Lennox AC Installation Nationwide

Lennox AC Installation in Marietta: What to Know First

Lennox AC installation in Marietta typically runs $3,500 – $7,500 depending on the system size, efficiency tier, and how much ductwork or electrical work the job requires. Most installs take one full day, sometimes two when we’re replacing an older unit that needs line-set or pad work. We’re an independent Lennox service provider, not a factory-authorized dealer, so our pricing leans on what the job actually needs rather than what a manufacturer program dictates.

Call (762) 240-5599

This page is for Marietta homeowners who already know Lennox is the brand they want or already have one in the house and need a straight answer on replacing it. If you’re weighing Lennox against Carrier or Trane, we service those too, but this page is about getting a Lennox installed right the first time. Call (762) 240-5599 and you’ll get a live person, not a phone tree.

Key takeaways:

• Written price before any work starts, no door-knock surprises.
• Most Lennox installs in Marietta land between $3,500 and $7,500.
• We install the full Lennox lineup: Merit, Elite, and Signature series.
• Every job backed in writing, including the 365-Day Done Right Promise.

How Lennox Products Fail and What It Means for Installation

Every brand has its fingerprints. After two decades across the Southeast, including plenty of Marietta attics and side yards, our techs know exactly what a Lennox looks like when it’s tired. Here’s what we see most, and what we do about it during an installation.

• Merit Series (ML14, ML17) condenser coil leaks at the tube sheet. The Merit line is Lennox’s entry tier, and in Marietta’s humidity-plus-pollen climate, we regularly see corrosion at the copper-aluminum joints. When a homeowner calls about low refrigerant on a six-year-old Merit, it’s usually not a slow leak from a valve; it’s the coil itself. During replacement, we pressure-test the new coil before it ever leaves our truck.
• Elite Series (EL18, EL22) inverter board sensitivity to voltage dips. The Elite line runs variable-speed inverter compressors, which are efficient but picky about power quality. Marietta’s summer thunderstorms cause brownouts that can scramble an Elite’s inverter logic. If the unit still cools but won’t modulate, that’s often the culprit. A surge protector at the disconnect is cheap insurance, and we include that recommendation on every variable-speed install.
• Signature Series (XC20, XC25) communicating thermostat mismatches after a partial replacement. The Signature line uses Lennox’s iComfort communicating protocol. If a previous contractor paired it with a generic thermostat, the system drops to basic on-off behavior and loses half its efficiency. We see this all the time in East Cobb homes where someone “upgraded” the thermostat at a big-box store. Our installs always match the communicating thermostat to the communicating system.
• SL280 and SL297 furnace heat exchanger rust-through from short-cycling. Single-stage furnaces tied to oversized air conditioners short-cycle, and that thermal stress cracks exchangers early. When we install a new Lennox AC, we look at the furnace too. If the blower is oversized or the ductwork is undersized, the new AC will inherit the problem. We fix the match, not just the box.
• Evaporator coil freeze-ups on systems with restricted returns. Marietta homes built in the 1970s and 1980s often have one undersized return per floor. A new Lennox coil running on a starved return will freeze, and the homeowner immediately thinks the install was botched. It wasn’t; the ducting was. We measure static pressure before the old unit comes out so the new one doesn’t start its life on a handicap.

Our Lennox AC Installation Process

Here’s how a typical Lennox installation runs with us, start to finish. No mystery, no radio silence, no truck rolling up unannounced.

1. 1
   The call. You reach a live person at (762) 240-5599. We ask what the system is doing, how old it is, and whether anyone’s looked at it before. Then we book a window that fits your schedule, not ours.
2. 2
   The site visit and load calculation. We don’t size a system by “it’s a 2,000 square foot house.” We do a Manual J load calculation: windows, insulation, orientation, ceiling height, the whole picture. For a Lennox replacement in Marietta, this tells us whether you actually need a 3-ton unit or whether the last guy oversold you.
3. 3
   The written quote. Before any tool comes out of the truck, you get a written price for the full job: equipment, line set, pad, electrical, permits, everything. That price does not change at the door. It’s how The Kingswell Way runs, and it’s non-negotiable for us.
4. 4
   The install. We pull the old unit, flush or replace the line set depending on condition, set the new condenser on a level pad, braze the connections under nitrogen, pull a deep vacuum, and charge the system to the exact spec. In Marietta’s clay soil, we also check the pad isn’t sinking, which is a common problem near Kennesaw Mountain’s slopes.
5. 5
   The test and walk-through. We run the system through every mode, measure airflow and temperatures, and confirm the drain line is clean. Then we walk you through the thermostat and show you the filter. If we installed a communicating system, we spend ten minutes showing you what the screen actually means.
6. 6
   The cleanup and paperwork. The job site is left cleaner than we found it. You get the written guarantee in your hand before anyone leaves, including the 365-Day Done Right Promise that brings us back at no charge if anything fails inside a year.

What Lennox AC Installation Costs in Marietta

The lead range on most Lennox installs we do in Marietta is $3,500 – $7,500. Here’s how that breaks down in the real world:

• Merit Series (ML14/ML17) basic single-stage replacement, 14 SEER: $3,500 – $4,500
• Elite Series (EL16/EL18) two-stage or variable-speed, 16 – 18 SEER: $4,500 – $6,000
• Signature Series (XC20/XC25) top-efficiency variable capacity, 20 – 25 SEER: $6,000 – $7,500
• Full system with new indoor coil and furnace match: adds $1,000 – $2,000 depending on efficiency tier

What moves the price: line set replacement, new duct transitions, electrical upgrades for variable-speed systems, and whether we’re adapting a communicating system to older wiring. The quote we hand you covers it all. Call (762) 240-5599 for a free estimate, and the number we give you is the number you pay.

Why Marietta Homeowners Call Cold Harbour Heating and Air Marietta for Lennox Work

Victor Mancini, our owner, learned the trade at Los Angeles Trade-Technical College and has spent nearly twenty years working HVAC across the Southeast. When he started Cold Harbour Heating and Air, he built it around one idea: put everything in writing so you never have to take a contractor’s word on faith. That’s why every Lennox install gets a written price before work begins and a written guarantee before the technician leaves.

The 365-Day Done Right Promise is exactly what it sounds like. If a repair or install detail fails within a year, we return and correct it at no charge. No argument, no fine print. That’s part of The Kingswell Way, the standard our independently owned company runs on. And because our technicians train on the full residential lineup including Carrier, Trane, Goodman, Rheem, York, Daikin, Bryant, and American Standard, we can honestly evaluate whether a Lennox is the right fit for your home, not just sell you what’s on our truck. A cold harbour, by the way, was a roadside shelter where travelers waited out the weather. Comfort in any season is the whole job.

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