Many Sacramento area homes heat with a gas furnace and cool with a separate air conditioner. When one of them nears the end of its life, some owners look at a heat pump instead. A heat pump retrofit replaces both jobs with one system that moves heat in or out of the house. This article explains what goes into that decision.
It separates legal requirements from optional choices. It also leaves rebate details to a separate incentive article, since program terms change often. Instead, the focus stays on fit, comfort and planning.
How a Heat Pump Differs
In simple terms, a heat pump works like an air conditioner that can also run in reverse. During summer, it pulls heat out of the house. In winter, it moves heat from outdoor air into the house. As a result, one outdoor unit and one indoor unit can handle both seasons.
Also, systems come in several types. Ducted systems use your existing ducts. Ductless systems use wall or ceiling units in individual rooms. Some homes use a mix of both.
Load Assessment Comes First
First, the right size depends on how much heat your home gains and loses. Insulation, windows, air leaks, shade and room layout all play a part. So a qualified designer should calculate the load rather than matching the size of the old equipment.
An oversized system may cycle on and off too often, which can affect comfort. In contrast, an undersized one may struggle on the hottest or coldest days. A proper load calculation helps avoid both problems.
Ducts in a Heat Pump Retrofit
If you have ducts, their condition matters a lot. Leaky, crushed or poorly sized ducts waste energy and reduce comfort. A heat pump may also need different airflow than the old furnace.
California’s energy code adds its own rules here. The California Energy Commission explains that replacing the outdoor or indoor unit of a split system triggers duct sealing and field verification requirements, with some exceptions. That means a certified rater may need to test the ducts. Ask your installer how they plan to meet this.
Which Energy Code Applies
The Energy Commission states that buildings with permit applications on or after January 1, 2026, must comply with the 2025 Energy Code. So a new HVAC permit today falls under the 2025 rules.
These rules come with the permit, so they are not optional. In contrast, choices such as a higher efficiency model or a smart thermostat are usually optional. Keep the two groups separate when you compare proposals.
Electrical Needs
A heat pump runs on electricity. If your old furnace used gas, the new system may need a new circuit. In some homes, the electrical panel may also need an upgrade to carry the added load.
A licensed electrician should review your panel and service before you commit. This is not a do it yourself task. In the City of Sacramento, new circuits and panel work fall under the city’s minor permit types, along with residential HVAC change outs.
Comfort and Noise After a Heat Pump Retrofit
Heat from a heat pump can feel different from a gas furnace, since run times and air temperature vary by system and settings. Some people like the steady warmth. Others notice the change at first, so ask the designer what to expect.
Noise depends on the model and where the outdoor unit sits. Ask for the manufacturer’s sound data, and think about bedrooms and neighbors when choosing a spot. Also check any local rules on equipment placement.
Operating Cost Assumptions in a Heat Pump Retrofit
Claims about savings depend on many assumptions. These include your electric and gas rates, equipment efficiency, how you set the thermostat and how well the house holds heat. So be cautious with any promise of guaranteed savings.
If someone gives you a savings estimate, ask what rates and usage they assumed. Then compare that with your own utility bills. A heat pump retrofit may lower costs in some homes and not in others.
Incentives Change Often
SMUD lists current rebates for heat pump HVAC systems with equipment and installer conditions. Programs can change or run out of funds. Therefore, confirm that your home is in SMUD’s service area and check the current terms before you count on any offer.
Federal tax rules also change. Check current IRS guidance rather than relying on older articles.
Improve the House Before the Equipment
Often, small fixes to the house can shrink the load. For example, sealing air leaks, adding attic insulation or shading west windows can reduce how hard any system must work. As a result, a smaller system may do the job.
These steps are optional, not required by the permit. Still, they can improve comfort on their own. So ask the designer whether any of them make sense before you settle on equipment size.
Questions to Ask Before You Decide
Before you sign, ask each bidder a few key questions:
- How did you size the system, and can I see the load calculation
- What will you do about duct testing and sealing under the energy code
- Does my electrical panel need changes, and who will handle that work
- What assumptions sit behind any savings estimate
Write down the answers and compare them side by side. The article on comparing estimates that include different work shows how to line up proposals. Before you hire, also review how to check a California contractor’s credentials.