Furnaces are supposed to be hot. Hot is what they do. However, if your furnace is not so hot, or is even running cold, you need a furnace repair technician. Here is what you should do next until the technician arrives and how the technician will diagnose and fix the problem.
Keep Everyone Warm
There are a dozen different ways to keep everyone warm until the technician arrives. Blankets are the best option. Electric heating blankets are even better. Huddling altogether under an electric heating blanket is about the best way, since all of that body heat combined with all of the heat from the electric blankets should make everyone quite toasty. Space heaters, gas fireplaces, electric fireplaces that throw off heat, cooking, and running all of your hot water appliances and dryers at the same time, etc., are all ways to keep warm if you cannot get an HVAC technician to your home sooner rather than later.
Check Your Thermostat and the Settings Button
You would be surprised at how many people fail to check their thermostats and the control buttons. It might also surprise you to know that your kids are often the ones responsible for flipping the control buttons from "heat" to "cool" or "heat" to "off." If it is especially cold in the house, but you hear the forced air blowing through the vents, there may be a good chance one of the kids flipped the control button to "cool." Flip it to heat, set the temperature, and then sit next to a heat register to see if hot air starts blowing at you. (It may just save you a service call fee, if that is the case.)
Diagnosing the Problem
The repair technician, once he/she arrives, will check all of the usual culprits for lack of heat. No fuel, electrical wiring has a problem, ignition switch is not working or disconnected, pilot light is out, etc., etc. As the technician moves through all of the things that are not the problem, they will eventually find what is. Then you can ask about cost and how quickly it can be repaired. Most of the time, technicians have spare parts on their trucks that they can sell to you at cost as part of the repair bill. Within an hour or so, your furnace will be up and running, but everyone may want to stay under the blankets or close to the heat source until the repaired furnace has heated up your home.