It's easy to mix the terms "kWh" and "kW" but it can confuse listeners. kW is power. If you expend a certain power, say 2000 watts (= 2kW) for an hour, you've spent 2kWh in energy. (You probably understand this; apologies as needed...)
The solar industry around me, 25 miles east of San Francisco, says that a mounted solar panel (which doesn't track the sun) will get the equivalent of 4.3 hours of sunlight on an average day. I had a company quote a small 1.5 kW system (4 panels I recall) and they wanted $11,000 for it. I understand there are some best-of-all-time rebates right now so the cost ought to be a lot lower than 11k.
So you can expect 4.3 kWh / day. That isn't much energy. My electric bill showed over 500 kWh for the month and it was so cool this past month that we didn't need air conditioning - so 500 kWh is a low figure for us (1140 sq ft, single story house, walnut creek, calif).
The posted comment about "tiered electric rates" is worth tracking down. A typical residence around us has a rate starting at 11.5 cents / kWh for the 1st 180 ish kWh, then the rate jumps to 13 cents, then to 22, then to 41 cents. If your setup can put a dent in the 41 cent usage, you may have a winner.
Also ask your power company if the panels don't qualify you for a tamer electric rate. Around here, having professionally installed panels does qualify you for such a rate. Just having some panels may qualify you for a rate which ends up saving you some money.