What size window AC do I need for my room?
Getting the right size window AC for your NYC apartment starts with the BTU-per-square-foot rule — match the cooling capacity to your room dimensions, and you’ll stay comfortable without wasting energy or money.
BTU sizing guide for NYC apartments
| Room size (sq ft) | Recommended BTU range | Typical NYC room type |
|---|---|---|
| 100–150 | 5,000–6,000 | Small studio, home office |
| 150–250 | 6,000–8,000 | Junior one-bedroom, large bedroom |
| 250–400 | 8,000–12,000 | One-bedroom living room, master bedroom |
| 400–550 | 12,000–14,000 | Large one-bedroom, small two-bedroom |
| 550–600 | 14,000–18,000 | Two-bedroom open layout |
Adjustments for NYC apartment conditions
- South- or west-facing room: Add 10% to the base BTU calculation — direct afternoon sun through large NYC windows heats the space significantly.
- Kitchen installation: Add 4,000 BTUs to account for heat from cooking appliances, ovens, and refrigerators running simultaneously.
- Ceilings above 8 feet: Add 10% for every extra foot of ceiling height — prewar apartments with 10- or 12-foot ceilings need more cooling capacity.
- Extra occupants: Add 600 BTUs per person beyond two people; a bedroom shared by three needs roughly 1,200 extra BTUs.
- Energy Efficiency Ratio (EER): Look for units with EER of 12.0 or higher — they cool the same space using less electricity, which matters with NYC rates around $0.25/kWh.
- Window AC Installation sizing rule: An undersized unit runs nonstop without hitting the set temperature, while an oversized one short-cycles and fails to remove humidity — both drive up your electric bill.
Measuring your window opening
Measure the width and height of the window opening itself — not the glass — using a steel tape measure. Standard double-hung windows in NYC apartments run 24–36 inches wide and 36–48 inches tall; the unit you select must fit within those dimensions with room for the accordion side panels to seal. I measure at three points across the width (top, middle, bottom) because older frames in Brooklyn brownstones and Upper West Side prewars often bow or settle unevenly. If your window opening is narrower than 23 inches or wider than 39 inches, you’re looking at a specialty unit or an alternative cooling approach — standard window ACs simply won’t fit, and forcing them leads to air leaks, condensate problems, and a voided warranty on the unit.
Can you install a window AC in a casement window?
Casement windows open outward on a crank, which means standard accordion side panels won’t seal the gap. Not every installer handles this window type, but the right approach makes it work.
Casement window AC installation options
- Casement AC kit ($30–$80): A vertical mounting bracket attaches to the window frame so the unit sits upright while the casement crank opens around it — works with most 5,000–8,000 BTU models.
- Custom Plexiglas panel ($100–$300): For non-standard casement windows — arched openings, unusually tall frames, or brownstone interior storms — a fabricated panel with a cutout for the AC provides a proper seal.
- Portable AC with casement kit: The vent hose connects to an adjustable vertical panel that fits the casement opening. It’s simpler than custom fabrication and avoids the weight concerns of mounting a window unit on a crank window.
- On-site assessment first: Casement installations need a technician to measure the frame depth, check the crank mechanism clearance, and verify the window can support the unit weight before any kit is ordered.
Many NYC apartments with casement windows end up using a portable AC with a casement kit instead — it’s often simpler and avoids the need for custom fabrication.
When to choose through-wall over casement window AC
We can assess your casement window on-site and recommend either a casement kit installation or a through-wall unit if the window can’t safely support a window AC. Casement windows in older Brooklyn brownstones often have rotted wood frames or interior storm panels that block the opening entirely — in those cases, a window AC isn’t viable no matter which kit you use. A through-wall unit cuts a hole through the exterior wall (brick, brownstone, or frame) and bolts directly into the structure, so it doesn’t rely on the window’s condition at all. Through-wall installation requires a DOB permit and costs more ($500–$1,500), but it’s a permanent solution that doesn’t block your window.
Window AC vs through-wall vs portable: which is right for you?
Your window type, building rules, and whether you rent or own determine the best cooling setup. Here is how the three options compare for NYC apartments.
Window AC vs through-wall AC
| Factor | Window AC | Through-wall AC |
|---|---|---|
| Installation type | Sits in open window, removable | Permanent hole cut in exterior wall |
| NYC DOB permit needed | No | Yes — structural modification |
| Installation time | 30–60 minutes | 4–8 hours |
| Installation cost | $150–$400 | $500–$1,500 |
| Security | Lower — can be pushed in from outside | Higher — bolted to wall |
| Efficiency | Moderate — air leaks around accordion panels | Better — sealed wall penetration |
| Window blocked | Yes — no light or view | No — window remains clear |
| Best for | Renters, seasonal use | Owners, permanent cooling |
Window AC vs portable AC
- Efficiency gap: We recommend window AC over portable whenever your window allows it — window units cool more efficiently, use 30% less electricity, and don’t take up floor space.
- Cooling reach: An 8,000 BTU window AC cools roughly 300 sq ft effectively, while the same BTU portable AC only handles about 200 sq ft because the exhaust hose radiates heat back into the room.
- Noise profile: Window AC places the compressor outside the room; portable AC keeps the compressor indoors, so it runs louder at the same BTU rating.
- Installation effort: Window AC needs a support bracket and professional mounting (30–60 min); portable AC just needs a vent hose kit in the window — you can set it up yourself.
- Operating cost over time: Because portable units have lower EER ratings (typically 8.0–10.0 vs 10.0–12.0 for window units), the 30% higher electricity draw adds up — over a 5-year summer season, the window AC saves roughly $150–$250 in NYC at current Con Edison rates.
When to choose each type for your NYC apartment
Choose window AC if you have a standard double-hung window and your building allows it; choose portable if you have casement windows or building restrictions; choose through-wall if you own and want permanent cooling. Casement windows — common in prewar buildings — don’t work with standard window AC accordion panels; a vertical casement kit ($30–$80) can adapt a window unit, but many owners find a portable AC with a casement vent kit simpler. Through-wall installation requires a NYC DOB permit, structural work, and typically a 230V dedicated circuit, so it’s a bigger investment — but it doesn’t block your window, and it seals tighter than any window unit can. Many NYC co-ops and condos prohibit window AC entirely or require specific quiet models — always check your building rules before buying a unit.
What is the best window AC for NYC apartments?
The “best” window unit depends on your room size, noise tolerance, and building rules. Below are our top picks by use case.
Best window AC models for NYC by use case
| Use case | Model | BTU | Price range | Noise level |
|---|---|---|---|---|
| Small studio / home office | Frigidaire FFRE0533U1 | 5,000 | $180–$220 | 54 dB |
| Junior one-bedroom | LG LW8016ER | 8,000 | $320–$380 | 54 dB |
| Noise-sensitive co-op | Friedrich Chill CP06G10B | 6,000 | $420–$480 | 49 dB |
| Energy-efficient pick | GE AHY08LZ | 8,000 | $370–$430 | 52 dB |
| Large room / bedroom | LG LW1216ER dual inverter | 12,000 | $450–$520 | 44 dB |
NYC-specific features to look for
- Inverter compressor: We recommend units with inverter compressors for quiet operation under 50 dB — critical for co-ops with noise rules and for bedrooms where compressor cycling wakes light sleepers.
- EER of 12.0 or higher: At NYC electricity rates of roughly $0.25/kWh, every 1.0-point EER increase cuts your summer bill by about $30 per season. Units below 10.0 EER cost noticeably more to run.
- Support bracket compatibility: NYC Local Law 39 requires a support bracket for any window AC above the first floor. Make sure the unit’s base pan has pre-drilled bracket holes — some budget models omit them, which complicates installation.
Brands we install and service
We install and service LG, Frigidaire, Friedrich, GE, Samsung, and Panasonic window AC units across all 5 NYC boroughs. Friedrich units are the most common in noise-sensitive co-ops because they run at 49 dB, while LG dual-inverter models are the top choice for energy efficiency. In our experience, the Friedrich Chill series also holds up better in brownstone windows — the chassis is stiffer, so it doesn’t flex and leak air the way thinner budget frames do after a season. Before you buy a unit, check your window opening dimensions and your building’s noise rules; we’ve seen co-op boards reject installations because the unit’s decibel rating exceeded the building’s limit by 3 dB. Friedrich units are the most common in noise-sensitive co-ops because they run at 49 dB, while LG dual-inverter models are the top choice for energy efficiency.
Window AC installation in brownstones and high-rises
Installing a window AC in an NYC building isn’t one-size-fits-all — brownstones with masonry walls and high-rises with strict building rules each demand a different approach.
Installing window AC in a brownstone
- Masonry anchors required: We install window ACs in brownstones by anchoring support brackets into brick or masonry with Tapcon anchors — wood-frame mounting won’t hold in 12–18 inch masonry walls.
- Window frame condition first: Half the time, the original wood window frame is rotted or painted shut, and we need to address that before we can safely install the unit.
- Interior storm windows: Many brownstones have interior storm windows that must be removed or modified — some are permanently installed and block access entirely.
- Condensate routing matters: Brownstone windows often open onto a street-facing facade, so we route condensate drainage away from pedestrian areas to avoid slip hazards.
- Older wiring check: Pre-1940 brownstones may have knob-and-tube wiring or ungrounded 2-prong outlets — a window AC needs a grounded 3-prong outlet, and we’ll flag if electrical work is needed first.
Installing window AC in a high-rise building
- Heavy-duty brackets and chains: We install window ACs in high-rise buildings across all 5 boroughs, using heavy-duty support brackets and safety chains rated for wind loads at height.
- Wind load considerations: At 20+ stories, wind speeds can be 20–30 mph higher than ground level — the support bracket and safety chain must be rated for the unit weight plus wind load, not just the unit alone.
- Condensate management: High-rise units may drip onto lower apartments or the building facade; some buildings require a condensate drain line connected to the building drainage system.
- Shared electrical risers: High-rise apartments often share electrical risers — a window AC on the same circuit as other appliances can trip the breaker, and we may recommend a dedicated circuit for units above 8,000 BTU.
- Board approval documentation: Many co-op and condo boards require written approval, proof of professional installation, and specific quiet-unit models — we can provide documentation and work with building management.
Building approval process for window AC
Most NYC co-ops and condos require a written request with unit specifications (brand, BTU, noise level), proof of professional installation, and the installer’s certificate of insurance. We provide the certificate of insurance and installation documentation directly to the board — no back-and-forth on your end. Approval can take 1–4 weeks, so start the process before buying your unit — some boards only meet monthly to review requests.
What’s included in professional window AC installation
A professional installation covers everything from mounting the support bracket to sealing gaps and checking your outlet — so the unit runs safely and efficiently from day one.
Step-by-step installation procedure
- Support bracket mounting: We anchor a heavy-duty bracket into the window frame or masonry wall — required by NYC Local Law 39 for any unit above the first floor.
- Leveling for condensate drainage: The unit gets a 1/4-inch downward tilt toward the exterior so water drains outside, not onto your sill or floor.
- Foam insulation sealing: We fill every gap around the accordion panels and between the sash and unit top — stops warm air infiltration and keeps your electric bill in check.
- Safety chain attachment: A steel chain secures the unit to the window frame or wall anchor, preventing it from falling if the sash mechanism fails.
- Electrical check: We verify the outlet is grounded and within 6 feet of the unit — if it’s not, we’ll flag it before plugging in, because an ungrounded outlet is a fire risk with a window AC.
Tools and materials we use
We bring a full kit: a hammer drill with masonry bits for brownstones, a spirit level for tilt adjustment, foam insulation strips, weatherstripping tape, and a heavy-duty support bracket with masonry anchors. The support bracket we use is rated for 150 lbs — most window ACs weigh 50–100 lbs, so there’s a safety margin even with wind loads at higher floors. In our vans we also carry a multimeter to confirm the outlet is grounded before we plug anything in.
Old unit removal and disposal
We can remove and dispose of your old window AC during the installation for an additional $25–$75, depending on the unit size and how it’s mounted. Old units often have refrigerant that must be recovered by an EPA-608 certified technician — we handle that as part of the removal so you’re compliant with federal regulations. On a call in a Chelsea walk-up last month, the old unit had been sitting in the window for eight years with the drain hole completely clogged; we cleared that, recovered the R-410A, and had the new unit installed within an hour.
Pricing, warranty, and what to expect
Here is a clear breakdown of what window AC installation costs in NYC, what our warranty covers, and how installation day runs — so you know exactly what to expect before you book.
Window AC installation pricing in NYC
| Service | Price range | What’s included |
|---|---|---|
| Standard installation (unit not included) | $150–$400 | Support bracket mounting, leveling, foam sealing, safety chain, electrical check |
| Old unit removal | $25–$75 | Disconnect, carry out, dispose of old AC |
| Installation with electrical work | $250–$500 | Standard install + GFCI outlet install or circuit upgrade |
Warranty and service guarantees
- 1-year warranty on parts and labor: Every installation is covered for 365 days — if the unit shifts out of level, the seal fails, or the bracket loosens within the first year, we come back and fix it at no charge.
- Same-day service with 60–90 minute response: For emergency calls — a unit that fell out of a window or is leaking water into the apartment — we arrive within 60–90 minutes across all 5 boroughs.
- Free diagnostic with repair: If we inspect your window and find an issue (old wiring, rotted frame), the diagnostic fee is waived when you proceed with the installation or any needed prep work.
- 7 days a week availability: We install window ACs Monday through Sunday, 8 AM to 9 PM, with a 24/7 emergency line for urgent situations.
What to expect on installation day
On installation day, our technician arrives within the scheduled window, inspects your window and electrical outlet, mounts the support bracket, installs the unit, and tests operation — typically 30–60 minutes total. We use a level to set the proper ¼-inch downward tilt for condensate drainage, seal every gap with foam insulation strips, and attach a safety chain from the unit frame to the window sash. Have your window area clear and your unit ready (still in the box) — if you haven’t bought a unit yet, we can recommend one that fits your window dimensions and meets your building’s noise or approval requirements. The warranty starts on installation day, so we document the serial number, model, and installation date before we leave.
Final thoughts on window AC installation in NYC
Main takeaways
Proper window AC installation in NYC requires matching the unit size to your room at 20 BTUs per square foot, using a support bracket per Local Law 39, and sealing all gaps for efficiency. The most common mistakes — incorrect tilt, missing support brackets, and poor sealing — lead to condensate leaks, energy waste, and safety hazards. A professional install avoids these by leveling the unit for proper drainage, anchoring the bracket into masonry, and sealing every gap with foam insulation strips. The tilt should slope downward about a quarter to half an inch toward the exterior so condensate drains outside, not onto your floor. Missing that step alone causes more callbacks than any other installation error.
