Ensure furnace vents are not blocked from the outside by any objects or any other obstructions; if so, CO¹(Carbon Monoxide: an invisible, odourless and poisonous gas produced by common household appliances) may be drawn back inside your house
Store fuel(i.e. gasoline in approved containers, propane tanks) outside and keep them away from direct sunlight and other heat sources
Inside the House:
Have the furnace, fireplace and chimney inspected
Make sure warm-air outlets and cold-air returns are clear of carpets, furniture and debris
When time to change your clocks, change the batteries in your smoke and carbon monoxide alarms.
For more information, please visit Safetyinfo website for more details.
note1: Common Sources of Carbon Monoxide: Furnace; Fireplace; BBQ; Water Heater; Dryer; Stove; Car; or blocked vents or chimney.