Furnace, heat pump or ductless mini split?
Three good ways to heat a North Bay home. Here's how to tell which one fits yours.
Updated October 2026 by the Green Core Heating & Air teamIt depends on three things: whether your home has ducts, whether you want air conditioning, and whether you want to keep gas. A gas furnace suits homes with good ducts that mainly need heat. A heat pump heats and cools from one electric system and handles our mild winters well. A ductless mini split is a heat pump for homes or rooms without ducts.
The three options at a glance
Gas furnace
Burns natural gas to warm air, then a blower sends it through your ducts. Heat only.
Best for
- Homes with ducts in good shape
- Keeping gas heat
- Cooler, foggy areas that rarely need AC
Good to know
- Want AC too? That's a second unit outside.
- Standard models turn about 80% of their gas into heat. High-efficiency models reach the mid-90s.
Heat pump
Moves heat instead of making it: into the house in winter, out of it in summer. Heating and cooling in one.
Best for
- Homes with ducts that want AC too
- Replacing an old furnace and AC together
- Homes with solar, or moving off gas
Good to know
- It has to be sized to your home, and your ducts must move enough air.
- Rebates may be available. The federal 25C credit ended for installs after Dec. 31, 2025.
Ductless mini split
A heat pump with small indoor units in the rooms that need them. No ductwork.
Best for
- Homes with wall heaters or baseboards
- Additions, ADUs and garage conversions
- One room that's always too hot or cold
Good to know
- You'll see the indoor units, so we help pick clean spots.
- Cost depends mostly on how many rooms you cover.
Find the line that sounds like your home
Ifyou have good ducts, you like gas heat and you don't need AC
Gas furnaceIfyou have ducts and want heating and air conditioning
Heat pumpIfyour furnace and AC are both getting old
Heat pumpIfyou want AC but also want to keep gas as a backup
Heat pump with your furnace (dual fuel)Ifyour home has no ducts, just wall heaters or baseboards
Ductless mini splitIfone room or an addition never feels comfortable
Ductless mini splitNot sure about your ducts? That's normal. We check them at every visit, because old ducts can hold back any new system.
Things homeowners often hear
"Heat pumps don't work when it's cold."
Our coldest design nights run from about 29°F in Sonoma County to 40°F in San Francisco, per ENERGY STAR. Today's heat pumps are built for much colder places. What matters is sizing it to your home.
"A gas furnace keeps you warm in a power outage."
A furnace needs electricity for its blower and controls, so it stops when the power does, just like a heat pump. A generator or home battery can keep either one running.
"Go one size bigger to be safe."
A system far bigger than your home needs turns on and off in short bursts, which means uneven rooms, more noise and more wear. We size to your house. Try our home sizing check.
"New equipment will fix my comfort problems on its own."
Old ducts are often the real problem. Ducts from before the mid-2000s are often R-4.2 or less, while California's current code calls for R-8 in most of Sonoma, Napa and inland Marin.
How a Green Core visit works
- We listen firstA broken system, a cold bedroom, high bills or no AC. Your problem shapes the plan.
- We check the whole homeInsulation, windows, sun, ducts and your electrical panel, so the size fits your house.
- You get clear optionsOften a furnace, heat pump and ductless option side by side, with upfront pricing and no pressure.
- We install and stay with youWe protect your home, walk you through the new system and stay a call or text away.
Quick answers
Can I keep my furnace and add a heat pump?
Yes. A dual fuel setup lets the heat pump handle most of the year while the furnace covers the coldest nights.
Are there heat pump rebates in Sonoma and Marin?
They may be available through TECH Clean California, BayREN, Sonoma Clean Power or MCE, depending on funding. We check your address and handle the paperwork.
Is the federal heat pump tax credit still available?
No. The federal 25C credit ended for systems installed after December 31, 2025.
Will new gas furnaces be phased out here?
The Bay Area Air District has set zero-NOx standards for new gas furnaces starting in 2029. They apply at replacement, not to furnaces already installed.
More on each option
Want us to look at your home?
Free estimates across Sonoma and Marin. We'll check your system and ducts, then lay out your options with upfront pricing.
(707) 988-5858 Book a free estimate