In San Jose a heat pump earns its keep in both seasons: it cools through hot, dry valley afternoons and heats through mild winters with cool nights, all from one outdoor unit. The equipment is rarely the hard part. In most homes the real questions are the electrical panel, the condition of the ducts and what happens to the gas furnace. We look at all three on a free estimate visit before recommending anything, and the price is fixed before work starts.
Sizing for hot summers and mild winters
A heat pump has to keep up on the hottest afternoon and still carry the house on the coldest night, and those are two different loads. We run a room-by-room calculation for both, using the insulation, windows, orientation and duct location of your house. West-facing rooms and ducts in a hot attic drive the summer number. In winter, a heat pump’s output drops as the outdoor temperature falls, so we check the model’s capacity at a cold-night temperature, not just its nameplate size. Homes on foothill streets, such as parts of Evergreen, cool off faster after sunset than the valley floor, and that shows up in the heating number.
Variable-speed (inverter) heat pumps suit this climate: most days here are mild, and they run low and steady instead of switching on and off. An oversized single-speed unit short-cycles, leaves rooms uneven and is noisier. Electric backup heat strips in the indoor unit are sized last; where the heat pump covers the heating load, they can be small, which also eases the load on your panel.
The electrical panel
A ducted heat pump needs a 240-volt circuit for the outdoor unit and another for the indoor air handler, larger if it has backup heat. If the heat pump replaces a central air conditioner of similar size, the AC’s circuit can often be reused. The added load comes from swapping a gas furnace for an electric air handler and its heat strips.
Many 1950s–60s homes in Cambrian and Willow Glen still have a main panel of 100 amps or less, sometimes with no spare spaces, and an EV charger or an induction range may already be on the list. A load calculation shows whether the panel can take the heat pump. If it can’t, the options are a panel upgrade, which needs coordination with the utility and adds time, a load-management device that keeps large loads from running at once, smaller backup heat, or a mix. We check the panel at the estimate, not on installation day.
Ducted or ductless
Ducted makes sense when the house has ducts in fair shape. Homes that never had central air often have ducts sized for a furnace alone, which can be too small for the airflow a heat pump needs when cooling. In Blossom Valley homes where the original 1970s–80s system is still in place, the ducts are about 40 years old too, and sealing or replacing sections is often part of the job.
Ductless mini-splits put a small indoor unit in each room or zone and need no ducts, which suits additions, converted garages and older homes where new duct runs would harm the house. See mini-split installation. Some homes combine both: ducted for the main rooms, a ductless unit for the room the ducts never reached.
Replacing a gas furnace
- All-electric: the outdoor heat pump plus an electric air handler in the furnace’s old spot in the attic, garage or closet. The gas line to the furnace is capped. If a gas water heater shared the furnace flue, its venting is re-checked on its own.
- Dual fuel: the heat pump takes the place of the AC, and the furnace stays for the coldest nights. This fits when the furnace is fairly new; if it is not, compare it with a furnace replacement.
- Partial: ductless units in the rooms you use most, with the furnace left as it is.
In Evergreen’s tract homes the builder-grade furnace and AC often reach replacement age together, which is the natural moment to replace both with one correctly sized heat pump. At the estimate we also talk through how the switch is likely to shift your gas and electric bills, since electricity rates matter as much as efficiency. As long as any gas appliance stays in the house, keep working CO alarms: if one sounds, get everyone out. If you smell gas, leave and call the gas utility or 911 from outside.
Rebates and the federal credit
Heat pump rebates come from several types of sources: the electric utility, regional and state programs, local electrification programs and manufacturer promotions. They change often, many set minimum efficiency ratings, and some need approval before installation, so check the terms before you sign. At the estimate we point out which types to look into for the equipment we propose. The federal tax credit for heat pumps ended for equipment installed after December 31, 2025, so an installation now does not qualify for it.
What affects the price
Heat pump installation in San Jose typically runs $5,000–$18,000. A single-zone ductless system or a like-for-like swap on good ducts sits at the low end. Whole-house variable-speed systems, moving the air handler, duct replacement and multi-zone ductless setups move it up, and any panel work is its own line on the written estimate. The heat pump installation cost guide goes into more detail. If you already have a heat pump that is acting up, start with heat pump repair.