The Btu per hour is a unit of power used in the power industry and heating/cooling applications. This tool converts btu per hour to volt-ampere (btu/h to va) and vice versa. 1 btu per hour ≈ 0.2931 volt-ampere. The user must fill one of the two fields and the conversion will become automatically. Kilowatts (kW) to amps (A) conversion calculator. This means that one BTU per hour is equivalent to 0.29307107 Watts. P (W) = P (BTU/hr) / 3.412141633. To determine the power in Watts, we divide the power in BTU per hour by 3.412141633. The BTU/hr to Watts's conversion table can also be used to determine the conversion of common values from BTU per hour to Watts based on a scale of 1 BTU/hr to. Please provide values below to convert volt ampere V.A to Btu (IT)/hour Btu/h, or vice versa. Volt Ampere to Btu (IT)/hour Conversion Table How to Convert Volt Ampere to Btu (IT)/hour 1 V.A = 3.
AC BTU Calculator
Use this calculator to estimate the cooling needs of a typical room or house, such as finding out the power of a window air conditioner needed for an apartment room or the central air conditioner for an entire house.
- Nominal voltage of 120V, the maximum heater rating is 120 Volts x 12 Amps max which means 1440 Volt-amps max assuming it is a standard resistance heater. If the circuit breaker (CB) is a 15 Amp 2-pole CB and the nominal voltage between the two poles is 240V; the maximum heater rating would be 80% x 15A x 240V = 2880 Volt-Amps max.
- The current I in amps is equal to the power P in watts divided by the voltage V in volts multiplied by the power factor PF multiplied by 3. How to Convert Watts and Ohms to Amps. It is also possible to convert watts to amps if the resistance of the circuit is known using the formula: I (A) = √(P (W) × R (Ω)).
Btu To Amp Conversion
General Purpose AC or Heating BTU Calculator
This is a general purpose calculator that helps estimate the BTUs required to heat or cool an area. The desired temperature change is the necessary increase/decrease from outdoor temperature to reach the desired indoor temperature. As an example, an unheated Boston home during winter could reach temperatures as low as -5°F. To reach a temperature of 75°F, it requires a desired temperature increase of 80°F. This calculator can only gauge rough estimates.
What is a BTU?
The British Thermal Unit, or BTU, is an energy unit. It is approximately the energy needed to heat one pound of water by 1 degree Fahrenheit. 1 BTU = 1,055 joules, 252 calories, 0.293 watt-hours, or the energy released by burning one match. 1 watt is approximately 3.412 BTU per hour.
BTU is often used as a point of reference for comparing different fuels. Even though they're physical commodities and quantified accordingly, such as by volume or barrels, they can be converted to BTUs depending on the energy or heat content inherent in each quantity. BTU as a unit of measurement is more useful than physical quantity because of fuel's intrinsic value as an energy source. This allows many different commodities with intrinsic energy properties to be compared and contrasted; for instance, one of the most popular is natural gas to oil.
BTU can also be used pragmatically as a point of reference for the amount of heat that an appliance generates; the higher the BTU rating of an appliance, the greater the heating capacity. As for air conditioning in homes, even though ACs are meant to cool homes, BTUs on the technical label refer to how much heat the air conditioner can remove from their respective surrounding air.
Size and Ceiling Height
Obviously, a smaller area room or house with shorter lengths and widths requires fewer BTUs to cool/heat. However, volume is a more accurate measurement than area for determining BTU usage because ceiling height is factored into the equation; each three-dimensional cubic square foot of space will require a certain amount of BTU usage to cool/heat accordingly. The smaller the volume, the fewer BTUs are required to cool or heat.
The following is a rough estimation of the cooling capacity a cooling system would need to effectively cool a room/house based only on the square footage of the room/house provided by EnergyStar.gov.
Area To Be Cooled (square feet) | Capacity Needed (BTUs per hour) |
100 to 150 | 5,000 |
150 to 250 | 6,000 |
250 to 300 | 7,000 |
300 to 350 | 8,000 |
350 to 400 | 9,000 |
400 to 450 | 10,000 |
450 to 550 | 12,000 |
550 to 700 | 14,000 |
700 to 1,000 | 18,000 |
1,000 to 1,200 | 21,000 |
1,200 to 1,400 | 23,000 |
1,400 to 1,500 | 24,000 |
1,500 to 2,000 | 30,000 |
2,000 to 2,500 | 34,000 |
Insulation Condition
Thermal insulation is defined as the reduction of heat transfer between objects in thermal contact or in the range of radiative influence. The importance of insulation lies in its ability to lower BTU usage by managing as much as possible the inefficient wasting of it due to the entropic nature of heat – it tends to flow from warmer to cooler until there are no longer temperature differences.
Generally, newer homes have better insulating ability than older homes due to technological advances as well as a more strict building code. Owners of older homes with dated insulation that decide to upgrade will not only improve on the ability for the home to insulate (resulting in friendlier utility bills and warmer winters), but also have the value appreciation of their homes.
The R-value is the commonly used measure of thermal resistance, or ability of heat to transfer from hot to cold through materials and their assembly. The higher the R-value of a certain material, the more it is resistant to heat transfer. In other words, when shopping for home insulation, higher R-value products are better at insulating, though they're usually more expensive.
When deciding on the proper input of insulation conditions into the calculator, use generalized assumptions. A beach bungalow built in the 1800s with no renovations should probably be classified as poor. A 3-year-old home inside a newly developed community most likely deserves a good rating. Windows normally have poorer thermal resistance than walls. Therefore, a room with lots of windows normally means poor insulation. When possible, try to install double-glazed windows to improve insulation.
Desired Temperature Increase or Decrease
To find the desired change in temperature to input into the calculator, find the difference between the unaltered outdoor temperature and the desired temperature. As a general rule of thumb, a temperature between 70 and 80°F is a comfortable temperature for most people.
For example, a house in Atlanta might want to determine the BTU usage during winter. Atlanta winters tend to hover around 45°F with chances to reach 30°F occasionally. The desired temperature of the dwellers is 75°F. Therefore, the desired temperature increase would be 75°F - 30°F = 45°F.
Homes in more extreme climates will obviously require more radical changes in temperature, resulting in more BTU usage. For instance, heating a home in Alaskan winter or cooling a home during a Houston summer will require more BTUs than heating or cooling a home in Honolulu, where temperatures tend to stay around 80°F year-round.
Other Factors
Obviously, size and space of house or room, ceiling height, and insulation conditions are very important when determining the amount of BTUs required to heat or cool a house, but there are other factors to keep in mind:
- The number of dwellers residing inside the living spaces. A person's body dissipates heat into the surrounding atmosphere, requiring more BTUs to cool and fewer BTUs to warm the room.
- Try to place the air conditioner condenser on the shadiest side of the house, which will usually be north or east of it. The more the condenser is exposed to direct sunlight, the harder it must work due to the higher surrounding air temperature, which consumes more BTUs. Not only will placing it in a shadier area result in greater efficiency, but it will extend the life of the equipment. It is possible to try and place shady trees around the condenser, but keep in mind that condensers also require good surrounding airflow for best efficiency. Make sure neighboring vegetation does not interfere with the condenser, blocking air flow into the unit and choking it.
- Size of air conditioning condenser. Units too big cool homes too rapidly. Therefore, they don't go through the intended cycles, which were intentionally designed for out of the factory. This may shorten the lifespan of the air conditioner. On the other hand, if the unit is too small, it will run too often throughout the day, also overworking itself to exhaustion because it isn't being used efficiently as intended.
- Ceiling fans can assist in lowering BTU usage by improving air circulation. Any home or room can be a victim of dead spots, or specific areas of improper airflow. This can be the back corner of the living room behind a couch, the bathroom with no vent and a big window, or the laundry room. Thermostats placed in dead spots can inaccurately manage the temperatures of homes. Running fans can help to distribute temperatures evenly across the whole room or house.
- The color of roofs can affect BTU usage. A darker surface absorbs more radiant energy than a lighter one. Even dirty white roofs (with noticeably darker shades) compared to newer, cleaner surfaces resulted in noticeable differences.
- Efficiency decrease of the heater or air conditioner with time. Like most appliance, the efficiency of the heater or air conditioner decrease with usage. It is not uncommon for an air conditioner to lose 50% or more of its efficiency when running with insufficient liquid refrigerant.
- Shape of the home. A long narrow house has more walls than a square house with the same square footage, which means heat loss.
Enter the power and voltage to convert watts to amps for DC, single-phase AC, and three-phase AC circuits.
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How to Convert Watts to Amps
Converting watts to amps can be done using the power formula, which states that I = P ÷ E, where P is power measured in watts, I is current measured in amps, and E is voltage measured in volts.
Given this, to find amps given power and voltage use the following formula:
I(A) = P(W)V(V)
Thus, the current I in amps is equal to the power P in watts divided by the voltage V in volts.
For example, find the amperage of 1200 watts at 120 volts
current = power ÷ voltage
current = 1200W ÷ 120V
current = 10A
Single-Phase AC Circuit Watts to Amps Conversion
Converting watts to amps for a single-phase AC circuit with power factor uses a slightly different formula.
I(A) = P(W)V(V) × PF
In other words, the current I in amps is equal to the power P in watts divided by the voltage V in volts multiplied by the power factor PF. If you’re unsure what the power factor is then a power factor calculator can help.
Three-Phase AC Circuit Watts to Amps Conversion
Using Line to Line Voltage
For three-phase AC circuits where the line to line voltage is known, the formula to convert watts to amps is:
I(A) = P(W)VL-L(V) × PF × √3
The current I in amps is equal to the power P in watts divided by the line to line voltage V in volts multiplied by the power factor PF multiplied by the square root of 3.
Using Line to Neutral Voltage
For three-phase AC circuits where the line to neutral voltage is known, the formula to convert watts to amps is:
I(A) = P(W)VL-N(V) × PF × 3
The current I in amps is equal to the power P in watts divided by the voltage V in volts multiplied by the power factor PF multiplied by 3.
How to Convert Watts and Ohms to Amps
It is also possible to convert watts to amps if the resistance of the circuit is known using the formula:
I(A) = √(P(W) × R(Ω))
The current I in amps is equal to the square root of the power P in watts multiplied by the resistance R in ohms.
It is not possible to convert watts directly to amps without also knowing voltage or resistance.
Because 1 kilowatt is equal to 1,000 watts, it is possible to use the formulas above to also convert kW to amps, but watts need to be converted to kW first. Use our kW to amps calculator to solve for kilowatts.
Btu To Amps Conversion
Equivalent Watts and Amps at 120V AC
Power | Current | Voltage |
---|---|---|
50 Watts | 0.4167 Amps | 120 Volts |
100 Watts | 0.8333 Amps | 120 Volts |
150 Watts | 1.25 Amps | 120 Volts |
200 Watts | 1.667 Amps | 120 Volts |
250 Watts | 2.083 Amps | 120 Volts |
300 Watts | 2.5 Amps | 120 Volts |
350 Watts | 2.917 Amps | 120 Volts |
400 Watts | 3.333 Amps | 120 Volts |
450 Watts | 3.75 Amps | 120 Volts |
500 Watts | 4.167 Amps | 120 Volts |
600 Watts | 5 Amps | 120 Volts |
700 Watts | 5.833 Amps | 120 Volts |
800 Watts | 6.667 Amps | 120 Volts |
900 Watts | 7.5 Amps | 120 Volts |
1000 Watts | 8.333 Amps | 120 Volts |
1100 Watts | 9.167 Amps | 120 Volts |
1200 Watts | 10 Amps | 120 Volts |
1300 Watts | 10.833 Amps | 120 Volts |
1400 Watts | 11.667 Amps | 120 Volts |
1500 Watts | 12.5 Amps | 120 Volts |
1600 Watts | 13.333 Amps | 120 Volts |
1700 Watts | 14.167 Amps | 120 Volts |
1800 Watts | 15 Amps | 120 Volts |
1900 Watts | 15.833 Amps | 120 Volts |
2000 Watts | 16.667 Amps | 120 Volts |
2100 Watts | 17.5 Amps | 120 Volts |
2200 Watts | 18.333 Amps | 120 Volts |
2300 Watts | 19.167 Amps | 120 Volts |
2400 Watts | 20 Amps | 120 Volts |
2500 Watts | 20.833 Amps | 120 Volts |
Equivalent Watts and Amps at 12V DC
Power | Current | Voltage |
---|---|---|
5 Watts | 0.4167 Amps | 12 Volts |
10 Watts | 0.8333 Amps | 12 Volts |
15 Watts | 1.25 Amps | 12 Volts |
20 Watts | 1.667 Amps | 12 Volts |
25 Watts | 2.083 Amps | 12 Volts |
30 Watts | 2.5 Amps | 12 Volts |
35 Watts | 2.917 Amps | 12 Volts |
40 Watts | 3.333 Amps | 12 Volts |
45 Watts | 3.75 Amps | 12 Volts |
50 Watts | 4.167 Amps | 12 Volts |
60 Watts | 5 Amps | 12 Volts |
70 Watts | 5.833 Amps | 12 Volts |
80 Watts | 6.667 Amps | 12 Volts |
90 Watts | 7.5 Amps | 12 Volts |
100 Watts | 8.333 Amps | 12 Volts |
110 Watts | 9.167 Amps | 12 Volts |
120 Watts | 10 Amps | 12 Volts |
130 Watts | 10.833 Amps | 12 Volts |
140 Watts | 11.667 Amps | 12 Volts |
150 Watts | 12.5 Amps | 12 Volts |
160 Watts | 13.333 Amps | 12 Volts |
170 Watts | 14.167 Amps | 12 Volts |
180 Watts | 15 Amps | 12 Volts |
190 Watts | 15.833 Amps | 12 Volts |
200 Watts | 16.667 Amps | 12 Volts |
210 Watts | 17.5 Amps | 12 Volts |
220 Watts | 18.333 Amps | 12 Volts |
230 Watts | 19.167 Amps | 12 Volts |
240 Watts | 20 Amps | 12 Volts |
250 Watts | 20.833 Amps | 12 Volts |