What is discomfort degree hours?

I am analyzing an existing house and a design prototype with Ecotect however I am experiencing some problems.

When I analyze my case study, the results shows that the spaces I am examining are too cold. These space receives little or no radiation in winter.

In contrast the same spaces in design prototype are now too hot. These spaces have full exposure to the winter sun.

The other thing that I have noted is that the sums of the DegHrs (Too Hot & Too Cold) for two spaces can be more than the sum of the DegHrs for the whole house. I wonder how this works.

I also want to know when is it necessary to provide heating or cooling.

Is cooling required at 8843.6 DegHrs (TOO HOT)?

Is heating required at 1568 DegHrs (TOO COLD)?

Your assistance would be highly appreciated.

Regards