This is a program to do residential peak heating and cooling loads by the Manual J method. This is a 20-year-old HVAC standard, so the values may be a little off.
It’s simple to use and gives valuable insights into the loads attributed to each building element. The calculations include a heating and cooling load for each zone, as well as heating and cooling cfm’s (air flow, in cubic feet per minute).
How to Use This Program
“Peak loads” are what contractors use to size your HVAC system. If you enter all the right data in this program, it will give you the size of the unit you need if one day you must replace your system.
Peak loads aren’t the end-all for saving energy (not compared to annual loads), but they give the maximum capacity of the system needed for keeping a building comfortable on the coldest/warmest day of the year.
Changing the thermostat settings shows how much you save by adjusting it. The airflow value relates to the airtightness of the ductwork. If you live in an older house, a lot of conditioned air might be going into the attic, making the system much more inefficient.
