What are the building code requirements for installing an appliance (furnace, air handler, water heater) in the attic?

Sunday, June 17, 2018

When an appliance like a water heater or air handler is placed in an attic, there is a potential safety risk for the living space below the appliance due to water leakage. Also, a person entering the attic to service any appliance must be able to get to it safely, and then be able to work around the appliance on a stable surface. Here’s how the Residential Edition of the Florida Building Code (FBC M1305.1.3) and the International Residential Code (IRC) address these safety issues: 

  •  There must be an attic access opening large enough to remove the appliance, but not less than 30 inches by 22 inches, and a clear passageway not less than 22 inches wide by 30 inches high.
  •  The passageway from the appliance to the opening must be unobstructed and large enough to remove the appliance, with continuous solid flooring a minimum of 24 inches wide and maximum of 20 feet long. There are two exceptions to the passageway requirements. The passageway floor is not necessary if the appliance can be serviced from the attic access opening and, when the passageway to the appliance is unobstructed and not less than 6 feet high and 22 inches wide for its entire length, it can be as long as 50 feet.
  • There should be a level floor in front of the service side, or sides, of the appliance a minimum of 30 inches by 30 inches.
  • A luminaire (light fixture) and receptacle must be installed near the appliance. The luminaire should be controlled by a switch near the attic access opening.

    The Energy section of the FBC has specs for installation of an air handler in the attic that are a little more restrictive than the general appliance requirements, such as that the passageway can only be a maximum of 6 feet long, a warning sticker is required, and a catch pan with drain or automatic shut-off/warning is necessary (FBC 403.3.6).  Also, a catch pan with drain piping is required is required under an attic water heater (FBC P2801.1), and the TPR valve must drain into the pan or to and exterior location (FBC 2803.1.6).

• • • • • • • • • • • • • • • • • • • • • • • • • • • • 

Here’s links to a collection of our blog posts about ATTICS:

What are the mistakes to avoid when doing attic improvements? 

What are the hazards to avoid when going into an attic? 

What is the most common type of roof-to-wall attachment? What are the building code requirements for installing an appliance (furnace, air handler, water heater) in the attic?

How do I safely remove a dead rodent (rat, mouse or squirrel) from the attic?

What are the common problems with attic insulation? 

Why is there no attic access hatch in the house?

How do I safely clean up rodent (rat, mouse or squirrel) urine or droppings the attic?

Why is there no attic access hatch in the house?

 Is an attic required to have a light by the building code? 

What is the building code requirement for an attic access hatch, scuttle, or door?

Why is vermiculite attic insulation a problem for both buyers and sellers of a home? 

What are the code requirements for NM-cable (nonmetallic-sheathed cable or Romex®) in an attic? 

What are the warning signs of a dangerous attic pull-down ladder?

Do home inspectors go on the roof? Do they get in the attic?

How much of a roof truss can I cut out to make a storage platform in the attic? 

• When was a fire separation in the attic first required between sides of a duplex? 

   Visit our APPLIANCES and ROOF AND ATTIC pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manfuactured and modular homes






Air Conditioner & Furnace Age/Size



Aging in Place


Click Below  

for Links

to Collections

of Blog Posts

by Subject


Doors and Windows


Energy Efficiency

Fireplaces and Chimneys

Heating and Air Conditioning

Home Inspection

Hurricane Resistance

Electrical Receptacle Outlets

Electrical Panels

Garages and Carports

Common Problems

Exterior Walls & Structures



Life Expectancy

Mobile/Manufactured Homes

Older and Historic Houses

Mold, Lead & Other Contaminants

Modular Homes

Metal Roofs



Pool and Spa

Roof and Attic




"Should I Buy A..."


Termites, Wood Rot & Pests

Structure and Rooms


Water Heaters

Water Heater Age

Septic Tank Systems

Plumbing Pipes


When It First Became Code

Park Model Homes

Shingle Roofs


Wind Mitigation Form

"Does A Home


"What Is The Difference Between..."


Concrete and Concrete Block


Rain Gutters


Crawl Spaces

Building Permits

Clay Soil




HUD-Code for Mobile Homes

Flat Roofs

Sprinkler Systems

4-Point Inspections

Frequently Asked Questions (FAQ)

Building Codes

Inspector Licensing

& Standards

Washers and Dryers



Electrical Wiring

Plumbing Drains and Traps

Smoke & CO Alarms

Top 5 results given instantly.

Click on magnifying glass

for all search results.