Penguinaire LLC

Very well, they were very professional and personable. Family owned and operated. Honest and punctual.

Got a recommendation from a neighbor who has used Penguinaire for several years. 
Phil responded to my call promptly.  We arranged a visit to survey what I had, and determine what I wanted.  I told him what I wanted - I had already had three estimates.  He didn't try to upsell, and gave me a fair price that was inline with the lowest bid I had gotten.
Since my system was still functioning, we were able to schedule the replacement for the first moderate day of temp scheduled.  Luckily, the weather predictions held.  Phil brought out extra crew to make sure everything got done in a single day.  He was able to move the exterior unit to the side of the yard, which has opened up the rear of the house for a patio.  Good customer service and follow up, making sure everything was functioning well.
Overall, his crew did a good job replacing the units, and cleaned up after themselves like one would expect.  I would recommend that you give them a call.

n

We purchased a foreclosure and moved in with no guarantee on any of the systems.  It was winter when we moved in so we new that the heating system worked but no idea if the A/C would work when needed.  June rolls around and to no one's surprise the A/C did not work.  We called Penguinaire and the guy came out.  He is an educator in the sense that he wants you to understand your system as much or little as you want to know.  He was not in a hurry nor did he inflate costs or the story behind his troubleshooting, unlike so many other technicians.  We ended up replacing a simple part, I don't remember what right now, and we were up and running.  
Note, if we flash forward to yesterday, 7 March 2013, we had a one day wonder snow storm here in Virginia.  Of course our heat went out as the storm rolled in over the night but the house was tolerable.  I called my home warranty company to have someone come out and asked if Penguinaire was one of their contractors; they are not.  They gave me a company who I looked up here on Angie's List and other sites who had only negative reviews.  I called my home warranty company back and requested a different contractor.  They balked at first especially when I mentioned Angie's List, go figure right, but they reluctantly scheduled another contractor.  This group is not on Angie's List and I really couldn't find anything on them from other sites.  They called and 50 minutes later my ear was sore from the rhetoric this guy was throwing at me.  By the time he was done talking he had determined that I needed a completely new system. because it is 20 years old.  Hmmmmm, he hadn't looked at it and I only answered his original question of what's wrong with, "The heat stopped last night and my thermostat now gives me an error code."
From that comment he explored the whole world of heating problems and then decided the sky had fallen and that I needed a new system...probably because it was under a warranty, right?!  I don't operate like that so I called Penguiaire back and the guy troubleshot my problem over the phone in 15 minutes.  It turns out I had let my air filter go too long (although it didn't look bad in my opinion) and that it tripped the high or low temp switch (or something like that).  All I had to do was hit the reset button and voila I was having a heat wave!
Penguiaire is awesome and I highly recommend them if you live in Fairfax County.