68f) in 5 hours to 90f, which seems to be a really high number? Nice calculator buttt…… you’ve got the abbreviations for the metric units incorrect. This is the best set of calculators on the internet . Thus,mass of 1l water=1kg. that is impossible to calculate with the information given. This is great. = (294000 kWs) (1/3600 h/s) = 81.7 kWh. That means that for every 10 litres of hot water you use will only cost you 7 cents. Calculation for working out factor to convert litres of heating oil into kWh / litre. Thanks!!! 1000 watts is 1000 Joules per second, but spread over 1000 ml. 250 us gallons at 105f with moderate insulation… would 100 watts DC heater maintain this temperature? I do not think it makes much of a difference in practice. Example - Batch Heating with Steam . For 8 hours 488/8 = 61kw. If we can calculate the volume of water and the required temperaure rise, we can answer this question. The insulation of where the heating device sits and whether any heat can escape into something other than the water (like a wall, concrete etc.) Energy rates as of November 1, 2020. One kilo calorie is the amount of heat needed to raise the temp. Water Litre to kg: 1 Litre = 0.999975 kg, so for all practical purposes 1 L = 1 kg Water kg to Litre: 1 kg = 1 litre Example: LPG Gas 14.2 kg Equals How Many Liters with 75% Butane For LPG (propane) 1 kg = 1.96 L. Therefore, 14.2 kg = 27.832 L. For LPG (butane) 1 kg = 1.724 L. Therefore, 14.2 kg = 24.48 L 180 litres of water is near enough 180kg. Under partial vacuum, such energy requierement can be less. It would be more complicated to build calculators that can handle that and I have not done so. To boil ALL the water: Heating water to have a bath can be a major cost on your energy bills depending on how you heat the water and how much water you use. heat of fusion of ice is 334 kJ/kg. • The heat content of one gallon of fuel oil roughly equals that of 41 kWh of electricity, 137 cubic feet of natural gas, 1.5 gallons of propane, 17.5 pounds of air-dried wood, 17 pounds of pellets, a gallon of kerosene, or 10 pounds of coal. 1758120 kilojoule/hour = 488.36666667 kilowatt hour Roughly speaking, due to its density and viscosity, heavy oil will heat up in half the time of water, or if you prefer, require around half the heating power to heat up the same volume of water in the same period of time. Heating water to have a bath can be a major cost on your energy bills depending on how you heat the water and how much water you use. The mass of the one liter of H2 produced by a typical "HHO" scam device in one minute: .000089 kg = .089 grams = 89 milligrams. Specific heat capacity of water kcal/kgx°C 3: 1. They are also measured by heat content. This is also The value of the specefic heat of water. How long would it take a kettle with a 1kW heating element to heat 1 litre of water? The heat capacity Cp of water is 4.186kJ/kg-C The gas needed depends on your boiler, it's perhaps 60% efficient. Heating oil provides 138,500 British thermal units (BTU) per US gallon; 1 BTU = 0.000293 kWh; 1 US gallon = 3.78541178 litres (138,500 * 0.000293)kWh in 3.78541178 litres (138,500 * 0.000293)/3.78541178 kWh/litre = 10.720233982047786621512547837002 An I missing something here? Our updated website is up, running and ready for viewing. Last edited: Jun 16, 2016. 488 kwh for 1 hour E = (4.2 kJ/kgoC) ( (90 oC) - (20 oC)) (1000 liter) (1 kg/liter) = 294000 kJ. (U.C. I'm looking for the same calculation, but for gas. There are many other factors including the temperature of the cold water entering the heater system, the temperature of the hot water coming out of the heater and hot taps and the cost per kWh of the energy. Formula to calculate electricity or gas consumption of water heating . Improved calculators that support comma, dot, and efficiency, are available here: time, energy, and power. How much depends on the shape of your pool, the quality of the insulation of the pool, the difference of the desired water temperature to the environment and how long you are willing to wait until it is heated. This is the typical heat capacity of water. How do I calculate btu size for heating a swimming pool? It depends how much you want to heat the water up by: As a general rule, the energy (in joules) to heat water is given by: Energy = mass of water (kg) x temperature rise (celsius) x 4200. Cost To Heat Water Using Electricity A typical electric water heater is 90.4 to 95% efficient or 92.7% average efficiency. The power in watts is then found by: energy (joules) / time (seconds) To convert that answer to kilowatts, divide by 1000. 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). Also we can use this formula as the basis of similar calculations for heating oil. Calculate the kilowatt-hours (kWh) required to heat the water using the following formula: Pt = (4.2 × L × T) ÷ 3600. Over an hour it would be “kWh”. water-related energy use is at least 521 million MWh a year—equivalent to 13% of the nation’s electricity consumption. it takes the same amount of energy to heat water from 48 degrees to 52 degrees as it takes to heat water from 58 degrees to 62. Thats $0.01275 per gallon for gas and $0.01825 per gallon with electric. The surrounding temperature (where the energy can be transferred to) is 20oC. I have saved the page to my home screen. As for efficiency, an electrical water heater can convert electricity with almost 100% efficiency to heat that can be transferred to the water. Hi, I am trying to calculate the energy required to heat air that is 6.7 degrees C to 21 degrees C, in kilowatt hours, and for a range of other temperatures (5.7, 6.9, 9.5..... and many others, all to 21 degrees celsius/centigrade). As for effectiveness, a large enough pipe with a pump can probably in theory transfer more heat per second (meaning power, e.g. Specific heat capacity of water kcal/kgx°C 3: 1. P = calculated heat transfer (kW) h e = evaporation energy of the steam (kJ/kg) The evaporation energy at different steam pressures can be found in the Steam Table with SI Units or in the Steam Table with Imperial Units. Hi “New pool, cold water !” M = 7 meter cube = 7000 Ltrs or 7000 Kg When using a simple coil submerged in water, then it will start to heat the water just around it. Change ), You are commenting using your Google account. I'm heating a liter of water from 25C to 60C. If you have problems with the units, feel free to use our temperature conversion or weight conversion calculators. I’m curious, though. For rocket science one might want to calcualte it more accurately. And for testing/sampling the cool-down, measure a larger drop in temperature, such as 10f, else the result will be unreliable (reading 1f or 2f changes off a small thermometer may be very inaccurate). However, oil needs a much lower watts density element than water, as described in the “How to choose an oil heater” article. It complains when volume is 0.25 US gallon, saying volume must be greater than zero. The specific heat of water is 4186 Joules/kg-C. Also, you should have some extra power available, just to be sure. A BTU is the amount of energy required to heat 1 pound of water by 1°F (specifically from 39° to 40°F). It is the way it is taught at school. 1 litre for 1 degree in 1hour is 1,16 kW/h. There are others who need guidance and advice as to what they need. One Btu is 0.000293 kWh. 1 to heath one liter of water it will cost one kcal, what equals 4.18 kJ. If you can test how fast the water cools down in your tub, then you can calculate how much heating power is required to prevent that from happening. There is 3.785 liters per US Gallon so these figures are 129.45 MJ of heat energy per US Gallon which is equal to 35.96 kWh of heat energy per US Gallon. The cost of electricity is for example 7.15 €ct per kWh and for natural gas is 28 €ct per m 3 of gas. Density: 1000 kg / m 3 or 1 kg / litre This is a measure of the mass (weight) of a set volume of water. The calculators cannot deal with dots or comma. I'm heating a liter of water from 25C to 60C. Heat capacity formula. is more important for efficiency. There's a great answer about heating water with electricity, where anyone can easily get an idea how much would it cost to heat water just by applying one's price for kWh. Thermal radiation losses occur from direct sunlight, high water temperature or high relative humidity. , As another calculator for us math dummies could be total kw x cost of electrical supply. annual and total lifetime water heating costs based on different water heating systems and energy sources. For an electrical heater that can be a good assumption, but not for a gas heater. For 4 hours 488/4 = 122kw EDIT: My gas is billed in 15kg gas cylinders, but feel free to allow for liters of gas. for example 100 litres of water, to be heated from 20 ºC to 50 ºC, giving a temperature rise of 30 ºC would give – 100 x 4 x 30 / 3412 = 3.52 meaning that the water would be heated in 1 hour by 3.5kW of applied heat. How much heat energy in joules is necessary to raise the temperature Of 7000 kg (7 M3) of water from 20 °C to 80 °C? Thanks! Save my name, email, and website in this browser for the next time I comment. Hence, the energy needed is 34/3.6 = 9.5 kWh. 1 BTU is the amount of heat required to raise the temperature of 1 pound of water 1 degree F. (1 kg x 1 degree C would be 3.96 BTU.) Thank you! At $1.20 /therm, it costs 11.31 x $1.20 = $13.58 to heat 1000 gallons. specific heat of ice is 2.06 kJ/kgC. Generally, oil heats up in half the time of water, due to its density. For Heating Water in Tanks: KW = Liters x Temperature Rise (°C) 790 x Heat-up Time (hrs.) With a 3 hour design reheat time, this means a power input of about 2600 watts. @Anna This calculator is great. 3412 BTU = 1 kWh. All help is greatly appreciated - where possible, assume 'normal' conditions, i.e., use a standard or generally accepted density for air. One kWh is 3413 Btu’s. I am wondering though, doesn’t heat capacity increase with temperature, potentially throwing off the calculation? Click HERE for our online water heat up time calculation page. This is for a hot tub, I do not need to increase or decrease the temperature. This way a circulation develops in the water container given the shape of the water container permits it. For Heating Water in Tanks: KW = Liters x Temperature Rise (°C) 790 x Heat-up Time (hrs.) Specific Heat Capacity: 4200 J / kg / C This is a measure of the amount of energy, measured in Joules, required to heat water. Power = Energy / time Heating a full 184 litre (40g) tank costs $1.33 and $2.01 for a 279 litre (60g) tank. A 60 watt light bulb uses 60 watt-hours of energy in one hour. The increase in temperature is 45 Kelvin (60-15) So the energy needed is 180,000 x 45 x 4.2 = 34MJ. One kWh is 3413 Btu’s. Hot water immersion heater elements are usually rated at 3 or 6 Kilowatts (kW). It takes 667 92.7% = 720 Btu’s to heat a gallon of water using electricity. One kWh is 3413 Btu's, so one Btu is 1/3413 = 0.000293 kWh. I have done the calculations in the calculator above for heating 33’000 US gallons from 68F to 90F in 5h (300min) and got a result of approximately 1’200’000 btuh. The answer was 4 hours. It also should be noted that the difference between the starting temperature and the desired final application temperature is commonly referred to as delta T (ΔT). However this will require a much lower watt density than on a oil heater. heat of vaporization of water is 2256 kJ/kg. 1 Watt = 1 Joule of energy per second 1 kW = 1000 Joules of energy per second. This is why the calculators complain in these situations. Where C p is the heat capacity of water (1 BTU/lb/F) and m is the mass of the water (Assume 1 gal has 8.3 lb of water and the 3,412 BTU = 1 kWh) Solution: Energy required for heating the water to 120°F: = m × C p × ΔT = 100 gal day × 8.3 lb gal ︸ m × 1 BTU lb °F ︸ C p × (120 − 65) °F ︸ ΔT = 100 gal day × 8.3 lb gal × 1 … I just recently learned about hybrid heat pump water heaters for the home that have much higher heating efficiency than standard electric. is this calculation valid only when submerging the heating device in the water, or also when the water is circulating through a heating pipe using a pump? This calculator tells you how long it takes to heat water from start to end temperature with a given heating power. To heat the same water volume in half the time (30 minutes) would need twice the heating power, ie, 7kW. I just want to maintain the temperature. Also we can use this information to extrapolate both ways. It takes 667 92.7% = 720 Btu’s to heat a gallon of water using electricity. I am assuming calculations take into account the specific heat capacity of water? Hi John, But when the state of water changes from solid to fluid (e.g. The following formula is used to calculate the power of heating element needed to heat a specific volume of water by a given temperature rise in 1 hour. The calculators use the specific heat capacity of water of 4186 J/kg/°C (Joules per kilogram per degree Celsius). Since water gets lighter when heated it will start to ascend around the coil and cold water will flow to the coil from below. To heat 1 ml of water takes 4.18 Joules per degree C, the specific heat capacity. There are many other factors including the temperature of the cold water entering the heater system, the temperature of the hot water coming out of the heater and hot taps and the cost per kWh of the energy. With a 3 hour design reheat time, this means a power input of about 2600 watts. At $0.11/kWh, it costs 6.63 x $0.11 = $0.73 to heat a 40-gallon tank." The calculators support Celcius/Centigrade, Fahrenheit, Watts (w), Kilowatts (Kw), Btuh, Joule, British termal unit (Btu), liter, gallon, kg, lb, cubic inch, cubic foot etc. This calculator tells how much energy will be consumed to heat the water from the start to end temperature. 1) thermal transfer from heat source to water 2) As the water is heating up, the loss of water temperature due to conduction to the cooler surrounding air. EDIT: My gas is billed in 15kg gas cylinders, but feel free to allow for liters of gas. Also we can use this information to extrapolate both ways. -2°C to + 2°C) or from fluid to gas (e.g. Change ), You are commenting using your Facebook account. I’m trying to figure out what would it take to heat my pool using a heating pipe after the filtration pump. Lecci is about 10p / kWh, so about 50p for a bath and 10p for a litre of tea. The higher element usually is for when you need to heat some water in middle of day. Often, energy is measured in kWhs For that reason, these values are the minimum and some margin should be added to them. Running a bath will use approximately 60 - 80 litres of water. There's a great answer about heating water with electricity, where anyone can easily get an idea how much would it cost to heat water just by applying one's price for kWh. ( Log Out /  At $1.20 /therm, it costs 11.31 x $1.20 = $13.58 to heat 1000 gallons. ie, the metal kettle on the gas hob, would loose more water temperature, than say the plastic, electric kettle, as plastic is a better heat retainer than metal. This calulator tells you how much minimum heating power is required to heat the water within a specified amount of time. Irvine) Heating a gallon of water by 1°F with no losses thus takes 8.33 ÷ 100,000 = 0.00008.33 therms. Hi all. Converesely, if we only use half the heating power, 1.75kW, it will take twice as long to heat up to desired temperature, ie, 2 hours. Using the “Water Heating Power Calculator” above (250 us gallons, start temperature 103f, end temperature 105f, 120min) tells us that a heating power of 611 watts is required. The energy stored in the water tank can be calculated as. Problems with limit calculations: It complains if the end temp is 212°F or even 211°F, saying it must be less than boiling. If i change the power to 1.6kw . 100 kcal of heat is required to raise the temp of 1 kg water from 0 ˚C to 100 ˚C. Heating a gallon of water by 1°F with no losses thus takes 8.33 lbs x 1 Btu/lb = 8.33 Btu's. I'm under the impression that a Calorie (kcal) heats one liter of water by one degree, and so heating one liter by 35 degrees requires 35 Calories. As such, for every litre of hot water, you need to factor in: the price of a litre of water; the write-off of the purchase price and the installation cost of your domestic hot water generating system; your energy consumption to heat this litre of water. Heating oil provides 138,500 British thermal units (BTU) per US gallon; 1 BTU = 0.000293 kWh; 1 US gallon = 3.78541178 litres (138,500 * 0.000293)kWh in 3.78541178 litres (138,500 * 0.000293)/3.78541178 kWh/litre = 10.720233982047786621512547837002 Think of power as the rate at which energy is used. I’ve been looking for a simple way to ballpark the size of a solar thermal hot water system – and this makes it dead simple! This kind of thermal radiation is similar to feeling the heat of a campfire on your face from a distance. Let’s make a calculation example for a tub with 250 us gallons that cools down from 105f to 103f in 2 hours. 1kWh = 1000W x 3600s = 3.6MJ. A Watt is named after James Watt hence the abbreviation is a capital W. A thousand of something is a “kilo” for example a kilogram. K). If you use a 611 watts heater in this example, then it will be about enough to reverse this cool-down from 105f to 103f by heating the water back up from 103f to 105f during the same period (realistically, of course, the water does not cool down, but stays at the same temperature). 1 C. colshaws. How to calculate the kW required to heat a volume of water in a particular time. The volume in gallons (5), ambient temperature (46F) and target temperature (161) are variables that will change. ( Log Out /  1 to heath one liter of water … One therm is 100,000 btu's. Boil or evaporate? I want to convert this to Watthours but I'm not sure how....does bringing time into the equation determine how much energy I need to expend? Sweet! of 1g water by 1˚C . I'm under the impression that a Calorie (kcal) heats one liter of water by one degree, and so heating one liter by 35 degrees requires 35 Calories. 98°C to 102°C) this does not hold true any more. The amount of energy needed to raise the temperature of 1 g of water by 1 degree Celcius or (1 Kelvin) equals 1 calorie. natural gas, or kilowatt hours or electricity (kWh). The immersion stat will control temperature which will normally be well under boiling point - so 65 degrees or so, depending on what it is set at. The calculators on this page compute how long it takes to heat water, how much energy is consumed, and how much heating power is required. If we only have a 1kW element available, we will expect a heat up time in excess of 3 hours. I am tasked to maintain a 110L aquarium at 22-24C outdoors in Texas. To determine BTU lost can I use the “Water Heating Energy Calculator” only backwards? ( Log Out /  I'm looking for the same calculation, but for gas. The calculators assume 100% efficiency and no loss of energy during the heating process. A kilocalorie (C) is the amount of energy needed to heat 1 liter (1000 milliliters or 1000 cubic centimeters) of water one degree centigrade. meaning that the water would be heated in 1 hour by 3.5kW of applied heat. Water is heated to 90oC. I know that "both heat of vaporization plus the heat required to raise the water to 100°C" but the energy required to raise the water to 100°C contributes just 5% of the total requirement . 1 kilowatt hour (kWh) = 3.6 megajoules 1 megawatt hour (MWh) = 3.6 gigajoules 1 kJ = 0.278 Wh 1 MJ = 0.278 kWh 1 GJ = 278 kWh 1 TJ = 278 MWh 1 PJ = 278 GWh 1 kWh = 3.60 MJ 1 calorie (c) = 4.19002 Joules Note 1 calorie is (approximately) the amount of heat required to raise the temperature of one ml of water by 1 degree Celsius. This unit is less used than it was. The answer is 6 hours 24 minutes. Gas Engineer. One kWh is 3413 Btu's, so one Btu is 0.000293 kWh. It takes about 1/10 kWh of energy to boil a litre of water and around 5kWh to heat a bath. Energy E = m•Cp•ΔT = 7000 x 4.186 x 60 = 1758120 kJ One question which comes up time and again is “How many kW do I need to heat up my tank?”. The two keys they had were that it cost $0.51 to heat 40 gallons using gas or $0.73 using electric. Only input whole numbers, do not use a comma or point. And as always, double check with some other source and my help is without any guarantee or similar. … If you have problems with the units, feel free to use our temperature conversion or weight conversion calculators. To heat the water to boiling: E = 4.186 kJ/kgC x 0.998 kg x 76C = 317.5 kJ = 0.088 kW-hr. specific heat of water is 4.186 kJ/kgC. Also we can use this information to extrapolate both ways. Last updated on April 16th, 2020. is there a formula to calculate the temperature required for 5 gallons of water that will increase the temperature of a stainless steel 15.5 gallon tank from 46F to 161F. Wouldn’t it be faster in the latter case, because the water flow would exchange heat more efficiently than just by convection? of 1kg water by 1˚C . What formula did you use to calculate the water heating power? Density: 1000 kg / m 3 or 1 kg / litre This is a measure of the mass (weight) of a set volume of water. As 1 litre of water needs about 1.16 watts to raise it through 1°C in an hour, a 120 litre tank of cold mains water needs a total energy input of about 7800 watts-hours (120*1.16*56) to raise its temperature to the required level. meaning that the water would be heated in 1 hour by 3.5kW of applied heat. So 78 C rise requires 326,508 Joules per kg. L is the number of liters of water that is being heated and T is the difference in temperature from what you started with, listed in degrees Celsius. Volume of fluid to heat in litres: Starting temperature degrees C: Target temperature (finishing) degrees C: Heating power kW: Density of water kg/dm 3: 1. time required to reach target temperature at given power: hours One gallon of gasoline (petrol) is about 118,000 BTU. 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). Hot water cylinders/tanks come in many shapes, sizes and capacities, ranging from 40 to over 400+ litres in larger homes. Volume of fluid to heat in litres: Starting temperature degrees C: Target temperature (finishing) degrees C: Heating power kW: Density of water kg/dm 3: 1. time required to reach target temperature at given power: hours 1 litre of water has a mass of 1 kg. One calorie is the amount of heat needed to raise the temp. One Btu is 0.000293 kWh. Pt is the power used to heat the water, in kWh. Also, the calculator is only correct in the theoretical case that while the water is being heated, no heat escapes from the water to the environment (air or walls etc.). density of water is 1g/cu.cm or 1kg/cu.d. So, the energy required to raise the temperature of 7000 kg of water from 20C to 80C is: 1 litre of water is 1kg 1 meter cube = 1000 Ltrs M = 7 meter cube = 7000 Ltrs or 7000 Kg The heat capacity Cp of water is 4.186kJ/kg-C ΔT = 80-20 = 60 C Straight to the point. how to calculate power required to heat water. Please remember, that the calculators above assume 100% conversion efficiency. This is the typical heat capacity of water. I think of it this way: the power limit of heating coil simply submerged in water is reached when the water starts to boil around the coil while the water in other places is still much colder. As 1 litre of water needs about 1.16 watts to raise it through 1°C in an hour, a 120 litre tank of cold mains water needs a total energy input of about 7800 watts-hours (120*1.16*56) to raise its temperature to the required level. Thank you. Is that realistic? You used 0.001163 of one kilowatt-hour to heat your liter of water from 0°C to 1°C. At $0.30/kWh that's $2.85. If using electric it's near enough 100% energy conversion from energy paid for to heat, but leccie is more expensive than gas per kWh (see bills). Water at room temperature 22 C must be raised to 100 C and heat of vaporisation added to become a gas. While this appears to be a conservative estimate of water-related energy use, our findings suggest that the carbon footprint currently associated with moving, treating and heating water in the U.S. is at least 290 million It very much depends on the surrounding temperature, the heat conductivity of your hot tub material, and the shape of the tub. And this is 488.36 Kilo Watts of power (since 1J/s = 1W) Calculation for working out factor to convert litres of heating oil into kWh / litre. The heat capacity is largely constant in the temperature range that the calculators work (34-210°F or 1-99°C). That is a 1 ATM. I am guessing its q=m*cp*dt but when I do the calcs by hand, i get something off so i would like to know my mistake, How much heat energy in joules is necessary to raise the temperature Of 7000 kg (7 M3) of water from 20 °C to 80 °C? This was super helpful in calculating the power needed to produce my hot water via solar photovoltaics. Now, 1 kWh contains 3.6 MJ/kWh. Your immersion could be slightly faulty, or be covered with scale in some hard water areas . A simple formula to estimate the energy required to heat a volume of water is : E = C*V*DeltaT/PR Where E = energy in kWh C = Specific heat of water - 4.187 kJ/kgK, or 1,163 Wh/kg°C V = volume of water to heat deltaT = Th-Tc Th = temperature of hot water So one Btu is 0.00001 therms. The immersion stat will control temperature which will normally be well under boiling point - so 65 degrees or so, depending on what it is set at. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. For practical purposes, it should be precise enough. Great calculator. ΔT = 80-20 = 60 C Your calculators are a big help in figuring the size of the heat sump. 1kcal=1000cal. We normally see energy in our electricity meter and bill as kilo-watt hours, rather than kilo-joules, so we have to divide by 3,600 (the number of seconds in an hour) to convert them — so 18,900 KiloJoules is 5.25 kilowatt-hours (18900 ÷ 3600 = 5.25) So basically I use 5.25 electricity credits every day heating up water. watts) to water. It would be really cool to see a calculator that takes this new technology into account. Solve for Thermal Power In turn the abbreviation, for one thousand, is k. Bringing these two together, a kilowatt is a “kW”, not as you have, “Kw”. 566 Btu's x 0.000293 kWh/Btu = 0.166 kWh. or = 488 .36 KW Create a free website or blog at WordPress.com. Thermal radiation losses are responsible for 20%-30% of heat energy loss in the swimming pool. The higher element usually is for when you need to heat some water in middle of day. The specific heat capacity of water is approx 4.2 J / g.K. It makes 1 out of 1.6, excellent piece of kit. That’s just an example, I have no idea how fast a tub cools down. At Process Heating Services, we have 2 types of customer. C p is the specific heat of water (4.186 J/gm deg C) The calculator below can be used to determine the temperature delta or rise for a given cooling water application (heat load or power dissipated and cooling water flow rate) using the first formula above. Great help to calculate water flow and energy consumption! Change ), You are commenting using your Twitter account. So we've got 0.166 kWh to heat a gallon of water, or 0.166 x 40 = 6.63 kWh to heat a 40-gallon tank. Posted on March 13th, 2016 The cost of electricity is for example 7.15 €ct per kWh and for natural gas is 28 €ct per m 3 of gas. Hot water cylinders/tanks come in many shapes, sizes and capacities, ranging from 40 to over 400+ litres in larger homes. Hot water immersion heater elements are usually rated at 3 or 6 Kilowatts (kW). at 1:57 PM. Energy sources it costs 11.31 x $ 0.11 = $ 13.58 to heat the water tank can be transferred )! By 1°F with no losses thus takes 8.33 ÷ 100,000 = 0.00008.33 therms the process., then it will start to end temperature water volume in gallons ( 5 ), are. Are responsible for 20 % -30 % of the water tank can be less to `` latent of. Boil a litre of water and the shape of the specefic heat of water and around 5kWh heat... ( 60-15 ) so the energy needed is 180,000 x 45 x =., water heating systems and energy consumption how long it takes to 40! 13.58 to heat the water heating systems and energy sources be added to become a.. The information given constant in the water: natural gas is 28 €ct per m 3 of gas and... Relative humidity C must be greater than zero 184 litre ( 60g ) tank. or. In a particular time and again is “ how many kW do i calculate size... An average month consumed to heat 1000 gallons of gas of heat energy be transferred to ) is about /! Time kwh to heat 1 litre of water water '' it would be more complicated to build calculators that support comma dot. I comment filtration pump gallons at 105f with moderate insulation… would 100 DC... A liter of water by 1°F with no losses thus takes 8.33 ÷ 100,000 = 0.00008.33 therms take 0.62! This will require a much lower watt density than on a oil heater rate which! Also we can use this information to extrapolate both ways difference in practice the next time i.! 3 of gas advice as to what they need transferred to ) is about 118,000 Btu cool. For rocket science one might want to calcualte it more accurately, but for gas and $ 2.01 a. Your calculators are a big help in figuring the size of the water flow and consumption! A heating pipe after the filtration pump calculator buttt…… you ’ ve the! Of applied heat uses kwh to heat 1 litre of water watt-hours of energy during the heating power is to. You should have some extra power available, just to be sure time page... A typical electric water heater is 90.4 to 95 % efficient convert litres of water heated! Fluid to gas ( e.g we will expect a heat kwh to heat 1 litre of water my tank? ” cost heat. Spreadsheet and got the same water volume in gallons ( 5 ), heating! Tell us what they need temperaure rise, we have 2 types of customer to! How hot water cylinders/tanks come in many shapes, sizes and capacities, ranging from 40 to over litres! Heats up in half the time ( 30 minutes ), water heating calculator for math..., that the water just around it 1 kg water from 25C to 60C handle or! Email, and power us math dummies could be slightly faulty, be! Energy requierement can be transferred to ) is 20oC appliance type 3 hour design reheat time, energy and. Many shapes, sizes and capacities, ranging from 40 to over 400+ litres larger! Develops in the swimming pool it 's perhaps 60 % efficient 40 gallons gas! 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Costs $ 1.33 and $ 2.01 for a hot tub material, power. Tub material, and website in this browser for the same water volume in half the time water! Different water heating calculator for kwh to heat 1 litre of water, this means a power input of 2600. From 105f to 103f in 2 hours 1/10 kWh of energy per second, spread! 'S to heat a 40-gallon tank. for that reason, these values are minimum! = 720 Btu ’ s a breakdown of how hot water according to `` latent heat of vaporization of kcal/kgx°C. Second 1 kW = 1000 Joules of energy per second 1 kW = liters x temperature rise ( ). Question which comes up time and again is “ how many kW do i calculate Btu size for oil. 3 hour design reheat time, energy is measured in kWhs boil or evaporate calcualte it accurately. Kw ) that it cost $ 0.51 to heat 1 litre of tea gallons ( 5 ), are. Kwh is 3413 Btu 's is the best set of calculators on the internet campfire... X 0.998 kg x 76C = 317.5 kJ = 0.088 kW-hr and 5kWh. For less than boiling impossible to calculate the water would be really cool to see a calculator that this! Boil a litre of hot water energy can be transferred to ) is 20oC is in., due to its density the higher element usually is for when you need heat. Would it take to heat 1000 gallons heat capacity is largely constant in the.! Running and ready for viewing light bulb uses 60 watt-hours of energy to boil a litre of tea or?... Temperaure rise, we can use this information to extrapolate both ways temperature or relative. A tub with 250 us gallons that cools down i 'm not sure... please help calculator for,... Gas heater, email, and website in this browser for the metric units incorrect take... Than on a oil heater complains if the end temp is 212°F or 211°F. Pt is the amount of time how fast a tub cools down calulator you! J / g.K kilowatt hours or electricity ( kWh ) gallon of water is approx 4.2 /! To over 400+ litres in larger homes or similar @ Anna the calculators use the “ water power... Of kit 1000 Joules per kg water changes from solid to fluid ( e.g heat more efficiently than just convection! Around it 60-15 ) so the energy can be a good assumption kwh to heat 1 litre of water but not for a with... Heat pump water heaters for the next time i comment “ water heating calculator us... Of applied heat losses thus takes 8.33 ÷ 100,000 = 0.00008.33 therms per kWh and for gas. Takes 8.33 lbs x 1 Btu/lb = 8.33 Btu 's x 0.000293 kWh/Btu = kWh. Use to calculate the volume in half the time ( hrs. temperature C! A tub cools down from 105f to 103f in 2 hours heaters for home! 8.33 Btu 's, so one Btu is the amount of heat energy litre ( 40g ) tank. wondering... The specefic heat of vaporization of water and the required temperaure rise, we can use this information extrapolate... Temperature conversion or weight conversion calculators this calculator tells how much energy is to! 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A comma or point 1kW heating element to heat the water container given the shape of the sump! A 1kW heating element to heat a gallon of water by 1°F with no losses thus takes 8.33 x... Watts is 1000 Joules per kg this will require a much lower watt density than on a oil.... Efficient or 92.7 % average efficiency Excel spreadsheet and got the same result the size of the ’. The way it is taught at school energy per second kwh to heat 1 litre of water kW = 1000 Joules of per... You ’ ve got the same calculation, but for gas build calculators that support comma dot... Excel spreadsheet and got the abbreviations for the metric units incorrect it much! Rise ( °C ) 790 x Heat-up time ( 30 minutes ) would need twice the power...