Getting the right sized ducted air conditioning system for your house is critical for effective cooling and proper energy usage of the unit. To calculate the size of the unit, you need to evaluate different factors such as the size of your house, its climate, number of furnished rooms, and how well insulated the ducts are. Let’s discover the process of calculating the correct size of ducted air conditioner for your space.
Understanding Ducted Air Conditioning
Ducted air conditioning systems are excellent for both cooling and heating large areas. It distributes the conditioned air throughout the house using a system of ducts which can either be placed on top of the ceiling or below the floor. There is a main unit that cools or heats air and sends it through the ducts to various zones of the house.
The size of the unit is usually measured in kilowatts (kW). Proper aircon size will help you control comfort levels and keep energy costs reasonable.
Importance of Air Conditioner Size
The size of the air conditioning system directly affects its efficiency and performance. Here are reasons why getting the correct size matters:
Efficiency: An air conditioner that is too small for the space will struggle to cool or heat your home. It increases energy bills. You will also spend money on maintenance cost as the system works harder to reach the desired temperature. In contrast, an oversized system cools too quickly, leading to short cycling and higher energy consumption.
Comfort: The right size ensures comfort as cooling and heating are well distributed within the home. If a system is undersized, some rooms may never reach the desired temperature. The opposite is true if the unit is oversized since the system lacks the ability to effectively dehumidify the air which creates clammy spaces.
Longevity: The system lifespan also gets affected by the size of the system. Aircon with wrong size will need frequent repairs.
Now that we understand why the size is important, let’s calculate the proper size ducted air conditioner your home or commercial space needs.
Things To Consider When Selecting The Size of Ducted Air Conditioners
These factors will influence the size of ducted air conditioning unit:
The Area of Your House
The total area of your home is one of the most critical factors when sizing an air conditioning system. For larger homes, you will require more powerful units. Smaller spaces will need less capacity. The total area of the home is usually measured in square meters (m²).
During the calculation, we will consider the ceiling height, type and thickness of the insulation, window size, positioning, and shading around the windows.
Quality of Insulation
In poorly insulated structures, the air moves comparatively freely out of the building. It means you will have to use a larger unit. Well insulated ones can afford to use smaller units.
A well-insulated building will enjoy better air conditioner performance and less energy consumption.
Climate Zone
The climate and geographical location has an impact on the capacity of ducted air conditioners. Homes located in hotter areas will require more powerful units and vice versa.
Number of Rooms and Zones
Ducted air conditioning is multi zoned which means different rooms or areas (zones) of your house can be controlled independently. The quantity of zones to cool or heat will determine the required size of the system.
In case of a large single living area, the system capacity will just slightly decrease compared to the capacity requirement for cooling multiple smaller rooms. How many zones exist and their size should be considered in the calculations.
Ceiling Height
The height of the ceiling will, in some way, influence the amount of air required to heat or cool the area. 2.4 meters is the standard height of a space. However, if your home has rooms with more than 3 meter ceilings, you will require a system with more capacity.
Windows and Glazing
Large windows, and especially those that are directly exposed to sunlight, can contribute remarkably to the amount of heat your house receives. More the number of windows in your house, more will be the size of the air conditioning unit.
Double glazed windows have better heat resistance. Therefore, they will increase the efficiency of your air condition.
How to Compute the Proper Size Ducted Air Con
Computation of the size of ducted air conditioner can be done using a formula based on the principles discussed previously. The steps are as follows:
Step 1: Calculate the Area
Estimate the total area (in square meters) of the space to be covered by the system. This means that if you are cooling a single floor of a house, you need to measure length and breadth of the space and compute the total area.
Step 2: Consider Temperature as a Factor
Adjust capacity according to your region. In hotter climates, we advise to add an extra kW or two to make sure the unit can withstand extreme heat. Cooler regions can afford to stay on the lower side of the recommended range.
Step 3: Insulation and Energy Efficient Windows
Poor insulation of a home or having large windows significantly impacts the size of the system needed. On the other hand, proper insulation allows the homeowner to use a smaller system.
Step 4: Account For Ceiling Height
If the ceiling height is more than 2.4 meter, increase the required kW capacity of the system.
Example Calculation
Assume that you are cooling a 200 m² house with standard 2.4 meter ceilings located in a warm region. The house is well insulated but has large windows facing the sun. Applying the formulae
- 200 m² × 150 watts (rule of thumb for warm climate)= 30,000 watts or 30 kW
- Adjust for windows and insulation:+ 2 kW for the good insulation and large windows.
You may consider a 32 kW ducted air conditioning system considering the factors above.
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Ducted System ServicesWhen to Talk to an Expert
The calculation above will give you an overall idea about the size requirement of the ducted system. However, before making your decision, discuss with an HVAC professional. They are able to do the exhaustive load calculation considering all aspects of your home, like, the insulation grade, exposure to the sun and much more.
Conclusion
Finding the right size ducted aircon system is essential for better cooling performance and longevity of the system. Calculate the capacity required as per our guidelines to get an estimation. It will help you plan your costing. However, as you can not definitely tell about many factors such as insulation, climate condition etc, you can not properly adjust these during the calculation unless you are a professional . Therefore, during final decision making stage, consult with HVAC experts.
