Calculation of BTU and kW power of an air conditioner
CONDITIONING
Do you need to buy and have air conditioners installed? How many BTUs do you need for a room in square meters? What is the power in kW of an air conditioner? We answer your questions about calculating BTUs for an air conditioner per square meter and see an example on how to calculate how many BTUs per square meter and the power of an air conditioner in kW (kilo watts).
To do this we will explain what BTUs are for sizing an air conditioner and what the BTU calculation formula is. Another useful formula is the conversion of the power of an air conditioner (in fact the power is measured with BTU) from BTU to Watt, in this way you can best choose your system with a btu or kw calculation. To conclude, let's get practical with a table to understand how to calculate the BTUs for an apartment per square meter or to heat a room.
- What are BTUs: power of an air conditioner
- Formula for calculating BTU and power in kW for sizing an air conditioner
- Air conditioner power kW and BTU
- How to calculate BTUs for an apartment
How many BTUs per square meter
What are BTUs: power of an air conditioner
To calculate the power of an air conditioner, BTU/h (British Thermal Unit per hour of operation) is used as a unit of energy measurement. The BTU identifies the cooling power of an air conditioning system for one hour of operation. Technically, one BTU is the amount of heat required to raise the temperature of 1 pound (i.e. 453.59237 grams) of water from 39°F to 40°F (i.e. 3.8°C to 4.4°C).
All brands of air conditioners provide the power expressed in BTU/hour for each splitter (generally we simply talk about btu). They typically range from 7,000 btu up to 14,000 btu for the most powerful splitters.
Formula for calculating BTU and power in kW for sizing an air conditioner
To make a quick calculation of the BTUs for sizing an air conditioner we must first calculate the cooling power of an air conditioner in Watts and then transform it into BTUs. The simplified formula for Watt power is:
Watt Power Calculation = K x Width x Length x Height
Correctly the calculation of the power of air conditioners in Watts starts from the calculation of the cubic meters of the volume of air to be cooled or heated present in a room and we from the square meters. Then for simplicity we talk about calculating BTUs in square meters because on average the height of a home ceiling is almost always 2.9 m.
In the formula for calculating the cooling power we find a constant K which is a standard parameter, which is used with two values:
Since 1 Watt equals 3.4 BTU/hour, to go from Watt to BTU/hour we need to multiply the result by 3.4. Here is the formula for calculating BTUs starting from the power in kW of an air conditioner.
BTU Calculation = Watt Power Calculation x 3.4
Let's see an example of BTU calculation to cool a 12 m2 (3x4) room with a height of 2.9 m:
From these simplified calculations you need to buy an air conditioner with at least 3,000 BTU.
These are quick and simplified calculations.
As we saw before, to understand the electricity consumption of each individual splitter, which has a certain power expressed in BTU, I have to convert the btu value into watts. Watt measures how much an appliance consumes per hour. So we need to transform btu/hour into watt/hour or, better yet, into kilowatt/hour.
To make this transformation it is decidedly simple, as we have seen 1 Watt = 3,416 Btu (before we had a rounded figure). At this point we need to divide the power in BTUs by 3.416 to find the power in kW. Let's see some examples to calculate the power in kilowatts starting from BTUs:
Calculation of air conditioner power in kW from BTUHourly consumption in kW7,000 BTU air conditioner2 kW/h9,000 BTU air conditioner2.6 kW/h12,000 BTU air conditioner3.5 kW/h14,000 BTU air conditioner4.1 kW/h
Counting the kW of power of your air conditioners has a dual utility for understanding:
With these examples of calculating btu in kW, we now know how to answer the question "how many kW are 12,000 btu?". The answer is 3.5Kw.
Once we understand what BTUs are, let's see how to calculate the power needed for our air conditioners. The purpose is how to calculate the BTUs for an apartment to cool the house based on square meters.
First we need to have the measurements of the house to calculate the volume of the house, i.e. the square meters and the internal height.
Subsequently, as we saw in the initial chapter, we must multiply the volume by a factor K which is used in this way:
The result of this simple operation provides us with the necessary cooling capacity expressed in calories/hour (technically they would be refrigerators/hour).
Finally we can convert the power expressed in Kcal (kilocalories) into BTU or Watt. Taking into account that 1 Watt = 0.860 Kcal/h and 1 BTU= 0.252 Kcal/h.
Let's see some examples to answer the questions: how many btu per square meter? As we saw initially we should talk about cubic meters and not square metres, but for simplicity we always talk about square meters considering the average height of a home ceiling of 2.9 m.
We have prepared a simple table that applies the formulas for calculating btu and kW. The table is developed on the basis of the square meters of the house or a room. Let's start by understanding how many BTUs per 20 m2 and then move on to larger sizes of 20 m2, 30 m2, 40 m2, 50 m2, 60 m2 and so on.
Table for calculating BTU per m²How many BTU per m²How many Kwatts per m²20 m²5,0001,530 m²8,0002,340 m²11,0003,250 m²13,0003,860 m²16,0004,770 m²19,0005,680 m²21,0006,190 m²24,0007 ,0100 m27.0007,9110 m230.0008,8120 m232.0009,4
From the previous table we can give examples of typical sizes (50, 70 and 100 m2) and the number of air conditioners to install. Commercial air conditioners generally have ratings of 7,000, 9,000 or 12,000 BTU.
In this case, to know how many BTUs to calculate the power of the air conditioner for 50 m2, the starting value is 13,000 BTUs. In this case we have two hypotheses, use a single 12,000 BTU air conditioner but it will be difficult to air condition the house well, or choose two 7,000 BTU air conditioners. Therefore, having to evaluate how many BTUs per 50 m2, the number of air conditioners to install is important.
A 70m2 house can consist of two bedrooms, a bathroom, a kitchen and a living room. For 70 m2 you will need 3 air conditioners, two for the rooms and one for the living room. Let's avoid placing them in the bathroom and kitchen. The BTU calculation for 70 m2 is approximately 19,000 BTU. Overall we can put three 7,000 BTU air conditioners. This means that if they ask you how many BTUs per 70 m2 the minimum value is 19,000 BTUs but then it also depends on how many splitters you need to install.
In the previous table we have rounded the BTUs and Kw to easily understandable measurements. For example, the air conditioner power per 100 m2 is approximately 24,650 BTU, for simplicity in the table we have reported 27,000 BTU per 100 m2, increasing the estimate by 10%. For a 100 m2 apartment we can install 4 splitters, one with 9,000 BTU and the others with 7,000. In this case the installed power per 100 m2 is 30,000 BTU.
The values expressed by the formulas are used exclusively to give you an idea of how many BTUs are needed for each room in the house. For precise calculations before buying any air conditioner, it is essential to rely on a professional installer. An installer can help you with the final calculation of BTUs, to understand how many air conditioners or individual splitters are needed, and what power you need in each room of the house.
Once the BTU calculation has been defined, the professional is able to evaluate other fundamental aspects with an inspection:
All these parameters influence the performance and comfort of air conditioners and which only a professional installer is able to do.
Maintenance of safety systems
Security systems: why maintenance is important
Once security systems, a video surveillance system, an anti-intrusion system or perimeter sensors have been installed, we must take into account that it will be necessary to carry out scheduled maintenance over time.
Maintenance of security systems is often underestimated.
In fact, it is thought that after having chosen, installed and tested the new system, it no longer needs checks and controls.
There is no bigger mistake.
We must remember that SAFETY systems are made up of various components, assembled and connected to each other.
Think of a video surveillance system, generally composed of a DVR, or digital video record, i.e. a digital image recorder with the support of a hard disk, which can be connected to one or more cameras (generally up to 64).
Another example is anti-intrusion security systems.
Think of the one via wire or via radio, in which we identify not only the heart of the alarm and therefore the control panel, but also the related infrared sensors, or magnetic contacts for doors and windows, opening keys and tags, remote controls, or external perimeter sensors and so on.
Ultimately, a security system is the result of a series of variables to be constantly kept under control.
So why schedule maintenance if our system is perfectly functional?
There are various reasons, including certainly the slow aging of the components themselves. In fact, the main cause of malfunction of the systems mentioned is to be found in slow wear.
Battery
The components that require the most maintenance are primarily the batteries.
In fact, security systems are equipped with numerous batteries, such as the control unit itself, or the individual infrared sensors, we find them in the magnetic contacts but also in the external sensors.
Batteries are susceptible to degradation over time, they can leak highly corrosive acid or overheat or in the worst case scenario catch fire.
They generally have a duration of 3 years, before which it is advisable to replace them.
Sensors
The sensors, whether internal or external, are calibrated during installation according to the specifications of the rooms and their surroundings.
We will certainly never erect a column inside the house, which would act as a shield for the sensor, but over time we could still change the arrangement of the furniture or insert shelves or plants on the ceiling, thus creating barriers that had not previously been budgeted, affecting the efficiency of the sensors themselves.
It would affect not only the protective cover, but inevitably over time we could detect problems with wear, opacity of the lenses or cracks in them.
This is the major cause of replacing sensors, especially external ones, because they are subject to bad weather, disturbances, insects, sun and high temperatures.
Technical maintenance
The technician called to carry out maintenance on your security systems will have to:
The LAQGIMPIANTI staff of the various offices are always available thanks to remote assistance, for the following services:
– Modification of the programming parameters of your system; – Verification and resolution of reported anomalies; – Support for every request on the functioning of the various systems.
Therefore we also offer our customers a scheduled maintenance service for the systems, to ensure full efficiency thanks to the periodic verification of the regular functioning of all devices and components.