Licensed Maryland HVACR contractor · 41 years in Montgomery County 24/7 emergency service
Poteete HVAC · since 1985

Potomac, MD · Cooling

Central Air Conditioning System Installation in Potomac, MD

Whole-house cooling design for large Potomac properties

Local detail

Central Air Installation in Potomac

Designing cooling for an 8,000 square foot house is not the same problem scaled up from a 2,000 square foot one. Duct runs are long, static pressure accumulates, west-facing glass walls create enormous afternoon loads in specific rooms, and two-story great rooms stratify badly. We do a room-by-room load and design the distribution to match it, including the returns — which in large homes are the most consistently undersized element we find.

  • Two-story great rooms need a return high in the space or they stratify regardless of supply airflow
  • Large west-facing glass creates a peak load hours after the rest of the house peaks, which argues for its own zone
  • Long duct runs in large homes accumulate static pressure — trunk sizing matters more than in typical housing
Trunk and branch duct system A supply plenum feeding a tapered trunk with branch runs to registers, alongside an undersized single return, with static pressure measurement points marked. Air handler Supply pressure Return pressure Tapered trunk Branch runs to registers Return
Total external static pressure is the sum of both readings, and it is the single most revealing number in a duct system. Above roughly 0.8 in. w.c., new equipment will run hard and die young — which is why we measure before quoting rather than after installing.

The housing

What we find in Potomac homes

Predominantly large single-family homes from the 1960s through the present, ranging from mid-century ranches on acre lots to 6,000–12,000 sq ft custom builds; substantial recent construction and gut renovation activity.

  • Three to five separate zoned forced-air systems in a single residence
  • Geothermal ground-source heat pumps with vertical or horizontal loop fields
  • Hydronic radiant floor heating, frequently in basements, baths and garages
  • Whole-house steam humidification and high-MERV or electronic air cleaners
  • Propane-fired equipment in Glen Hills and other areas without a gas main

Scope of the work

  • Whole-house Manual J load calculation plus Manual D duct design
  • Supply and return routing plan drawn before any drywall is opened
  • Air handler placement in attic, basement or closet with proper platform, pan and safety switch
  • Insulated supply trunk and branch runs, sealed with mastic rather than tape alone

Utilities · Potomac

Electric: Pepco. Gas: Washington Gas where mains exist; propane or oil in Glen Hills, Travilah and outer areas. Water: WSSC Water in served areas; private wells common in Glen Hills and outer Potomac. Permitting authority: Montgomery County Department of Permitting Services (DPS).

Neighborhoods covered

Potomac Village, Avenel, River Falls, Falconhurst, Glen Hills, Bedfordshire, Piney Meadows, Travilah, Potomac Falls, Normandy Farms Estates, Fox Hills and the surrounding 20854, 20859 ZIP codes.

Local factors

Conditions that shape this job in Potomac

  1. HOA and design review

    Avenel and several other Potomac communities operate architectural review with specific requirements for equipment screening, placement and visibility from common areas. Getting approval before installation is straightforward; getting forgiveness afterwards is not. We prepare the submission as part of the project.

  2. Long runs and access

    On acre-plus lots with mechanical rooms far from the exterior wall, line set runs are long, vertical lifts can be significant, and refrigerant charge must be adjusted for line length rather than left at the factory charge. Long runs are also where poor installation practice shows up first, usually as a system that never quite performs to its rating.

Questions

Central Air Installation in Potomac — common questions

Our two-story family room is always uncomfortable. Why?
Stratification. Warm air collects at the top of the volume and the thermostat, mounted at eye level, never sees it. The fix is usually a high return in that space to pull the warm layer back to the system, sometimes combined with dedicated zoning for the west-facing glass. Simply adding more supply air to the room typically makes the draft worse without solving the temperature.
Can central air be added to a house with radiators and no ductwork?
Yes, and it is one of the most common projects we do in Silver Spring, Takoma Park and older Bethesda. The hot-water or steam heating stays exactly as it is, and we add a separate cooling-only system — conventional ducted if there is routing space, high-velocity or ductless if there is not.

More central air installation questions answered on the Maryland service page →

Talk to a technician

Central Air Installation in Potomac? Tell us what the system is doing.

Describe the problem and we will tell you what it usually means, what it typically costs to diagnose, and when we can be there. No obligation, no scripted sales call.

Call (301) 555-0182 Request a quote

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