Review: Keystone KSTAP14B portable AC kept us cool during Seattle’s 2016 heatwave

Last updated: 8/26/2016

Our Keystone KSTAP14B portable AC rating: 4.5/5

It’s roasting here in Seattle, Keystone portable AC saved us from melting

It’s HOT here in Seattle, but our Keystone KSTAP14B portable AC unit arrived just in time for yet another 90 degree day.


It’s about the size of a mini fridge and it vents hot air out your nearest window while expelling cold air into the room. Depending on your room size, it maintains anywhere from -6 degrees to -15 degrees difference from the ambient temperature of your home. How fast it does it also depends on the room size, but you should feel a difference within 10 minutes in a bedroom-size room and in about 25 mins in a bigger room.




There’s a lot to love with the Keystone portable AC:

  • It’s portable! Or at least, relatively easy to move around compared with other styles of air conditioners thanks to its wheels and upright design. (However, at ~80 lbs, it is not a travel air conditioner.)
  • Cools a bedroom fast and effectively
  • About as loud as a box fan on high, and the noise is smooth and consistent so I found it easy to sleep in the same room
  • It has a remote! And that remote has all the same buttons as the AC unit itself
  • Caster wheels for easy re-positioning
  • Flexible exhaust tube is generously long, ~6 feet total
  • Runs on normal 115V outlet (just be careful not to run too many other things on the same circuit, it does take most of the circuit’s power)
  • No water pan to empty (on AC mode and fan mode; dehumidifier mode requires some emptying)
  • No protrusion from the window, so it looks nice from the outside
  • Washable mesh filter
  • Programmable 24-hour on/off timer so you can set it up to cool your place before you get home
  • Move it from room to room in under 10 minutes, like you might a box fan, since you have to redo the window kit. We moved it from our living room to our bedroom at nighttime, though, and we had the whole thing up and running again in about 8 minutes.

Here’s a video showing how it doesn’t “cycle” or rattle or sound annoying like a lot of in-wall AC units do.


  • Heavy! But this is true of any portable AC unit
  • Included window kit only works with windows that slide sideways or up and down
  • Exhaust hose is very warm, countering some of the cooling effect. I wish it came with better insulation (supposedly you can get an insulated sleeve for it)
  • At 48″, the included window kit isn’t quite tall enough for our windows (we solved this with a piece of cardboard)
  • Adjusting the temp makes it beep, which might not be ideal in the middle of the night

Here’s a video I made of how the beeping sounds when you change the temp or mode:

Where it really shines


Even though it’s been somewhere between 77-84 degrees in the rest of our apartment as we went to bed every night this week, the AC unit brought the bedroom temp down to 65 and kept it down there until the daylight heat returned.

It’s the difference between sleeping uncovered and uncomfortable vs. cozying up under an actual blanket and not feeling like the other person in the bed is trying to roast you with their body heat.

The AC unit is about as loud as a box fan running on high. If you can sleep through a hotel air conditioner, you can sleep through the Keystone. We are used to sleeping with white noise and box fans, so this wasn’t a big deal for us, but people used to sleeping in silence may find it loud. It’s a consistent loud, though – it doesn’t cycle or stutter like hotel air conditioners and some window air conditioners. It just runs steady, and that makes all the difference in terms of this AC unit’s “sleepability”, in my opinion.


This AC is basically designed for small spaces. It did pretty well in our 500 sq. foot living room/kitchen (we live in a 1 bedroom apartment now), though not as well as it does in the bedroom. We’ll tolerate a warm living room as long as there’s a nice, cool bedroom waiting for us at bedtime, so putting the AC in the bedroom made more sense for us.

Is it worth it for a Seattle apartment? We think so. I don’t know who convinced Seattle builders that we don’t need air conditioning in our homes here, but July – September can be brutal (and 2016 was one such year). We see lots of window ACs and exhaust tubes in windows around our neighborhood, so it’s not just us being wusses about the heat.

That room that never gets cool enough even though you have central air

Even in homes with central air, I could see this being useful for lofts or rooms that just never get cool enough. A lot of two-story homes struggle to get the 2nd floor bedrooms and living spaces cool enough in the hottest parts of summer. A portable air conditioner might save you having to move your mattress downstairs or staying out of that loft area you enjoy during the cooler months of the year.

Homes with strict community rules

Portable AC units are almost invisible from the outside. It doesn’t protrude from the window at all and its “in window” footprint is small. This should please your HOA, landlord, or busybody neighbors.

No DIY required

Just plug it in and go – no holes to drill, no insulation to stuff into cracks, no wiring. Much better than some of the alternatives out there…


Photo credit:

Keystone portable AC unboxing

The Keystone portable AC unit arrives in a large, two-piece cardboard box with a plastic strap holding the halves together. With the plastic strap removed, you can easily separate the two halves of the box, but you shouldn’t separate them until you’ve got the AC unit inside your home or apartment.

Heads up: it’s heavy

It’s about 80 lbs and pretty big so plan on wheeling it into your place and having a helper for stairs unless you are a muscle god.

Not much assembly required!

The exhaust tube and collar parts are on the top and separated from the AC unit itself with a block of packing Styrofoam. I expected to have to put a lot more fiddly bits together, but this is about as pre-assembled as Keystone could’ve made it.


Lift them out and remove the Styrofoam  here’s the AC unit itself. Fortunately, you don’t have to lift the AC unit out of the box or cut the box off from around it. The box is already in two parts, so all you do is lift the cardboard box up and the unit is left sitting on the other half of the box.


The AC unit is on casters, so it’s (relatively) easy to wheel it into place once you’ve unboxed it.

Keystone AC on-unit controls

You can operate the Keystone AC with the remote or the on-unit controls. They’re pretty self explanatory, but some notable things here are Swing (which causes the lid to lift and lower so air isn’t just emitted straight out of the unit) and Sleep (which gradually shuts the unit off after 30 minutes).




The “Follow Me” feature is a nice touch that separates this Keystone portable AC from some of the similarly priced competition. When it’s on and the remote is pointed at the unit, the remote sends a temperature reading to the mothership AC unit every 3 minutes.

This is a nice little touch that helps you get the room to the temperature you actually want it, not the temperature the AC unit thinks it is from a reading taken at the unit itself.

Other than that, the great thing about this remote is it duplicates all of the same buttons that exist on the unit itself (because the last thing anyone wants to do in this heat is get up again).


Window kit appearance, dimensions

That plastic piece that holds the hose up to the window (the “window kit”) is, at minimum, 26.5″ tall. At maximum, with both pieces in position, it’s 48″ tall. You’ll need a window that slides horizontally or vertically to hold it in place. Our windows slide horizontally, so our kit is placed vertically.

Here’s what it looks like from the outside:


Cost to run

This AC unit uses about 1580 watts as it runs. At 10 cents a kilowatt hour (your utility costs may vary), that works out to about $3.80 day to run it for 24 hours a day, which you probably won’t.

It’s probably closer to $1/day with typical use. (So worth it) 

How noisy is the Keystone portable AC unit?

As stated earlier in this review, it’s about as loud as a box fan running on high. However, it’s a consistent noise, a lot like a white noise machine might generate. It doesn’t cycle on/off like some AC units, beep, click, or anything annoying like that.

From the manufacturer:

  • 55 dBA on high (close to a dishwasher or clothes dryer)
  • 52 dBA on medium
  • 49 dBA on low

Why we chose Keystone over competitors

Basically, it had the best BTU to cost ratio we could find.

The more BTUs, the more powerful the AC. Our budget was firmly “under $500”, so we wanted the most bang for our buck. The reviews on Amazon were great and we were dying in this heatwave, so we ordered it and we love it!

The things that really sold us on the Keystone portable AC:

BTUs matter

Portable air conditioners vary in terms of BTU. Generally, the more BTUs, the more cooling power and the larger a room the AC unit is recommended for.

The Keystone KSTAP14B is rated at 14,000 BTUs, and the manufacturer states that this is suitable for a 700 sq. ft room. Meanwhile, this well-rated and less expensive EdgeStar model is rated at 12,000 BTUs, which doesn’t look like that much less until you see that the manufacturer only recommends it for a 425 sq. ft space. That’s a pretty big difference in the amount of space cooled, and it’s a pretty big difference in how effective two different AC units might be in the same room. We figured we were best off getting the most BTUs and beating back the heat with raw cooling power, and that strategy seems to have worked.

Generally speaking, portable AC manufacturers pair these BTU ratings with these sq. footage recommendations:

  • 14,000 BTU : 700 sq. feet
  • 12,000 BTU : 425 sq. feet
  • 8,000 – 10,000 BTU : 350 sq. feet
  • 5,000 BTU : 150 sq. feet

Keystone KSTAP14A vs. Keystone KSTAP14B

Shopping around a bit will reveal that there are two Keystone models with similar names. The only difference as far as we can tell is the body styling; the A looks straight out of the 80’s and the B has a sleeker body design. The rest is the same.

The bottom line

Summer 2016 in Seattle shall be remembered for its hot, record-breaking heat. I’m also 9 months pregnant as I write this, so this summer has already felt like trying to medal in the misery Olympics. I hadn’t had a decent night of sleep in over a month when the Keystone KSTAP14B portable air conditioner arrived and transformed our ability to sleep through the night. You can’t go wrong with this AC unit!

» See the Keystone KSTAP14B on «

Keystone KSTAP14B


Price to BTU ratio


Cost to run




Compatibility with variety of windows



  • It works! Really well, too
  • No DIY skills needed
  • Unobtrustive design
  • Uses normal electrical outlet for power


  • Only works with windows that slide open
  • Heavy!
  • A bit pricey, but after a few summers should feel worth it


One response to “Review: Keystone KSTAP14B portable AC kept us cool during Seattle’s 2016 heatwave”

  1. Jason Craig Avatar
    Jason Craig

    I have a Keystone portable. Yes it’s heavy but is so much easier than a window unit and doesn’t mess up my windows. My house has central but my bedroom doesn’t get cool enough and it’s wasteful to turn the central down when rest of space is empty at night. The sound is no louder than a window unit and as stated it’s constant so you tune it out. I find the sound helps me sleep. It does moan or grunt a bit on occasion when compressor cycles but it’s not really noticeable. I’ve used it for three years bought it in 2017. Since I’m upstairs I leave it out of the way in the corner during winter. That fact means I can set it up as soon as I get stuffy when weather changes for comfortable sleep. Not sure how many years these last but I will definitely be looking at a Keystone again when time comes. I believe I bought it at My electric bill is still average no huge shock. Maybe $15 a month and it runs about 10 hours a day from late May to end of September. I do use foam in my window and duct take to seal the exhaust vent so bugs don’t get in. You can screw it in for security but it’s not a issue for me. Outside it’s barely noticeable much less than my neighbors who leave ratty window units in. I considered a window unit to reduce up front cost. These are more expensive but the ease of install removal and storage are worth it. No carrying a dirty window unit up and down steps each year and cleaner storage I don’t have to set it in a garage or basement. You can easily roll it into a closet or leave it in the corner like I do. The next thing I’d like to find on my next is heat so when winter comes I can take chill out of room in early mornings. Nice thing is this unit is self draining. It evaporates the water with the exhaust heat. You do need to drain it before storing. I roll it in my shower or you can use a hose. Keystone is made by a little know company for the USA market but they are a major manufacture elswhere I believe Keystone is just the name used here in the USA. Search the brand when buying if you find a different brand as it may be same company selling under a name for a chain but same decent equipment. .

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