TLDR:

Lightning nodes use a lot more bandwidth than Bitcoin nodes. 5-10x more.

Details

I have been running a Bitcoin+Lightning node for a few years. Recently I deployed a Bitcoin only node(i.e. no Lightning). This gave me an opportunity to compare the behavior of nodes running Bitcoin vs Bitcoin+Lightning.

I used my network router to measure bandwidth usage of each node on a daily basis for a week. I noticed that the Bitcoin-only node uses about ~1GB/day. The Bitcoin+Lightning node uses a lot more, about ~8GB/day.

Digging a bit deeper, I found that the Bitcoin node was quite consistent in terms of upload vs download per day. The Bitcoin node downloaded about ~500MB of data and uploaded about ~600MB of data everyday.

The Lightning node on the other hand had a lot more variance. It downloaded about ~2.5GB/day. Unlike the Bitcoin node, the lighting node uploaded more data than it downloaded. The numbers vary wildly on a daily basis but average around 4GB/day.

Why does a Lightning node use more bandwidth?

Let’s start with the obvious fact that most Lightning nodes(like mine) sit on top of Bitcoin nodes. Therefore, Lightning+Bitcoin nodes will at minimum use the same amount of bandwidth as plain Bitcoin nodes. In addition, Lightning nodes also use network bandwidth to stay connected to existing peers, discover new nodes on the network and route transactions. The amount of bandwidth being used depends on the number of connected peers and volume of transactions being routed. At the time of my testing, my lightning node has less than 10 channels open with peers. I would think that a much bigger node with hundreds of peers and channels would use a lot more bandwidth.

More Details

The Bitcoin only node was running Umbrel. The Bitcoin + Lightning node was running myNode. Both nodes were running on Raspberry Pi with 4GB of RAM over Tor.