AC Installation
Long Island

AC Installation for Long Island Homes

Upgrading or installing central air conditioning is one of the most impactful home improvements for Long Island homeowners — adding comfort during humid summers, reducing humidity levels inside the home, and increasing resale value. Whether you're replacing an aging system, adding cooling to a home without ducts, or installing AC in a new addition, LI Heating & Cooling handles the full installation from estimate through final walkthrough.

We install all major AC system types across Nassau and Suffolk County: central air conditioning (with existing or new ductwork), single-zone and multi-zone ductless mini-splits, and heat pump systems that provide both heating and cooling. Every installation starts with a proper Manual J load calculation — no guessing on system size.

Long Island's mix of housing stock creates unique installation challenges. Many older homes in established Suffolk County towns were built without central ductwork — ductless mini-splits are often the most practical and cost-effective solution for these homes. Newer construction typically already has duct systems, making central air the natural fit.

Central Air vs. Ductless Mini-Split: Which is Right for Your LI Home?

Central air conditioning provides even, whole-home cooling through your existing duct system. It's ideal when your home already has ductwork (or a forced-air furnace system), and gives every room consistent temperature control through a single thermostat or zone system. Central air is generally more familiar and easier for homeowners to manage.

Ductless mini-splits require no ductwork — an outdoor compressor connects to wall-mounted indoor air handlers in each zone via a small refrigerant line through the wall. They're the right choice for homes without existing ducts, room additions, converted garages, and coastal homes where running new ductwork isn't practical. Each zone is controlled independently, which can reduce energy use in rooms that are rarely occupied. For a full comparison and installation details, see our ductless mini-split installation page.

AC Sizing Matters on Long Island

Oversized AC units short-cycle — they cool the space quickly but shut off before removing adequate humidity. This leaves homes feeling clammy even at the set temperature, which is a real problem on Long Island where summer relative humidity regularly exceeds 70%. Undersized units run constantly, driving up energy costs and wearing out faster.

We perform a Manual J load calculation on every new installation — accounting for square footage, insulation levels, window area, orientation, shading, and ceiling height. This determines the correct tonnage for your home, not a rule-of-thumb guess.

Energy Efficiency and SEER Ratings

New AC systems are rated by SEER2 (Seasonal Energy Efficiency Ratio). The minimum for New York is SEER2 14.3 for split systems. High-efficiency systems at SEER2 18–22 cost more upfront but reduce cooling bills by 20–35% compared to minimum-efficiency equipment. NYSERDA and PSEG Long Island offer rebates for qualifying high-efficiency systems — we help identify what incentives you qualify for before you choose a system.