# Replacing an AC with a Heat Pump in Sacramento > Replace an AC with a heat pump in Sacramento: same summer cooling, plus winter heat. What happens to the furnace, coil, permit and SMUD rebate. Get an estimate. URL: https://tulesacramentoheatpump.com/replace-ac-with-heat-pump/ A heat pump in place of a failing central air conditioner, with the furnace kept as backup, removed, or replaced by the heat pump's own air handler. [Tule Sacramento Heat Pump](https://tulesacramentoheatpump.com/) installs heat pumps in place of failing central air conditioners in homes across Sacramento County, south Placer County, east Yolo County and El Dorado Hills, through licensed and insured contractors. A heat pump is an air conditioner with a reversing valve, so it cools the house the same way the old AC did. It also runs backward in winter and moves heat indoors. When an AC fails, the decision is about more than the outdoor unit. The heating side of the house, whether a gas furnace, an electric furnace or strip heat, is what the choice really changes. ## Why the AC replacement is the moment to decide Sacramento’s air conditioners work hard. NOAA’s 1991-2020 normals for Sacramento Executive Airport count about 76 days a year at 90°F or hotter and 14 at 100°F or hotter. When a compressor quits in July, the new outdoor unit, the coil, the line set and the permit are going in anyway, and a heat pump fits the same pad, lines and ducts. ### What a heat pump adds The reversing valve flips the refrigerant flow so the outdoor coil gathers heat and the indoor coil releases it. In winter the outdoor coil can frost over, so the unit runs short defrost cycles. Those two parts, plus the controls that manage them, are what separate a heat pump from the AC it replaces. ### Cooling in the valley’s heat Equipment is sized for the cooling load, which governs in this climate. The California Energy Commission’s design data for Sacramento runs from 98°F at the 1% level to 104°F at the hottest 0.1%. July air at 3 p.m. averages about 91°F with a dew point near 53°F, so the load is mostly dry heat, and airflow of at least 300 cfm per ton suits it. The [hot weather guide](https://tulesacramentoheatpump.com/guide/heat-pump-hot-weather/) covers capacity at the top of that range. ## What happens on the first visit The visit sorts out which version of the project fits the house. - **The heating system.** Gas furnace or electric furnace, its age, blower type and cabinet width, the coil on top and the flue. - **The load.** A Manual J calculation for cooling and heating, so the heat pump isn’t sized from the old AC’s tonnage. - **The ducts.** Return size, static pressure and leakage, since the furnace blower now has to move heat pump airflow in both seasons. - **The electrical side.** The existing AC breaker, the disconnect and panel space if backup strips are planned. - **The utility.** SMUD, Roseville Electric or PG&E, which sets both the rebate and the winter operating cost. The written scope names the outdoor unit, the coil or air handler, the line set decision, the thermostat and the permit. ## Three ways to handle the heating side ### Keep the gas furnace as backup The heat pump coil sits on the furnace, the heat pump handles cooling and most heating, and the furnace runs only below a set outdoor temperature or when the heat pump can’t keep up. This is a dual fuel system, and the changeover setting decides how much gas the house still burns. [Dual fuel heat pumps](https://tulesacramentoheatpump.com/dual-fuel-heat-pump/) covers the controls and the economics. ### Retire the furnace too If the furnace is near the end of its life, a heat pump with its own air handler replaces both appliances, and the gas branch is capped. On SMUD power that project can qualify for the $3,000 or $2,000 gas-to-electric rebate. [Gas furnace to heat pump conversion](https://tulesacramentoheatpump.com/gas-furnace-to-heat-pump-conversion/) covers the full project. ### Homes that heat with electricity already Where the AC sits on an electric furnace or a strip-heat air handler, the heat pump becomes the main heat and the strips drop to backup. Resistance heat delivers one unit of heat per unit of electricity; a heat pump delivers several in mild weather. In the CEC’s 2019 survey, 18% of SMUD households used conventional electric heat. That swap falls under SMUD’s electric-to-electric rebate. ### Swamp cooler homes The same survey found evaporative coolers in 13% of SMUD households. Moving from one to a ducted heat pump depends on whether the house has ducts that can carry heat pump airflow, which the [heat pump vs swamp cooler guide](https://tulesacramentoheatpump.com/guide/heat-pump-vs-swamp-cooler/) explains. Not sure which heating option fits your furnace? A look at the furnace, its blower and your utility answers it. The visit covers all three before anything is ordered. ## The coil, the furnace blower and the refrigerant ### Why the old coil rarely stays New heat pumps use lower-GWP refrigerants such as R-454B or R-32, and each outdoor unit is rated with specific indoor coils. An AC coil built for R-410A is not a rated match, so a new coil goes on the furnace. It has to fit the cabinet width, often with a sheet-metal transition sealed at every seam, and its drain pan needs a working trap and overflow switch. The [refrigerant guide](https://tulesacramentoheatpump.com/guide/heat-pump-refrigerant-r454b/) explains the change. ### Can the furnace blower keep up? A heat pump needs at least 300 cfm per ton in both heating and cooling. An older single-speed furnace blower may have been set for a smaller AC, or for heating airflow only. If it can’t deliver the airflow through the existing ducts, the options are adjusting the blower, fixing restrictive returns or moving to an air handler. [Heat pump ductwork](https://tulesacramentoheatpump.com/heat-pump-ductwork/) covers the duct side. ### Thermostat and controls The thermostat has to drive the reversing valve and stage the backup heat, gas or electric. Title 24 requires a digital setback thermostat whenever refrigerant components are replaced, and SMUD’s rebate requires a Wi-Fi seven-day programmable model. ## The permit and the Title 24 visit Swapping only the outdoor unit still counts as an alteration. The California Energy Commission’s HVAC FAQ says replacing the outdoor unit of a split system by itself triggers duct sealing, and the existing ducts must be tested by the installer and an ECC-Rater. Refrigerant charge verification applies to heat pumps in every climate zone, and to air conditioners in zones 2 and 8 through 15, which includes Sacramento’s zone 12. The [heat pump vs air conditioner guide](https://tulesacramentoheatpump.com/guide/heat-pump-vs-air-conditioner/) compares the two in more detail. ## Winter operating cost once the heat pump heats Summer bills barely change: a heat pump and an AC with the same [SEER2 rating](https://tulesacramentoheatpump.com/guide/seer2-hspf2-ratings/) use about the same energy to cool. Winter is where the utility matters. | Electricity supplier | Winter price per kWh used for the comparison | Heat pump beats a 95% gas furnace above COP | | --- | --- | --- | | SMUD, off-peak | $0.1285 | 1.41 | | Roseville Electric, Tier 2 | $0.1989 | 2.18 | | PG&E E-ELEC, off-peak | $0.28468 | 3.13 | Those break-even figures are derived from the utilities’ tariffs and PG&E’s residential gas rate, energy charges only. On SMUD power almost any modern heat pump heats for less than gas. On PG&E power, keeping the furnace for the coldest hours is a closer call. The [electric bill guide](https://tulesacramentoheatpump.com/guide/heat-pump-electric-bill-sacramento/) covers what changes month to month. ## Rebates and budgeting ### SMUD tiers SMUD’s heat pump rebate depends on what the heat pump replaces. Gas heating removed: $3,000 for variable-stage, $2,000 for two-stage at 15.2 SEER2 or higher. An existing electric system replaced: $1,000. SMUD does not state whether a heat pump added to a kept gas furnace qualifies, so that is confirmed before the equipment is chosen. All tiers require qualifying equipment installed by a participating contractor in the SMUD Contractor Network; rebate-qualified installations are available on request. Roseville Electric lists no heat pump rebate, and none was found from PG&E. ### What it costs No local data isolates the cost of adding a heat pump to a kept furnace, so it is quoted from the furnace, coil and control work it needs. For full conversions, about half of recent Sacramento-area projects land between roughly $15,000 and $24,000 before rebates; SMUD’s published median for electric-to-heat-pump upgrades is about $17,000 for split systems. The [cost estimator](https://tulesacramentoheatpump.com/tools/heat-pump-cost-estimator/) gives a range for your house. ## What's included - A load calculation for cooling and heating - A check of the furnace or air handler, its blower and its cabinet size - Removal of the old condenser with its refrigerant recovered - A new indoor coil matched to the heat pump, with any cabinet transition sealed - Refrigerant lines replaced, or cleaned and tested where reuse is allowed - Electrical disconnect and breaker checked against the heat pump's nameplate - A heat pump thermostat with reversing valve control and backup heat staging - Condensate drain and overflow protection checked at the coil - Pressure test, evacuation and charge to the manufacturer's specification - The permit, inspection and ECC-Rater visit - A walkthrough of heating mode, defrost and when backup heat runs ## What happens to the heating side when the AC is replaced | | Heat pump plus existing gas furnace | Heat pump with its own air handler | New AC, nothing else changes | | --- | --- | --- | --- | | Cooling | Heat pump | Heat pump | Air conditioner | | Winter heat | Heat pump, furnace below a set outdoor temperature | Heat pump, electric strips only as backup | Existing furnace or electric heat | | Indoor equipment | New coil on the furnace | New air handler; furnace removed | New coil on the furnace | | SMUD rebate | Eligibility not stated by SMUD; confirmed first | Gas-to-electric or electric-to-electric tier, on qualifying systems | None | | Fits best | A furnace with years of life left | An old furnace, or electric heat already | A tight budget and a newer furnace | | Check first | Furnace blower, coil fit, controls | Panel capacity and air handler location | Coil match with the new refrigerant | ## Related resources - Decision Guide [Should you replace a central air conditioner with a heat pump or another AC?](https://tulesacramentoheatpump.com/guide/heat-pump-vs-air-conditioner/)A heat pump is an air conditioner that can also heat. Here is what that one difference changes in the Sacramento area: price, rebates, winter bills, Title 24 testing, the furnace you already have and how long the outdoor unit works each year. - Learn [How does a heat pump hold up in Sacramento's hot weather?](https://tulesacramentoheatpump.com/guide/heat-pump-hot-weather/)What happens inside a heat pump on a 100-degree afternoon, how the design temperature for your town sets its size, why attic ducts and outdoor-unit placement matter, and how to run it around summer peak pricing. - Decision Guide [Should a Sacramento home replace its swamp cooler with a heat pump?](https://tulesacramentoheatpump.com/guide/heat-pump-vs-swamp-cooler/)Evaporative coolers suit the valley's dry summers, up to a point. This guide compares them with a ducted heat pump on cooling limits, smoke days, winter heating, running cost and the duct and roof work a switch can involve. - Learn [What do SEER2 and HSPF2 ratings mean for a Sacramento heat pump?](https://tulesacramentoheatpump.com/guide/seer2-hspf2-ratings/)How the cooling and heating efficiency ratings are built, how to turn HSPF2 into a COP you can compare with your utility's break-even figure, and why installation quality decides whether a system reaches its rating. - Learn [How does the SMUD heat pump rebate work?](https://tulesacramentoheatpump.com/guide/smud-heat-pump-rebates/)What SMUD pays on a ducted heat pump, which homes and systems qualify, the permit and Title 24 steps the claim depends on, the Go Electric panel and circuit add-ons, and who files the paperwork. ## 1. Your house and your bills What you have now, what isn't working, your utility and what you want the new system to do. 2. Load, ducts and panel A room-by-room load calculation, a look at the ducts and returns, the electrical panel and where the outdoor unit can go. 3. Permit, set, braze, test Permit pulled, old equipment recovered and removed, new units set, lines brazed, pressure-tested and evacuated before charging. 4. Verified and explained Airflow, charge and backup heat checked, the ECC-Rater visit for Title 24, and the thermostat set up and walked through. ## What this work looks like Heat pump outdoor unit on a concrete pad along the tan stucco side wall of a 1960s Sacramento ranch house, in place of the old central AC Insulated flexible ducts hung on straps from the rafters in the attic of a Sacramento ranch house, running off toward the rooms Technician's gloved hands connecting gauges to a heat pump outdoor unit beside the brick side wall of a Sacramento ranch house Slim wall thermostat with a dark screen beside a hallway opening in a Sacramento ranch house, a return air grille beyond Before After Your AC is due. Decide the heating side at the same time. Tell us how old the AC and the furnace are, whether you heat with gas or electricity, and who supplies your power. The options follow from those three answers. ## AC to heat pump questions ### Does California require a heat pump when my central air conditioner is replaced? No state rule found requires it. The California Energy Commission's heat pump baseline in Title 24 applies to new construction, so a homeowner replacing an AC in an existing house can still install a new air conditioner. What every change-out does require is a building permit, duct sealing and an ECC-Rater visit, whichever equipment goes in. ### Does a heat pump use more electricity than an air conditioner in summer? Not by being a heat pump. In cooling mode it works the same way an air conditioner does, and two units of the same size and SEER2 rating use about the same energy. The extra kilowatt-hours come in winter, when the heat pump takes over heating the furnace used to do with gas. ### What happens to the old AC coil sitting on top of the furnace? It is usually replaced. The new heat pump is rated with a specific indoor coil, and new systems use a different refrigerant from older AC coils. The replacement coil has to fit the furnace cabinet, often with a sheet-metal transition, and its drain pan and condensate line are checked before the system starts. ### Which SMUD rebate applies when a heat pump replaces an AC and an electric furnace? SMUD's electric-to-electric tier, which pays $1,000 for a qualifying two-stage or variable-stage heat pump replacing an existing electric system. The equipment has to be installed by a participating contractor in the SMUD Contractor Network, with a permit, a connected thermostat and a passing Title 24 verification. Eligibility is confirmed per project. ### Can I replace the AC with a heat pump now and retire the furnace later? Yes. The heat pump goes on the existing furnace as a dual fuel system, and the furnace is replaced with an air handler when it wears out. Most air handlers include their own coil, so the coil installed now is usually replaced in the second step. The two-step path costs more in total than one project, but it spreads the spending and uses the furnace's remaining life. ## Related services Dual fuel heat pump A heat pump added to a gas furnace that still has life in it, with the changeover point set from your utility's rates and the house's heat loss. Furnace to heat pump conversion One ducted heat pump in place of the gas furnace and the central AC, sized from a load calculation and tested to Title 24. Heat pump ductwork Duct testing, sealing, resizing or full replacement so a heat pump gets the airflow it needs and passes the Title 24 test.