Hello. The whine from our neighbor's vent fan, directly opposite our dining room window, has been so severe and at such an unfortunate frequency that its noise could be heard even in the farthest corners of our big house. We tried a variety of acoustic solutions, some suggested on websites like this one - basically following the idea that a longer pipe, or a "tee," or stepping up the pipe diameter, or running it to the ground behind bushes, adequately kills he noise. No go in our case. We ended up piping the vent into an old plastic garbage can filled with discarded fiberfill pillows and comforters. They must be packed loosely enough to allow the very moist hot air to escape freely, but densely enough, obviously, to kill the noise. It's also important to drill air vent holes in the sides, top, and bottom of the garbage can. It's an experiment,but so far, so good. - SL

They're VERY loud IMHO. Totally NOT worth it for that feature alone. My cousin put one in for the garage apartment he did, and we stayed there for a couple of weeks. The heater was in a tiny laundry room space that didn't have the wall and access door put in yet, and the whole place has wood floors, but the bathroom and 1 bedroom were in between us and the heater. We could barely hold a conversation with the door closed while that thing was running. We had suggested a tankless gas fired for the application, as that is what we have and love, but he couldn't find anyone that'd give him a decent install price on it so he went "conventional". At least with a power vent tankless, you'd only hear it when someone was using the hot water. We were there for 2 weeks, and I never did get used to the sound of that thing kicking on in the middle of the night to keep the tank warm. Even in the daytime when you were up and around, it was startling. And,my cousin is kicking himself for installing it and not casting the net a little wider to find someone to do the tankless. What good is saving money when you have to use it to buy earplugs?

I found out I can get a Generac brand 5000W unit for about 525 (plus tax). Hubby reminded me he would be able to take it tailgating! I found out there are interlock devices where it is wired in to the breaker box but for less money than a separate panel. I have to ask my electrician friend about that. It sounds cool. I think the 5000w would be all I need to be comfortable as I think it can run the furnace as well. We'd just have to be conscious of what we were running at one time and not overload it. Does anybody know if these power vent hwh are usually hard wired to the breakers, or if they plug into an outlet? (which I believe would have to be wired separately.)Since it's a new install I'd think I could go either way if installer was willing. I never considered getting one until people pointed out the power loss issue with the water. That doesn't concern me THAT much, but it did get me thinking...

You may want to consider an atmospheric vent style with a flue damper. These heaters can get an efficiency of 0.67 to 0.69. This is as good as some of the powered vent models. They should be much less expensive to install and buy. See this announcement from Rheem. On venting out the side of the house and fumes I would not worry about it, if you install to code. We have gas furnace that vents out near a window and it is no problem at all. You just have to allow for ice and snow build up below the vent if you live in a freezing winter climate. Here is a link that might be useful: Rheem Energy Star Phase II Heaters