Heating & Cooling Load Calculations

Is bigger better?

Not when it comes to your heating and cooling equipment.  Oversized air conditioners cycle on and off quickly which leads to three problems: 1) short cycles don't allow the equipment enough time to remove moisture from the air (think cold, clammy, smelly houses), 2) HVAC equipment is built for long, steady cycles so short-cycling reduces the life of the equipment, and 3) a home with equipment running short cycles will not have steady, comfortable temperatures (think short periods of cold followed by stagnant air until the next cycle).

Much of the same is true of heating equipment as well.  Even though heating won't necessarily remove moisture, you have the same temperature and comfort control issues with short cylcles.

The Solution

The solution is to carefully determine the heating and cooling loads that your home will have, size the HVAC equipment properly from there, and then design a duct system that will deliver the conditioned air in the correct quanitity to each room of the home. 

Most HVAC contractors do not do this because it requires a fair amount of time and some expertise in an appropriate software program.  At Green Insight we have invested in both the training and the software to make load calculations as accurate as possible in any climate situation.  From there, we can recommend equipment sizing and help design a duct system.


All of our calculations are compliant with ACCA Manual J (room-by-room load calculations), Manual S (HVAC equipment sizing), and Manual D (duct sizing).

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Edward O. Paschich, Paschich Design Group

In 1976 I built my first house. It was a “Solar Adobe.” I went on to “Environmentally Responsible,” then to Tire Houses, Straw houses and even a small Daub and Wattle building pursuing Sustainable building.

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