Heat pump blowing cold in heat mode could mean defrost trouble, low refrigerant, or a stuck reversing valve

https://southcentralusa.blob.core.windows.net/home-fix-hub/hvac-failing-signs-alpharetta-ga/signs-your-hvac-system-is-about-to-fail.html

Heat pump blowing cold in heat mode could mean defrost trouble, low refrigerant, or a stuck reversing valve. Don’t wait—quick diagnostics in Alpharetta can spare you higher bills and longer run times.