Check the furnace and water heater
Give your furnace a careful visual review. Do you see any rust or corrosion? Are there water spots or if an oil furnace, signs of fuel leakage on the floor? Any signs that it has shifted its position? Unusual odors? Signs of soot? Odd sounds as it turns on and off? Also check the age of the furnace and look for stickers that document routine service needs. Note that spring is a good time to schedule annual furnace maintenance; repairmen aren’t as inundated with calls as they during the fall and haven’t started servicing air conditioners yet. Note too that a sign of furnace trouble is excessive condensation on your windows. That could be a signal of a failed heat exchanger or an ailing furnace. Look for similar issues with your water heater. There shouldn’t be any leaking, corrosion or blackening near the burner, or corrosion to the piping leading in and out of the heater.