215 ILCS 5/143.10c

No insurance company that is authorized to do business in this State and which issues policies for personal multiperil property coverage, commonly known as homeowners insurance, may refuse to issue or renew a homeowners insurance policy to the owner or tenant of any single family dwelling, or to any owner of or tenant residing in a multi-unit residential dwelling which contains from 2 to 4 units in a single building, solely on the grounds that a space heater is being used inside the dwelling.

For purposes of this Section space heater means a heat radiating device used to warm rooms of a house or apartment and which is approved by Underwriters' Laboratories and uses gas, electricity or oil as its primary source of energy.