I contacted them when I first moved into this house in late 1990 and put my old furnace under contract, and I have had their services expanded now three times over; not just the furnace but for other things that all attach to heating and cooling and humidifying, for the past however many years that is - 27. I've been using them for quite a long time. I have searched others and went on Angie's List to do a search of others and actually had a couple out to the house, but always felt more comfortable - and I won't say better-treated necessarily - but more secure in my decision that A-Advantage was worth continuing with all these years. They did two projects very close together. One was installing what's known as a mini-split in an addition to the house, which is a heating and cooling unit designed to work in one particular space. It's a wall secured mount and is very common throughout the world with the exception of the U.S. and it's now becoming more common here than not. Interestingly enough, we're the only country that continues to use whole house central heating and air conditioning. That was the more major project, but the minor project done almost contemporaneously was installation of a whole house humidifying system, or humidifier. So they did those two things for me not too long ago. In terms of cost and complexity, the mini-split was the bigger project. The humidifier was suprisingly not at all complex and not at all that expensive. For everything, I'd give them an A. It was an honest deal, they gave me alternatives, and I did comparable pricing elsewhere. And the company that came to the house that said that an inspector would be unnecessary offered something which was mostly cosmetic, but their price was for a somewhat smaller unit, was just a little bit less than that, so they weren't giving me any big deal and they would have given me some headaches. And the warranty was not nearly as good either. You buy cheap and deal with cheap or spend just a bit more and get the quality you want. For quality, A - totally responsive. I had a problem for example with one humidifier after they installed it. They were here the same day and took care of it. Not only did they show up on time, but they sometimes show up en masse if there's an issue and one of the fellows says well, I'm not sure, let me call. And I may get two or ... another one or two people from the same company showing up, and among them they work it all out and they get it done. Everybody's been totally professional, totally personable, and extremely responsible. I don't think there's anything left for me to use them for. They come in; they do service on each of their things annually. If the humidifier wasn't done in November, it was certainly the next month. The humidifier was very inexpensive, interestingly. I think that probably cost, if I'm thinking correctly, that maybe cost, all things considered, which includes not just the unit itself but running what the call a condensate line- that cost, I wanna say something under $700, maybe $675 or something like that. This one was designed to work with the furnace that I bought from them after my big old monster gave out a few years ago. Right down the list, I give them A on everything. I'm thinking it may have been a little bit more than $675; let's do $750 just to be safe.