TJE Ventures

The Upfront Cost

Average installed cost for a residential solar system, 2026 (National Renewable Energy Laboratory):

• System size: 6–10 kW (covers most single-family homes)
• Gross cost before incentives: $18,000–$30,000
• National average for a 7 kW system: ~$21,000

That number varies considerably based on location, installer, roof complexity, and panel brand. The spread is not trivial: two quotes for identical systems on identical houses in the same zip code can differ by $5,000 or more. The solar installation market is fragmented, and installer margins vary widely. Getting three quotes is not optional if you care about price.

What drives the cost:

• Panels (30–40% of total cost): Monocrystalline panels dominate the residential market in 2026. Premium brands (SunPower, REC) add $2,000–$4,000 vs. Tier-2 alternatives with similar efficiency ratings on paper. Whether that premium reflects real performance or marketing is debated.
• Inverter (10–15%): Converts DC power from the panels to AC power your home uses. String inverters are cheaper; microinverters (Enphase) or power optimizers (SolarEdge) add $1,500–$3,000 but provide panel-level monitoring and better performance under partial shading.
• Labor and permitting (30–40%): Electricians, structural work, permit filing, utility interconnection. This portion does not benefit from technology cost reductions and has risen with labor inflation.
• Racking and hardware (10–15%): Mounting hardware, conduit, disconnect switches, monitoring equipment.

Panel costs have fallen roughly 90% since 2010 and continue to decline gradually. Labor has not followed that curve. The result is that total installed cost has not dropped in proportion to the component price — labor is now the dominant cost driver for most residential installs.

The Federal Tax Credit

The Residential Clean Energy Credit (commonly called the ITC, or Investment Tax Credit) allows homeowners to deduct 30% of the installed cost of a solar system from their federal income tax bill. On a $21,000 system, that is a $6,300 reduction in what you owe the IRS.

Several important caveats apply:

• It is a tax credit, not a rebate. You must owe at least $6,300 in federal taxes in the year of installation to capture the full credit. If your tax liability is lower, the unused portion carries forward to future years — but it does not come back as a check.
• It requires ownership. Leased systems and PPAs (Power Purchase Agreements) do not qualify for the homeowner credit. The installer owns the system and claims the credit instead. This is a significant consideration in the financing section.
• The 30% rate runs through 2032, then steps down to 26% in 2033 and 22% in 2034, and expires for residential installations in 2035 unless Congress extends it again. Given the credit’s track record of repeated last-minute extensions, most analysts expect some continuation past 2035, but building a financial case around that assumption is speculative.

After the federal credit, the effective cost of the $21,000 average system drops to roughly $14,700. Many states layer additional incentives on top: Massachusetts offers a 15% state credit (capped at $1,000), New York has a 25% credit (capped at $5,000), and New Jersey provides Sales Tax exemption and Property Tax exemption for added system value. California, despite being the largest solar market, eliminated its statewide rebate program years ago and now relies on federal incentives plus local utility programs.

State incentives require research specific to your location. The Database of State Incentives for Renewables & Efficiency (DSIRE) maintains a current list. Do not rely on installer quotes for incentive accuracy — they have an obvious interest in making the numbers look favorable.

How Much Electricity Will You Actually Generate?

A 7 kW system in a favorable location (Phoenix, Los Angeles) will generate approximately 10,000–11,000 kWh per year. The same system in a less favorable location (Seattle, Chicago, Boston) will generate 7,500–9,000 kWh. The difference is solar irradiance — the amount of usable sunlight your location receives — and it determines everything downstream in the financial calculation.

Roof orientation compounds this further. A south-facing roof at a 30° pitch in a mid-latitude location captures close to the theoretical maximum. An east/west-facing roof at the same latitude captures roughly 15–20% less. A shaded roof can lose 30% or more, depending on how much shadow falls on the panels and when during the day.

Annual savings depend entirely on what you pay per kWh. At the national average of $0.18/kWh:

• 10,000 kWh generated × $0.18 = $1,800/year in electricity offset

In high-rate states where residential electricity costs $0.28–$0.35/kWh (California, Hawaii, Massachusetts, Connecticut):

• 10,000 kWh generated × $0.30 = $3,000/year in savings

This single variable — your electricity rate — is the most powerful driver of whether solar makes financial sense. A homeowner in Connecticut paying $0.32/kWh and a homeowner in Louisiana paying $0.10/kWh are looking at entirely different financial propositions from an identical system.

Net Metering: The Policy That Makes or Breaks the Math

Most solar systems produce more electricity than the home uses during daylight hours and zero electricity at night. Net metering is the utility policy that determines what you get paid for that surplus daytime power sent back to the grid.

Under full retail net metering (the original model), each kWh you export is credited at the same rate you pay to import power. If you pay $0.18/kWh, you receive $0.18/kWh credit. This makes the math clean: a kWh generated equals a kWh offset, and the annual production estimate directly translates to annual savings.

The problem is that full retail net metering is disappearing. Utilities argue — with some legitimacy — that solar customers export power at retail rates but avoid paying for the grid infrastructure they still use at night. States are rewriting the rules:

• California (NEM 3.0, 2023): Export rates dropped to roughly $0.05/kWh during midday peak solar hours, down from $0.30. New solar customers in California face a payback period that has more than doubled under the new rules.
• Nevada, Arizona, and several southeastern states have adopted reduced export compensation models. The trend is clearly toward lower export rates, not higher.
• States with strong net metering (New Jersey, Massachusetts, New York, Illinois) still offer relatively favorable terms, but that can change with a single utility commission ruling.

If you are evaluating solar based on a salesperson’s net metering assumption, verify the current policy in your state and understand the risk that it changes during your system’s 25-year life. Systems installed under full retail net metering in California in 2020 are now producing half the expected savings for their owners. Policy risk is real and belongs in your underwriting.

How Long Do Solar Panels Last?

Modern monocrystalline panels carry 25–30 year performance warranties, and real-world data from early installations suggests the hardware holds up. The relevant question is not whether the panels physically survive — most do — but how much output they lose over time.

Panel degradation rates:

• Industry average: 0.5% per year
• Premium panels (Tier 1): 0.25–0.4% per year
• Budget panels: 0.7–1.0% per year

At 0.5% annual degradation, a panel producing 400W on day one produces roughly 380W after 10 years and 350W after 25 years — an 87.5% output retention at the end of the warranty period. That is meaningful degradation in absolute terms but not catastrophic. Your 10,000 kWh/year system becomes a 9,000 kWh/year system by year 20, which affects long-term savings projections and should be factored into any payback calculation.

What actually limits panel life in practice: physical damage from hail, falling debris, or installation errors. Panels cracked by hail are not a manufacturing defect — most warranties exclude weather damage beyond certain thresholds. Homeowner’s insurance typically covers it, but you may face a deductible plus a 2–6 week replacement delay.

How Long Do Inverters Last?

This is the part of the solar pitch that often goes unmentioned: the inverter is the weakest link in the system, and it will need to be replaced before your panels do.

Inverter lifespan by type:

• String inverter: 10–15 years. Single central unit. When it fails, the entire system goes offline.
• Microinverters (Enphase): 20–25 years (per Enphase warranty). Individual units on each panel. A failure affects one panel at a time rather than the whole system.
• Power optimizers (SolarEdge): Optimizers carry a 25-year warranty; the central inverter they connect to carries 12 years. In practice, you are replacing the central inverter once during the system’s life.

Inverter replacement cost (2026):

• String inverter replacement: $1,500–$3,500 installed
• Single microinverter: $300–$500 installed per unit; full-system replacement $1,800–$4,000
• SolarEdge central inverter: $1,200–$2,500 installed

For a 25-year financial model, budget for one inverter replacement. If you install a string inverter today, plan for a $2,000–$3,500 bill somewhere around year 12–15. This cost is routinely omitted from installer payback estimates. Ask specifically whether the quote includes a replacement reserve.

Battery Storage: Optional, Expensive, and Often Misunderstood

Home battery storage (the Tesla Powerwall is the most recognized product) is increasingly bundled with solar sales. The pitch: store your excess daytime solar power and use it at night instead of drawing from the grid. The reality is more complicated, and the financial case for adding a battery is substantially weaker than for the panels alone — in most circumstances.

Cost of a single Tesla Powerwall 3 (2026): $9,200–$12,000 installed. A second unit for a larger home adds another $7,500–$10,000. The 30% federal tax credit applies to battery storage, reducing the effective cost to $6,500–$8,400 for one unit.

Battery lifespan and degradation:

• Powerwall warranty: 10 years to 70% of original capacity
• Expected usable life: 10–15 years in most climates
• Cycle degradation: roughly 2–3% capacity loss per year under daily cycling
• Heat accelerates degradation significantly — batteries in hot climates (Arizona, Florida) age faster than the warranty suggests

The financial case for battery storage depends almost entirely on your utility’s rate structure:

• Time-of-use (TOU) rates: If your utility charges significantly more during peak evening hours (5–9 PM), a battery lets you avoid those rates by discharging stored solar power. In markets where peak rates are $0.40–$0.50/kWh vs. $0.18/kWh overnight, the arbitrage is real.
• Degraded or no net metering: Under California’s NEM 3.0, where export rates dropped to ~$0.05/kWh, storing solar power for self-consumption is worth $0.30/kWh more than exporting it. In that market, batteries now make genuine financial sense.
• Flat-rate net metering: If your utility credits exports at or near retail rates, there is essentially no financial reason to add a battery. You are already effectively “storing” power in the grid and withdrawing it later at the same rate.

The primary non-financial reason to add a battery is backup power during outages. If your grid reliability is poor or you live in an area prone to prolonged outages (hurricane zones, wildfire regions with preemptive shutoffs), the backup value can justify the cost on its own terms. Just do not pretend it is a financial investment — in most markets, a battery alone will not pay for itself over its usable life.

Payback Period: What It Really Takes

The payback period is the time it takes for cumulative electricity savings to equal the net upfront investment. It is the most important single number in a solar financial evaluation, and it is the one most frequently misrepresented.

Payback period varies significantly by scenario. Three representative cases:

Variable	Best Case (High-Rate State)	Average Case (Mid-Rate State)	Poor Case (Low-Rate State)
Gross system cost (7 kW)	$21,000	$21,000	$21,000
Federal tax credit (30%)	−$6,300	−$6,300	−$6,300
Net cost after credit	$14,700	$14,700	$14,700
Electricity rate ($/kWh)	$0.30	$0.18	$0.10
Annual generation (kWh)	10,000	9,500	8,500
Annual savings (100% offset)	$3,000	$1,710	$850
Simple payback period	~4.9 years	~8.6 years	~17.3 years

Best Case — A homeowner in Massachusetts or Connecticut paying $0.30/kWh with a well-oriented roof and full retail net metering. Payback under 5 years, and the 25-year net gain is substantial. Solar is a clear financial win here.

Average Case — A homeowner in a mid-rate state (Texas, Georgia, Colorado) at the national average electricity rate with average sun exposure. Payback around 8–9 years. Solar makes sense if you plan to stay in the home, less so if you might sell in the next 5–7 years.

Poor Case — A homeowner in a low-rate state (Louisiana, Oklahoma, Idaho) paying near the national low of $0.10/kWh. Payback approaches 17 years. At that point the first inverter replacement is due and panel degradation is meaningfully cutting into output. The system may never fully pay back on electricity savings alone.

These calculations assume the system offsets 100% of consumption and that net metering remains in place. Both are optimistic assumptions. Most systems offset 70–90% of consumption, and net metering policy risk is real and growing. Adjusting for both would lengthen the average-case payback to 10–12 years.

Home Value: The Wild Card

Solar systems do increase home resale value in most markets — but not as much as the solar industry typically claims, and only under specific conditions.

Research from Lawrence Berkeley National Laboratory found that owned solar systems add an average of $4 per watt of installed capacity to home sale prices. For a 7 kW system: $28,000 in added home value. At face value that sounds exceptional — the system costs $14,700 after the credit and adds $28,000 in value. Two complications undercut that math:

• Markets vary widely. The $4/watt finding reflects national averages across markets with strong solar uptake. In markets where solar is less common or buyers are less familiar with it, the value premium is lower or absent. In some rural markets, solar may actually complicate the sale — buyers unfamiliar with the technology, insurance implications, or lease obligations may simply walk away.
• Leased systems complicate sales. A system you do not own does not transfer cleanly. The buyer must either qualify to assume the lease or you must pay to buy out the lease before closing. This can and does kill deals.

If you own the system outright and plan to sell within 10–15 years, the home value premium can meaningfully shorten your effective payback period. If you are leasing, the home value argument largely does not apply to you.

How to Pay for It

The financing structure you choose affects both your upfront exposure and your long-term return. The four main options are not equivalent.

Cash Purchase

Highest long-term return. You own the system, capture the full 30% federal credit, and collect 100% of the electricity savings. No interest, no monthly payments, no lease complications at resale. The payback period is shorter than any other option because you are not paying financing costs on top of the system.

The catch is obvious: most households do not have $15,000–$21,000 sitting idle. And tying that capital to a rooftop asset with a 8–12 year payback may not be the highest-returning use of it. If you can earn more than 8–10% annually investing that capital elsewhere, a cash solar purchase is not obviously the best use of funds.

Solar Loan

You borrow to buy the system, own it from day one, and qualify for the tax credit. Many installers offer zero-down secured or unsecured loan products at 4.99–9.99% APR. The monthly loan payment replaces your electricity bill (ideally for less).

At 7.99% over 12 years on a $14,700 net system cost, you pay roughly $175/month and $25,200 total — $10,500 in interest. That interest reduces your net savings materially. The financial case still works in high-rate states, but in average-rate markets a solar loan at 7.99% may save you very little over the loan term even if the system runs perfectly.

One important detail on dealer-arranged loans: some include a “dealer fee” that inflates the principal by $2,000–$4,000, effectively pricing the financing into the system cost invisibly. Get the all-in principal amount, not just the monthly payment.

Lease / Power Purchase Agreement (PPA)

You pay nothing upfront. A solar company installs the system on your roof and either charges you a fixed monthly lease payment or sells you the power generated at a contracted rate (PPA). The company owns the system and claims the tax credit.

The appeal is obvious: zero upfront cost, immediate electricity savings, no maintenance responsibility. The tradeoffs are significant:

• You do not own the system and cannot claim the federal tax credit. The installer captures that $6,300.
• Contracts run 20–25 years with annual price escalators of 2–3%. A PPA at $0.12/kWh today with a 2.9% annual escalator costs $0.22/kWh in year 20. If grid rates do not rise as fast, you end up overpaying for the power you locked into.
• Resale complications. The buyer must assume the lease or you pay to buy out the contract. Buyout prices are typically set in the lessor’s favor. This is a real friction that can affect the sale of your home.
• Savings are smaller. Because you are paying for the power or the lease, your net savings over a cash purchase are substantially lower. The lease is priced to be profitable for the installer after they capture the tax credit; the homeowner captures whatever is left.

The lease / PPA is the right choice for homeowners who have no upfront capital and no ability to finance. If you have the ability to take a solar loan and can qualify for the tax credit, the loan almost always produces better financial outcomes than the lease.

PACE Financing

Property Assessed Clean Energy financing attaches a lien to your property and collects repayment through your property tax bill. No credit check, competitive rates (5–8%), and terms up to 30 years. You own the system and qualify for the tax credit.

The risk: the lien is senior to your mortgage, which complicates refinancing or sale. PACE lenders must be disclosed to mortgage servicers, and some servicers require PACE liens to be paid off at closing. Available primarily in California, Florida, and Missouri. Useful in the right circumstances, but the lien structure warrants careful review before signing.

When Solar Makes Sense

The financial case for home solar is strong when most of these conditions apply:

• You pay high electricity rates. Above $0.20/kWh, solar savings are meaningful and payback periods are reasonable. Above $0.28/kWh, solar is one of the better financial investments a homeowner can make.
• Your roof gets ample direct sunlight. South- or southwest-facing roof with minimal shading and at least 20 years of life remaining before replacement.
• You plan to stay in the home long-term. The full financial benefit requires 10–15 years of ownership in average markets. If you plan to sell in 5 years, the home value premium may cover the gap — but only in markets where buyers value solar.
• You can capture the full federal tax credit. If you owe at least the amount of the credit in federal taxes, the 30% ITC is effectively a $6,300 discount. If you cannot use it (very low tax liability, AMT considerations), the economics soften.
• Your state has favorable net metering policy. Full retail net metering makes the math clean. Degraded export rates require a battery to compensate, adding cost and complexity.

When Solar Might Not Make Sense

• Low electricity rates. Below $0.12/kWh, the savings rarely justify the upfront investment, even with the tax credit. States like Louisiana ($0.08–$0.10/kWh) or parts of the Pacific Northwest are difficult markets for residential solar economics.
• You are planning to move soon. In most markets, the home value premium does not fully replace the payback period calculation. Selling in the next 5 years exposes you to the difference between what you invested and what the market credits you for.
• Your roof needs replacing. Installing panels on a roof with 5–7 years of remaining life is a significant mistake. Removing and reinstalling panels to replace the roof costs $1,500–$3,000 and is your expense, not the installer’s.
• Your roof has significant shading. Trees, chimneys, and neighboring buildings that shade the panels for even a few hours during peak production can reduce output by 30–50%. No panel technology fully compensates for significant shading.
• You cannot capture the tax credit. Low-income households, retirees with modest income, and others with minimal federal tax liability may not benefit from the credit. Some states have low-income solar programs that substitute, but coverage is inconsistent.

What Other Costs to Watch For

Several costs routinely appear after installation that are absent from most installer proposals:

• Monitoring and maintenance. Most modern systems include online monitoring. When panels degrade faster than expected, fail silently, or lose connectivity, many homeowners do not notice for months. A 20% output loss from a failed panel costs you money every day it goes undetected.
• Homeowner’s insurance adjustment. Adding $20,000+ of equipment to your home typically requires a coverage limit review. Some carriers charge a modest premium increase; a few require a separate rider. Budget $50–$150/year and verify with your insurer before installation, not after.
• Interconnection fees. Many utilities charge a one-time interconnection fee ($50–$200) and an ongoing monthly grid access fee ($5–$15) for solar customers. These are small but real, and they reduce net savings over time.
• Panel cleaning. In dry or dusty climates (Arizona, Southern California), accumulated dust and debris reduce output meaningfully. Professional cleaning runs $100–$200/visit. Rain handles most of it in wetter climates.
• HOA restrictions. Some homeowners associations restrict panel placement for aesthetic reasons. While many state “solar access rights” laws limit HOA veto power, compliance requirements (specific panel colors, placement restrictions) can reduce your system’s optimal output. Check before buying.

Bottom Line

Who actually saves money?

Home solar makes strong financial sense when most of these conditions are true:

• You pay $0.20/kWh or more for electricity
• Your roof faces south or southwest with minimal shading
• You plan to stay in the home at least 10 years
• You own the system (not a lease or PPA)
• You can capture the 30% federal tax credit
• Your state has full or near-full retail net metering

Under those conditions, solar is one of the few home improvements that genuinely pays for itself and then generates positive returns. Under average conditions, it is a reasonable long-term investment with real uncertainty. Under unfavorable conditions — low rates, poor sun, imminent move, lease structure — the math does not close.

Conclusion

• Unlike EVs, solar can genuinely make financial sense for the right homeowner under the right conditions.
• The 30% federal credit is real, material, and available through 2032 — use it while it exists.
• Your electricity rate is the single most important variable. If you pay under $0.15/kWh, the numbers are difficult to make work.
• Net metering policy can change. Build your case on what the rules are today, not what they were when your neighbor installed panels three years ago.
• Budget for inverter replacement. No installer includes it. It is coming.
• A lease avoids upfront cost but transfers much of the financial benefit to the installer. If you can own it, own it.

Solar is one of the few home improvements that can pay for itself — but only if you do the honest math first, not the installer’s math.