<p>does that closet have a load bearing wall? perhaps that is where the expensive part. also, if you are using forced air, the duct work is very expensive.</p>
<p>I would talk to more than 10 contractors before making a decision. Listen to their thinking/presentation carefully.</p>
<p>Make sure that there is enough space in the garage for the two heaters and your cars! The city code might require you to install some sort of a protective barrier if the heaters are to be located where they can be hit by a car, which might not leave much space for the car when all is said and done. :)</p>
<p>What artlovers said: talk to several contractors (I think you already know the drill). Good luck! I would not want a hot water heater in the middle of my house.</p>
<p>two floors - duct work on both floors? Right now how does this work? vents in the ceiling of the lower level? vents in the floor of upper?</p>
<p>I am spending a lot of time lately learning on how ductwork can be installed, both what contractors prefer to do, and what works adequately for my needs even if they don’t see it as the best method.</p>
<p>I really like artsloversplus suggestion of 10 contractor interviews, if you have enough time in your life for that. Any advice and opinion you get in an estimate interview is on their dime. Later you are paying while they stand still to answer your questions. Probably this is the first thing that occurs to anybody having work done except me.</p>
<p>edit: I guess you are going to need additional plumbing, too?</p>
<p>Along the same line, I once tried to put central air in a house, and was told individual room units would work better because of the duct work - there were several additions to the house. And, if you are going to have any type of centralized humidifier or dehumidifier, that has to be included.</p>
<p>Hotel type heating/cooling units have been recommended to me by two contractors recently. That won’t work for me but might for someone else. The cost quoted: around $1500 for a unit that is adequate for a very large space: maybe 600 sq ft?</p>
<p>Although hvac units in the attic seem to be the norm… they really make me nervous and I am trying to avoid it if possible. Yes there is a overflow pan, but still… And they are sometimes hard to access to repair… And you have to make a decision about putting them in conditioned or unconditioned space. After much investigation, in a hot climate, I am pretty sure I am only comfortable with it in conditioned space. That means a higher cost for insulation… at least for my project.</p>
<p>I am doing several small renovations: the first had a heater go in attic about six months ago and it has already proved to be a very very bad idea.</p>
<p>The current project will not have a heater in the attic. If necessary I will just run an extension cord from the main house to plug in some space heaters till someone is willing to come up with a better (and affordable!) solution for me.</p>
<p>I interviewed 7 contractors just for a small roof repair work, it was not leaking and just replace some broken tiles. I got wild quotes ranging 2000 to 500, I finally got the $500 guy did the work, he was very good.</p>
<p>Your job is a major endever, I would spend 2-3 months to talk to every HVAC guy I can get a hold of and thinking over their quotes before making a decision. You may save over $10,000 :)</p>