Sunrun Solar & Battery: 8 Questions You Should Ask Before Signing (Based on 3 Years of Mistakes)

Everything I Thought I Knew About Solar (And How I Was Wrong)

I've been handling solar + battery orders for about three years now. Maybe three and a half, I'd have to check the system. In that time, I've personally made—and documented—at least six significant mistakes that cost us roughly $14,000 in wasted budget and rework. Not counting the time I had to explain to a homeowner why their 'whole home backup' didn't cover the AC unit. That was fun.

This article isn't a Sunrun sales pitch. It's the checklist I wish someone had handed me before my first installation. I'm going to answer the questions I get asked most often—and a few you probably haven't thought of but should.

1. What's the real Sunrun battery price? (Not the advertised one)

Here's something vendors don't always lead with: the price you see in the ad is base hardware. It doesn't include installation complexity, panel upgrades, or permit fees.

Based on what I've seen across 30+ Sunrun battery projects in California and Texas (I handle orders for both regions), a typical LG Chem or Tesla Powerwall installation through Sunrun runs:

• One battery (13.5 kWh usable): $8,500–$11,500 installed
• Two batteries (27 kWh): $14,000–$18,000 installed
• Add battery to existing solar: $9,500–$13,000 (labour and re-wiring cost more)

Does this match what's on Sunrun's site? Not exactly. The first quote we got was $12,000 for one Powerwall. After we asked about 'what's included,' the price came down to $9,800. I should add: that was after we agreed to a 2-year PPA for solar. The standalone battery price would've been higher.

Everything I'd read said 'just ask for a quote.' In practice, I learned to ask: 'What's NOT included in that price? Permits? Electrical panel upgrades? City inspection fees?' Those add up fast.

2. Should I buy the solar panels or lease them through Sunrun?

Most buyers focus on monthly payment and completely miss the long-term flexibility. I made this mistake myself.

In my first year (2022), I recommended a lease to a client because the $0-down option looked great on paper. The problem? Two years later, they wanted to move, and transferring the lease was a headache. The new buyer didn't qualify. We had to buy out the lease at a premium.

Here's the breakdown I now give everyone:

• Lease/PPA: Lower upfront cost, no maintenance worries. But you don't own the system. Selling your home? The buyer must agree to take over the lease. About 20% of lease transfers fall through, based on industry data (SEIA, 2023).
• Own (cash or loan): Higher upfront, but you own the asset. The 30% federal tax credit applies. If you sell, it's easier to include in the sale.

The question everyone asks is: 'What's the monthly payment?' The question they should ask is: 'What happens if I sell my house in 5 years?'

3. What is 'load shifting' with energy storage? (And why it matters)

This is one of those terms that sounds technical but is actually simple—and useful.

Load shifting means: use stored energy from your battery during peak hours when electricity rates are highest, and recharge the battery during off-peak hours when rates are low.

In California (with Time-of-Use rates), peak is 4-9 PM. Our battery charges from 12-3 AM at ~$0.15/kWh, then powers the AC and fridge during peak at $0.45/kWh. Net result: our peak usage dropped by about 60%. Savings: roughly $500-$700/year on a 13.5 kWh battery.

What most people don't realize: load shifting only works well with a battery large enough to cover your evening usage. A single Powerwall (13.5 kWh) covers about 3-4 hours of typical home usage (AC, lights, fridge). If you have an electric car charging at home, you'll need two batteries minimum.

4. What size solar generator do I actually need for my home?

I get this question a lot, often from people comparing solar generators (like the Patriot portable power station) with home battery systems. They're not the same thing.

A solar generator (e.g., Jackery, EcoFlow) is portable, has limited capacity (1-3 kWh typically), and is meant for camping or emergency backup for essentials. A home battery (like Sunrun's offering) is fixed, 10-20 kWh, and tied to your electrical panel for whole-home backup.

If you're asking 'what size solar generator for home backup?'—you probably actually want a home battery. Here's a rule of thumb:

• 1-3 kWh (portable): Powers a phone, laptop, lights, a CPAP for one night. Good for camping.
• 5-10 kWh: Powers fridge, lights, router, and a TV for 8-12 hours. Good for short power outages.
• 13.5+ kWh (home battery): Powers AC, fridge, lights, and basic appliances for 6-8 hours. Or whole home backup for 4-6 hours.

Most homes I've worked with need at least a 13.5 kWh battery for meaningful backup. The Patriot portable power station, for reference, is 1-2 kWh—fine for a few outlets, not for keeping the fridge running overnight.

5. How does Sunrun solar panel installation actually work?

The conventional wisdom is: you sign up, they install in a week, you're done. In practice, for our clients, the timeline looked more like this:

• Step 1 - Site visit & design: 1-2 weeks (they assess roof, shade, electrical panel)
• Step 2 - Permitting: 2-8 weeks (city-dependent; some are fast, some are not)
• Step 3 - Installation: 1-3 days (weather permitting)
• Step 4 - Inspection & PTO: 2-6 weeks (city inspection, then utility 'permission to operate')

Total time: 6-14 weeks from contract to active system. That's the honest range. We had one project in Austin that took 5 weeks total. Another in Visalia took 14 weeks because the city required a structural engineering review.

We didn't have a formal timeline tracking process at first. Cost us credibility when we told a client 'two weeks' and it took eight. Now I include a buffer note: 'Expect 8-12 weeks, and feel free to check in at week 8.'

6. Can I add a battery to an existing solar system? (Yes, but...)

One of the most common upgrades I see: someone has solar panels installed 3-5 years ago, now wants a battery. Sunrun does offer this, but there's a catch.

The most important factor: your existing inverter and battery compatibility. If your solar system uses a string inverter (common for systems installed before 2020), you may need to replace it with a hybrid inverter to support battery integration. That costs extra—usually $1,500-$3,000 on top of the battery price.

Another thing: if your system was sized for net metering (sell excess power to the grid), adding a battery changes your usage pattern. In California under NEM 3.0, this matters a lot—you want to store power for self-use, not sell it back at low rates.

Bottom line: adding a battery is doable, but budget for inverter upgrades and a consultation on your specific system. The question everyone asks: 'Can you just add a battery?' The question they should ask: 'What modifications does my current system need to support a battery?'

7. Does the battery save enough to pay for itself?

I used to say 'yes, absolutely.' Now I say: 'It depends on your utility rates and usage patterns.'

Let's do the math for a typical scenario:

• Battery cost: $10,000 installed (after federal tax credit)
• Annual savings from load shifting: $500-$700 (based on $0.30/kWh peak vs. $0.15/kWh off-peak)
• Annual savings from backup power (avoided food spoilage, hotel costs during outages): hard to quantify, but real
• Payback period: 14-20 years just from load shifting

That's not great. But if you factor in:

• Utility incentives: some CA utilities offer $200-$500 per battery
• Increased home value: solar + battery adds about $15,000-$20,000 to home value (Zillow data, 2023)
• Peace of mind during outages: priceless for some

For me, the most 'worth it' scenario is: high time-of-use rates (like CA), frequent power outages (like Texas in 2023), and a plan to stay in the house 10+ years. For others, a portable generator or a smaller battery might make more sense.

8. What's the one question I should ask before signing?

I've learned to ask: 'What happens to the solar panels if I buy a battery from you but not the solar? And vice versa?'

The third time we ordered a battery for a client who already had non-Sunrun solar, we discovered the battery wasn't compatible with their inverter. It cost $450 in wasted labor plus a 1-week delay to swap out the inverter. Should have asked upfront.

Another good question: 'Does the battery work during a power outage without sunshine?' (Answer: yes, for about 10-12 hours on a full charge, assuming moderate usage. But if it's cloudy for days, you'll need grid power to recharge once battery is depleted. Or a generator.)

And one more: 'What's the warranty on the battery, and what does it cover?' Sunrun typically offers a 10-year/70% capacity warranty. But read the fine print on labor costs for replacement after year 5.

Per FTC Green Guides (ftc.gov, 16 CFR Part 260), environmental claims like 'recyclable' or 'sustainable' must be substantiated. Not a direct quote, but the principle applies: ask for documentation on your system's output estimates, not just verbal promises.

I've made enough mistakes that I now keep a checklist. It's saved us from at least 5 significant errors in the past 18 months. If you're considering Sunrun or any solar + battery system, ask these questions before you sign. And if you've made a mistake I haven't listed here, I'd love to hear it—I'll add it to the list.