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NuWatt designs, installs, and manages solar, battery, heat pump, and EV charger systems across 9 states. One company, one warranty, one point of contact.
Get a Free QuoteSolar panels can add $20,000+ to a home's value — or saddle you with a 20-year lease you did not sign up for. This guide covers everything a homebuyer needs to verify before closing on a solar home: ownership type, system performance, warranty status, and state-specific considerations.
$4/watt
Avg Value Premium
25-30 yr
Panel Warranty
9
States Covered
12+
Checklist Items
Last updated: April 2026. Based on Lawrence Berkeley National Lab research, Fannie Mae guidelines, and NuWatt transaction records across 9 states.
This is the most consequential question. The ownership type determines whether solar is an asset (adding value) or an obligation (adding payments). There are three possibilities:
The homeowner purchased the system outright or financed it with a solar loan. The system is a permanent fixture of the home, like HVAC or a new roof.
A third-party company (Sunrun, Tesla, Vivint, etc.) owns the panels. The homeowner pays monthly rent for the equipment, typically with an annual escalator.
Similar to a lease, but instead of renting the equipment you buy the electricity it produces at a locked-in rate (usually with an annual escalator).
If the home has a leased system or PPA, you have three options. Understanding these before making an offer gives you negotiating leverage.
Transfer the remaining lease or PPA to your name. The solar company runs a credit check and must approve the transfer. You inherit all terms — monthly payment, escalator, and remaining term.
Timeline: 2-6 weeks for transfer approval
Cost to you: $0 upfront
Risk: You are locked into the contract terms
Negotiate for the seller to buy out the remaining lease before closing. This converts the system to owned — the cleanest outcome for buyers. Typical buyout costs range from $5,000 to $15,000 depending on system age.
Timeline: 2-4 weeks for buyout processing
Cost to you: $0 (seller pays)
Benefit: System becomes owned, adding value
The lease company removes the panels at no cost and patches roof penetrations. You lose the solar benefit but get a clean, unencumbered property. The roof should be inspected afterward.
Timeline: 4-8 weeks for removal
Cost to you: $0 (but you lose the solar)
Risk: Verify roof patches and warranty
A solar system is only as valuable as its production. Request performance data and verify the system is producing as expected.
Ask for Enphase, SolarEdge, Tesla, or utility portal exports showing monthly production. Compare actual kWh produced against the original design estimate. A healthy system should be within 5-10% of projections after accounting for 0.5% annual degradation.
Solar panels degrade approximately 0.5% per year. A 10-year-old system should be producing about 95% of its original capacity. Anything below 90% may indicate damaged panels or equipment issues. Modern panels (manufactured after 2020) have 25-30 year performance warranties guaranteeing at least 80-87% production at year 25.
String inverters typically last 12-15 years with a 12-year warranty. Microinverters (Enphase) and DC optimizers (SolarEdge) last 25 years. If the system uses a string inverter that is 10+ years old, budget $2,000-$4,000 for replacement within a few years.
Sudden drops in production may indicate inverter failures, new shading from tree growth, panel damage, or wiring issues. Monthly production should follow a seasonal pattern — high in summer, low in winter. Flat production across seasons or erratic month-to-month swings are warning signs.
Panels are mounted with roof penetrations. If the roof under the panels needs replacement, removing and reinstalling panels costs $3,000-$5,000. Ask the seller about roof age and whether it was new when panels were installed. Most installers recommend a roof with at least 15 years of remaining life.
Estimate the value solar adds to a home based on system size, age, state, and ownership type. Based on the Lawrence Berkeley National Laboratory $4/watt premium for owned systems.
Estimate the value solar adds to a home you are considering
$28,000
Based on Lawrence Berkeley National Laboratory $4/watt premium, adjusted for system age
20 years
Inverter: 7yr (string) / 20yr (micro)
9,362 kWh
97.5% of original capacity
$2,902
at Massachusetts avg rate ($0.31/kWh)
Over the next 20 years, this system is estimated to produce 178,615 kWh of electricity, saving approximately $55,371 at current rates (not accounting for utility rate increases, which would increase savings).
Massachusetts property tax: 20-year property tax exemption. The added home value from solar will not increase property taxes.
Estimates based on Lawrence Berkeley National Laboratory $4/watt home value premium for owned systems, 0.5% annual panel degradation, and standard 25-year panel / 12-25-year inverter warranties. Actual values depend on system condition, local market, installer warranty terms, and utility rates. This calculator provides estimates only — a professional appraisal is recommended for home purchase decisions.
Lenders and appraisers handle solar differently depending on whether the system is owned or leased. Here is what you need to know.
Solar loan lien: If the seller financed with a solar loan, the remaining balance is a lien on the property. This is similar to a home equity loan — the lien gets paid from the seller's proceeds at closing. Your title search will catch this. It is not a red flag, just a normal payoff item.
In most states, solar panels increase your home value without increasing your property taxes. This is a significant financial benefit for buyers — you are getting a more valuable home with the same tax bill.
| State | Exemption | Legal Reference | Impact for Buyer |
|---|---|---|---|
| Massachusetts | 20-year exemption | MGL c.59 s.5 clause 45th | Full system value exempt for 20 years |
| Connecticut | Local option | CGS 12-81(56) | Most towns exempt; verify with assessor |
| Rhode Island | 20-year exemption | RIGL 44-3-21 | Equipment + installation exempt |
| New Hampshire | Local option (RSA 72:62) | ~66% of towns exempt | $584/yr avg tax savings where exempt |
| Vermont | Partial exemption | 32 V.S.A. 3845 | Equipment exempt, not land value |
| Maine | 100% statewide | 36 M.R.S. 655(1)(Q) | Full exempt in all municipalities |
| New Jersey | Full exemption | N.J.S.A. 54:4-3.113a | No increase to assessed value |
| Pennsylvania | No statewide exemption | Varies by county | Some counties offer local exemptions |
| Texas | 100% statewide | Texas Tax Code 11.27 | Full value exempt from property tax |
See how much a solar home could save you on electricity with a custom estimate.
Get a Free Solar EstimateMost solar homes are great purchases. But these warning signs should prompt further investigation or a price reduction.
If the seller cannot provide production data, you have no way to verify the system works as expected. Walk away or demand a professional inspection.
Check with the local building department. An unpermitted system may not meet electrical code, could void your homeowner's insurance, and creates title issues.
If the roof is old, you will need to remove panels ($3,000-$5,000), reroof, and reinstall. Factor this cost into your offer.
String inverters last 12-15 years. If the warranty is expired or expiring soon, budget $2,000-$4,000 for replacement.
The workmanship warranty is only as good as the company behind it. If the original installer is out of business (orphaned system), the manufacturer warranties still apply but there is no labor coverage.
Some older leases have 2.9% annual escalators that, after 10-15 years, push the lease payment close to or above the utility bill. Calculate what the lease payment will be at the end of the term.
Squirrels, birds, and other animals can nest under panels and chew through wiring. Ask if critter guards are installed. If not, budget $500-$1,500 for installation.
The utility interconnection agreement (net metering application) should be on file. Without it, the system may not be properly connected for net metering credits.
Ask the seller for these items before closing. Print this list and bring it to your home inspection.
Battery storage systems (Tesla Powerwall, Enphase IQ Battery, Franklin WH, etc.) add another layer of due diligence. Batteries degrade faster than panels and have shorter warranties.
Degradation rates are approximate and vary by manufacturer, usage pattern, and climate. Check the monitoring app for actual state-of-health data.
Multiple independent studies confirm that owned solar panels add measurable value to a home. Here are the key findings:
~4%
Average Value Premium
Zillow analysis of 5.3M home sales (2024)
$4/watt
Per-Watt Premium
Lawrence Berkeley National Lab (22,000 solar home sales)
20%
Faster Sale
Homes with owned solar sell faster on average
Higher premiums in:
Lower premiums in:
The seller's perspective: how solar affects your sale price, process, and buyer perception.
Honest comparison of leasing vs buying solar in the post-ITC landscape.
Third-party ownership with $0 down, fixed payments, and no escalators.
Everything you need to know about panel, inverter, and workmanship warranties.
How solar affects your homeowner's insurance policy and what coverage you need.
The seller's companion guide: lease transfers, disclosure requirements, and pricing strategy.
How to evaluate solar proposals and compare quotes from multiple installers.
State and utility incentives that remain available in 2026 and beyond.
Research
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