Licensed & insured general contractors · Broward · Miami-Dade · Palm Beach
HVAC-Related Construction & Repairs project by 12X Construction

Systems, Repairs & Restoration

HVAC-Related Construction & Repairs

Ductwork, closets, chases, and returns: the construction side of comfort.

When rooms won't cool, the cause is often duct design, return sizing, or a leaking, mold-prone air handler closet, not the equipment. We handle the construction side of HVAC: duct routing, chases, platforms, returns, and building back cleanly.

Typical timeline

2 days–2 weeks

Typical investment

Quoted per scope; duct and closet work commonly $2,500–$14,000

Get a hvac-related construction & repairs estimate

Free on-site visit, written scope, no obligation.

More details (optional): timeline, budget, notes
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Licensed & insured
20+ years in the trades
Fixed written scope & price
Permits pulled & closed
Built on word of mouth
In-house crews, no subs roulette
Line-itemed estimates
Workmanship warranty in writing
Licensed & insured
20+ years in the trades
Fixed written scope & price
Permits pulled & closed
Built on word of mouth
In-house crews, no subs roulette
Line-itemed estimates
Workmanship warranty in writing

How we approach it

The duct system is usually the real problem

South Florida AC units run almost year round, and most complaints about a hot bedroom or a short-cycling unit trace back to construction, not the compressor: undersized returns, crushed flex duct in the attic, or a closet never built to code.

We work alongside licensed mechanical contractors to fix the building side of comfort. That means reframing an air handler closet with a proper drain pan and secondary line, resizing a return, or rebuilding a chase so a mini-split line set stops rattling behind drywall.

Humidity is the other half of the problem here. A system that's sized right but starved for return air runs long cycles that leave moisture in the walls. We correct the construction so the equipment can actually do its job in our climate.

HVAC-Related Construction & Repairs project in South Florida
Representative project photo

When to call

Signs it's time

  • One or two rooms never reach the thermostat setting
  • Air handler closet door won't close over the equipment
  • Musty smell near vents or a visibly rusted drain pan
  • Condensate line drips onto drywall, baseboards, or ceiling below
  • Ductwork crushed, disconnected, or resting on insulation in the attic
  • New mini-split needs a line-set chase built and finished

What the work involves

The breakdown

01

Closet and platform rebuild

Reframe the air handler closet to code clearances, add a sloped secondary drain pan, float switch, and condensate line routed to daylight or an approved drain, not the ceiling below.

02

Duct correction

Pull crushed or disconnected flex duct, replace with properly sized and insulated run, reseal joints with mastic instead of tape that fails in attic heat within a year.

03

Return and supply resizing

Calculate actual airflow needs for the room and correct undersized returns that are forcing the system to run long, humid cycles.

04

Chases and soffits

Build and finish wall or ceiling chases for mini-split line sets and new duct runs so the finished look matches the rest of the room.

05

Equipment coordination

Schedule and sequence our framing and drywall work around the licensed mechanical contractor's changeout so nobody waits on the other.

Step by step

How a hvac-related construction & repairs job runs

  1. 11 visit

    Diagnose the construction cause

    We inspect the closet, attic duct runs, and return sizing before assuming the equipment is at fault.

  2. 21-2 days

    Coordinate with mechanical trade

    We bring in or work alongside the licensed HVAC contractor for load calculations and equipment specs.

  3. 31-4 days

    Demo and rebuild

    Remove damaged duct, drywall, or closet framing and rebuild to current code clearances.

  4. 41-3 days

    Duct and drain install

    Run new insulated duct, set drain pans and lines with proper slope and backup protection.

  5. 51-3 days

    Finish and close up

    Drywall, paint, and trim the closet or chase so it reads as original construction.

  6. 61 visit

    Final airflow check

    Confirm the rooms that were hot before now hit the thermostat setting.

Choices

Options we'll walk you through

Standard duct replacement

Insulated flex duct sized to manual-J load, mastic-sealed joints

Best for: Attic runs with crushed or aged duct

Hard duct transitions

Sheet metal boots and trunk sections at closet connections

Best for: High-traffic returns and supply plenums

Mini-split chase build-out

Framed and finished vertical or horizontal chase for line sets and drain

Best for: Additions or rooms without existing ductwork

Secondary drain pan with float switch

Code-required backup pan that shuts the unit down before overflow damages ceilings

Best for: Attic or closet-mounted air handlers above finished space

Example project

Chronically hot primary bedroom fixed at the duct, not the thermostat

Plantation, FL4 days

The challenge
A homeowner had replaced their AC unit twice in five years because one bedroom never cooled, while the rest of the house was comfortable.
What we did
We found a crushed, undersized return duct buried under blown insulation and a supply run with three kinked sections losing most of its airflow before reaching the room.
The result
We replaced and resized the duct run and resealed every joint. The bedroom reached the thermostat setting within the hour, and the existing equipment has run normally since.

Illustrative example based on typical jobs of this type.

Standards we hold

  • We check return air sizing with actual measurements, not a guess
  • Every secondary drain pan gets a float switch wired to shut the unit down
  • Duct joints are mastic sealed, not wrapped in tape that dries out in attic heat
  • We coordinate directly with the licensed mechanical contractor instead of guessing at their sequence
  • Closets are rebuilt to current clearance code, not just patched around the old unit
Air conditioning technician connecting refrigerant gauges to an outdoor condenser unit in South Florida

On the job

Cooling that keeps up

Diagnosing before replacing

Pressures and temperatures read at the unit first; a lot of 'needs replacing' systems don't.

Representative example

What's included

Our hvac-related construction & repairs scope

  • Duct routing, replacement, sealing, and insulation
  • Air handler closets, platforms, drain pans, and condensate lines
  • Return and supply sizing corrections for hot rooms
  • Mini-split installation support, line-set chases, and wall penetrations
  • Soffits, chases, and vent boxing built and finished to match
  • Coordination with licensed mechanical contractors on equipment changeouts

Questions we get about hvac-related construction & repairs

How it works

What happens after you call

01

Free on-site visit

We come out, measure, photograph, and listen. You get straight answers about what's possible and what it really takes, usually within 24–48 hours of your call.

02

Line-itemed proposal

A written scope with materials, allowances, timeline, and payment schedule. You see exactly what you're buying before you commit to anything.

03

Selections & permits

We help you pick finishes that hit your budget, then handle drawings, permits, HOA packets, and inspections so nothing stalls the job.

04

Build with daily updates

Dedicated crew, protected work area, photo updates, and a single project manager you can reach directly at any point.

05

Walkthrough & warranty

We walk the job with you, fix every punch-list item, close the permit, and hand over your written warranty and care instructions.

Our commitments

Put in writing on every project

Fixed written scope & price

Every estimate is line-itemed before a single tool comes out of the truck. No mid-project surprises, no vague allowances.

One accountable project manager

You get one direct number, one person who knows your job, and daily progress updates, not a call center.

Licensed, insured, permitted

Licensed general contracting, full liability and workers' comp coverage, and permits pulled and closed out properly.

Workmanship warranty

Written warranty on our labor plus full manufacturer warranties on the materials we install.

Clean, respectful crews

Floor protection, dust containment, daily cleanup, and crews that treat an occupied home like an occupied home.

On-schedule or we tell you first

A real timeline with milestones. If anything shifts, you hear it from us before you notice it yourself.

Client feedback

Referred, again and again

“They gutted and rebuilt two bathrooms and our kitchen while we lived in the house. Every day the site was clean, every question got answered the same day, and the final number matched the estimate.”
Daniel R. · Fort Lauderdale, FL · Kitchen + 2 bathroom remodel
“We had water damage behind a wall that two other contractors misdiagnosed. 12X found it in an hour, handled the drying, rebuilt the drywall, and dealt with the insurance paperwork.”
Melissa T. · Hollywood, FL · Water-damage restoration
“Pavers, a pergola, an outdoor kitchen, and turf, done in five weeks and permitted properly. Our backyard is the reason we stopped talking about moving.”
Andre & Sofia P. · Coral Springs, FL · Full backyard renovation
“We turn over rental units on tight deadlines. They have never once missed a make-ready date, and their punch lists are cleaner than anyone we've used.”
Property manager · Miami, FL · Property turnover program

Free, no-pressure estimate

Ready to price your hvac-related construction & repairs project?

Free on-site visit, written line-itemed estimate, no pressure. Most visits are scheduled within 24–48 hours.

Licensed & insured 5-star word-of-mouth Written fixed price