Daylight Saving Time

This article helps explain how Daylight Saving Time (DST) is handled in HelioScope.

1. Keepout from Shade - cast shadows use solar time, so shadows rendered in the design won't match local time during Summer if DST is observed.

2. Simulations and Reports and Weather Files - use solar time. Weather files are typically provided in TMY format, which removes any DST adjustments, making it straightforward to match with the sun's position in the sky, which doesn't depend on local timekeeping. You can confirm that DST is not present in a report by viewing the Hourly CSV data and looking at the hours in March and November.

3. Financials Analysis and Consumption Files - use local time, which will adjust for DST where relevant. Daylight Savings has a meaningful impact on utility rates and financial results, therefore, HelioScope adjusts the time series data from an energy simulation to match Daylight Savings when modeling financial returns.

To see how we adjust the data to account for DST, please see the example below:

Every hour in the 8760 still maps to an absolute hour of the year in its local time, even if locally, time on the clock is shifted via DST. So. when DST starts on March 14, the local time shifts an hour forward, and when it ends since "we go back in time" this means on the data that 2:00 AM repeats.