When purchasing a new compressor, you want the right amount of CFM at your necessary pressure for the smallest horsepower. This means that you need to consider the required CFM (cubic flow/minute) and HP (horsepower) of your application., as well as your budget.
How to Select a New Compressor
Cost is the primary consideration, both immediate and over time. While a new compressor can be expensive, it’s worth noting that when the cost of ownership over a ten year life span is taken into account, the actual purchase price of the new compressor is only around 10% of the overall cost, with electricity bills being the major expense by far (around 75%). Other factors that will influence your decision whether to repair or replace include the age of the compressor, its energy efficiency compared with newer models and its former repair history and overall reliability (i.e. is it likely to break down again in the near future?).
Initial vs. Overall Cost
When considering an air compressor, a primary concern should be: “How can I get the most amount of compressed air for the lowest overall cost?” Many consumers may consider only a small fraction of the life-cycle cost – primarily the initial cost of the machine, not realizing they will likely spend more in electricity the first year to run the machine than the purchasing price. That’s why, when comparing compressors, it’s important you examine all aspects of the costs associated!
Understanding Pressure and Flow
Compressed air flow is typically measured in cubic feet per minute (CFM). Compressed air pressure is typically measured in pounds per square inch (PSI) or bar. Think of flow as the ability to perform a process within an acceptable time frame, and pressure as the ability to support multiple processes at once.
Selecting the Right Size Compressor
A compressor that’s too small won’t produce enough flow and pressure to complete required tasks. A compressor that’s too large will cost more to buy and operate and can lead to mechanical problems. Correctly sizing your compressor requires real data about your needs, not guesswork. Whether you’re upgrading your current compressor or designing a new system, ask a compressed air sales professional to conduct an air system audit to measure your actual demand.
If you’re planning for future capacity, keep in mind that a compressor should be sized to address actual demand. Instead of anticipating potential future demand by oversizing today, add a compressor when the time comes to provide flexibility and redundancy as your operation expands. Also keep in mind that process improvements often reduce air demand; you may be able to expand your operation without expanding air production.
Base Compressor Size on CFM, not HP
The first step in choosing the proper compressor is finding the CFM demand your plant requires. CFM (Cubic Feet per Minute) describes the volume flow rate of compressed air. Improperly sizing your compressor can cost thousands of dollars in wasted electricity if you select an oversized compressor.
On the other hand, if you had more demand than you originally thought, the new compressor that you just purchased may be insufficient. Accurately determining your CFM demands is a critical first step in selecting an air compressor. Engineers work hard to improve the efficiency of air compressors and the design to produce more air than previous generations. If you are replacing an existing compressor, check your CFM rating and choose a new compressor with the same CFM rating.
More HP isn’t Always Better
A higher horsepower air compressor uses more electricity than a smaller one, so the important question is “Am I getting any more CFM for my increased cost?” For compressors with the same advertised horsepower, the CFM output can vary by as much as 25% between companies and models. As an educated customer, you want the right amount of CFM at your necessary pressure for the smallest horsepower. This will allow you to manufacture at the lowest cost and generate the highest profit.
A Critical Understanding
In order to make an educated purchase, it is critical to understand that all compressors are not designed equally and that depending on your requirements, you may be able to use a smaller horsepower, more efficient compressor. Buying a smaller HP compressor that produces the same amount of CFM allows you to keep profit in your pocket.
Not Sure Where To Begin?
Start by analyzing your air system’s life-cycle costs! You can analyze your usage and potential cost savings by conducting a no-contact compressed air energy assessment. Best of all - it causes no harm or downtime to check.