In both 2.2 and 2.3, the LS-F report which shows the annual heating and cooling from the LOADS run has an issue. There are two LS-F reports - the Design Day report and the Standard Report which shows annual LOADS results. The issue is the totals row in the Standard Report is not the sum of the monthly results but rather also includes the Design Day report total.

This is less of an issue in 2.2, for a couple of reasons. Firstly in 2.2 the default heating and cooling design days are a single day although more may be specified. Further in 2.2 if no design day is defined then the Design Day LS-F report is not triggered. In 2.3 conversely, the default design days are a 7 day period. If no design day is defined in 2.3 then the sizing is done for a full year for heating plus a full year for cooling (which is why the simulation takes notably longer) and the Design Day LS-F report reflects this two year period.

Until recently, I had not spent much time looking at LS-F. However, with Thermal Energy Demand Intensity (TEDI) being a required metric in several jurisdictions, the question of what impact individual envelope components have on TEDI comes into play. It seems LS-F is the only place to get a measure of the annual heat loss through windows (for example). We had seen a number of .sim files where the LS-F exceeded the SS-D. I believe this issue with the total row explains that situation. The sum of the monthly Standard Report LS-F values or the Standard Report total less the Design Day LS-F total should be used.

It does not appear that the LS-E report which provides the same information but on a space by space basis has the same issue.

Cheers,

Brian

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Brian Fountain
Associate