Heating installation: what to know

What the job involves, what changes the price, and what to ask a pro.

What heating installation is

Heating installation puts in a new furnace, boiler, heat pump or other heat source, along with its venting, controls and a safety test. People need it when an old system cannot be repaired economically, when a home is remodeled, or when the old system no longer heats the house evenly.

Signs you need it

  • The system keeps failing and the parts for it are hard to find.
  • Some rooms never reach the set temperature, even after the registers are adjusted.
  • There is rust, soot or water at the base of the furnace or boiler.
  • Gas use rises while heat output falls, or the burner flame looks yellow or lifts off the burner.
  • You are adding a heat source during a remodel, an addition, or a change from oil to gas or electric.
  • The old unit is a different size or type than the ductwork was designed for.

What the pro does

  • Run a load calculation for the home to size the new unit, and inspect the ductwork and the venting route.
  • Remove the old unit, disconnect the gas, oil or electric supply, and recover refrigerant as a certified technician if the system holds any.
  • Set the new unit, connect the supply and return ducts, the flue or vent, the condensate line where it applies, and the gas line or electrical circuit.
  • Wire the thermostat and set the control board for the new equipment.
  • Perform the start-up test: combustion readings for gas or oil, temperature rise across the heat exchanger, airflow and the safety shutoffs.
  • Walk the homeowner through the thermostat, the filter and the maintenance schedule.

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Fuel type and the new heat source, since gas, oil, electric, heat pump and boiler systems each need different equipment and connections.
  • The size the home needs, set by a load calculation rather than by the old unit.
  • Ductwork condition, including whether ducts can be reused or need resizing or sealing before the new unit goes in.
  • The venting route, and whether a new flue liner, vent pipe or chimney work is needed.
  • Gas line or electrical service upgrades needed to support the new equipment.
  • Access to the installation space, such as a tight attic, a crawl space or a basement with a narrow door.
  • Added features such as zoning, humidifiers, air cleaners or smart controls.

What a written quote should spell out

  • The model and size of the new unit, with the load calculation it is based on.
  • Removal and disposal of the old unit, including any refrigerant recovery.
  • Duct repairs, sealing and any new supply or return runs, listed separately.
  • Venting materials and the gas or electrical work needed to connect the unit.
  • The start-up test, with the readings recorded in writing.
  • Warranty terms for the equipment and for the installation work.

Questions to ask before you hire

  • How did you calculate the size of the new unit, and can you show me the load calculation for my home?
  • Will you inspect the existing ductwork and tell me what needs sealing or resizing before the new unit runs?
  • Who pulls the permit, and will the installation be inspected?
  • What venting will you use, and does it fit the existing chimney or wall penetration?
  • Which parts of the job will your own crew do, and which will be subcontracted?
  • What start-up readings will you give me in writing?
  • Who handles a warranty claim, the manufacturer, the installer or both?

Red flags

  • The pro sizes the new unit to match the old one without a load calculation.
  • The pro wants to skip the permit, the inspection or the duct check to save time.
  • The pro cannot explain what venting the new unit needs or how it will connect.
  • The quote leaves out removal, disposal or refrigerant recovery.

What you can do yourself

Clear the space around the old unit, move stored items, and make sure the installer can reach the ductwork, attic or crawl space. Write down the model and serial numbers of the old equipment and keep the warranty paperwork. Gas, electrical, venting and refrigerant work belong to a licensed technician.

Licenses and permits

Heating installation is commonly done under a contractor license, and it often requires a permit with an inspection, especially for gas and venting work. Check with your state or local licensing agency for the rules that apply to your installation.

Heating installation questions

How long does a heating installation take?

A like-for-like replacement in a home with sound ductwork is often finished in a single work day. Added ductwork, new venting or gas line work extends the schedule. Ask the installer for a timeline that lists each step.

Should I replace the ductwork when I replace the furnace?

Not always. Ducts that leak, are undersized or are dirty can waste much of what the new system produces. Ask for a duct inspection with the quote so you can decide with the facts in front of you.

Can I keep my old thermostat?

Sometimes. Older thermostats may lack the wires or control signals the new system needs. Ask the installer to confirm compatibility before you keep it.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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