Aerosys Replacement Units
Every discontinued model, matched to what actually fits your wall opening
Aerosys has permanently closed. If a unit just failed and you are holding a nameplate with a TTWC, TTWH, THHP, or THDC number on it, find it in the tables below. We match replacements by wall opening, because that is the constraint that actually decides what you can install. 45 discontinued models are cross-referenced here.
On refrigerant: no R-410A through-the-wall replacement is available from any manufacturer. Production ended January 1, 2025 and the install-through window closed at the end of 2025. Every replacement below is R-454B or R-32. Your existing system can still be serviced.
The 36" x 19" replacements we build
The P Series opening is the one no manufacturer serves, and it is the most common opening in New York City. These are custom fabricated to drop into the sleeve you already have. They also replace the AboveAir VCU-C units, which use the same opening.
36"W x 19"H 1.5-Ton Thru-Wall R-454B Condenser Replaces Aerosys TTWC-R18P21, TTWC-R18P21LX, VCU-C-018-1-S, VCU-C-018-1-X
$10,716
As low as $894/mo
36"W x 19"H 2.0-Ton Thru-Wall R-454B Condenser Replaces Aerosys TTWC-R24P21, TTWC-R24P21LX, VCU-C-024-1-X, VCU-C-024-1-S
$11,968
As low as $998/mo
36"W x 19"H 2.5-Ton Thru-Wall R-454B Condenser Replaces Aerosys TTWC-R30P21, TTWC-R30P21LX, VCU-C-030-1-S, VCU-C-030-1-X
$12,619
As low as $1052/mo
P Series
36" W x 19" HCustom built for this openingThe opening no manufacturer serves
The 36" x 19" P Series opening is the NYC building standard, and no manufacturer builds a unit for it today. We have ours custom fabricated to fit the existing sleeve, charged with R-454B. Built to order, 14 to 21 day lead time.
| Aerosys model (discontinued) | Tons | Replacement | Refrigerant |
|---|---|---|---|
| TTWC-R18P21 | 1.5 | 36"W x 19"H 1.5-Ton Thru-Wall Condenser | R-454B |
| TTWC-R18P21LX | 1.5 LX | 36"W x 19"H 1.5-Ton Thru-Wall Condenser | R-454B |
| TTWC-R24P21 | 2.0 | 36"W x 19"H 2.0-Ton Thru-Wall Condenser | R-454B |
| TTWC-R24P21LX | 2.0 LX | 36"W x 19"H 2.0-Ton Thru-Wall Condenser | R-454B |
| TTWC-R30P21 | 2.5 | 36"W x 19"H 2.5-Ton Thru-Wall Condenser | R-454B |
| TTWC-R30P21LX | 2.5 LX | 36"W x 19"H 2.5-Ton Thru-Wall Condenser | R-454B |
T Series
24" W x 32" HWe source and installNCP 3000 Series
The NCP 3000 Series cabinet is 24-1/8" W x 32" H, which drops into the T Series opening. Available in R-454B (NCP5 prefix) or R-32 (NCP3 prefix). We source and install these.
| Aerosys model (discontinued) | Tons | Replacement | Refrigerant |
|---|---|---|---|
| TTWC-R18T21 | 1.5 | NCP5183000A | R-454B |
| TTWC-R18T21LX | 1.5 LX | NCP5183000A | R-454B |
| TTWC-R24T21 | 2.0 | NCP5243000A | R-454B |
| TTWC-R24T21LX | 2.0 LX | NCP5243000A | R-454B |
| TTWC-R30T21 | 2.5 | NCP5303000A | R-454B |
| TTWC-R30T21LX | 2.5 LX | NCP5303000A | R-454B |
S Series
26" W x 28-5/8" HWe source and installNCP 1000 Series
The NCP 1000 Series cabinet is 26-1/4" W x 28-5/8" H, a direct match for the S Series opening. Available in R-454B or R-32. We source and install these.
| Aerosys model (discontinued) | Tons | Replacement | Refrigerant |
|---|---|---|---|
| TTWC-R18S21 | 1.5 | NCP5181000A | R-454B |
| TTWC-R18S21LX | 1.5 LX | NCP5181000A | R-454B |
| TTWC-R24S21 | 2.0 | NCP5241000A | R-454B |
| TTWC-R24S21LX | 2.0 LX | NCP5241000A | R-454B |
| TTWC-R30S21 | 2.5 | NCP5301000A | R-454B |
| TTWC-R30S21LX | 2.5 LX | NCP5301000A | R-454B |
R Series
30" W x 23" HWe source and installNCP 4000 Series
The NCP 4000 Series covers the R Series opening. Available in R-454B or R-32. We source and install these.
| Aerosys model (discontinued) | Tons | Replacement | Refrigerant |
|---|---|---|---|
| TTWC-R18R21 | 1.5 | NCP5184000A | R-454B |
| TTWC-R18R21LX | 1.5 LX | NCP5184000A | R-454B |
| TTWC-R24R21 | 2.0 | NCP5244000A | R-454B |
| TTWC-R24R21LX | 2.0 LX | NCP5244000A | R-454B |
| TTWC-R30R21 | 2.5 | NCP5304000A | R-454B |
| TTWC-R30R21LX | 2.5 LX | NCP5304000A | R-454B |
H Series
27" W x 44" HWe source and installFirstCo WHSC Series
The tall H Series opening is served by the FirstCo WHSC cabinet in R-454B. Less common in NYC than the P and T openings, but we can source it.
| Aerosys model (discontinued) | Tons | Replacement | Refrigerant |
|---|---|---|---|
| TTWC-R18H21 | 1.5 | FirstCo 18WHSC | R-454B |
| TTWC-R24H21 | 2.0 | FirstCo 24WHSC | R-454B |
| TTWC-R30H21 | 2.5 | FirstCo 30WHSC | R-454B |
Heat Pumps
TTWH & THHP modelsWe source and installNCP NHP Series
Aerosys heat pumps map to the NCP NHP Series, which heats and cools from one unit on 208-230V. Note the NHP 5000 Series uses a larger cabinet than the S Series opening, so an S Series swap may need the opening modified. Send us the model and we will tell you before you commit.
| Aerosys model (discontinued) | Tons | Opening | Replacement | Refrigerant |
|---|---|---|---|---|
| TTWH-R18T21 | 1.5 | 24" x 32" (T) | NHP5183000A | R-454B |
| TTWH-R24T21 | 2.0 | 24" x 32" (T) | NHP5245000A | R-454B |
| TTWH-R30T21 | 2.5 | 24" x 32" (T) | NHP5305000A | R-454B |
| THHP-30TGB | 2.5 | 24" x 32" (T) | NHP5305000A | R-454B |
| TTWH-R24S21 | 2.0 | 26" x 28-5/8" (S) | NHP5245000Acheck opening | R-454B |
| TTWH-R30S21 | 2.5 | 26" x 28-5/8" (S) | NHP5305000Acheck opening | R-454B |
M Series
42" W x 23" HNo single-unit replacement existsNo single-unit replacement exists
Nobody builds a 3, 4, or 5 ton through-the-wall condenser as one unit anymore. The honest answer is two smaller units, which usually means a second sleeve and a second circuit. That is a design conversation, not a part number. Call us and we will lay out the options for your building.
| Aerosys model (discontinued) | Tons | Replacement | Refrigerant |
|---|---|---|---|
| TTWC-R36M21 | 3.0 | Two 1.5-ton units | R-454B |
| TTWC-R36M21LX | 3.0 LX | Two 1.5-ton units | R-454B |
| TTWC-R48M21 | 4.0 | Two 2.0-ton units | R-454B |
| TTWC-R48M21LX | 4.0 LX | Two 2.0-ton units | R-454B |
| THDC-60MG21 | 5.0 | Two 2.5-ton units | R-454B |
| THDC-60MG21LX | 5.0 LX | Two 2.5-ton units | R-454B |
Chilled Water Fan Coils
DCW modelsQuoted per jobDCW replacements
Aerosys DCW chilled water fan coils have direct replacements available in galvanized or painted cabinets. These are matched on cabinet size and coil rows rather than refrigerant, so send us the model number and the loop details and we will spec it.
| Aerosys model (discontinued) | Tons | Replacement | Refrigerant |
|---|---|---|---|
| DCW-20-115V | 1.5 | Contact us to spec | Chilled water |
| DCW-26-115V | 2.0 | Contact us to spec | Chilled water |
| DCW-32-115V | 2.5 | Contact us to spec | Chilled water |
AboveAir VCU-C
36" W x 19" HCustom built for this openingAboveAir VCU-C units use the same 36" x 19" opening as the Aerosys P Series, so they take the same custom replacement.
| AboveAir model | Tons | Replacement | Refrigerant |
|---|---|---|---|
| VCU-C-018-1-S / VCU-C-018-1-X | 1.5 | 36"W x 19"H 1.5-Ton Thru-Wall Condenser | R-454B |
| VCU-C-024-1-S / VCU-C-024-1-X | 2.0 | 36"W x 19"H 2.0-Ton Thru-Wall Condenser | R-454B |
| VCU-C-030-1-S / VCU-C-030-1-X | 2.5 | 36"W x 19"H 2.5-Ton Thru-Wall Condenser | R-454B |
What this actually looks like in a New York City building
Finding the right part number is the easy half. The half that decides your schedule is everything around it. A through-the-wall changeover in a co-op means board approval, a certificate of insurance naming the building, a reserved service elevator, and a protected path from the loading dock to the apartment. In a prewar building it can also mean discovering that the sleeve was mortared into masonry in 1962 and nobody has touched it since.
Order the equipment before you have the approvals and you will be storing a two-hundred-pound condenser somewhere for a month. We sequence it the other way: confirm the opening and the sleeve condition, get the board package moving, then order against a real installation date. With a 14 to 21 day build on the 36 by 19 units, that sequencing is what keeps a summer failure from becoming a summer without cooling.
If you manage a whole line of these
Buildings rarely have one Aerosys unit. They have one per apartment on a line, all installed the same year, all now aging out together. Once the manufacturer is gone the question stops being whether to replace them and becomes when and in what order. The buildings that handle this well pick the failures off in planned batches during the shoulder season, when crews are available and residents are not sweating. The ones that wait end up paying emergency pricing in July, one apartment at a time, with a board meeting between each.
If your building already runs R-410A elsewhere, our R-410A equipment catalog covers what is still available in existing stock for the rest of the system. For the wider picture on planning a changeover, see our through-wall sizing guide, the co-op and condo approval guide, and our PTAC replacement guide if some of the building is still on PTACs.
Aerosys Replacement Questions
Tell us your model number and we will tell you what fits
Read the nameplate, measure the wall opening, and call. If it is one of the models above we can usually answer on the phone. If it is the 36 by 19, we build it, install it, and handle the building paperwork.
Or send us the details and we will get back to you.