Furnace replacement cost varies with the furnace's efficiency (AFUE) and stage, the size your home needs, venting, ductwork, and permits — so an honest answer is a range plus a free in-home estimate, never a flat phone price. And before you replace like-for-like, it's worth asking whether a heat pump is the better value here. Below is how to read the ranges and what moves the number.
Why won't a reputable company quote a flat price by phone?
Because the real cost depends on what only an in-home visit can confirm: the correct size from a Manual J load calculation, your venting and gas line, the condition of your ducts, and access. A phone "price" is a guess that gets corrected upward mid-job. We give you a defensible range now and a written, itemized quote after we've seen the home.
What moves a furnace quote up or down?
- Efficiency (AFUE). A high-efficiency condensing furnace costs more upfront and needs different venting than an 80% model.
- Staging. Single-stage vs. two-stage vs. variable-speed — more comfort and efficiency, higher price (see variable-speed vs. single-stage).
- Size. Correctly sized to your home, not the old unit's nameplate.
- Venting & gas. Condensing furnaces need new venting; gas-line work adds cost.
- Ductwork. Reusable ducts keep costs down; sealing or repair adds to them.
- Permits & testing. Required and worth doing right — see our permit guide.
How should I read the ranges?
| Option | Relative cost | Best for |
|---|---|---|
| Standard-efficiency (80% AFUE) furnace | $ – $$ | Tight budgets, like-for-like swap |
| High-efficiency / variable-speed furnace | $$ – $$$ | Lower gas bills, even comfort |
| Heat pump (replaces furnace + AC) | $$ – $$$ | Electrifying, adding cooling, rebates |
Relative tiers only — not dollar quotes. Your written, itemized number comes from a free in-home estimate. [GATHER: if Air Synergy wants published dollar ranges, supply approved figures.]
Should I replace the furnace — or switch to a heat pump?
In our mild climate, a heat pump can do the furnace's job and add cooling from one efficient system — and rebates currently favor it. That doesn't make a furnace wrong (gas heat is fast and inexpensive to run in some cases), but it's worth comparing before you spend. Read heat pump vs. furnace and, if you're leaning electric, should I electrify my home?
Use ranges to compare, not to decide alone. The costliest mistake isn't a high price — it's signing a bid you couldn't compare. Put quotes side by side with our checklist and check the scope (size, efficiency, venting, ducts, permits), not just the bottom line.
What about rebates and financing?
Today's incentives lean toward electrification, so a heat pump may carry rebates a gas furnace won't — a real factor in the math. We offer financing to spread the cost and confirm current eligibility during the estimate. [GATHER: current Bay Area / California furnace and heat-pump rebate programs and amounts.]
Why trust Air Synergy's number?
We're family-owned with decades of combined technician experience in the Bay Area, a 4.9-star rating across 189 reviews, and a Mitsubishi Diamond Elite Contractor. Every estimate is itemized in writing with model numbers, sized with a Manual J, and includes permits — so you can compare it honestly against anyone. Explore heating & cooling.
Your next step
Get a free, no-obligation in-home estimate with a written, itemized quote and current rebate guidance — for a furnace, a heat pump, or both compared side by side.
Figures are relative ranges, not quotes — exact pricing requires an in-home evaluation. Rebate programs and dollar ranges are marked [GATHER] pending confirmation. Terms in the glossary. Company facts per Air Synergy.
Common questions
How much does furnace replacement cost in the Bay Area?
It depends on the furnace's efficiency (AFUE) and stage, the size your home needs, venting and ductwork, and permits — which is why an honest answer is a range plus an in-home estimate, not a flat phone price. Use our relative tiers to sanity-check bids, then get a free in-home estimate for your exact figure.
Should I replace my furnace or switch to a heat pump?
It's worth asking before you buy. In the Bay Area's mild climate, a heat pump can replace both your furnace and AC with one efficient system and is the focus of current rebates — so 'like-for-like furnace' isn't always the best value. We compare both honestly so you don't overspend on the wrong system.
Are there rebates on a new furnace?
Rebates today heavily favor electrification (heat pumps and heat-pump water heaters) over gas furnaces, so the incentive picture can tilt the math toward a heat pump. Programs and amounts change, so we confirm current eligibility during your estimate. [GATHER: current Bay Area / California furnace and heat-pump program eligibility and amounts.]