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Have You Seen What’s in Your Hotel Room Air Conditioner?

Ptac Hvac Dirty Moldy Fan Air Conditioner Hotel

You just never know what you’ll find in a hotel room. I’m a curious guy so I have to check things out, and this week I found some interesting stuff in the air conditioner of the room they gave me here in Hattiesburg. As I was sitting at the desk, I noticed that the fan looked white as the squirrel cage blades spun around. So I popped the cover off and here’s what I saw.

The blades are coated with what is either some kind of corrosion or a white microbial infestation (a.k.a. mold). It looks nasty and seemed to be a little bit wet. When I looked at the inside of the cover, I saw the stuff below.

ptac hvac dirty moldy fan housing air conditioner hotel

This type of unit is called a package terminal air conditioner (PTAC, or PTHP if it’s a heat pump). It’s a through-the-wall unit, and hotels often don’t maintain them well, as you can see in the photos above.

I’ll be in a different room soon. Even though it doesn’t smell much, I get a little whiff of something when I first walk in the room and also each time the unit kicks on when I’m sitting at the nearby desk. I’m lazy and would prefer not to have to move, but after having suffered through a month-long sinus infection recently, I’d rather not take chances.



I talked to the front desk person this morning to ask for a new room, but the hotel is sold out. Instead, they sent a maintenance person to my room today and did a good job of cleaning it up. I can’t see any of the gunk that was there before, and the smell is gone. Thank you, Hilton Garden Inn!

ptac hvac clean fan air conditioner hotel


Allison A. Bailes III, PhD is a speaker, writer, building science consultant, and the founder of Energy Vanguard in Decatur, Georgia.  He has a doctorate in physics and is the author of a bestselling book on building science.  He also writes the Energy Vanguard Blog.  For more updates, you can subscribe to the Energy Vanguard newsletter and follow him on LinkedIn.


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This Post Has 15 Comments

  1. Wow! I’m curious if the hotel
    Wow! I’m curious if the hotel has a Maintainance contractor for AC service and if so the hotel needs to renegotiate the contract to say the least. This is neglect and is inexcusable. Good catch Allison! Enjoying your articles.

  2. This is neglect at its peak.
    This is neglect at its peak. The hotel surely has a mechanical Maintainance service contract and if so the hotel needs to reconsider the contractor. Awful! Disgusting but interesting. Good catch!

  3. I’d say this is probably the
    I’d say this is probably the case in 99.9% of hotels nationwide. I’ve looked at everyone in rooms I’ve ever stayed at when possible, ESP when the conditioner is turned and the smell is terrible. 
    Move? Were you any luckier in another room? I can’t imagine they care at all in most hotels. The most neglected, aside from mattresses, fixture we’ll be unfortunate to survive in the industry.

  4. And here I was thinking poor
    And here I was thinking poor temperature control was the biggest problem.

  5. Nice images to enjoy with my
    Nice images to enjoy with my morning coffee;~) 
    A few years back, when I was running a C&I; efficiency program I spent quite a bit of time dealing with PTACs and PTHPs. In addition to the inefficiency and poor control this was one of the major problems I saw. I remember pulling covers off these things, looking for nameplate data, and finding all sorts of unidentifiable globs, coatings and smells. 
    When I’m traveling in areas I’m familiar with I use my select list of hotels/motels that have a track record of cleaning their units. Unfortunately it’s a small list. 
    Lot’s of people are concerned about cleanliness in commercial kitchens. Having spent a lot of time in them as well I can tell them they should worry more about the HVAC systems in the room they’re staying in.

  6. Health issues are of course
    Health issues are of course top priority, 
    This is the same thing as a homeowner who doesn’t change their furnace filter for 2 years. 
    How much longer does that PTAC or PTHP have to run to warm or cool the room to the desired temperature with all that dust clogging up the airflow? How much more energy will it use? 
    You’d think the hotel would care about that even if they don’t care about the health concern.

  7. Southern climate +
    Southern climate + overcooling + short cycling + little or no maintenance = your pictures  
    Btw, cut a patch out of the vinyl wallpaper on the exterior wall and tell me what you see 
    I don’t want to you guys what’s on the bed sheets…

  8. Allison 

    This is exactly what the bed bug exterminator requested.

  9. My first full time job out of
    My first full time job out of high school was in hotel maintenance. It was the tail end of the summer of 1980, the hottest summer on record in Dallas/Fort Worth, Texas. I was initiated into my new gig via moving tons of ailing PTACs to the on-site shop for repair and then back to closets on the floors to be kept as spares. At least we had a regular filter change program, but these things even when maintained decently are beat to death in hotel settings. At another hotel I worked at a few years later, I’d try to remove the PTAC whenever we had a room down for maintenance needs. I’d take it outside and wash it…incredible how much gunk would stream out and onto the pavement. 
    The PTAC design itself is problematic: I have yet to see one that can maintain consistent temperature control and not cause uncomfortable drafts for room occupants. The most comfortable air conditioning in a hotel room I ever experienced was at a Hilton in Indianapolis; instead of a PTAC it had an upflow chilled water fan coil unit in the wall controlled by a remote thermostat…and the filter was CLEAN! It was also quiet, which I’ve never seen from a PTAC. PTACs….a window unit on steroids…and sounds like it, also! 
    Oh, and when I was a kid we would occasionally stay in Rodeway Inns on family vacations. They were built out of concrete block and had chilled water fan coils in a soffit near the bathroom. And they were whisper quiet. Hotels should consider the noise and health hazards PTACs pose when proposing to build or remodel…whisper quiet HVAC, as well as sound deadened rooms, would certainly entice me to stay there vs. the typical PTAC plagued “bumps in the night” via thin walls and ceilings place that’s all too familiar to a weary traveler.

  10. So what’s the best type of
    So what’s the best type of HVAC system to put in a hotel room? Ductless mini split?

  11. Oh great,  

    Oh great,  
    I am getting ready to take a few day road trip, guess we will have to stay in my truck – the wife won’t be happy 
    Thanks Allison

  12. Motel and HVAC maintenance
    Motel and HVAC maintenance contract are about as likely together as oil and water. 
    Miserable though they are, the attraction of PTAC / PTHP units is that they can be installed and (not) maintained by non-HVAC contractors or even licensed EPA techs. 
    In Florida, if a heat pump has an electrical plug, is self-contained and has less than 3 tons capacity, no license needed. I imagine similar rules apply in other states. 
    Unless the in house maintenance guy / gal feels the need to open up the sealed refrigeration system, they needn’t even have an EPA card. If they have the card, they can perform repairs without a contractors license as an owner’s employee. 
    Most complaints are meant as Allison’s was – move guest to another room.

  13. Scott W.:
    Scott W.: Yeah, I’ve pulled off covers before but this is the worst I’ve seen. 
    Marty: This is the worst I’ve seen before. I didn’t end up moving because the hotel is fully booked, but they did send someone to clean the unit. I’ll post a photo above after I finish commenting. 
    David B.: Yeah, it’s definitely more than temperature control. 
    Bill S.: I don’t know if this one’s on your list, but it’s Hilton Garden Inn, which has become my favorite hotel over the last several years.  
    Ira E.: I don’t think the air flow is affected all that much. The coil was pretty clean. 
    Mike M.: This hotel doesn’t have wallpaper. I think a lot of the better hotels learned in the ’80s and ’90s that vinyl wallpaper and Gulf coast humidity didn’t go together. I make a point of not looking at the mattress, but at least they clean the duvets between guests at Hilton Garden Inn. 
    pat: I’m not saying anything about bed bugs because I don’t want to jinx myself. I saw my in-laws go through the huge hassle of trying to get of them a couple of years ago. 
    Cameron T.: The filter on the PTAC in my room was completely clean. It was the downstream side of the unit that was all gunked up. Yeah, chilled water fan coils would work well. So would a ductless multi-split, especially one of the models that can bypass the condenser and move heat from one zone to another. One of the reasons I like to stay at Hilton Garden Inns is that they do have soundproofed rooms. I’ve never been kept awake in one by noise in a neighboring room. 
    David: I like mini-splits or multi-splits. As Cameron mentioned, chilled water fan coils would work well, too. 
    Carl C.: Just pop the cover and see what it looks like before you settle in. 
    Curt K.: Actually, they didn’t move me because the hotel is full. Instead they sent someone to the room to give the unit a good cleaning. See the photos above that I’m about to post.

  14. Good information. No one
    Good information. No one really checks the AC unit in the hotel. What kind of smell was coming? 
    The hotel management must do a repair on the AC units on monthly basis. Curious on their carelessness.

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