How Does a Heater Work? A San Jose Homeowner’s Guide

Quick Answer: A heater works by converting energy into heat and distributing it throughout your home. Gas furnaces burn natural gas to create warmth, electric heaters use resistance coils like a toaster, and heat pumps transfer existing heat from outside air—making them 2-4x more efficient than traditional systems. For San Jose’s mild climate, heat pumps are increasingly the smart choice.

 

Heat pump along side of house in backyard of home in Silicon Valley, California.

Understanding Your Home Heating Options

If you’re a San Jose homeowner, knowing how your heating system works isn’t just about comfort—it affects your energy bills, indoor air quality, and alignment with California’s clean energy goals. Let’s break down the three main heating technologies and why your choice matters more than ever.

 

How Gas Furnaces Work

Gas furnaces are the most common heating system in Bay Area homes, and they’re straightforward workhorses.

The Basic Process:

  • Your thermostat detects the temperature drop and tells the furnace to start
  • Modern furnaces use electronic ignition to light the burners (older models have pilot lights)
  • Flames heat metal chambers to 140-170°F, keeping combustion gases separated from breathable air
  • A blower motor pulls cool air from your home through return ducts
  • Cool air passes over the hot heat exchanger, warming to 120-140°F, then flows through supply ducts to your rooms
  • Combustion gases exit through the flue pipe to outside

Efficiency Ratings:

  • Standard: 80% AFUE (Annual Fuel Utilization Efficiency)
  • High-efficiency: 95-98% AFUE
  • California minimum: 80% AFUE

Pros:

  • Fast, powerful heating
  • Lower cost than electric resistance
  • Works in any weather
  • Familiar technology

Cons:

  • Produces carbon monoxide (requires annual safety inspection)
  • Greenhouse gas emissions
  • Not aligned with California’s electrification goals
  • Shorter lifespan (15-20 years)

 

San Jose Reality: While gas furnaces remain common, California’s push toward carbon neutrality means they’re becoming less favored. New rebates and regulations strongly encourage alternatives.

 

How Electric Heaters Work

Electric heating is the simplest technology—it converts electricity directly into heat using resistance coils.

The Basic Process:

  • Current passes through high-resistance wire coils (like a toaster)
  • Resistance creates heat (up to 1,500°F at the element)
  • A blower pushes air across the hot coils
  • Warm air flows through ducts or directly into the room

Types of Electric Heating:

  • Electric furnaces (central systems with ductwork)
  • Baseboard heaters (individual room units)
  • Wall heaters (mounted units, often in bathrooms)
  • Radiant floor heating (cables embedded in floors)

The Efficiency Paradox:

  • Electric heating is 100% efficient at converting electricity to heat—but electricity costs 3-4x more per BTU than natural gas in California. So while the conversion is perfect, the operating costs are high.

Pros:

  • No combustion = no carbon monoxide risk
  • No venting required
  • Lower installation costs
  • Minimal maintenance
  • Can be powered by solar panels

Cons:

  • Expensive to operate (highest utility bills)
  • Slower heating response
  • Less comfortable (drier heat)

 

San Jose Sweet Spot: Electric resistance makes sense for supplemental heating in specific rooms or if you have solar panels. For whole-home heating, there’s a much better electric option: heat pumps.

 

How Heat Pumps Work: The Game-Changer

Heat pumps are revolutionizing home heating in California—and they work completely differently than furnaces.

The Revolutionary Difference:

Heat pumps don’t create heat—they move it. Even when outdoor air feels cold at 40°F, it contains usable heat energy. Heat pumps extract this existing heat and concentrate it indoors.

The Basic Process:

  • Refrigerant in the outdoor coil absorbs heat from outside air (yes, even cold air contains heat)
  • Liquid refrigerant absorbs heat and becomes a gas
  • The compressor squeezes the refrigerant, raising its temperature to 130-140°F
  • Hot refrigerant flows to your indoor unit, releasing warmth as it condenses back to liquid
  • Your air handler circulates warm air throughout your home
  • The process continues until you reach your target temperature

 

In Summer: A reversing valve simply flips the process, making your heat pump an air conditioner. One system, year-round comfort.

 

Why Heat Pumps are 200-400% Efficient:

This seems impossible, but heat pumps don’t create energy—they move it. Moving heat requires far less energy than generating it.

Example:

  • 1 kWh of electricity through electric resistance = 3,412 BTUs
  • 1 kWh of electricity through a heat pump = 8,000-15,000 BTUs

 

Types of Heat Pumps:

 

Air-Source Heat Pumps (most common)

  • Extract heat from outdoor air
  • Work efficiently down to 25-35°F (newer models to -15°F)
  • Perfect for San Jose’s mild winters

Ductless Mini-Splits

  • No ductwork required
  • Wall-mounted indoor units
  • Ideal for older homes or additions
  • Ultra-quiet and efficient (SEER 20-30+)

Pros:

  • Lowest operating costs (2-4x more efficient)
  • Dual heating and cooling
  • Zero combustion = perfect indoor air quality
  • No carbon monoxide risk
  • Federal tax credits up to $2,000
  • California rebates up to $3,000+
  • Longer lifespan (20-25 years)
  • Quieter operation

Cons:

  • Higher upfront cost ($6,000-12,000 vs. $3,000-6,000 for gas)
  • May require electrical service upgrade
  • Slightly reduced efficiency in extreme cold (not an issue in San Jose)

 

Why Heat Pumps Are Perfect for San Jose:

 

  • Mild winters (rarely below 40°F = optimal heat pump conditions)
  • Need both heating and cooling year-round
  • Pair beautifully with solar panels
  • Aligned with California’s clean energy future

 

What About Oil Furnaces?

Oil furnaces are extremely rare in San Jose and California. They burn heating oil stored in an on-site tank and require regular fuel deliveries. While common in the Northeast, they’re impractical here due to:

 

  • No fuel delivery infrastructure
  • Higher costs than gas or electricity
  • Environmental concerns
  • California’s clean energy policies

 

Still Curious About Your Heater? We’ve Got Answers!

Can I switch from gas to a heat pump?

Yes! Most homes with ductwork can easily transition. Ductless mini-splits work for homes without ducts. We’ll assess your electrical service and recommend the best approach.

 

How often should I maintain my heating system?

Annual professional maintenance is essential. Best timing: September-October before heating season. Our ProPlan program includes comprehensive inspections, cleaning, and safety testing.

 

Are there rebates for heat pump installation?

Yes—significant ones! Federal credits ($2,000), California rebates ($3,000), and utility incentives can total $3,000-6,000+. We help navigate all available programs.

 

Not Sure How a Heater Works? Leave it to Us

 

Ready to explore heat pump options, improve your indoor air quality, or schedule maintenance? Call us today for a free consultation. Our expert technicians will assess your home and help you choose the heating solution that’s right for your comfort, budget, and values.

Let’s make your home more comfortable, efficient, and sustainable—together.