The W stands for Winter. The oil is 20 weight when cold so it will flow easier, and becomes 50 weight when it is at full operating temperature.
SAE stands for Society of Automotive Engineers. Sae ratings pertain to the oils Viscosity. Viscosity is the flowability (resistance to flow) at a particular temperature.
To add the sae 10 non detergent oil to your furnace blower motor you will have to open the motor section.
SAE 30 motor oil if the temperature is between 30 & 75°F.Colder use SAE 10 oil.Warmer use SAE 40 oil.
SAE 20W40 type SE motor oil for > 40deg F SAE 10W30 type SE motor oil for < 60deg F
SAE 10W30
sae document j300 defines the highest single grade as 60. this is in reference to viscosity and not the quality of the oil
A motor oil with a high viscosity (resistance to flow) like SAE 50, will be your greatest density motor oil. Low viscosity like SAE 20 will have the least density.
SAE 5W - 30 is the preferred oil
I'm not sure what you are asking - SAE stands for Society of Automotive Engineers
SAE 10w30
SAE 10w30
Use exactly what your owners manual recommends which is SAE 30 or SAE 10w30 in the summer. In the winter use SAE 5w30. You can use synthetic oil after the first oil change. If you want to view the owners manual click the link.