The air coming out should be 14 to 20 degrees cooler than the air flowing in. Move the thermometer to a vent in each room or area of your home. If any of the vents are much colder or warmer than another, there may be a problem with the ductwork, or the distance may be too great from the blower.
Beside above, how hot should heat be coming out of car vents? Cabin heat comes from hot coolant, so drive long enough to warm up the engine. The coolant temperature should hit at least 160°, preferably 180° to 220°. The air conditioner compressor should be disengaged with the climate control selector out of the defrost position.
Keeping this in view, why does cold air come out of the heat vent?
Explanation: Leaks in your ductwork means that cold, unconditioned air from inside your attic gets sucked into your ductwork. That cold air mixes with the warm air from your furnace, causing the air coming from your vents to feel considerably cooler than it should.
How cool should my house be if its 100 outside?
More specifically, for our area, most systems are designed to lower your indoor temperature about 20°F from the outdoors. So, on days when its 100°F outside, and your system is running at its peak efficiency, your indoor temperature will likely never maintain a level lower than about 80°F.