A heat pump needs a panel upgrade when a load calculation shows the existing service cannot carry it alongside everything else in the house. Replacing a central air conditioner with a similar-sized heat pump often adds little load. Electric backup strips, an EV charger or other gas appliances going electric are what usually tip an older 100-amp service over. A standard 100- to 200-amp upgrade typically costs $1,500 to $4,500 in the Sacramento area.
Tule Sacramento Heat Pump installs and converts ducted heat pumps across the Sacramento region, and the electrical work is done by licensed and insured contractors. This guide explains how the panel question gets answered before the equipment is ordered.
What a heat pump adds to the electrical load
A conversion swaps a gas furnace and an air conditioner for one electric system. Part of that is a wash; part is new load.
The outdoor unit
The compressor and outdoor fan run on a 240-volt circuit, the same kind the old condenser used. A heat pump of similar capacity usually has a similar nameplate rating, so on its own it may not change the panel picture much.
The indoor air handler
A gas furnace’s blower ran on a 120-volt circuit. A heat pump air handler with an electric motor and controls may need a 240-volt circuit of its own, especially when strips are installed in it.
Backup heat strips
Electric resistance strips in the air handler draw far more current than the compressor. They warm the supply air during defrost and back up the heat pump on the coldest mornings. Their size is a design choice, and the aux heat and defrost guide explains how much the valley floor actually needs.
How the panel question gets answered
Counting open breaker slots does not answer it. The electrical code’s load calculation for existing homes adds up the house’s actual loads, applies the code’s demand factors and compares the result with the service rating.
The Davis worksheet as an example
The City of Davis’s residential service-load worksheet shows how it works. It lists a heat pump’s nameplate load at 100%, counts electric space heating at 65%, includes EV charging, applies the general-load reduction in section 220.82(B) of the California Electrical Code, and asks the electrical contractor to sign for the existing service size. A heat pump plus an EV charger on an older 100- or 125-amp service is where the numbers tighten.
What goes into the calculation
| Load | Why it matters |
|---|---|
| Heat pump outdoor unit | Counted at nameplate |
| Air handler and backup strips | Strips are often the largest single heating load |
| Water heater, range, dryer | Counted at their ratings if electric, now or planned |
| EV charger | A large continuous load |
| General lighting and outlets | Based on floor area, with the code’s demand factor |
Planning for what comes next
Going electric rarely stops at heating. If a gas water heater, range or dryer will switch later, or an EV is coming, the calculation should include them now, so one upgrade covers the whole plan.
What the permit data shows
Panel work and electrification travel together. Among City of Sacramento permits issued from January 1 to October 25, 2026, 719 descriptions mention a main service panel or a service or panel upgrade. The count is a text match, not a panel census, but it shows how often the two appear on the same project.
Elk Grove runs a separate online electrical permit for replacing or upgrading a service up to 200 amps, used 131 times between October 26, 2025 and October 25, 2026. In the City of Sacramento, main and sub service panels are on the list of online minor permits for residential work.
What an upgrade typically costs
A standard upgrade from 100 to 200 amps, with the panel staying in the same place on an overhead service, typically runs about $1,500 to $4,500 for Sacramento-area homes. Relocating the panel, an underground service or meter work can push it past $5,000. These are budgeting ranges, not quotes.
What moves the electrical price
- The service drop. Overhead or underground, and how much coordination the utility’s side of the meter needs.
- Panel location. Same spot or relocated, and how much wall is opened.
- The heat pump circuit. Distance from the panel, breaker space, conductor size for the unit’s rating and the outdoor disconnect.
- Labor. Electricians in the Sacramento-Roseville-Folsom metro earn a mean $38.40 an hour against $34.37 nationally (BLS); a wage is not a billing rate, which also carries insurance, licensing, vehicles and overhead.
The conversion cost guide shows how panel work sits inside a full project price.
Ways to avoid or shrink an upgrade
Where the calculation comes out close, the design can sometimes keep the existing service:
- sizing backup strips to the actual design need rather than a default
- choosing a heat pump whose nameplate rating fits the existing circuit
- a subpanel near the air handler, where the main service has capacity but the panel lacks space
- load-management devices that keep two large loads from running at once, where the code and utility allow them
Homeowners report adding a heat pump to a subpanel only to find the breakers would exceed its rating, which is why the subpanel’s own capacity goes into the calculation too.
SMUD’s rate and rebate details
Two SMUD details are worth knowing before an upgrade:
- Go Electric rebates. SMUD pays toward a panel, subpanel or new circuits when a gas furnace or gas water heater is replaced with a qualifying heat pump. Amounts are confirmed with SMUD per project. The SMUD rebate guide covers the conditions.
- Low Use rate. SMUD’s optional Time-of-Day (Low Use) rate, with a $17 fixed charge instead of $27, is limited to panels of 125 amps or smaller and low monthly use. A household adding a heat pump will likely outgrow that profile, so check the rate as well as the panel.
Permits for the electrical side
A panel upgrade or new circuit is permitted separately from the mechanical change-out. In the City of Sacramento both can go through the online minor-permit path for one- and two-family homes. The permit and Title 24 guide covers each office.
Getting the answer for your house
The home readiness check flags whether your panel is likely to need attention, and the cost estimator includes panel work in its budget. A gas furnace to heat pump conversion always includes a panel and circuit review. To have yours checked, call (916) 516-1454 or request an estimate.
