ADU loads, service capacity, and solar planning in Northridge 91324

An ADU turns one household forecast into two

Last year's utility bills do not include an ADU that is still under construction or not yet occupied. Estimate the ADU's HVAC, water heating, cooking, refrigeration, laundry and general loads separately.

Ask whether the ADU will share the main electrical service and meter or use another approved configuration. That decision changes where solar production is credited and how the service calculation is performed.

The solar array should reflect the actual permitted electrical arrangement, not a sales assumption made before the ADU design is complete.

Service capacity should be checked before both projects are locked

An ADU can add significant load to a service that was sized for one dwelling. Solar does not erase the need to evaluate service capacity because the household still draws from the grid when solar is not producing.

Ask whether a service upgrade is required by the ADU load calculation, by the solar interconnection method, or by both. If the project includes an EV charger or battery, include those in the same calculation.

If the contractor proposes a panel upgrade, ask for the specific electrical basis and whether the LADWP service side also requires work.

Roof allocation should consider both dwellings and future maintenance

If solar is going on the main house, the system may be serving energy used by both the main dwelling and the ADU. If the ADU roof is also available, compare whether splitting arrays adds complexity or improves orientation and shade performance.

Do not fill every roof plane simply because it is available. Preserve service access, consider roof age, and avoid placing panels on a roof section likely to be rebuilt soon.

If the ADU is new construction, coordinate conduit pathways and equipment locations before finishes are complete.

Battery backup can serve different priorities in each dwelling

A multigenerational or rental ADU arrangement can create different backup priorities. One dwelling may need refrigeration and internet while the other needs medical equipment or temperature control.

Ask whether backup circuits from both spaces are included, how the backed-up loads are distributed and what happens if both dwellings demand high power simultaneously.

A battery proposal should show usable capacity, continuous and surge power, reserve settings and expected runtime for the selected circuits.

LADWP and LADBS assumptions should be explicit

Northridge is served by LADWP, while the construction and electrical permit path is through LADBS. Those are two separate approval systems and both should be reflected in the schedule.

Ask who handles City permit revisions if the ADU electrical plan changes after the solar design is complete. Ask who handles LADWP interconnection and whether service changes require additional utility coordination.

The homeowner should see those responsibilities in writing.

Financing should not hide the cost of ADU-related electrical work

When solar, a battery and ADU electrical work are financed together, a monthly payment can hide where the project cost comes from. Request itemized cash prices for solar equipment, battery, panel upgrade, EV charger, roofing and other electrical work.

Then compare the financed price, interest rate, term and any dealer fees. The homeowner should know whether a large monthly-payment increase is paying for solar generation or for unrelated upgrades.

Tax-credit assumptions should also be treated carefully when costs cover mixed project scopes. Homeowners should seek qualified tax advice rather than relying on a sales estimate.

Northridge 91324 homeowner checklist

Coordinate ADU electrical plans, LADWP usage, service capacity, solar size, roof allocation, battery backup and future EV charging before signing.

Compare current-load and post-ADU load scenarios. Keep non-solar electrical work visible as separate line items.

Ask who manages LADBS permits, LADWP interconnection, inspections, monitoring and long-term service.

How Home Solar Simplified reviews a solar proposal

Every local guide uses the same homeowner-first review standard so a proposal can be evaluated without relying on a sales presentation. Start with the home's actual electric bills and identify which future loads are genuinely likely: electric vehicles, heat pumps, electric water heating, pool equipment, an accessory dwelling unit, or battery storage. Ask the installer to separate today's usage from future assumptions instead of blending them into one unexplained annual number.

Next, compare the physical system. Write down the proposed DC system size, first-year production estimate, degradation assumption, module and inverter models, battery usable capacity and power rating if storage is included, roof planes used, shade assumptions, attachment method, equipment locations, and any service-panel or roofing work. The production model should match the final permitted layout. If panels move during engineering, HOA review, planning review, or permit corrections, request an updated production estimate before installation.

Then compare money on a cash-price basis before looking at monthly payments. Ask for the cash price of the solar array, battery, roof work, service upgrade, EV charger, trenching, permits, and other add-ons as separate line items. If financing is used, compare the financed amount, interest rate, term, dealer fees or prepaid finance charges, total scheduled payments, and prepayment rules. Tax-credit assumptions should be treated as estimates for discussion with a qualified tax professional, not as guaranteed discounts from the contractor.

Review the utility assumptions separately. The proposal should identify the actual electric utility, current rate structure, estimated self-consumption, exports, remaining grid purchases, and any battery dispatch strategy. A city, ZIP code, or neighboring home does not prove the exact service arrangement at a property. Utility rules, rates, interconnection requirements, and equipment eligibility can change, so the installer should confirm the current rules for the specific account before the homeowner relies on projected savings.

Finally, review responsibility after the sale. Ask who handles permit corrections, utility interconnection, inspection failures, monitoring problems, inverter or battery warranty claims, roof leaks near attachments, and future array removal for roof work. Keep the signed contract, approved plans, equipment cut sheets, inspection record, permission-to-operate documentation, warranties, and final one-line electrical diagram together. A solar project should remain understandable years after the original salesperson is gone.

When comparing two or three proposals, normalize them before deciding. Put the same fields into one worksheet: cash price, financed price, system size, first-year production, estimated annual consumption, future-load assumptions, battery capacity and power, roof work, service upgrades, permit responsibility, workmanship warranty, equipment warranties, monitoring support, and the estimated utility bill that remains. If one proposal uses a different roof layout, rate assumption, financing term, utility escalation rate, or battery operating strategy, mark that difference instead of treating the monthly payments as directly comparable. Ask each contractor to correct obvious assumption mismatches so the homeowner is comparing systems on equal footing. The lowest payment is not necessarily the lowest project cost, the largest array is not necessarily the best value, and the highest production estimate is not necessarily the most credible. A useful comparison makes the assumptions visible enough that a homeowner can explain why one proposal is stronger without repeating a salesperson's slogan.

Related homeowner research

Adjacency QA: ZIP-to-ZIP links are topical and geographic-navigation links, not claims of municipal physical adjacency.

Frequently asked questions