Quick Answer
A heat pump needs its own dedicated 240-volt circuit sized to the unit, and enough spare capacity in your electrical panel to carry it. In many Marin homes that’s straightforward; in older homes on 100-amp service already running other big loads, a panel upgrade may come first. A load calculation tells you which.
Heat pumps are having a moment in Marin — they heat and cool efficiently, they’re central to the state’s electrification push, and rebates have made them attractive. But the HVAC quote is only half the story. The electrical side, handled as part of your residential electrical services, is what determines whether your heat pump is a clean install or a project with a panel upgrade attached.
The BasicsWhat a Heat Pump Needs Electrically
Most whole-home and mini-split heat pumps run on a dedicated 240-volt circuit, sized to that specific unit’s requirements — there isn’t a one-size number, because it depends on the model’s capacity and its minimum circuit ampacity, which the manufacturer specifies. The electrician sizes the breaker and the wire to match that spec, runs the circuit from the panel to the equipment location, and makes the final connections and disconnect the code requires near the unit. On a home with capacity to spare, that’s a clean, contained job.
The Real QuestionDoes Your Panel Have Room?
The deciding factor is spare capacity in your panel. A heat pump is a meaningful load, and if you’re adding it to an older home already running — or planning to add — an EV charger, an induction range, or a heat pump water heater, the combined draw can exceed what a 100-amp service was built for. That’s where a 200-amp panel upgrade can enter the picture. The way to know for certain isn’t a guess — it’s a load calculation.
What a load calculation tells you — it’s the code-prescribed method for adding up your home’s existing and planned electrical loads to see whether your service can carry a new one. It’s the honest answer to “do I need to upgrade my panel first?” — and it’s cheap insurance against an overloaded service.
Planning AheadElectrify Once, Not Three Times
If a heat pump is your first electrification project but not your last, plan for the whole arc now. Homeowners who add loads one at a time can end up paying for panel work twice; those who size their service for the full electrification picture — heat pump, EV, induction, maybe a heat pump water heater — upgrade once and are done. Tell your electrician everything you’re considering, even the loads that are a year or two out.
Rebates and CodeThe Marin Context
California is actively encouraging heat pumps, and the incentive landscape is worth checking before you buy — the U.S. Department of Energy outlines how the systems work, and California’s Title 24 standards increasingly favor efficient electric equipment. All of the wiring must meet the current National Electrical Code as adopted in California, and the circuit and disconnect are permitted, inspected work.
Step by StepHow to Prepare Your Electrical for a Heat Pump
Get the unit’s electrical spec
Your HVAC pro or the manufacturer sheet lists the voltage, minimum circuit ampacity, and breaker size — the electrician sizes the circuit to that.
List your other big loads
EV charger, induction range, heat pump water heater — existing and planned. This determines whether your service can carry the total.
Get a load calculation
A licensed electrician runs the numbers to confirm your panel can take the heat pump, or whether an upgrade comes first.
Run the dedicated circuit
With capacity confirmed, the electrician installs the 240-volt circuit, disconnect, and final connections to code.
Coordinate the permit and inspection
The circuit is permitted and inspected; your electrician handles both alongside the HVAC install.
Key Takeaways
- A heat pump needs a dedicated 240-volt circuit sized to the specific unit’s spec.
- The deciding factor is spare panel capacity — a load calculation gives the real answer.
- Older 100-amp homes stacking multiple big loads may need a panel upgrade first.
- If more electrification is coming, size the service once for the whole picture.
Thinking about a heat pump? We’ll run the load calculation and tell you honestly whether your panel is ready or needs an upgrade first.
Reviewed by Alex Towery
Owner & Licensed Electrical Contractor · CSLB C-10 #989290
Alex has wired heat pumps, mini-splits, and full electrification projects across Marin, including plenty of older homes where the panel had to be sorted out first. Every Towery Electric article is reviewed against current California Electrical Code before publishing.
The Bottom Line
A heat pump’s electrical needs come down to two things: a properly sized 240-volt circuit, and enough panel capacity to carry it. In many Marin homes that’s simple; in older ones stacking several new loads, a panel upgrade may come first. Get a load calculation before you commit, and if more electrification is on your horizon, size the service once for all of it.
Frequently Asked Questions
Does a heat pump need its own circuit?
Yes. A heat pump runs on a dedicated 240-volt circuit sized specifically to that unit — you don’t share it with other equipment. The exact breaker and wire size come from the manufacturer’s minimum circuit ampacity for the model, so there isn’t a single universal number. Your electrician reads that spec, sizes the circuit to match, runs it from the panel to the equipment, and installs the disconnect the code requires near the unit.
Will I need to upgrade my panel to add a heat pump?
Maybe — it depends on how much spare capacity your panel has and what else it’s running. A heat pump is a significant load, and if you’re adding it to an older 100-amp service that’s already near its limit, or you’re also planning an EV charger or induction range, the combined demand can exceed what the service can safely carry. A load calculation is the honest way to find out. Many Marin homes have room; older ones stacking multiple new loads often don’t.
What is a load calculation and why does it matter?
A load calculation is the code-defined method an electrician uses to total your home’s existing and planned electrical loads and compare them against your service capacity. It’s what turns “I think my panel can handle it” into a real answer. It matters because adding a big load to a service that can’t support it isn’t just a code violation — it’s a safety and reliability problem. The calculation is inexpensive relative to the cost of an overloaded panel or a redo.
Can I add a heat pump and an EV charger to the same panel?
Often yes, but it’s exactly the scenario where capacity gets tight, especially on older service. Two large 240-volt loads plus your existing usage add up quickly. Sometimes the answer is a panel upgrade; sometimes a load-management approach lets the loads coexist. The smart move is to tell your electrician about every major load you’re planning — heat pump, EV, induction, water heater — so the service is sized once for the full picture instead of being upgraded twice.
Is the electrical work included in a heat pump installation?
Not usually — HVAC contractors handle the equipment and refrigerant side, while the dedicated circuit, panel work, disconnect, and permit are electrical scope. On many Marin projects the HVAC installer and a licensed electrician coordinate, but they’re separate trades and often separate line items. It’s worth clarifying up front who is pulling the electrical permit and running the circuit so nothing falls through the cracks between the two.
Do heat pump circuits need a permit in Marin?
Yes. Installing a new 240-volt circuit and disconnect for a heat pump is permitted, inspected electrical work under your local Marin County jurisdiction. A licensed C-10 pulls the permit and coordinates the inspection as part of the job. Permitted work protects you at resale and with insurance, keeps you eligible for electrification rebates that require code-compliant installation, and ensures the circuit was sized and installed correctly for a load your home will run for years.
How We Sourced This
Guidance reflects common 2026 residential heat pump installations in Marin County and is for planning only. Authored by Healthcare Marketing Group’s editorial team and reviewed for technical accuracy by Alex Towery, owner of Towery Electric, Inc. and a California-licensed C-10 (CSLB #989290). Circuit sizing follows manufacturer specifications and the California Electrical Code (Title 24, Part 3) as adopted from NFPA 70.
References
- U.S. Department of Energy. “Heat Pump Systems.” www.energy.gov
- California Energy Commission. “Building Energy Efficiency Standards (Title 24).” www.energy.ca.gov
- National Fire Protection Association. “NFPA 70 — National Electrical Code.” www.nfpa.org