how to calculate hvac unit size

The sizing chart below is useful to help you determine your approximate central air conditioner size requirements. If you still need help, don't worry! Chat with or call one of our factory trained advisors to help get you the answers you need. As an alternative to the sizing chart below we offer MANUAL J - a professional load calculation based on your floor plan, location, and all variables. Please follow the link below for pricing. The turnaround for this service is 1-2 days. MANUAL J Residential Load Calculation Air Conditioning Square Footage Range by Climate Zone In order to scientifically calculate the right central air conditioner size, you can perform a Residential Load Calculation. Another way to size air conditioners is to determine the system size that is currently in place. The manufacturers do not list the air conditioner size on the unit. The system capacity will be coded into the model number of the outdoor unit. For example, model CKL24-1 is a 2 ton unit.
There are 12,000 Btu's per ton. The number 24 in the model number indicates the unit is 24,000 Btu's, divided by 12,000 Btu's per ton, equals 2 tons. 24,000 Btu's/12,000 Btu's per ton = 2 tons Use the following conversion information to determine your existing system size (use the system model number NOT the serial number) 18 = 1.5 tons 24 = 2 tons 30 = 2.5 tons 36 = 3 tons 42 = 3.5 tons 48 = 4 tons 60 = 5 tons When sizing air conditioners, be careful not to make the mistake of getting one that is too large. If the system you install is too large for the space, it will short cycle. In other words, the compressor will not run long enough to dehumidify the space and will limit your comfort. In addition, it will cycle on and off more frequently, increasing operating costs and reducing the system life. Proper air conditioner sizing is critical to optimize performance. If you're still unsure which system size is right for you, or if you're having difficulty downloading the Air Conditioner Size Calculator , please e-mail us or call us toll free number at 1-855-634-5588.
Sizing air conditioners by phone is difficult but we can provide you with the tools to get you started. Heating Square Footage Range by Climate Zone Use the lower of the two numbers if your home is well insulated and the higher number if it is older or poorly insulated. (Hint: Use the larger of the two numbers above if you're unsure of your home's insulation) Simply multiply the appropriate factor above by your home's total heated square footage to arrive at your approximate required heating capacity. For example, if you live in the yellow zone, your home is well insulated, and you have 2000 heated square feet, the equation will look like this: X .40 heating factor (from the chart above) 80,000 Btu actual output Then, to calculate the output on a gas furnace, multiply its efficiency rating by its listed input rating for the actual Btu output of heat. For example, if a furnace has a listed input rating of 100,000 Btu's and an efficiency rating of 80%, it will produce
If the same 100,000 Btu furnace has an efficiency rating of 93% it will produce:used ac units for homes 93,000 Btu actual outputbest large window ac unit For this example, using an 80% efficient furnace, the 2000 square foot home above would require a 100,000 Btu input furnace which will produce the necessary 80,000 Btu's output of heat.how much is an ac unit motor If you're still unsure which system size is right for you, please e-mail us or call our toll free number at 1-855-634-5588. An experienced design technician will be happy to assist you. Variables such as your insulation, type and number of windows, number of stories, construction type, etc. will greatly affect the required Btu's per square for both heating and cooling.
A general rule of thumb is that if your home is well insulated with newer style windows, you can select the smaller size system that falls within your total square footage. If your home is two story it will place less of a load on the system in the downstairs area as the second floor acts as additional insulation. If your home is not well insulated, has older style windows, and/or a larger than average number of windows, you will want to select the larger system which falls within your square footage range. The less insulated and more windows within the environment, the more likely you will experience greater air and heat loss. Contact Us for More Info If you're still unsure which system size is right for you, or if you're having difficulty downloading the Air Conditioner Size Calculator, please e-mail us or call our toll free number at 1-855-634-5588. An experienced design technician will be happy to assist you.Insist on professional HVAC calculations instead of guesswork.
The biggest problem with sizing your furnace and air conditioner is that so few people know how to do it accurately. Even many contractors rely on a simplified rule of thumb (which is, incidentally, illegal) that translates square footage into a one-size-fits-all answer. The result is usually oversized units that cost more, use more energy and fail to maintain the temperature you desire inside your home. Professional calculation factors in many of your home's unique characteristics to obtain the correct HVAC sizing. Online calculators can often get you close. So will calculating some of these measurements yourself. It may not be as precise as an engineer's, but it will ensure you can spot any gross inaccuracies. Find your home's total square footage if you will be heating and cooling the entire area. Multiply the length by the width to obtain the figure if you don't have the exact amount from the house plans or sales contract. Include home additions and multiple stories in the square footage.
Exclude areas of your home that will not be heated nor cooled. Calculate the British thermal units required to heat and cool your house, based on square footage alone. Multiply the square feet by 25. The result is the base BTUs needed. Adjust the base BTUs if you have unusually high ceilings (more thab 8 feet). Multiply the BTUs by 25 percent. Add the result to the base BTUs. Factor in the people who are usually in the house as each will affect the heat generated inside the home. Multiply the normal number of occupants by 400 and add that result to the base BTU calculation. Alternatively, for high levels of activity, boost the BTUs per person to 600, if desired. Divide the total BTUs by 12,000 to calculate the equivalent air conditioning tonnage. Alternatively, use the BTUs to size the furnace required. With heating, the BTUs multiplied by the efficiency rating equals the output BTUs, which is the number your estimates require. For example, if you need 30,000 BTUs and the furnace is 85-percent efficient, you need a furnace with 36,000 BTUs to match an output of 30,000 BTUs.