The calculation engines in EnergyPro that are now used for Title 24 code compliance are developed and maintained by the California Energy Commission. The new Residential and Nonresidential calculation engines they provide are significantly slower than the prior ResSim and DOE-2 engines we provided in older versions of EnergyPro. The new engines incorporate CSE and EnergyPlus, which are more powerful than the older calculations, and simulate the zones much more thoroughly, resulting in longer simulation runtimes.
Try to keep the number of zones in your model to an absolute minimum, but it is not unusual to see run times of over an hour on more complex models.
To speed up run times, you can select the Quick Analysis option, which will run a partial year simulation. In the bottom left, click on the Calculations. In the list that appears above, select either Res T24 Performance or NR T24 Performance. On the right will appear the option for Quick Analysis. This will cut your runtime in half. However that option will trigger a report that includes a watermark that states “Not useable for compliance” since you must run the full year for code compliance.
Another option is to check the box for “Do Not Generate PRF01/CF1R” This will skip the report generation feature that occurs at the end and can save additional time, but you will not get the Title 24 reports needed for permitting.
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