My air conditioner is blowing warm air, home is just getting warmer instead of cooler, we replaced filter, outdoor unit is running

Can you touch the copper tubes coming from the compressor or the other end going into the air box (plunum)

This advise is on the right track.

There are two copper pipes that carry the refrgerant from the compressor and condenser (outside) to the air handler and evaporator (inside). If you can touch the larger of the two pipes (suction line) and it is not cool to cold but luke warm and the smaller of the two (liquid line) is not warm to hot but also lukewarm then possibly you are low on refrigerant or out due to a leak.

The is assuming that all the components are operating - indoor blower motor, outdoor condenser fan motor and compressor. If you suspect a low refrigerant issue than I would shut off the system and refer to a tech for help on this one so other components are not damaged.