The fastest way to tell a serious solar proposal from a bad one is to notice where it starts. A serious one starts with your actual electricity usage, month by month, for a full year. A bad one starts with a monthly payment and works backwards. Before anyone quotes you anything, spend ten minutes with your own bill so you can tell which conversation you are in.
Find your annual kilowatt-hours
The single most important number is total annual consumption in kilowatt-hours. Not dollars, kilowatt-hours. Dollars move when rates change; kWh describe your house.
Most utility online portals will show twelve or twenty-four months of usage history, often as a downloadable CSV or a bar chart on the account page. Add up twelve consecutive months. A typical Central Texas single family home lands somewhere between 12,000 and 20,000 kWh a year, but the spread is enormous depending on square footage, insulation, pool equipment, and whether the home heats with gas or electricity.
If you cannot get a full year, take your highest summer month and your lowest spring month and be aware that anything estimated from a partial year will be wrong for a Texas home, because the summer peak dominates the annual total.
Separate energy charges from delivery charges
In a deregulated market your bill has two halves. The retail electric provider charges you for energy, expressed in cents per kWh. The transmission and distribution utility charges you for delivery, usually as a fixed monthly customer charge plus a per-kWh delivery rate. Both appear on the same statement and many people read only the total.
This matters because solar offsets energy consumption, and it reduces the per-kWh delivery charge in proportion, but it does not eliminate the fixed monthly customer charge. You will still have a bill after solar. Anyone who tells you your electric bill goes to zero is either ignoring the fixed charge or is not being careful.
Compute your real blended rate
Take your total annual cost, including energy, delivery, fixed charges, and taxes, and divide by your annual kWh. That is your blended rate, and it is the number a solar payback calculation should use. It is almost always higher than the advertised rate on your plan, because the advertised rate excludes the fixed charges and often assumes a usage level you do not hit.
If your blended rate comes out at 15.8 cents and a proposal assumes 12 cents, the proposal is understating your current cost, which makes solar look worse. If it assumes 22 cents, it is overstating it, which makes solar look better than it is. Either way you now know.
Look at the shape of the year, not just the total
Pull up the monthly bar chart. A Central Texas home usually shows a tall summer block from June through September and a much lower shoulder in spring and fall. Solar production runs the opposite way in one important respect: output peaks in the long days of late spring and early summer and falls in December and January.
The overlap is good but imperfect, and how the utility handles that mismatch is the whole ballgame. Under a plan that credits exported energy at the full retail rate, spring overproduction offsets winter shortfall. Under a plan that credits exports at a lower wholesale rate, it does not, and a system sized to your annual total will underperform against a proposal that assumed full retail credit.
Check your rate plan and contract end date
Find the plan name and the contract expiration date on your bill or in your portal. Two things follow from it. First, if you are inside a fixed-rate term with an early termination fee, you may need to wait before switching to a plan with better solar buyback terms. Second, the plan you are on today is probably not the plan you want after solar, because solar buyback plans are priced differently and are often worse for consumption and better for exports.
Do the cheap things first
Solar is priced per watt, so every kilowatt-hour you stop using is a kilowatt-hour you do not have to buy panels for. Before sizing a system, look at:
- Attic insulation. Many Central Texas homes built before the mid 2000s have well under current recommended levels. This is usually the highest return item in the house.
- Duct leakage. Leaky ducts in a hot attic waste conditioned air into the space you least want it.
- Pool pump. A single-speed pump running long hours is often the second largest load in a home that has one. A variable speed pump on a shorter schedule can cut that dramatically.
- Water heater and thermostat scheduling. Small, cheap, and immediate.
An energy audit that costs a few hundred dollars can move your annual kWh enough to change the system size by a meaningful margin, and a smaller system costs less.
What to bring to the first conversation
Show up with four things: twelve months of kWh, your blended rate, your current plan name and end date, and the age and material of your roof. A proposal built on those four inputs can be checked. A proposal built on a guess about your bill cannot, and any installer who does not ask for the usage history is telling you something about how they work.