Hello eQuest Users,

I am modeling an apartment complex that has a central gas boiler system
serving in-unit heat pumps. The baseline building has code minimum EER
and COP for heating and cooling. The first measure I performed was
increasing the EER and COP, and this produced accurate results. Upon
adding a variable speed drive to the heat pump loop as an improved
measure, there is a significant increase in the amount of therms being
used for space heating, but as expected the electrical consumption and
peak decrease significantly. Does anyone have an explanation as to why
this increase in therms is happening?

Thanks,

Jay