Offset Percentage with no net-metering

[Jerlaff]

Hello,

When installing a system and the power company is not offering net-metering, what type of offset should one use? I heard 70%, but not sure if that is too high or low?

 

[zanydroid]

Hello,

When installing a system and the power company is not offering net-metering, what type of offset should one use? I heard 70%, but not sure if that is too high or low?

I am not sure how to understand your proposal. It sounds too primitive to be useful. Perhaps explain in more detail

An annual offset calculation of 70% does not properly match how the financial math works for non net meter setup. You need some offset calculation at probably month by month granularity. Daily would probably be better but that may be hard to do manually.

Storage makes a difference too. You probably need storage if there is no net metering. Unless you get netting within one day.

 

[zanydroid]

That said 70% may be the right rule of thumb, for the “average home and latitude” in some parts of the world. But that must follow from an analysis from the starting point I outlined. And it would be better to do that monthly or daily offset anyway than to do a low effort hacky ballparking with inappropriate model

And even with net metering a simple kWh based offset is bad. The largest net metering market in the US (California) has very aggressive time of use rates. Everybody that planned solely by kWh offset % in 2013 is mega sad in 2024