Space heaters can be expensive to run and are generally less efficient than central heating units. However, if you are usually in a single room of the house during the winter and do not want to heat up the entire home, then a space heater can cost less to operate. You can lower the temperature of the entire house (experts suggest no higher than 68 degrees as a general rule, but much lower if you are only occupying one room) and set up a space heater in the room you occupy the most. If your home has good insulation and can retain heat in a single room well, this would save you a great deal of money. The average 1500 watt space heater will cost nearly $36 a month to operate for just 8 hours a day. If you can get away with it, running only a few throughout your house while keeping your main thermostats set very low will likely be the best scenario for you. However, running multiple space heaters in addition to your central unit can cause your bill to jump pretty quickly! There are some models of space heaters that use less energy (as little as 400-500 watts compared to the 1500 watt giant pictured).
Space heaters can be dangerous if they are not carefully monitored. Always read the manual of your space heater, and never leave it unoccupied.