# Through-wall air conditioners: are you stuck when they need replacement? **URL:** \ **Category:** Factual Questions\ **Created:** [May 6, 2018, 7:44pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713 "2018-05-06T19:44:47Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [May 6, 2018, 7:44pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/1 "2018-05-06T19:44:47Z")
About those air conditioners that mount in the wall, through a sleeve that’s the size of a small window: when they wear out, and need replacing, do you have to find the exact same model to fit the same sleeve? Or do you have to replace the sleeve? Does it take a carpenter to replace them every few years? Or are there standard sleeves that fit multiple brands and models? ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [May 6, 2018, 8:48pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/2 "2018-05-06T20:48:55Z")
Unless the sleeve cut into the wall is too small for the new AC, it should work. Any excess open space around the edges could be filled in easily with foam insulation & duct tape. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [May 6, 2018, 11:32pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/3 "2018-05-06T23:32:26Z")
I’ve got expandable edges to fit the space, but that was to fit a window (which used to be a standard mounting method) Same for the bigger wall-mounts. The smaller ones I’ve got in walls, the hole has been cut to fit exactly. But yes, the small one were more or less standard size. Because the wall studs are at standard spacing, ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [May 7, 2018, 1:27am UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/4 "2018-05-07T01:27:09Z")
Apparently they’re a fairly standard size, and some manufacturers like Friedrich make units that fit other manufacturer’s sleeves. However, because they’re relatively less common and usually higher capacity (sometimes requiring 240 volts) than typical window a/c units, they can be quite expensive. You can’t really use a window a/c unit without getting creative with sheet metal and other unorthodox modifications because wall units are designed to intake and exhaust air out the back (when viewed from inside) only, whereas window units usually intake air from the sides and sometimes the top. There’s supposedly some units out there that can be converted between window and wall installations, but I haven’t really looked into the particulars. ---
**Author:** ![TSBG](https://avatars.discourse-cdn.com/v4/letter/t/77aa72/32.png) [@TSBG](https://boards.straightdope.com/u/TSBG)\ **Post date:** [May 8, 2018, 5:52am UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/5 "2018-05-08T05:52:25Z")
Depending on how the exterior walls are made–thickness, basically–it’s possible to put a window unit through a wall. Optimal, no, but it can be done. I lived in a place where the prior tenants had done this in one room because there was no central AC and the windows were not double-hung. When that unit died we could have put in a proper wall-through AC unit but it was cheaper to kludge in a new window unit through the existing hole. Funnily enough my daughter (whose room it was) hated AC and we rarely used it. ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [May 8, 2018, 1:04pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/6 "2018-05-08T13:04:52Z")
By the way, the trade name for those types of air conditioners is PTAC, for packaged terminal air conditioner. Nice to know if you need to search for them. ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [May 8, 2018, 2:13pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/7 "2018-05-08T14:13:17Z")
PTACs are different, or at least they’re a very specific variant. They’re usually much larger and mounted near or on the floor (you see them in hotels mostly, or New York City apartments/condos). Inside they look like enclosed radiator cabinets or very large a/c units. They’re almost always heat pumps with electric resistance heaters, or they’re hooked up to the building’s hot water heating loop if it has one. A through-wall a/c is maybe half the size and simpler in design and function. The one main advantage to a PTAC is that their larger size allows for bigger fans and more sound insulation, so they can run quieter. ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [May 8, 2018, 3:28pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/8 "2018-05-08T15:28:37Z")
> [@](#): > > PTAC units are available in a variety of different capacities; however, most of the time, no matter what manufacturer they are made by, they all tend to be approximately the same size; this is especially true of the through the wall units. Why? There is already a hole in the wall that is built for the PTAC unit and if the manufacturer’s made them in different sizes, it would be hard for the consumer to upgrade their existing units. > > Size > There is an industry standard dimension for through the wall PTAC air conditioner units. The dimensions for the wall sleeve are 42" wide, 14 1/8" deep, and 16 1/16" in height, on average. This makes fitting a new sleeve into the hole that has already been created for the existing unit easy. Customers are able to update their existing units without any worries at all. Of course, ptac air conditioner units are designed to fit perfectly within the wall sleeves; therefore, it is also easy for the consumer to switch to a different brand if needed or wanted. For example, at the current time Carrier ptacs are no longer being manufactured and parts are becoming scarce. This will probably force many consumers to update to new units by a different manufacturer in upcoming years. [http://ptacairconditioner.org/ptac-unit-size-and-capacity.shtml](http://ptacairconditioner.org/ptac-unit-size-and-capacity.shtml) ---
**Author:** ![Doubticus](https://avatars.discourse-cdn.com/v4/letter/d/e56c9b/32.png) [@Doubticus](https://boards.straightdope.com/u/Doubticus)\ **Post date:** [May 8, 2018, 3:47pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/9 "2018-05-08T15:47:08Z")
I bought a floor mounted unit for my son’s room. It has a flexible duct that attached to an adjustable window insert. It works really well. ---
**Author:** ![ZonexandScout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zonexandscout/32/544_2.png) [@ZonexandScout](https://boards.straightdope.com/u/ZonexandScout)\ **Post date:** [May 8, 2018, 3:57pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/10 "2018-05-08T15:57:31Z")
> [@Doubticus](#): > > I bought a floor mounted unit for my son’s room. It has a flexible duct that attached to an adjustable window insert. It works really well. I’ve used these several times for computer and data rooms and they usually do the job very nicely. The only problem is that you have to consider the condensate (water) pan that most of them have. On one of my units, we had to drain the pan at least once a day, but most of them have a small pump and you simply route the drain tube to a convenient point. They also seem a bit noisier than the in-wall units. ---
**Author:** ![jjakucyk](https://avatars.discourse-cdn.com/v4/letter/j/3d9bf3/32.png) [@jjakucyk](https://boards.straightdope.com/u/jjakucyk)\ **Post date:** [May 8, 2018, 5:12pm UTC](https://boards.straightdope.com/t/through-wall-air-conditioners-are-you-stuck-when-they-need-replacement/813713/11 "2018-05-08T17:12:38Z")
Those portable units are a whole other ball of wax. There was a big discussion at [Portable air conditioner - one hose or two? - Factual Questions - Straight Dope Message Board](https://boards.straightdope.com/sdmb/showthread.php?t=569887) regarding one hose versus two hose units, and how they should work versus how they’re actually constructed, and all the bizarre operational issues they can have. That said, I don’t recall any discussion about draining condensate. All the ones I’m familiar with sling the condensate across the condenser coil via the fan to help cooling efficiency and to evaporate the condensate and blow it outside with the hot air. It does create some splashing noise along with everything else, but it eliminates the need for a drain pan or hose.