Does a Furnace Installation Require a Building permit?

There really is one reason to skip the building permit and that reason is to skimp on materials and skimp on labor.

Do I need a building permit to install a replacement furnace?

In order to install a furnace replacement a Mechanical permit is required. A plumbing permit maybe required and an electrical permit may also be required depending upon what needs to be performed and the local regulations.

In the Uniform Mechanical Code Book under the first section this is the terminology used for when a permit is required:

Section 112.1
Permits Required. Except as permitted in Section 112.2, mechanical system regulated by this code shall be installed, altered, repaired, replaced, or remodeled unless a separate mechanical permit for each separate building or structure has first been obtained.
112.2                     Exempt Work. A mechanical permit shall not be required for the following:
112.2.1                  A portable heating appliance…
112.2.2                  A closed system of steam, hot, or chilled water within the heating or cooling equipment regulated by this code.
112.2.3                  Replacement of any component part or assembly of an appliance that does not alter its original approval and complies with other applicable requirements of this code.

Why is a permit required to change out a furnace?

The reason is very simple. In order to ensure that you have a safe up to code installation and have the correct furnace for your application. The vast majority of problems that furnaces have over the years are directly related to the installation being faulty. This isn't to say that all installations are faulty, but studies show that the majority of furnace installations are subpar.

Check out the video to the right

This installation was filmed by Tim in the attic of a home. The video quality is poor, but you can definitely see that whoever installed this furnace really didn't care about following safety rules and also didn't care whether or not the homeowners were comfortable. As a result of this poor installation the inducer draft motor broke in half due to stresses from the vent pipe. This could have caused carbon monoxide poisoning.

The current fine for failing to obtain a permit for the installation of a furnace is up to $5,000 and double permit fees. It really isn't worth it when you consider that a properly installed furnace will operate longer and with less problems than a furnace that is not installed properly.