Your load shape, not your annual total
Most solar sizing conversations start with twelve monthly bill totals and work out an annual kilowatt hour figure. Under a retail-rate net metering tariff that is reasonable, because timing washes out over the settlement period.
Tennessee has no net metering. Exports go to TVA at avoided cost, so timing does not wash out. It determines the value of every kilowatt hour.
What matters therefore is your load shape: how much power your house draws hour by hour through a day, and how much of that overlaps with the hours your roof is generating.
Ask whether the design was built from interval data, if your meter provides it, or from monthly bill totals. That single answer tells you how seriously the sizing question was taken.
Middle Tennessee summers are on your side
Air conditioning is a large load that runs hardest in the middle of hot afternoons, which is exactly when a solar array is producing most. In a Middle Tennessee summer that overlap is substantial.
That is genuinely favourable under an avoided-cost export tariff, because it means a high share of summer generation lands inside your own consumption at the full retail rate.
Winter is the weaker season on both sides: less generation, and heating load that is often concentrated in early mornings and evenings when the sun is low or absent.
So ask for the analysis seasonally rather than annually. A design that works well in July and poorly in January is a normal outcome, but you should be able to see it rather than have it averaged away.
The levers you actually control
Shifting flexible loads into daylight is free and effective. Dishwasher, laundry, pool pump and, if you have one, electric vehicle charging are all movable, and each moved kilowatt hour is upgraded from avoided cost to retail value.
Pre-cooling on hot afternoons is the largest free lever for most households, because it uses the biggest load in the house during the generating window and reduces what is needed after sunset.
A battery does this automatically and at larger scale, and there is a genuine economic case for it here. But with retail electricity around 13 cents per kWh the absolute value is modest, so ask for the system modelled with and without storage.
And sizing itself is the largest lever. A system covering 70 to 80 percent of annual consumption frequently returns better in Tennessee than one covering 100 percent, because the marginal panels produce mostly exports.
Costing it out on TVA terms
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase in Murfreesboro receives no federal tax credit, and Tennessee has no state solar tax credit.
Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask what a provider claims and what reaches you in the rate.
What exists is retail value on self-consumed generation, avoided cost on exports under Dispersed Power Production, and an interconnection agreement with your local power company.
Ask for the projection built from your load shape rather than your annual total, seasonally rather than averaged, with the self-consumption share stated and a smaller system shown alongside.