Could be any number of issues.
Heat loss via air loss or conduction losses can drive temperature differentials.
Poorly sealed or balanced ducts can also affect distribution and balance.
Much more information would be needed about the home to clearly identify the causes.
Heat loss via air loss or conduction losses can drive temperature differentials.
Poorly sealed or balanced ducts can also affect distribution and balance.
Much more information would be needed about the home to clearly identify the causes.