245 West 99th Street (Ariel West)

The building reads from Broadway as a stepped glass slab. COOKFOX's massing takes the bulk down in setbacks as it rises rather than holding a single plane, which produces the upper-floor terraces and gives the tower a silhouette distinct from the flat curtain-wall vocabulary of its contemporaries. Glazing is full-height across the residential floors, and the exposures divide cleanly: west and north toward the Hudson, Riverside Park and the George Washington Bridge; east and south toward Central Park and the midtown skyline.

Interiors carry the specification standard of a 2007-vintage Extell condominium at the upper end: approximately ten-foot ceilings, hardwood floors, central air conditioning, in-unit washer/dryer, and kitchens offered in three finish packages at the original sale. Configurations run from two bedrooms to five, with layouts drawn to separate a broad entertaining volume from a bedroom wing — a family-apartment discipline more common in prewar cooperative planning than in contemporary condominium construction, and the building's most durable design decision.

City records count 71 total units, of which 68 are residential. The balance is the commercial section — roughly 19,242 square feet — occupying the base.

Ariel West is a mixed-use condominium, and its governance reflects that. The documents on file distinguish among a Condominium Board governing the whole, a Residential Board governing the residential section, and a separate Commercial Section. Residential owners deal with the Residential Board on house rules, alterations, pets and amenity use; building-wide matters run through the Condominium Board. Understand which body governs which decision before relying on a policy answer.

The approved operating budget on file shows a building that runs close to break-even by design: roughly $2.60 million of income against roughly $2.60 million of expense, a planned surplus under $1,000, and a 3.00 percent common charge increase built in for that year. Common charges supplied roughly $2.43 million of the income; commercial charges contributed approximately $31,000. On the expense side the building is labor-heavy — staffing and related costs ran approximately 52 percent of the operating budget, with repairs and maintenance near 24 percent and utilities together near 15 percent. That labor share is the direct cost of the doorman, concierge and resident-manager model and the staffed amenity floors; compare current unit charges against apartments with similar services, size and reserve requirements.

Two items deserve attention. The budget carried no capital assessment and no capital improvement line for the year — a clean posture, though one that says nothing about years since. And the building is amortizing an energy-efficiency retrofit loan through the operating budget, a New York City Energy Efficiency Corporation facility carried as a recurring line item. That is constructive: a 2007 glass tower approaching Local Law 97's compliance periods has real emissions exposure, and financed retrofit work is the standard response. Ask the managing agent for the current Local Law 97 position, the balance and maturity of that loan, and whether further retrofit is contemplated — those three answers determine the trajectory of common charges over the next decade.

This is the single most commonly confused fact about the building, and it is worth stating precisely.

They are two separate condominiums. Ariel West at 245 West 99th Street is BBL 1018717501. Ariel East at 2628 Broadway is BBL 1018717502. They are separate condominium declarations recorded against separate tax lots, with separate governing documents and separate boards. The house rules on file are titled "Rules and Regulations of the Residential Section" of Ariel West, incorporated into Schedule A of the By-Laws of Ariel West, and administered by the Ariel West board. A purchaser at 245 West 99th Street is buying into Ariel West and nothing else.

They share a tax block but sit on opposite sides of Broadway. Both lots fall within Manhattan Block 1871. This surprises people, but it is a consequence of Broadway's diagonal: the avenue cuts through the block between 99th and 100th Streets, and the block spans both sides of it. Ariel West sits on the west side toward West End Avenue; Ariel East sits on the east side toward Amsterdam.

They differ materially in scale. Ariel East is 37 to 38 stories with 64 residential units, completed in 2006. Ariel West is 31 stories with 68 residential units, completed in 2007 or 2008. Ariel East is the taller and more slender; Ariel West carries more apartments across fewer floors. Story and unit counts alone do not show which tower's apartments are larger; compare the apartment schedules and floor plates.

Amenity access runs between them by arrangement. The Ariel West house rules refer to "the common rooms located in Ariel East that Ariel West Residents and their guests are permitted to use." That is a reciprocal-use arrangement between two independent condominiums, not co-ownership. It has worked for close to two decades — but a buyer underwriting the amenity package should ask the managing agent which facilities sit in which building and on what terms the access is held, because the answer is contractual rather than proprietary.

The condominium form governs the transactional questions — leasing by owners is permitted with conditions, the board's remedy on a sale is a right of first refusal rather than an approval right, and a lease application is administered by the managing agent for rentals; confirm pied-à-terre use, LLC and trust ownership and foreign purchase in the declaration and bylaws. In-unit washer/dryer is original to the apartments. No flip tax is documented in the plan and budget materials on file; confirm any capital contribution with the managing agent at contract. What is worth reading closely is the house-rule layer, which is more prescriptive than the ownership form suggests.

Alterations. Governed by a written alteration agreement on file with the managing agent. No heating, ventilating or air conditioning device may be installed without prior written board approval, which the rules make discretionary rather than reasonable. Noise-generating work is confined to weekdays, holidays excluded, 8:00 A.M. to 5:00 P.M.

Floor covering. At least 80 percent of each unit's floor area — excluding kitchens, pantries, bathrooms, closets and foyers — must be covered with rugs, carpeting or equally effective noise-reducing material unless the board expressly authorizes otherwise. In a glass tower with hardwood floors this is a real constraint on how an apartment can be finished.

Terraces. Plantings and installations require prior written board approval. Nothing may be stored on a terrace other than outdoor furniture, and barbecuing is prohibited except in designated areas.

Enforcement. The supplemental house rules adopted in January 2014 set an escalating fine schedule: a written warning first, then $150, then $150 more for each subsequent violation, attributed to the apartment rather than the individual.

Recent sales

Recent closings at this building, from The Roebling Research Library. Prices are the transfer amounts recorded with the NYC Department of Finance; apartment-level detail is checked against the building’s own file in The Roebling Research Library before publishing.

Market read. Most recent trades (2026 to date) cleared a median $1,433/sf (floor-adjusted) across 3 sales. Floor-adjusted means each sale is restated to a constant mix of floors, so the figure can differ from the plain median of the sales listed above. Median listing discount 2.4% from the last ask — a recurring negotiation gap worth pricing into any offer or listing strategy.

Sales sourced from NYC Department of Finance recorded transfers (BBL 1-01871-7501; each condominium apartment is its own tax lot). Apartment-level facts (line, condition, asking-price context) curated and cross-verified in The Roebling Research Library. Not all transactions cross-verify with ACRIS records — sponsor and LLC purchases sometimes record at stipulated values rather than market price; square footage from recorded condo declarations and offering plans.

Confirm which condominium you are buying into. Ariel West and Ariel East are separate condominiums. Contracts, financials, house rules, board minutes and reserve positions are Ariel West's alone, and a due-diligence package assembled for the wrong tower is worthless.

Confirm the amenity access terms. Several of the marketed amenities sit in Ariel East and are available to Ariel West residents by reciprocal arrangement. Ask the managing agent what is owned versus what is licensed, and on what terms.

Ask about Local Law 97 and the retrofit loan. The building is amortizing energy-efficiency financing through its operating budget. Get the balance, the maturity, the current emissions position and whether further work is planned. For a 2007 glass tower, this is the single most consequential forward-looking cost item.

Understand the mixed-use governance. A Condominium Board, a Residential Board and a separate commercial section occupying roughly 19,000 square feet of the base. Confirm which body decides what, and how commercial-section costs are allocated.

Verify the unit count and square footage on the plan, not the listing. City records say 68 residential units; the sponsor's materials say 73. On any individual apartment, the offering plan Schedule A and its amendments govern. Plan for the 80 percent floor-covering rule if you intend to finish in hard flooring throughout.

Lead with the building's scale. Recorded floor area is roughly twice a simple comparison with the site's current zoning; that does not establish legal zoning floor area or permitted future work, and it does not protect views, which depend on floor, position and exposure.

Lead with apartment size. Two- through five-bedroom condominium inventory with ten-foot ceilings, floor-to-ceiling glass and in-unit laundry is thin above 96th Street. The buyer pool for a four-bedroom here is competing against a much smaller and more expensive set downtown.

Price on the line, not the building. Recent comparables in the same line with the same exposure — and, where applicable, the same terrace condition — should set the number.

Be forward about carrying cost. Sophisticated buyers will diligence the operating budget, the energy loan and the Local Law 97 position themselves. Closing pace is condominium-fast: right of first refusal rather than board approval, 30 to 45 days typical.

If you're considering Ariel West, also evaluate:

• 2628 Broadway (Ariel East) — the sister tower across Broadway; same sponsor, same development, separate condominium, taller and slightly smaller in unit count
• 275 West 96th Street — full-service Upper West Side condominium tower a few blocks south; the closest peer on scale and service
• The Ansonia (2109 Broadway) — the landmark Broadway condominium; the opposite architectural argument at a comparable price tier
• 250 West 96th Street — postwar Broadway-corridor full-service building; a more accessible alternative in the same submarket
• 2280 Broadway — prewar Broadway condominium conversion; large-apartment inventory in a different idiom
• 100 Riverside Boulevard — Riverside South new-development condominium; the direct competitor for large-apartment, amenity-heavy Upper West Side buyers
• 200 Riverside Boulevard — same corridor, comparable service model and family-sized inventory
• 2505 Broadway — contemporary Broadway-corridor condominium north of 93rd Street
• 255 West 98th Street — immediate-neighborhood full-service alternative one block south
• 310 West 99th Street — prewar cooperative on the same street toward Riverside Drive; the co-op alternative; compare current unit carrying costs