Furnace Replacement Cost in Florida: What Drives It

First, find out what kind of furnace you have

Before you compare quotes, find out what the quote is for. One electric furnace manual, printed in 2000, covers an E2 series that is also labeled an air conditioner and heat pump air handler. Our reading: an electric furnace on an estimate may be the indoor unit of the cooling system, so ask which part is being replaced. Gas furnace vs electric strip heat covers how the two make heat. Central heating in Florida homes covers the options for Florida homes. Furnace types and efficiency explains the furnace types and the ratings used to compare them.

A gas furnace also needs gas service at the address. Peoples Gas, a Florida natural gas utility with pages for Tampa and Saint Petersburg, offers a ZIP code check for service. Even when the check matches, its result asks the customer to call to see whether service reaches the neighborhood. Our reading: a ZIP code match is a first check, and the utility that serves your address has the final answer.

Repair or replace: what the public sources say

ENERGY STAR also lists rooms that are too hot or too cold, but says improper equipment operation, duct problems or inadequate insulation could be the cause. A DOE Building America study removed nine gas furnaces, with 15 to 24 years of field service, from Iowa homes and tested them in a lab. AFUE stands for annual fuel utilization efficiency. It is a gas furnace's efficiency rating: roughly, the share of the fuel's heat that becomes heat for the house. Measured efficiency was close to the rated AFUE, which the study took to mean that performance did not significantly decrease over 15 to 24 years. It concluded that rated AFUE is a good guide to a furnace's performance throughout its life, if it is installed per the maker's instructions. Our reading: nine furnaces cannot show how yours is doing, but they suggest that age alone is a weak sign of lost efficiency. Our reading: at 15 years, ask for an inspection and a written explanation, because age alone is not proof that replacement is due.

Some signs are about safety, not age: EPA lists leaking chimneys and furnaces, and back-drafting from furnaces, among the sources of carbon monoxide in homes. Carbon monoxide is an odorless, colorless and toxic gas, so you cannot rely on noticing it. The DOE guideline lists three problems: a failed vent system, a blocked masonry chimney and a sounding carbon monoxide alarm. For any of them, it says to shut down the equipment, ventilate the house and contact a service technician immediately. A furnace that will not light is a different problem, and furnace won't ignite covers it along with what to do if you smell gas.

Peoples Gas says to have a gas heating system checked by a professional every year before cold weather arrives. Our reading: the yearly check is a natural time to ask the technician about the furnace's condition and about replacement. AC repair or replace: a framework for deciding weighs age, repair history and comfort for cooling equipment.

Gas, electric or heat pump: what each choice adds to the job

The DOE guideline names electric heat pumps and combined heating and hot water systems as alternatives that use the same ducts as a gas furnace. Heat pump vs furnace covers how to choose, so this section covers only what each choice adds to the job.

• Gas furnace: the DOE guideline lists sizing, ducts, gas piping, vents, combustion air, condensate, electrical connections, cooling, filters and humidifiers as details to get right.
• Electric furnace: our reading is that it has no burner, so the gas, vent and condensate items do not apply, but the power supply does. The maker's manual says some local codes require licensed personnel for installing and servicing this type of equipment.
• Heat pump: it replaces the furnace with refrigerant equipment. EPA requires technicians who work on equipment that could release refrigerants to be certified under Section 608. Heat pumps in Florida and EPA 608 certification and the refrigerant rules cover those two subjects.

What drives furnace replacement cost, item by item

The DOE guideline lists six things that make the installed cost of a high-efficiency furnace vary. They are an existing cooling system, a humidifier, an air cleaner, a filter box, the distance to the vent end and where the condensate drains. Our reading: the list is about high-efficiency gas furnaces, but the items below are worth looking for on any furnace estimate.

• The vent: if another appliance shares the furnace's vent, the guideline says that appliance's vent must be reviewed after the furnace is removed. It adds that exterior masonry chimneys will need relining, and that overlooking vent changes will underestimate the cost of the replacement. A Carrier manual warns that when a furnace is replaced, the old vent may be the wrong size for appliances still attached to it.
• The condensate drain: high-efficiency furnaces produce condensate, which is water that forms as the exhaust gases cool. The guideline says the installer should look for a gravity drain below the furnace's condensate trap. Without one, a condensate pump can carry the water to a higher drain.
• The ducts: the guideline says replacing a furnace commonly requires changes to the duct connections for the new furnace's height and depth. Duct leaks and airflow are covered in ductwork in Florida.
• The cooling coil: if the home has central air conditioning, the DOE guideline says to consider the existing coil when it stays in place. The evaporator coil explains the part.
• The gas supply: Peoples Gas says most customer-owned piping is designed, permitted, installed and inspected under local building codes. It also says Florida soil can corrode metal piping and cause leaks over time, and it advises periodic inspection of underground piping. Our reading: on a home with buried gas piping, ask whether it has been inspected before a new gas appliance depends on it.
• The power supply: for an older electric furnace, its maker says to have a qualified serviceman inspect all furnace components and field wiring before each heating season. Our reading: the condition of the supply wiring is a fair question to ask before an older electric furnace is replaced.
• Permit and inspection: who pulls the permit, and why the rules differ by county, are covered in HVAC permits in Florida.

What a replacement involves, in order

The DOE guideline says to inspect the home before installing the equipment, and its field inspection has seven steps. They cover safety, combustion air, where the vent exits, the condensate drain and clearance to combustible material. They also cover other appliances on a shared vent, and the seventh step covers attics where freezing can occur. The guideline lists twelve basic installation steps, from removing the existing furnace to testing per the maker's instructions. In between, the new furnace goes in and the ducts, gas piping, condensate drain, wiring and thermostat are connected.

At start-up, the guideline says to check that the furnace's temperature rise and gas input rate match the maker's installation instructions. Temperature rise is how many degrees the air warms as it passes through the furnace. Gas input rate is how much gas the burners are set to use. The lab study called setting the furnace on rate and tuning the fan to the maker's rise range the two most significant factors in good performance. The guideline's test steps also cover leaks in the gas lines and vent, and the performance of the high limit and pressure safety switches. A Carrier manual says improper installation, service or use can cause carbon monoxide poisoning, explosion, fire or electric shock. Our reading: these checks belong to trained people, and this page lists them only so you know what to expect. The matching readings for the cooling side are in AC installation done right: evacuation, charging and commissioning.

Who should do the work, and how to check the license

The DOE guideline says installation should be performed by a trained and qualified contractor. The Carrier manual says only trained and qualified personnel should install, repair or service heating equipment. The electric furnace manual says some local codes require licensed personnel for installing and servicing that type of equipment. In Florida, the Construction Industry Licensing Board licenses contractors under Chapter 489 of the Florida Statutes. The state licensing agency says that to verify a contractor you need the license number, the contractor's name or the business name. Its website, MyFloridaLicense.com, has a Verify a License search.

What to ask and check before you sign

These six questions come from the sources above.

1. Did you inspect the vent, the drain, the ducts and the cooling coil before pricing the job? ENERGY STAR says the contractor should spend significant time inspecting your current system and home to assess your needs.
2. How was the furnace size chosen? ENERGY STAR says the contractor should use the actual characteristics of your home and not just a rule of thumb. AC tonnage and sizing in Florida explains the load-calculation idea for cooling.
3. Are the vent, drain, duct and coil changes written as separate lines, with model numbers, the job schedule and warranty information? ENERGY STAR advises getting itemized estimates in writing and signing a proposal that lists costs, model numbers, the job schedule and warranty details.
4. Who pulls the permit, and who makes the gas or electrical connection? Ask for both answers in writing.
5. Will the start-up record the temperature rise and the gas input rate against the maker's range, and will you leave me the readings? The DOE guideline lists both as start-up checks.
6. Is the license number on the proposal, and does it check out in the state's license search? The state licensing agency says you need the license number, the contractor's name or the business name to verify a license.

Our reading: a one-line estimate cannot be compared with one that lists the work, so ask for the lines before choosing.