Case Study: Parking Garage EV Charging Conversion for 200+ Spaces

Crestwood Plaza is a 240-unit luxury condominium in suburban Northern Virginia, built in 2008 with a four-level subterranean parking garage offering 280 deeded spaces and 30 visitor spaces. By late 2024, the HOA board was fielding two or three EV charging requests per month from residents. Six owners had already paid out of pocket for individual circuits run from their breaker panels, creating a patchwork of cabling, mismatched equipment, and complaints about who paid for what kilowatt-hour.

The board's goal was straightforward but ambitious: provide a path for any of the 280 deeded spaces to support Level 2 charging within five years, without raising assessments more than residents could absorb. They voted to pursue what their consultant called a make-ready first approach — install conduit, panels, and load management infrastructure capable of serving every space, then deploy chargers in phases as demand grew.

The board hired a turnkey installer in early 2025 after issuing an RFP to four firms. Construction ran from May through August 2025, with the first 24 chargers energized on September 12, 2025.

The site assessment, performed before the RFP went out, revealed both opportunities and constraints common to mid-2000s buildings.

The good news: the original electrical service had 2,500 amps of utility capacity, of which roughly 1,400 amps was actually used at peak. That left meaningful headroom — but not enough to run 280 chargers at full 9.6 kW (40 amps) simultaneously. Without intervention, full deployment would have required a service upgrade costing around $180,000.

The constraint: the existing electrical rooms were on the parking levels but undersized. Installing the new charger panels meant building two small enclosures off-corner from the main switchgear, plus running a 1,200-foot trunk of feeder conduit along the garage ceiling. That structural work added cost but eliminated the need to upgrade utility service.

The technical heart of the project was dynamic load management. With 1,100 amps of available capacity and a goal of supporting 280 spaces eventually, the only realistic path was to share that capacity across all active sessions through software.

The installer specified networked Level 2 chargers running OCPP 1.6 protocol, all reporting to a central management platform. The platform measures real-time draw across all chargers and modulates each session's amperage so the total never exceeds the 1,100-amp ceiling. In practice, when only ten cars are charging, each gets the full 40 amps. When fifty cars are charging, each gets roughly 8 to 11 amps — slow, but more than enough to add 30 to 50 miles of range overnight.

Future phases will add chargers in groups of 20 to 30 as demand grows. Because the conduit and panels are already in place, each future install costs roughly $1,800 to $2,400 per charger instead of the $6,000 to $9,000 typical for ground-up retrofits.

Total Phase 1 cost came in at $612,000. The largest line was make-ready electrical work — panels, feeders, and conduit for all 280 spaces — at $310,000. The 24 Level 2 chargers and their installation added $186,000. Fire suppression upgrades on two parking levels were $58,000. Communication infrastructure cost $22,000, and permitting, engineering, and project management added $36,000.

Incentives offset roughly $148,000 of that total. The federal 30C Alternative Fuel Vehicle Refueling Property Credit covered 30% of qualifying costs because Crestwood's census tract qualifies as non-urban under the IRS definition, returning approximately $98,000. Dominion Energy's Smart Charging Infrastructure Pilot rebate added $50,000 for the make-ready and load management components.

Net cost to the HOA after incentives was $464,000. The board funded $200,000 from reserves and financed the remaining $264,000 over seven years through a building-improvement loan at 6.4%, resulting in a special assessment of $19 per unit per month for 84 months.

Residents who use the chargers pay $0.22 per kWh, which covers the building's electricity cost (roughly $0.11 per kWh blended), maintenance reserve contributions, and software fees. Visitor sessions are billed at $0.34 per kWh.

Eight months in, the system is serving 31 active EV-driving households across the 24 deployed chargers, with sessions averaging 14 per day. Chargers are typically available within 20 minutes of request during peak evenings, and the load management software has never tripped a main breaker.

Boards facing similar decisions should confirm their local fire code requirements early, since amendments to NFPA 13 and NFPA 855 vary widely by jurisdiction and can add 10% or more to total project cost when discovered late. They should also build in time for resident communication — Crestwood's board held three town halls before the vote, including a dedicated session for non-EV-driving owners explaining why they were paying $19 a month for infrastructure they wouldn't immediately use.