If you have a gas furnace that isn't working quite as well as you might like, then you should try troubleshooting it on your own before calling in a professional. Here are some common problems and the associated places that you should take a look at:
Not turning on at all?
If your furnace isn't turning on at all, then you want to take a look at the power and the unit itself.
In order to accurately check the power, you will need to know whether your furnace purely uses gas or if it uses an electric start system. A purely gas-based furnace will run even if the electricity isn't working, while an electric start furnace will not run if you have problems with your electricity or gas.
First, check the pilot light to determine whether or not there is gas currently flowing into the furnace. If the light is lit, then the flow of gas isn't your problem. If it isn't lit, then you should make sure that your gas main is on and that the settings on the furnace are correctly set to allow gas to flow into the furnace.
What about electric-start furnaces?
If you have an electric-start furnace, then the problem might be solely with your electricity rather than with your gas line. To test this, you will want to take a look at the circuit breaker. In most cases, this will be either on the outside of your home, in a closet or in the garage.
If there is nothing wrong with your circuit breaker, then you should check the power line directly to the furnace. The cord may be frayed or otherwise damaged, which would mean that you need to replace the cord. If you plan on doing this yourself, make sure that you take all the necessary precautions, such as turning off the furnace and wearing insulated gloves.
Is your heater not putting out enough heat?
If your problem is that your heater is working, but not as well as it should, then you should consider cleaning out the filter before anything else. The filter on the furnace will catch a ton of dust and dirt over time, which will prevent heat from getting to the rest of your home. By removing this dust and cleaning the filter, you can restore the flow of heat and enhance the efficiency of your furnace.
You should also make sure to check whether you have a permanent or disposable filter system, since you don't want to make the wrong decision and throw away a permanent filter.
If your furnace is still having problems, it may be time to call in a licensed heating contractor like Kangas Burner & Heating Service.