Can my 100-amp panel handle central AC plus an EV charger in my Evanston home?

Most 100A panels cannot safely handle both central AC and an EV charger without risking overload, especially in Calgary's extreme temperature swings. You'll likely need a load calculation by a licensed electrician and potentially a panel upgrade to 200A service.

A central air conditioning system typically draws 20-30A when running, while a Level 2 EV charger requires a dedicated 40-50A circuit. Combined, these two major loads alone consume 60-80A of your panel's 100A capacity. However, electrical load calculations aren't simply additive — they must account for demand factors and coincidental usage patterns.

In your Evanston home (likely built in the 1980s-1990s based on the community's development timeline), your 100A panel is already serving your existing electrical loads: furnace blower, water heater, kitchen appliances, lighting circuits, outlet circuits, and potentially electric baseboard heating in some rooms. During Calgary's extreme cold snaps when temperatures hit -30°C, electric heating loads spike dramatically. If you're running the AC during a hot summer day while simultaneously charging your EV, you're creating peak demand that could easily exceed your panel's capacity.

Calgary's chinook winds create additional electrical stress that's unique to our region. The rapid temperature swings from -25°C to +10°C within hours cause repeated expansion and contraction in your electrical connections. An already-loaded 100A panel operating near capacity is more susceptible to loose connections, voltage drops, and breaker nuisance tripping during these thermal cycles.

The proper approach is a professional load calculation performed by a licensed electrician. They'll assess your home's actual electrical demand by cataloging all existing circuits, measuring current loads, and calculating the additional demand from AC and EV charging. This calculation follows Canadian Electrical Code requirements and determines whether your existing 100A service can safely handle the additional loads or if you need to upgrade to 200A service.

A 100A to 200A panel upgrade in the Calgary market typically costs $1,800-$4,500 depending on whether your service entrance cable and meter base also need replacement. If your existing service entrance is already rated for 200A (common in 1990s Evanston homes), the upgrade involves swapping the panel and coordinating with ENMAX for temporary disconnection. If the service entrance cable from the street is only rated for 100A, you'll need a complete service upgrade including new cable and meter base.

EV charger installation on an undersized panel often leads to chronic problems: breakers tripping when the AC and charger run simultaneously, voltage drops that damage sensitive electronics, and potential overheating in panel connections. These aren't just inconveniences — they're safety hazards that can lead to electrical fires.

Timing considerations for your project: If you're planning both installations, schedule the work for Calgary's building season (May through October) when outdoor electrical work is feasible. Panel upgrades involving service entrance work require ENMAX coordination, which can add 1-2 weeks to the timeline. Indoor panel swaps can proceed year-round.

Don't attempt to solve this with a smaller EV charger — reducing from a 40A to a 30A charger doesn't eliminate the fundamental overload issue and significantly increases charging time. The proper solution is ensuring adequate electrical capacity for both loads.

A licensed electrician will pull the necessary electrical permits (required for both panel upgrades and EV charger installation), perform the load calculation, coordinate with ENMAX if needed, and ensure your installation meets Alberta Building Code requirements. The permit and inspection process protects your family's safety and maintains your home's insurability.

Need help finding a licensed electrician for your load calculation and potential panel upgrade? Calgary Electrical Services can match you with local professionals who understand Calgary's unique electrical challenges and housing stock.