Best Gas Furnace Replacement in Marietta, GA
What to look for in Gas Furnace Replacement in Marietta
A gas changeout is permitted, combustion-safety work — not a like-for-like swap a handyman can do. We weight installers who pull the permit, size with an ACCA Manual J load calc, and commission the combustion with instruments over those quoting a tonnage rounded off the old unit.
- Combustion-safe install method. Provider names measured combustion (CO, draft, gas pressure) at commissioning and correct venting — the safety core of a gas changeout.
- Manufacturer authorization. Factory-authorized status preserves the furnace warranty and reflects factory training on the equipment.
- Manual J sizing. An ACCA Manual J load calculation right-sizes the furnace instead of copying the old (often oversized) equipment.
Verify before you book
- Whether a permit was actually pulled and the install inspected — confirm both before final payment.
- Whether combustion was measured at commissioning — ask to see the CO / draft / gas-pressure readings.
- License status with your state board — verify TDLR (TX), ROC (AZ), DBPR (FL), or your local equivalent before paying.
Gas Furnace Replacement in Marietta: licensing + combustion
A gas changeout is judged on the permit and inspection, an ACCA Manual J load calc, and measured combustion at commissioning — not a tonnage rounded off the old unit. Here is what each of the 3 installers below publishes: In Georgia, HVAC contractors hold a Conditioned Air Class I or II license through the Secretary of State — verify before signing.
Top picks
Casteel Heating, Cooling, Plumbing & Electrical★ Best for Gas Furnace Replacement
Consistently strong customer feedback (4.8★ from 10,410+ Google reviews; 2.1★ from 355+ Yelp reviews).
Google 4.8★ (10,410+)Yelp 2.1★ (355+)
Consistently strong customer feedback (4.9★ from 1,830+ Google reviews).
Google 4.9★ (1,830+)
Consistently strong customer feedback (4.9★ from 10,915+ Google reviews; 2.4★ from 165+ Yelp reviews).
Google 4.9★ (10,915+)Yelp 2.4★ (165+)
Typical Gas Furnace Replacement costs in Marietta, GA (2026)
Last updated
Estimated ranges for Marietta, GA. Actual cost varies with home size, equipment, and scope — always request a written quote for your job.
| Service | Typical range |
|---|---|
| Full gas furnace replacement (80% AFUE, installed) | $2,650–$5,700 |
| Gas line / electrical / permit modification (changeout) | $130–$795 |
| Condensing-furnace venting + condensate conversion (80%->95% AFUE) | $530–$1,600 |
Why Marietta's winters make choosing a "Furnace Replacement" contractor different
Marietta winters bring chilly nights and occasional freezes that expose aging heating systems in older bungalows and brick ranches. Choosing the best furnace replacement companies in Marietta, GA matters because local installers know county codes and common duct layouts. Also consider advertised warranties and emergency service availability.
How quickly do Marietta "Furnace Replacement" pros usually respond and what should I ask?
- Does a gas furnace changeout need a permit?
- Almost always. Unlike a repair, replacing a gas furnace is permitted work in our launch states — the installer pulls a mechanical (and often gas) permit and a building inspector signs off the venting, gas connection, and combustion safety before the system goes into service. A quote that skips the permit to save money is skipping the inspection that protects you.
- Can a handyman replace my gas furnace?
- No. Connecting gas and venting combustion is licensed mechanical work, and an unlicensed 'handyman furnace install' is the single biggest red flag. Verify the contractor's state license (TDLR in TX, DBPR in FL, ROC in AZ) plus general liability insurance, and confirm they measure combustion (CO, draft, gas pressure) at commissioning rather than just lighting it and leaving.
- What credentials should I check for a gas furnace installer in Marietta?
- Check the contractor's Georgia trade license, proof of insurance, and any NATE or manufacturer training certificates for gas equipment. Ask to see the license number and confirm the business files permits with the city. Also request evidence of past gas-furnace installs and references from Marietta homeowners if available.
- How do I find a high-efficiency furnace specialist in Marietta?
- Look for providers who document Manual J load calculations and list high-efficiency furnaces with manufacturer-dealer status. Ask for written load calculations, equipment efficiency ratings that meet the 2021 IECC, and examples of recent installs in similar brick ranch or bungalow homes. Verify technician NATE or manufacturer certifications.
- Can Marietta contractors offer same-day furnace replacement and what are the limits?
- Some contractors advertise same-day replacement for like-for-like equipment and available stock. Same-day service typically depends on dealer inventory, permit needs, and access to the home's existing venting. Confirm whether same-day work includes permit filing, gas-line inspection, and warranty activation before agreeing.
- How do I get a quote from these furnace replacement companies?
- Submit one request on this page and we send it to the vetted furnace replacement pros in Marietta, GA listed here. They send quotes back — no obligation.