TL;DR: Five years ago the answer was solar first — net metering paid customers near-retail rate for exported solar, so more solar always made sense. In 2026 the default answer is battery first for almost every retrofit conversation. RMP's net-metering credit has dropped while import rates have risen, meaning a kWh of stored solar is worth roughly 3× a kWh of exported solar. Solar still goes first if you have no solar yet, undersized solar, or shaded roof. Doing both at once saves $2,500–$4,000 on a bundled install.
Why the answer flipped
Two things changed between 2020 and 2026 that flipped the math:
1. RMP's net-metering credit dropped. Through most of the 2010s, Rocky Mountain Power paid Utah solar customers retail or near-retail rate (~$0.10–$0.11/kWh) for exported solar. That made every additional kWh of solar production directly bankable against your bill.
By 2026, the export credit has dropped to roughly $0.04–$0.06/kWh while imports cost $0.11–$0.13/kWh. The gap between what you sell solar for and what you buy electricity for has widened from ~10% to roughly 3×. Exporting solar back to the grid is now worth a fraction of using your own solar at night.
2. Battery prices dropped while net-metering eroded. A Tesla Powerwall 3 in Utah nets to $11,495 after rebates in 2026 — cheaper than it was in 2022 nominally, and dramatically cheaper after the $2,500 Wattsmart + Tesla rebate stack. Full rebate breakdown.
The combined effect: a battery doesn't just give you backup power. It captures the gap between export rate and import rate on every kWh you would have exported. That's the new math.
The battery-first math, concretely
Example household: 30 kWh/day usage, 7 kW solar producing ~25 kWh/day, no battery.
Without a battery, this household's solar profile looks roughly like:
- Daytime production: 25 kWh
- Daytime consumption (while you're at work): 8 kWh
- Exported to grid: 17 kWh at $0.04/kWh = $0.68/day = $20/month
- Evening consumption (imported from grid): 22 kWh at $0.13/kWh = $2.86/day = $86/month
Net evening bill: $86 - $20 export credit = $66/month from grid
Add a 13.5 kWh battery to that same household:
- Daytime production: 25 kWh
- Daytime consumption: 8 kWh
- Stored in battery: 13.5 kWh (full charge)
- Excess exported to grid: 3.5 kWh at $0.04/kWh = $0.14/day = $4/month
- Evening consumption (battery first, grid second): 22 kWh — 13.5 kWh from battery, 8.5 kWh from grid at $0.13/kWh = $1.10/day = $33/month
Net evening bill with battery: $33 - $4 export credit = $29/month from grid
Battery savings: $66 - $29 = $37/month, or about $440/year in pure bill reduction. On top of $2,500 in stacked rebates and outage protection.
Now run the comparison with more solar instead of a battery. Adding another 4 kW of solar to that household (~15 kWh/day extra production, almost all of it exported) would earn at $0.04/kWh = $0.60/day = $18/month in export credit. So $18/month vs $37/month from a battery on the same money invested. The battery wins.
When solar first still makes sense
Scenario 1: You have no solar yet. Obvious. Start with solar to offset the bill. But seriously consider bundling battery with the install (better unit economics — see below).
Scenario 2: You have undersized solar (1–3 kW) with a $250+/month bill. Bigger solar pays back faster than a battery in this case, because your monthly bill is the bigger lever to pull. The export math is bad, but you're consuming most of the additional solar in real-time, not exporting it. Build solar to ~75% of your daily kWh consumption before layering battery on top.
Scenario 3: Shaded roof or complex orientation. Maximize solar production first via more panels and microinverters or optimizers. A battery is useless if you can't generate the kWh to fill it.
When to do both at once
If you have no solar today and you're sizing for both, doing them together saves real money:
- One permit, one inspection, one PTO process (instead of two)
- One trip charge for our crew (not two)
- One hybrid inverter doing both solar conversion and battery management (instead of two separate inverters)
- One trenching / conduit run for both systems
Cost savings: typically $2,500–$4,000 on a combined install vs sequential installs.
The combined install also opens DC-coupling options (Tesla PW3 has built-in 20 kW solar inverter; Sigenergy SigenStor has 23 kW PV input; EG4 FlexBoss has 21 kW). DC-coupled is slightly more efficient than AC-coupled. The efficiency difference is real but small, $30–$80/year. The unit-economic savings on the combined install matter more.
When to do battery first (most 2026 retrofits)
- You already have solar and your bill is reasonable.
- You want backup power for outages.
- You want to maximize the value of solar already on the roof.
- You want to enroll in Wattsmart and pull the $2,000 RMP rebate.
This is roughly 70% of the retrofit conversations we have at BYOP.
What about "I'll wait until ITC comes back"?
The federal residential ITC expired December 31, 2025 and is not coming back in this congressional term. Full ITC breakdown. Waiting is just leaving money on the table — both in monthly savings from the battery and in the $2,500 Wattsmart + Tesla rebate stack that's still active.
Most homeowners who tell me "I'll wait" are waiting for an incentive that's not coming. The cleanest move in 2026 is to size your project to current 2026 economics, not 2024 economics.
Frequently Asked Questions
Should I add solar or a battery first in Utah in 2026?
Battery first in most cases. RMP's net-metering credit is roughly $0.04/kWh in 2026 while imports cost $0.13/kWh — meaning exported solar is worth about one-third of what stored solar saves you. A battery turns wasted export value into stored value at 3× the rate. Solar still goes first if you have no solar yet, undersized solar, or shaded roof.
How much do I save by adding a battery vs more solar?
On a kWh basis, a battery saves you the difference between import rate ($0.13/kWh) and export rate ($0.04/kWh) per stored kWh = about $0.09/kWh. Adding more solar that exports to the grid only earns you the export rate ($0.04/kWh). The battery captures 3× the value per kWh routed through it. For a typical 15 kWh/day evening usage pattern, that's roughly $400/year more value from a battery vs an equivalent kWh of new solar production.
When should I add solar before a battery?
Solar first makes sense when (1) you have no solar yet and need to start somewhere, (2) you have undersized solar (1–3 kW) with a $250+/month bill, or (3) you have shaded or complex-orientation roof where maximizing solar production matters before adding storage. For everyone else with adequate existing solar, battery first wins on 2026 math.
How much do I save by doing solar and battery together vs sequentially?
Typically $2,500–$4,000 on a combined install. You save on one permit instead of two, one trip charge instead of two, one hybrid inverter instead of two separate inverters, and one trenching/conduit run instead of two. The unit economics of bundling are real and meaningful.
About the author
Batsaikhan(Bat) Ariun-Erdene is the owner of BYOP Electric, a licensed Utah Master Electrician (E200). More about Bat and BYOP Electric.