Manual-J is used by Heating Ventilation and Air Conditioning (HVAC) installers and contractors when determining a home’s heating and cooling needs. Manual-J calculations were developed by HVAC industry engineers to determine what volume of heating and cooling a structure needs to stay comfortable year-round, and has been used industry-wide for decades with great success.
A HVAC professional will need to obtain three pieces of information (heating load, sensible cooling load and latent cooling load) to determine what the load requirements are and what type and size equipment your home will require. This information can be obtained by using Manual-J calculations.
Heating load is figured as being the coldest temperature your home will reach in the middle of the night on the approximately coldest day of the year. A sensible cooling load is the amount of heat, as measured with a thermometer, the HVAC system should be able to remove from your home at mid-day on the approximate-hottest day of the year. Finally, the latent cooling load is the measurable volume of moisture that your home’s HVAC system can remove under the most extreme conditions. The best time to determine the latent load is a hot, humid and rainy day in mid-summer.
Your HVAC professional will take into consideration the two cooling loads (sensible and latent) when selecting your heat pump and A/C, ensuring – based on Manual-J – that they are no more than 15 percent over-sized. This will ensure proper cooling and dehumidification.
Contact an industry professional from Energy 1 Heating & Air Conditioning for all of your home-comfort needs, including proper sizing when you’re upgrading your heating or cooling system. We’ve been serving homeowners in Lorain, Erie and Cuyahoga counties for more than 33 years.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about Manual J and other HVAC topics, download our free Home Comfort Resource guide.
Energy 1 Heating services the Lorain, OH area. Visit our website to see our special offers and get started today!
Angie Lyczkowski is the owner and manager of operations at Energy 1 Heating and Air Conditioning... 
Energy 1 Heating & Air Conditioning
1 (440) 246-5440
Serving the Lorain, OH Area