Choosing the Right Size for Air Conditioner Rentals

Portable AC units can be a welcome addition to any commercial or industrial facility, complementing an existing HVAC system, or they can be a lifeline in critical situations, such as in case of unexpected equipment failure.

While they are, without a doubt, incredibly useful and versatile devices, they aren’t one-size-fits-all solutions. Therefore, before you rent air conditioning units in San Diego, it is crucial to learn how to properly size them, so as to ensure maximum efficiency and reliability.

How do I determine what size air conditioner I need?

The importance of correctly sizing your air conditioner cannot be overstated. Choose an undersized system, and it will work non-stop in a futile attempt to reach optimal performance, leading to rapid wear and tear. Choose an oversized one, and it will switch on and off, causing temperature variations, pockets of high humidity, and excessive energy expenditure.

For these reasons, it is highly recommended to have a certified professional do the sizing calculations in your stead. Experts use advanced equations that factor in elements such as:

  • Window quantity and size;
  • Amount and quality of insulation;
  • Heat produced by the equipment;
  • Building’s orientation relative to the sun.

This allows them to size the unit with complete accuracy, helping you choose the most optimal solution for your specific applications.

Calculating air conditioner size for your space

To determine the size of your A/C, first, you need to determine how much heat the system must remove from the premises to maintain an optimal temperature. This value is commonly referred to as the “cooling load” and it’s expressed in British Thermal Units (Btu). Here’s how to calculate it:

  • Step 1: Calculate the square footage of the space;
    • Note: For spaces where ceiling height drastically exceeds the standard 8ft (for instance, 36ft as is the standard in industrial facilities), it is advisable to use cubic footage instead of square;
  • Step 2: Divide the square (cubic) footage by 500;
    • Note: 500 is the “rule of thumb” factor that considers the insulation quality as average. If the building’s weatherization is above average or excellent, you can multiply this factor by 1.5 or 2.0 (respectively), to arrive at a more accurate value;
  • Step 3: Calculate the basic cooling load by multiplying the value from Step 2 by 12,000, which will give you the Btu/hour value;
    • Note: This value represents the preliminary cooling load of the space and can already be used to determine the A/C unit size. However, we suggest going through with steps #4 and #5 to increase the relative accuracy of calculations.
  • Step 4: Add 380 Btu for each occupant;
    • Note: If the number of occupants varies by day, or is in any way inconsistent, use the average value or a rough estimate;
  • Step 5: Add 1,000 Btu for each window;
    • Note: Windows significantly attribute to the heat gain/retention properties of the space, which is why they should be taken into account.

Conclusive with Step 5, you now have a minimum cooling capacity requirement that your air conditioner must meet. However, A/C unit sizes are rated in tons and they come in half-a-ton increments. Therefore, to now determine the size of the unit, we need to:

  • Step 6: Divide the value from Step 5 with 12,000 to convert Btu/h back to tons.

The value you arrived at after Step 6 is the minimal adequate size of the air conditioning unit for your space. 

rent air conditioning units in san diego

Where can I confidently rent air conditioning units near me in San Diego?

Aerco Systems is San Diego’s leading provider of portable cooling and heating units suitable for indoor or outdoor applications. Since 1978, we’ve been serving commercial and industrial properties from Mission Bay to San Carlos and beyond, delivering complementary and emergency solutions to a diverse range of clients.

Our units are characterized by high energy efficiency and reliability, and we’re available 24/7/365 to correctly size, deliver, and install them. Reach out to us today and reap the benefits of our cutting-edge heaters and coolers!