The HVAC system in your home is essential during the cold months of winter, so make sure that it is working efficiently. You will want to make sure the filter is checked on a regular basis, and is replaced when necessary. If the system switches on and off, the system will have to work hard and it could cause the system to wear our quickly. If you have pets, you will want to change the filter more often. Remember to never operate the furnace without a filter. This is because the dirt and dust can get into the system, and cause further wear with it.
If you are able to open up the inside of the furnace, you are likely to see some debris or dust buildup. You do not need anything special to clean this out, just grab a regular vacuum and clean it.
Also be aware of any strange sounds coming out of your system, or if the system does not seem to be acting right, do not ignore these signs any longer. You will also want to make sure the system is inspected and maintained before further issues happen with it. This can lead to a breakdown that will require repairs. If it is cold out, your home will be less that ideal for the temperature, especially if the part has to be ordered.