From 1960s Floor Furnace to Modern Dual Fuel: An Oakland Hills Transformation
Last week, we completed one of our most dramatic HVAC transformations yet—converting a 1960s Oakland Hills home from an aging floor furnace to a complete Carrier Infinity dual fuel system with brand new ductwork throughout.
This project showcases exactly why so many Oakland Hills homeowners are upgrading from floor furnaces to modern central heating and cooling systems.
The Challenge: An Outdated Floor Furnace in a Beautiful Oakland Hills Home
The Homeowner’s Situation
The homeowners, Jennifer and Mark, purchased their charming 1958 mid-century home in the Oakland Hills three years ago. Like many Oakland Hills properties from that era, the home relied on an original floor furnace for heating.
The problems they faced:
- Inconsistent heating – The floor furnace only heated the living room area effectively
- Cold bedrooms – Back bedrooms never got warm, especially on foggy Oakland Hills mornings
- Safety concerns – The open-flame floor furnace was a hazard with young children
- No air conditioning – Increasingly necessary with Bay Area heat waves
- High PG&E bills – The inefficient floor furnace was costing $250+ per month in winter
- Poor air quality – No filtration meant dust and allergens throughout the home
What Is a Floor Furnace?
For readers unfamiliar, floor furnaces were common in Bay Area homes built between 1940-1970. They’re metal grates set into the floor (usually in a central hallway) with a gas burner underneath. While simple and reliable, they have serious limitations:
- Heat rises straight up—doesn’t distribute through the home
- No ductwork means no air filtration
- Open flame is a burn hazard for children and pets
- No cooling capability
- Typically only 50-65% efficiency (half the heat goes up the chimney)
Oakland Hills is full of these vintage systems. We replace 15-20 floor furnaces per year in the Oakland Hills and Montclair neighborhoods alone.
Our Solution: Complete Dual Fuel System with New Ductwork
After evaluating Jennifer and Mark’s 2,200 square foot home, we recommended a comprehensive solution:
- Remove the old floor furnace and cap the gas line
- Install a Carrier Infinity dual fuel system (heat pump + gas furnace backup)
- Design and install new ductwork throughout the home
- Add whole-home air filtration
The Equipment We Installed
Heat Pump: Carrier Infinity 25VNA048A003
This is Carrier’s flagship 4-ton variable-speed heat pump:
- Capacity: 48,000 BTU cooling / 47,000 BTU heating
- Efficiency: 22-24 SEER2 / 10 HSPF2
- Compressor: Greenspeed variable-speed inverter
- Refrigerant: R-454B (next-generation, environmentally friendly)
- Sound level: As low as 51 dB (quieter than a conversation)
- Operating range: Efficient heating down to 0°F
- Warranty: Lifetime compressor, 10-year parts
Why variable-speed matters for Oakland Hills: The microclimates in Oakland Hills mean temperatures can swing 20°F between morning fog and afternoon sun. Variable-speed technology continuously adjusts output to maintain perfect comfort without the temperature swings of single-stage systems.
Furnace: Carrier Infinity 59TP6A080E21
For backup heating during the coldest nights and power optimization:
- Input: 80,000 BTU
- Efficiency: 96% AFUE (vs. ~55% for the old floor furnace)
- Burner: Two-stage modulating for quiet operation
- Blower: Variable-speed ECM motor
- Compatibility: Greenspeed Intelligence for seamless dual fuel operation
- Warranty: Lifetime heat exchanger, 10-year parts
Why dual fuel for Oakland Hills: Oakland Hills gets colder than flatland Oakland—winter mornings regularly drop into the mid-30s. The gas furnace backup ensures reliable heat during cold snaps while the heat pump handles the other 95% of heating demand at 300%+ efficiency.
Smart Controls: Carrier Infinity System Control
The system is managed by Carrier’s most advanced thermostat:
- Automatic fuel switching based on outdoor temperature and energy costs
- Zoning ready for future expansion
- Remote access via smartphone app
- Maintenance alerts for proactive service
- Energy usage tracking to monitor savings
The New Ductwork System
Since the home had no existing ductwork, we designed and installed a complete forced-air distribution system:
Supply Runs:
- 6 supply registers strategically placed throughout the home
- Living room, dining room, kitchen, master bedroom, two additional bedrooms
- Insulated flex duct in attic space with R-8 insulation
- Properly sized for 400 CFM per ton (1,600 CFM total)
Return Air:
- Central return in hallway (where the floor furnace used to be)
- Properly sized for balanced airflow
- EZ Flex filter cabinet for easy filter changes
Ductwork Materials:
- Sheet metal trunk lines for durability
- Insulated flex duct for branch runs
- Mastic-sealed joints (no duct tape)
- All connections secured with zip ties and tape
The Installation Process
Day 1: Demolition and Preparation
Morning:
- Protected all flooring and furniture
- Disconnected and removed the floor furnace
- Capped gas line safely
- Patched the floor opening with matching hardwood
Afternoon:
- Installed furnace platform in garage
- Ran new gas line to garage location
- Began attic work for supply duct routing
- Installed new 240V electrical circuit for heat pump
Day 2: Ductwork Installation
Full Day:
- Installed sheet metal trunk line in attic
- Connected insulated flex runs to each room
- Cut and installed supply registers in ceilings
- Installed central return grille in hallway
- Sealed all duct connections with mastic
Day 3: Equipment and Commissioning
Morning:
- Set Carrier 25VNA048A003 heat pump on composite pad
- Installed 59TP6A080E21 furnace on platform
- Connected refrigerant lines and evacuated system
- Connected gas line with sediment trap
Afternoon:
- Mounted Infinity thermostat
- Connected all low-voltage wiring
- Started system and tested all modes
- Commissioned dual fuel switchover settings
- Measured and verified airflow (1,600 CFM)
- Trained homeowners on operation
The Results: A Transformed Oakland Hills Home
Before vs. After Comparison
| Aspect | Before (Floor Furnace) | After (Dual Fuel + Ducts) |
|---|---|---|
| Heating efficiency | ~55% AFUE | 300%+ COP (heat pump) / 96% AFUE (furnace) |
| Rooms heated | 1-2 rooms | All 6 rooms evenly |
| Air conditioning | None | Yes, 22-24 SEER2 |
| Air filtration | None | MERV 10 whole-home |
| Temperature consistency | ±8°F swings | ±0.5°F consistency |
| Monthly heating cost | $250+ | ~$100 estimated |
| Safety | Open flame hazard | Sealed combustion, no exposed flame |
| Noise level | Loud ignition | Whisper-quiet operation |
Homeowner Feedback
Two weeks after installation, Jennifer shared her experience:
“The difference is incredible. For the first time ever, our bedrooms are actually warm in the morning. Our daughter can walk around the house without her feet getting cold. And the AC during the October heat wave was a lifesaver. We should have done this years ago.” — Jennifer M., Oakland Hills
Energy Cost Projections
Based on the home’s characteristics and PG&E rates:
Before (floor furnace only):
- Annual heating: ~$2,400 (inefficient floor furnace running constantly)
- Annual cooling: $0 (no AC, but suffered during heat waves)
- Total: ~$2,400
After (dual fuel system):
- Annual heating: ~$600 (heat pump) + ~$150 (furnace backup) = $750
- Annual cooling: ~$300
- Total: ~$1,050
Estimated annual savings: $1,350
Comfort Improvements
- Every room heated and cooled – No more cold bedrooms
- Consistent temperatures – Variable-speed maintains ±0.5°F
- Whisper-quiet operation – Hear the birds, not the HVAC
- Clean air – MERV 10 filtration removes dust, pollen, and allergens
- No more cold floors – Heated air distributed from ceiling registers
Why Oakland Hills Homes Need Central HVAC
Oakland Hills presents unique challenges that make central HVAC especially beneficial:
Oakland Hills Climate Factors
Morning fog: The Oakland Hills regularly experience dense morning fog that keeps temperatures in the 40s until late morning. A floor furnace can’t keep up—by the time it warms the living room, the bedrooms are still freezing.
Afternoon warmth: Once the fog burns off, Oakland Hills can be significantly warmer than flatland Oakland. Without AC, homes become uncomfortably hot.
Temperature swings: 30°F daily temperature swings are common. Variable-speed systems handle this gracefully; floor furnaces cannot.
Fire season considerations: During wildfire season, whole-home filtration is critical. Floor furnaces provide zero air filtration. Our Carrier system with MERV 10 filter captures smoke particles during poor air quality days.
Oakland Hills Home Characteristics
Most Oakland Hills homes share characteristics that make them ideal candidates for HVAC upgrades:
- Built 1940s-1970s – Era when floor furnaces were standard
- 2,000-3,000 square feet – Large enough to need central distribution
- Hillside construction – Often have crawl spaces or basements suitable for equipment
- High ceilings – Variable-speed systems excel at mixing stratified air
- Quality construction – Worth investing in proper HVAC
Floor Furnace Replacement Cost in Oakland Hills
For Oakland Hills homeowners considering a similar upgrade, here’s what to expect:
Typical Investment Range
Complete system with new ductwork: $20,000 - $30,000
This includes:
- High-efficiency heat pump or dual fuel system
- New ductwork throughout the home (6-8 supply runs)
- All electrical and gas connections
- Permits and inspections
- Removal and disposal of old floor furnace
Factors That Affect Cost
Lower cost:
- Single-story home (easier duct routing)
- Accessible attic space
- Existing electrical capacity
- Standard system sizing (3-4 tons)
Higher cost:
- Multi-story home (more complex duct routing)
- Limited attic access
- Electrical panel upgrade needed
- Larger home requiring 5+ ton system
Available Rebates and Credits
Oakland Hills homeowners can offset costs with:
- Federal tax credit: Up to $2,000 for heat pump systems
- PG&E rebates: Energy efficiency incentives
- BayREN programs: Additional local rebates
- Financing: 0% interest available for qualified buyers
Jennifer and Mark received $2,000 in federal tax credits, bringing their net investment down significantly.
Is a Floor Furnace Replacement Right for Your Oakland Hills Home?
Consider upgrading from your floor furnace if you experience:
✅ Uneven heating – Some rooms cold while others are warm
✅ High energy bills – Floor furnaces are notoriously inefficient
✅ Safety concerns – Open flame with children or pets
✅ No air conditioning – Suffering during heat waves
✅ Poor air quality – No filtration in current system
✅ Planning to stay – Investment pays back over 5-7 years
Not ready for full replacement? We also offer:
- Floor furnace repair and maintenance
- Portable AC solutions for temporary cooling
- Wall heater installation as an intermediate step
Why Choose Bay Area Climate Control for Oakland Hills HVAC
Oakland Hills Experience
We’ve completed 50+ floor furnace replacements in Oakland Hills, Montclair, Rockridge, and surrounding neighborhoods. We understand:
- Oakland Hills building codes and permit requirements
- Optimal duct routing for hillside homes
- Equipment placement challenges on sloped lots
- The specific climate needs of Oakland Hills microclimates
Carrier Factory Authorized Dealer
As a Carrier Elite Dealer, we offer:
- Access to premium Infinity series equipment
- Extended warranty options
- Factory-trained technicians
- Direct Carrier support for complex installations
Comprehensive Service
- Free in-home estimates with Manual J load calculation
- Permit handling included
- Financing available with 0% interest options
- Lifetime workmanship warranty
Ready to Replace Your Oakland Hills Floor Furnace?
If you’re tired of cold bedrooms, high energy bills, and an outdated heating system, let’s talk about upgrading to modern central HVAC.
We’ll provide:
- Free in-home assessment
- Custom ductwork design for your home
- Multiple equipment options and pricing
- Rebate and tax credit assistance
- Detailed written quote
📞 Call us today: (510) 391-5597
Serving Oakland, Oakland Hills, Montclair, Rockridge, Berkeley, Piedmont, and all East Bay communities.
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