How to determine natural gas line size for your furnace?

Answer by  Matt62 (36)

This is determined by the number of BTU/hr that the furnace is rated for most owners' manuals will say what is required.

Answer by  Advisor (1032)

This depends on several factors. The size of furnace, age of gas line and tanks, whether supply is above or underground and existing line size. If you already have gas furnace, choose new unit with same size connections. If this is your first, consult your gas provider for connection assistance.

Answer by  facemuscles (19)

Make sure to disconnect the furnace's current gas lines and then measure the distance from the meter to the furnace. Next, find out the number of BTU's for the furnace. Then, call the local natural gas provider in your area and they can tell you the line size you are going to need.

Answer by  Keri89 (6)

The size of the line is determined by two factors. One being local building codes and the other is by the amount of gas required for the mamimum BTU output. Most new units will tell you the size needed for the unit. In older residential HVAC'S the size most commenly used is half inch galvanised pipe or copper tubeing.