Are you thinking about buying a new air conditioner? If so, no doubt there are a variety of factors that you’re considering. One of the most important? Ensuring that you get a properly sized unit for your home or office.
If the unit that you select is too small, it may be cheaper upfront than a larger unit, but it will cost more to operate because it won’t properly cool your space and will run for longer periods than is necessary. It also will have a shorter operating life because it’s working harder than it needs to. Conversely, a unit that is too large will not dehumidify your indoor air properly, and create a damp chill rather than a comfortable, evenly humidified coolness. This can foster undesirable moisture, which can lead to mold and mildew in your indoor air.
Calculating just the right size with manual J
Manual J is a calculation that you can use to determine the ambient amount of warm and cool air that you need to create a comfortable indoor environment. Manual J also is known as a heat or cooling load calculation. This calculation considers the hottest or coldest days and times, along with the latent cooling load, which uses the wettest days, to determine the optimal amounts of heat and moisture to add or remove from the indoor area. The three loads are used to select the machinery required for optimal air operations and correct unit sizing.
Block loads versus room-by-room loads
Manual J protocol calculates the heat or cooling loads for a building, and you also can calculate loads room-by-room or in a block manner:
For more expert advice about Manual J, proper HVAC loads, and other issues related to home comfort, contact the experts at Paschal Heat, Air, Geothermal and Generators. We proudly serve customers in the Northwest Arkansas area, and can help you with all of your heating and cooling needs.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about sizing your new air conditioner and other HVAC topics, download our free Home Comfort Resource guide.