Hello,

For some reason this year my air conditioner is not producing enough
cold air to cool the upstairs of my house. When I go to the ground
floor there is enough cold air coming out, and it's nice and cold, but
upstairs, it's too hot. I try to lower the thermostat to 70 degrees,
and "cool" air comes out of the vents on the upstairs, but for some
reason, the house is not cooling down enough to make the thermostat
shut off. What's the most likely culprit?

Thanks
Sam