Central Heating in Florida Homes

What central heating means

An older Department of Energy fact sheet says furnaces and boilers are often called central heating systems because the heat is made in one place and then spread through the house. It describes a furnace as heating air and moving it through ducts with a blower, and a boiler as heating water to make hot water or steam that travels through pipes. Ducts are the channels that carry air from the equipment to each room, and a blower is the fan that pushes the air through them.

The Energy Information Administration (EIA) publishes independent statistics on energy, and its home surveys use three terms for central equipment.

• Central warm-air furnace: a central combustor or resistance unit makes the heat and sends warm air through ducts, and heat pumps are not counted here.
• Central heat pump: a heat pump that heats or cools an entire house or a large part of it, with warm or cool air carried through ducts.
• Steam or hot-water system: a boiler sends steam or hot water to radiators, baseboard units or heating pipes.

A resistance unit is a set of electric coils that heat up when current runs through them, so a furnace in this survey can be electric. An air handler is the indoor cabinet that holds the blower. Our reading: an air handler that heats only with electric strips fits that furnace definition. ENERGY STAR describes a ducted heat pump as a central air conditioner that also works in reverse to heat the whole house in winter.

What the 2020 federal survey found in Florida, next to the nation

EIA's 2020 Residential Energy Consumption Survey counted primary homes, which leaves out vacant, seasonal and second homes, and its Florida total was about 8.06 million. Here is each share of homes by main heating equipment, Florida first and then the whole country.

• Furnace: 33% in Florida, 60% nationwide.
• Central heat pump: 31% in Florida, 13% nationwide.
• Steam or hot-water boiler: none in EIA's Florida sample, 8% nationwide.
• Also uses secondary heating equipment: 19% in Florida, 42% nationwide.

EIA defines secondary heating as equipment used less often than the main heating equipment. The fuel side shows the same split: electricity is the main heating fuel in 66% of Florida homes against 34% nationwide, and natural gas in 5% against 51%. Counting every use of fuel in the home, 77% of Florida homes are all-electric, against 25% nationwide. All-electric means a home uses no natural gas, propane, wood, fuel oil or kerosene for any purpose.

These are survey estimates for the whole state in 2020, not counts of Tampa Bay homes, and EIA warns that differences between states may not be statistically significant. In plain terms, a small gap between two numbers can be survey noise, which is why this page reads 33% and 31% as about equal. EIA lists its 2024 state tables for space heating as due in spring 2027. Our reading: until then, the 2020 tables are the newest state figures for heating equipment. The table has no column for dual-fuel systems, which pair a heat pump with a furnace, so how many Florida homes have one is not reported. The central air conditioning guide reads the furnace and heat pump counts for what is paired with the air conditioner, so this page does not repeat that reading.

Why Florida looks different: very little cold

Heating degree days add up how far each day's average temperature falls below 65°F, and cooling degree days add up how far it rises above 65°F. NOAA's National Centers for Environmental Information 1991-2020 normals for Tampa International Airport (base 65°F) show about 433 heating degree days a year against about 3,928 cooling degree days. A normal here is an average over the 30-year span from 1991 to 2020, so it describes a typical year and not a cold snap. January has the lowest average temperature in those normals, with an average high of 71.3°F and an average low of 52.8°F.

The National Weather Service also tabulates days at or below 32°F in Tampa, with records that begin in 1890 and run through April 2024. Of the 134 winters in that table, 78 reached 32°F or lower at least once, the average winter had 1.7 such days, and the worst winter had 8. Our count from the same table: the ten winters ending in 2023-24 had three such days in all, spread over two winters. The table is for one station in Tampa, so it cannot say how often inland or coastal neighborhoods freeze.

ENERGY STAR's heat pump advice for climates where winter temperatures regularly dip below freezing is to talk to your contractor about a unit suited to your home. Our reading: with so few freezing days, that advice carries less weight in Tampa Bay than in a northern state. ENERGY STAR's furnace label also treats the southern half of the country separately, with its own logo for gas furnaces where homes require less heat.

Why the heat rides on the air conditioner and on electricity

ENERGY STAR says a central heat pump can use the ductwork a home already has to deliver heating and cooling. Our reading: a Florida house needs a large air conditioner, so it already has a blower, ducts and a thermostat, and the heat can share all three.

In EIA's 2020 data, homes exposed to the warmest temperatures all year were more likely to use electricity as their main heating fuel, or to report using no fuel for space heating. ENERGY STAR lists two points for heat pumps: no fuel storage or risk of running out of fuel, and no direct emissions from combustion. EIA's fuels table shows propane in use somewhere in 5% of Florida homes and natural gas in 16%. Our reading: a gas furnace needs a gas line or stored propane, so without either the choice narrows to a heat pump or electric heat strips.

Which setup you have decides where to read next

• Heat pump with an air handler: heat pumps in Florida covers humidity, salt air and flood height. Auxiliary heat and emergency heat explain the backup settings on the thermostat.
• Furnace, gas or electric: gas furnace vs electric strip heat compares making heat by burning fuel with making it from electric coils. Furnace types and efficiency covers the kinds of furnace and their ratings, and furnace replacement in Florida covers replacing one.
• Dual fuel: ENERGY STAR says a heat pump plus a gas or oil furnace lets you use each system where its costs and environmental benefits are best.
• Ductless heat pump: ENERGY STAR says it can heat and cool a portion of a house without ductwork, and ductless mini-splits explains how they work.
• Boiler with radiators: EIA's Florida sample shows none as main equipment, so this page goes no further into hot-water heat.

Questions to ask when choosing or replacing central heat

These questions work with any contractor's proposal, and the answers belong in writing.

1. Is there gas service at this address, and does the proposal compare a gas furnace, an electric furnace and a heat pump on the same terms?
2. What heating and cooling loads does a written load calculation give for this house, rather than a rule of thumb?
3. If the proposal is a heat pump, what supplies the backup heat, and when does the thermostat call for it?
4. If the proposal is a furnace, what fuel does it burn, how does it vent, and who inspects it each year?
5. Will the existing ducts be reused, and has anyone checked that they suit the new equipment?
6. Is the contractor's license number on the proposal, and does the state's license search show it?

ENERGY STAR says your contractor should verify the proper size using Manual J, a calculation of the heating and cooling your home needs.

Work that stays with licensed professionals

EPA recommends that a trained professional inspect, clean and tune up a central heating system, including furnaces, flues and chimneys, every year. The same EPA page says the Consumer Product Safety Commission recommends carbon monoxide alarms on each level of a home, outside each sleeping area. Under Section 608 of the Clean Air Act, technicians who service equipment that could release refrigerants must be certified, and heat pumps hold refrigerant. Furnace controls and electric heat strips carry household current, so this page gives no steps for opening, wiring or repairing any heating equipment. To check a Florida contractor's license, you need the license number, the contractor's name or the business name, and then you use the Verify a License option on MyFloridaLicense.com.