How long do Intertherm HVAC systems last?

Most Intertherm air conditioners and heat pumps run 12 to 16 years, while Intertherm furnaces typically last 15 to 20 years when serviced annually. After about year 12 the cost of repairs tends to climb and efficiency drops noticeably compared with a current SEER2-rated unit.

Should I repair or replace my old Intertherm unit?

A common rule of thumb: multiply the repair cost by the age of the system. If that number is over $5,000, replacement usually makes more financial sense. Intertherm systems older than 12 years that still use R-22 refrigerant are particularly strong replacement candidates because R-22 has been phased out and recharging it has become very expensive.

Intertherm HVAC Age Lookup Tool

Made by Nortek for manufactured and mobile homes, Intertherm covers HUD-code furnaces, air conditioners, and heat pumps. The manufacturing date helps you plan maintenance and judge when a replacement makes sense. Decode your Intertherm serial number, free and without an account, to see the manufacturing date and system age.

Selected Brand

Intertherm HVAC System

Change

2Enter Your Serial Number

Affiliate Partner

Need an HVAC pro? Get free quotes from trusted local HVAC contractors

Get Quotes Are you an HVAC contractor? Learn about our partner program

Affiliate Partner

Protect your HVAC system and 20+ home systems with a home warranty

Get a Free Quote

Finding Your Intertherm Serial Number

Check these four spots on your HVAC system

Common Locations

Outdoor unit

data plate on the side

Electrical panel

inside the access door

Indoor air handler

inside the cabinet door

Rating plate

top or rear of the unit

What to Look For

White or metallic manufacturer sticker
Labeled "Serial No." or "S/N"
Typically 8–12 characters long
Usually near the model number

Can't find it? Try the electrical access panel on the front of the outdoor unit or inside the air handler cabinet.

Serial Number Examples

Intertherm

FGA030310579G6R9905-05028

Two serial styles; positions 4-7 = two-digit year then month

Don't worry if yours looks different — each brand has multiple formats and our system can decode most variations.

About Intertherm HVAC Systems

Owned by Nortek Global HVAC

Intertherm is Nortek's brand for manufactured and mobile homes. The line focuses on electric and gas furnaces, air conditioners, and heat pumps sized and certified for HUD-code housing, where space and airflow requirements differ from site-built homes.

Intertherm uses two Nortek serial styles. The common style has a three-character prefix, then a two-digit year in positions 4 and 5 and a two-digit month in positions 6 and 7. A second style starts with a letter, a digit, and another letter, then the year and month, like G6R9905-05028 for May 1999.

Common Intertherm HVAC Models & Series

The most-installed Intertherm residential systems on the market today, organized by tier. Knowing your series helps narrow down service parts and warranty terms.

Series	Type	Tier	Efficiency	Notes
M1 Series Electric Furnace	Electric Furnace	Entry	Electric resistance	Downflow electric furnace built for manufactured homes.
MGHA Series Gas Furnace	Gas Furnace	Entry	Up to 80 AFUE	Sealed-combustion gas furnace for mobile homes.
Manufactured-Home Air Conditioner	Air Conditioner	Entry	Up to 14 SEER2	Single-stage condenser matched to mobile-home air handlers.
Manufactured-Home Heat Pump	Heat Pump	Entry	Up to 14 SEER2	Single-stage heat pump for HUD-code homes.

Intertherm HVAC Quick Facts

Warranty

Intertherm equipment generally carries a 10-year parts warranty with registration. Mobile-home installs sometimes have terms set by the home manufacturer or retailer, so it is worth confirming coverage with the original seller.

Expected Lifespan

AC / Heat pumps: 12 to 16 years
Furnaces: 15 to 20 years

Where It's Built

O'Fallon, Missouri, on Nortek Global HVAC's shared production lines.

Price Positioning

Budget tier, positioned for the manufactured-home market.

Known Intertherm Issues to Watch For

A short list of patterns reported on Intertherm equipment. Most have been addressed with revised designs or service bulletins, but they're useful context if you're diagnosing an older system.

•Manufactured-home equipment is sized for specific cabinet and duct setups, so replacement parts and matched components should be ordered for the mobile-home line rather than site-built models.
•Older Intertherm electric furnaces use sequencers and elements that are common wear items and inexpensive to replace.
•Service literature is sometimes filed under Nordyne or Miller, the sister mobile-home brand.

Intertherm HVAC FAQs

Look for the data plate on the furnace or air handler cabinet inside the home, and on the side of the outdoor condenser. Both serial styles place the year and month in positions 4 to 7.