How far away should a thermostat be from the return air register. Ours is located directly under the return air and we have cold spot in our home.

Normally this is a good location for a thermostat. But its hard to say without knowing the layout of your home. Where is the coldspot? May be a supply problem. Can you give some more details? Hope to hear back from you. Take care,

Lee

Ps. Shouldn't be so close that it gets a draft, just should be in general area of return.