Case Study: EV Charging for a Mixed-Use Commercial and Residential Property

Nine Mile Commons is a six-story mixed-use development in suburban Denver, completed in 2014. The building has 80 condominium units on the upper four floors, two floors of professional office and medical space, and ground-floor retail anchored by a coffee shop, a fitness studio, and a sit-down restaurant. The underground parking garage has 112 spaces divided across three groups: 60 deeded to condo owners, 28 leased to commercial tenants, and 24 marked for retail customers and visitors. The condo association and the commercial association share the building through a master association that owns the garage, the lobby, and the main electrical service.

In early 2024, the master association began receiving regular requests from condo owners for EV charging. The fitness studio operator separately asked about adding two charging spots to attract customers. With multiple stakeholders, mixed-use billing, and a single utility service feeding the entire building, the master association faced a coordination problem more than a technical one. Hiring a single installer and writing one set of rules that satisfied all three groups took close to fourteen months of planning before the first conduit was pulled.

The master association formed a four-person EV committee with two condo representatives, one commercial tenant representative, and the property manager. Their first task was answering a basic question: who pays for what, and who controls what.

After three meetings and a legal opinion from the master association's counsel, the committee landed on a clear split between common-area infrastructure and individual hardware. The condo board adopted a parallel rule that any owner installing a charger had to use one of two approved equipment vendors, sign a license agreement covering maintenance and removal, and pay a one-time $450 wiring fee to the master association. That fee feeds a small reserve that handles future repairs to the shared conduit.

A load study by a Denver-area electrical engineer found the building's 2,000-amp main service had roughly 280 amps of available headroom during peak hours — enough for about 30 Level 2 chargers running simultaneously without any upgrade, or up to 80 chargers with intelligent load management software.

The master association chose the load-managed approach. Upgrading the service to 3,000 amps would have cost an estimated $185,000 plus an Xcel Energy interconnection wait of nine to twelve months. Adding a load management system layered on top of the existing service cost about $42,000 in equipment and software and added no wait. The system continuously monitors building demand and throttles charging speeds during peak periods so the total load never exceeds a programmed ceiling.

This was the single biggest cost-saving decision in the project. It also meant the same backbone could serve residents charging overnight and commercial customers charging midday, since the load manager prioritizes by time of day rather than treating one group as second-class.

Phase one installed 18 Level 2 chargers across all three user groups: 12 for condo owners who pre-committed, 4 for the fitness studio's customer-facing spots, and 2 reserved for visitor parking. All chargers came from a single OCPP-compliant manufacturer to keep maintenance and software simple. Each unit is networked over the building's Wi-Fi and reports back to a single management dashboard the property manager monitors.

Billing was the trickiest piece. The condo chargers bill the resident directly through the network's app at the actual kWh used plus a small administrative markup the master association keeps to cover software fees. The fitness studio's customer spots use a session-based fee — $2 to start, then $0.39 per kWh — set by the studio. Visitor spots are free for the first hour and $5 per hour after, to discourage all-day parking. The dashboard separates revenue by user group so the master association can produce clean monthly reports for each sub-association.

Total project cost for phase one came in at $186,400. The master association captured three stacked incentives that meaningfully reduced that number. The federal 30C Alternative Fuel Vehicle Refueling Property Credit covered 30% of qualifying hardware and labor — about $42,000 — passed through the association's tax preparer because the property sits in an eligible census tract. Xcel Energy's multifamily make-ready program rebated $4,000 per port for the four customer-facing chargers, totaling $16,000. Colorado's Charge Ahead Colorado grant added $1,200 per port for the 12 resident chargers and the 2 visitor spots. Stacked together, incentives covered roughly $74,000, dropping net cost to about $112,400.

The master association financed the balance through a 10-year loan at 6.4% from a credit union that specializes in HOA capital projects. The annual debt service works out to about $190 per parking space across the 60 condo spaces, layered into the existing master assessment without a special vote.

Eight months after commissioning, all 18 chargers are in regular use. Average resident charger utilization is 41% — meaning an active charging session about 10 hours per day, almost all overnight. The fitness studio's customer spots run 67% utilization during open hours and have driven measurable foot traffic increases in the studio's own analytics. Total electricity revenue from the visitor and commercial spots is about $1,400 per month, roughly half of which goes back to the master association after the studio's share.

Three lessons stood out for the committee, and they apply to most mixed-use buildings considering a similar project. Nine Mile Commons is now planning phase two for late 2026, adding 14 more chargers funded entirely from the established assessment line and remaining make-ready rebates. Because the conduit and load management capacity were sized for growth on day one, phase two is projected to cost roughly half of phase one on a per-port basis.