Phase 5 solar offset blueprint
Solar-first, grid-backed.
The goal is not off-grid living. Phase 5 should reduce daytime grid use, carry useful solar into the evening, and keep the existing grid-backed HVAC comfort system available during peak summer and winter.
Measured average
60.5 kWh/day
Jan 14 through May 20, 2026.
Peak day
178.7 kWh
Feb 8, winter heat driven.
Peak demand
11.9 kW
Highest 15-minute measured demand.
Major circuit
45A / 240V
Heat pump breaker capacity, not normal draw.
Fit against Emporia data
The design fits offset, not full backup
The full EG4 build produces about 51.9 kWh/day on an annual average basis against a measured 60.5 kWh/day house average. That is a strong offset match, but the 178.7 kWh winter peak day shows why HVAC still needs grid fallback.
Annual coverage
~86%
18,947 kWh solar estimate vs. about 22,083 kWh/year from measured average use.
Average day
51.9 / 60.5 kWh
Solar average is close to the house average, so daytime load shifting matters.
Battery scale
32 kWh class
About half an average day, but only about 18% of the measured winter peak day.
Load priority
HVAC first
Heat pump is 44.0% of mains; water heater is 18.1% and easier to shift.
Quick compare
Use the summary page first.
If you want the ranked view with total cost, monthly payment pressure, and bill-offset context, start at the Solar Option Summary. This page stays as the offset model and calculator.
Budget model
Phase 5 MVP Pricing Snapshot
Hardware cart and allowances reviewed June 14, 2026. Installer labor is not included.
| Item | Qty | Unit | Total | Share | Purpose |
|---|---|---|---|---|---|
| ZNShine 550W bifacial solar panel | 10 panels | $1,925.00 | $1,925.00 | 9.8% | 5.5 kW DC starter array. |
| EG4 Indoor WallMount Battery 16 kWh | 1 | $3,059.99 | $3,059.99 | 15.5% | Evening carryover and peak support. |
| EG4 FlexBOSS21 + GridBOSS MID bundle | 1 | $5,674.88 | $5,674.88 | 28.8% | Inverter, MID, and load-management base. |
| GridBOSS Breaker Kit - 90A | 1 | $272.99 | $272.99 | 1.4% | Breaker set for GridBOSS installation paths. |
| Staubli MC4 connector pairs | 10 | $16.56 | $165.60 | 0.8% | PV connector allowance. |
| Chiko GroundFlex U2V high-wind mount, 30-panel | 1 | $6,230.00 | $6,230.00 | 31.6% | Starter ground rack block. |
| Chiko GroundFlex U2V high-wind mount, 10-panel | 1 | $2,375.00 | $2,375.00 | 12.1% | Smaller rack block; leaves 4 unused positions across 40-panel capacity. |
| EG4 RS232 and USB cables | 2 | $0.00 | $0.00 | 0.0% | Included support cables. |
| Hardware subtotal (all itemized hardware) | $19,703.46 | 100% | Before shipping, tax, BOS, permit, labor, and site work. Core items (panels, battery, inverter) alone are $10,659.87 with vendor-quoted delivered total $12,200.87. | ||
Vendor-quoted delivered (core items only): $12,200.87 — original cart quoted by Signature Solar, includes estimated shipping and tax. Updated battery price ($3,059.99 vs $3,399.99 quoted) may shift the delivered total.
Electrical balance-of-system allowance: $1,500–$3,500 — wire home runs, conduit, disconnects, grounding, labels, combiner/fusing as needed.
Tinicum permit placeholder: $560.60+ — $435.60 alternative-energy fee, $100 application review, $25 electrical processing; third-party review not included.
Modeled Phase 1 planning total: $33,600.75–$35,600.75 — before labor, engineering, trenching/site work, and utility review.
Staged EG4 path
A smaller first stage keeps the system expandable.
The full layout is still the best offset model, but the first purchase is now a real MVP. A staged EG4 build can start with the inverter, one 16 kWh battery, and a 10-panel ZNShine 550W starter array. That keeps the investment on the same platform as the full design instead of buying a portable system that may not scale into HVAC offset. The caveat is that the battery vendor may require freight delivery or a loading dock, so this is a logistics-heavy MVP rather than a simple porch-drop purchase.
Starter equipment idea
FlexBOSS21 inverter
Keeps the same inverter platform as the full solar-first plan.
1x EG4 16 kWh battery
Enough to prove solar capture and selected load support; not enough for long HVAC autonomy. Check freight delivery / dock requirements before buying.
10x ZNShine 550W panels
5.5 kW DC starter array at the best large-panel price in the reviewed list.
GridBOSS decision
Use upfront if whole-home/MID/load-management is part of stage 1; defer only if the installer supports a simpler code-compliant critical-loads path.
| Stage | Hardware | Solar / storage scale | How it fits your usage |
|---|---|---|---|
| Stage 1: proof of platform | FlexBOSS21, 1x 16 kWh battery, 10x ZNShine 550W panels, required BOS, disconnects, permits, mounting, and electrician work. | 5.5 kW DC, about 14.4 kWh usable storage. | This is the MVP stage: enough PV to make the system feel real, enough storage to carry evening load, and still aligned to the same long-term EG4 platform. |
| Stage 2: battery catch-up | Add a second EG4 16 kWh battery, but confirm freight delivery and site handling first. | 32 kWh nominal, about 28.8 kWh usable. | Better evening carryover and selected outage support. This makes the smaller array easier to use, but still does not make winter HVAC off-grid. |
| Stage 3: array expansion | Add more mounted panels after the site, permitting, and rack layout are proven. | Grow from 5.5 kW toward 11 kW, 16.5 kW, or 19.8 kW DC later. | This is where HVAC offset improves. Solar has to be large because the heat pump is about 44% of measured mains use. |
| Stage 4: full integration | GridBOSS/MID/load-management finalization if not installed at the start. | Whole-home solar-first, grid-backed operation. | Best match for your long-term goal: solar/battery/grid blending without changing behavior at each appliance. |
| Starter pricing line | Qty | Known price | Read |
|---|---|---|---|
| ZNShine 550W bifacial panels | 10 | $1,925.00 | Recommended starter panel if small quantity ordering is allowed: 5.5 kW DC at $0.349/W, bifacial, and consistent with the full-system panel family. |
| Aptos 550W bifacial panels | 10-panel minimum | $2,145.00 | Good alternate if the ZNShine small-order terms are worse. Same 5.5 kW DC, but $220 more per 10 panels. |
| EG4 Indoor WallMount Battery 16 kWh | 1 | $3,059.99 | Starter storage. Add the second battery before expecting meaningful HVAC carryover. Freight/dock delivery may still be the practical blocker. |
| FlexBOSS21 / GridBOSS decision | 1 | TBD | Full bundle is $5,674.88 in the current cart. Confirm whether a code-compliant FlexBOSS-first install can defer GridBOSS without undermining the goal. |
| Mounting, BOS, permit, shipping, tax, labor | As required | TBD | Still required. A staged system lowers panels and battery count, but not electrical safety requirements. |
| Reviewed panel | 10-panel array | 10-panel cost | Decision |
|---|---|---|---|
| ZNShine 550W bifacial | 5.5 kW DC | $1,925 | Best staged pick if available in small quantity: strong output, bifacial ground-mount upside, and lowest cost among the 550W options. |
| Aptos 550W bifacial | 5.5 kW DC | $2,145 | Good alternate with a clear 10-panel minimum; costs $220 more for the same nameplate size. |
| Jinko 460W bifacial | 4.6 kW DC | $1,702 | Reasonable if smaller panels fit the site better, but the lower array size weakens HVAC offset. |
| Peimar 450W monofacial | 4.5 kW DC | $1,530 | Cheaper upfront, but loses bifacial ground-mount upside and gives less production. |
| Boviet / Phono / URE 385-390W monofacial | 3.85-3.9 kW DC | ~$1,078-$1,092 | Lowest panel cost, but too small for the HVAC-offset goal unless the site or budget forces a very small first stage. |
| Callsun 450W bifacial 2-pack | 0.4 kW per kit | $294.06 | Useful as an Amazon-returnable test panel kit, but too small and too high per watt for the main EG4 staged array. |
Design read
The 10-panel stage is a reasonable real-solar entry if the full array is too large right now. It will not carry peak summer or winter HVAC by itself, but it should offset daytime loads, help with shoulder-season usage, and prove the EG4 platform before adding the second battery and more panels.
Runtime model
Battery runtime by sun and HVAC use
Uses two 16 kWh batteries, modeled at 28.8 kWh usable, with measured average loads.
| Solar condition | With HVAC average load | Without HVAC average load | Read |
|---|---|---|---|
| Full sun average | ~80 hours | Daily surplus | Solar nearly covers the measured average day; non-HVAC loads should refill the batteries on average. |
| Partial sun, about 50% | ~20 hours | ~88 hours | Good for lights, fridge, outlets, and water-heater scheduling; HVAC still pulls the reserve down quickly. |
| No sun | ~11 hours | ~20 hours | Battery-only operation is short once HVAC is included. A measured winter peak day would drain much faster. |
The no-HVAC case removes the measured heat-pump share of mains, about 26.6 kWh/day. Real runtime will move with outdoor temperature, thermostat behavior, inverter losses, battery reserve settings, and whether solar production lines up with the actual loads.
Expected offset
Savings and payback
The model uses 18,947 kWh/year of production. Recent bills show the avoidable energy cost is closer to $0.184-$0.217/kWh, not the older $0.13760/kWh planning rate.
- Annual production
- 18,947 kWh
- Gross value
- $3,486-$4,111/year
- Practical capture
- 80%-95%
- Simple payback
- 8.6-12.8 years
Practical modeled savings are about $232-$325/month, or $2.8k-$3.9k/year, before labor. Equal Payment Plan billing does not change the underlying avoided kWh value.
| Bill period | kWh used | Avoidable cost/kWh | Read |
|---|---|---|---|
| Nov 3-Dec 1, 2025 | 3,064 | $0.213/kWh | AEP winter bill; high usage and high supplier rate. |
| Dec 2-Dec 30, 2025 | 2,101 | $0.214/kWh | AEP winter bill. |
| Dec 31-Jan 29, 2026 | 2,663 | $0.217/kWh | AEP winter bill. |
| Jan 30-Mar 1, 2026 | 3,110 | $0.217/kWh | Highest reviewed bill period. |
| Mar 2-Mar 30, 2026 | 1,744 | $0.189/kWh | Supplier switch month. |
| Mar 31-Apr 29, 2026 | 940 | $0.184/kWh | Current Town Square rate period. |
| Season | Expected pattern | Modeled savings |
|---|---|---|
| Peak summer | Cooling load should use a lot of production while the sun is available. | $281-$437/month |
| Peak winter | Solar production is lower, but heat-pump self-consumption is high. | $143-$249/month |
| No HVAC shoulder months | Production can be strong, but value drops if batteries fill and daytime loads are low. | $148-$314/month |
Permitting
Tinicum Township review path
A six-panel experiment may look minor in the yard, but Tinicum lists solar as a permit item. A larger ground array is about 999 square feet of module surface before row spacing, access paths, trenching, and equipment pads, so it should be treated as a real site-plan project.
Paperwork links
Likely review topics
- Scaled site plan with array location, setbacks, lot lines, wells, septic, slopes, woods, wetlands, and overlays.
- Electrical permit, third-party PA electrical review, rough inspection, and final inspection.
- Ground-mount height, building envelope, 110% property-energy sizing limit, and any historic-resource review.
- Stormwater or grading review if trenching, equipment pads, access work, or disturbance triggers it.
Technical fit
Panel, inverter, and battery fit
The panel pallet fits the FlexBOSS21 on paper when arranged conservatively. The installer still needs to verify cold-weather voltage, parallel current, grounding, breaker placement, and the final one-line diagram.
- Best string shape: four strings of nine panels, with two strings on MPPT 1 and two strings on MPPT 2.
- Why not ten per string: ten-panel strings create more cold-weather high-voltage risk against protection limits.
- Voltage read: nine panels are about 452V Voc and 377V Vmp at STC.
- Array sizing: 5.5 kW starter PV is comfortably under the FlexBOSS21 ceiling; rear-side bifacial gain may clip at times once the array expands.
- Battery read: two batteries are sized for capture and evening carryover, not full winter HVAC autonomy.
Panel size
~999 sq ft
36 panels at roughly 27.8 sq ft each before spacing and access.
Bifacial upside
Ground mounts help
Rear gain is better with air gap and reflective ground such as gravel, concrete, snow, or open light surfaces.
Starter option
18 panels first
Two nine-panel strings can reduce first-stage site work while keeping the rest of the pallet for expansion.
Speculation
Could the stack get cheaper or smaller?
This is not part of the purchase model. It is a timing guess based on current solar, battery, inverter, mounting, freight, and permit cost behavior.
10% cheaper stack
~2028-2030
A 10% cut means roughly $3.4k-$3.6k off the modeled stack. Panels and batteries may drift down, but mounts, freight, permits, wire, and labor may not. Freight-only delivery can also erase some of the apparent savings.
Battery price risk
Flat locally
Global lithium-ion pack prices have fallen, but the homeowner battery you priced has not clearly dropped over the last year. Retail storage is stickier than cells.
Double density
Not soon
The large-array footprint is still about 999 sq ft at full scale. True double-density commercial panels would require roughly twice current module efficiency, which is not a near-term homeowner product.
| Stack part | Likely direction | Planning read |
|---|---|---|
| Panels | Low single-digit to modest declines, with tariff/supply risk | Modules already fell hard globally. Waiting may save money, but probably not enough to erase mount/site costs. |
| Batteries | Global decline, retail home storage slower | Expect better deals over time, but do not assume the exact EG4 battery drops on a predictable schedule. |
| Inverter / MID | Mostly feature churn, not guaranteed price collapse | Waiting may improve hardware, but the FlexBOSS/GridBOSS class solves an integration problem now. |
| Mounts, cable, freight, permits | Flat or inflation-sensitive | These are the reason the whole stack may not fall as fast as panels or cells. |
| Panel density | Incremental gains likely, true 2x unlikely soon | A 20%-30% area improvement is more plausible before true double-density modules. |
Sources informing this speculation include NREL Q1 2025 PV cost benchmarks, IEA/IRENA reporting on module and battery price declines, and 2025 reporting showing commercial module efficiencies moving from roughly the low-20% range toward the mid-20% range. Perovskite/silicon tandem cells are promising, but durability and full-size module scale remain the blocker.