Air purifier and humidifier installation: what to know

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

What air purifier and humidifier installation is

Air purifier and humidifier installation adds whole-home air cleaners or humidifiers to the HVAC system. The work ties the unit into the ducts, the water line and the electrical controls so the treated air reaches every room, and the humidity level stays where you set it.

Signs you need it

  • The air feels dry in winter, you get static shocks, or wood floors and trim gap or crack.
  • Windows fog up or the air feels damp in the house, and you want a way to control it.
  • Dust, pet dander or smoke linger in the house even after the filter has been changed.
  • Someone in the home has allergies or asthma that flare up at home.
  • A portable unit is too small or noisy for the house, and you want the system to do the work.
  • The old humidifier has stopped working, is leaking or has built up mineral scale.

What the pro does

  • Choose the location on the supply side or the return side of the furnace or air handler, and check the ductwork for a clean connection point.
  • Mount the purifier or the humidifier bypass housing, and cut the duct opening to fit it.
  • Run the water supply line and the drain line for a humidifier, with a shutoff valve and a drain that carries the water away.
  • Connect the power and the control wiring to the furnace or air handler, and set the humidistat or the control settings.
  • Install the media or electronic cell, and check the airflow across the purifier or humidifier pad.
  • Test the system through a heating and cooling cycle and show the homeowner how to change the pad, the cell and the filter.

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Every job is different, so we do not publish prices.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.

  • Unit type, such as a media cabinet, an electronic air cleaner, a UV lamp, a steam humidifier or a bypass humidifier.
  • Whether the unit must be installed on a new duct opening or on an existing one.
  • Water supply access and whether a new line or a shutoff valve is needed.
  • Drain route for the humidifier, and whether a drain pump is required.
  • Electrical work, such as a new circuit or a control connection to the furnace.
  • Furnace or air handler type, which changes where the unit can mount and how airflow is affected.
  • Whether the system needs a larger blower or ductwork changes to keep the airflow right.

What a written quote should spell out

  • The unit model and type, with the cleaning or humidifying capacity listed.
  • The mounting location and the duct opening work.
  • The water supply and drain work, listed as separate lines.
  • Electrical and control connections, including any new circuit.
  • Replacement pads, cells or filters needed in the first year.
  • Warranty on the unit and the installation work.

Questions to ask before you hire

  • Where will the unit mount, and how will it affect the airflow of my system?
  • Will the humidifier tie into a water line I can shut off, and where does the drain go?
  • Will you connect the controls to the furnace or air handler, and set them up for my climate?
  • How often do the pads, cells or filters need changing, and what do they cost to replace?
  • Will you check the airflow after the install and tell me the result?
  • Who pulls the permit, if one is needed, and will the work be inspected?
  • What does the warranty cover on the unit and on the installation?

Red flags

  • The pro uses a saddle valve to tap the water line instead of a proper shutoff.
  • The pro mounts the humidifier so that its drain has no route away from the system.
  • The pro does not check the airflow after the unit is in.
  • The pro sells a whole-home unit without testing the house and the system first.

What you can do yourself

You can change the filter, replace the humidifier pad when the manufacturer's schedule calls for it, and clean the water tray with the power off. Do not cut into the ducts, tap the water line or wire the unit to the furnace controls. Installation, the water and drain connections, and the electrical connections belong to a licensed technician.

Licenses and permits

Air purifier and humidifier installation is commonly done by licensed HVAC contractors, and water and electrical connections may need separate licensed trades. Check with your state or local licensing agency for the requirements that apply to your installation.

Air purifier and humidifier installation questions

Should a whole-home humidifier be on the supply or the return?

It depends on the system. Installers choose the spot where the humidified air mixes well and the unit can be serviced. Ask the installer to show you where it goes and why.

How do I know the humidity is right?

A humidistat or a whole-home humidity sensor shows the level. A reading that is too high can cause condensation and mold, and one that is too low can dry the air and the wood.

Do air cleaners slow the furnace down?

They can, if the filter or the cell is restricted or the airflow is wrong. A technician checks the airflow across the unit before the install is finished.

Can I use a portable air purifier instead?

Yes, for a single room. A whole-home unit treats the air as the system moves it through the house, so it covers more space but depends on the system running.

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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