Monday, November 16, 2009
The attic area
Here's the ERV hanging from chain/springs to isolate any noise or vibration. That's my rat's nest of vent pipe going up through the ceiling. It's common practice to just go up through the roof several times with the vents to simplify the system (and save on pipe). However, if you talk to a roofer, they'll tell you that they figure in $50-100 for every vent they have to flash, so there's no money savings by having 3 or 4 roof penetrations. On the closest duct, you can see that it has a damper. That allows balancing the system so that the ERV doesn't cause high or low pressure in the house when running.
This is one end of the L-shaped attic. The ERV intake is out the gable end. The insulated duct isn't hooked up in this picture. Code requires that it be insulated, in part because it could get condensation on it. In practice, I haven't seen that happen where an ERV is used to control humidity. Even still, there's no reason to have 25' of cold 6" pipe in your conditioned attic. I used insulated duct for several feet on the other distribution pipes from the ERV. A few feet really cuts down on the fan noise that runs through the system. Makes it whisper quiet.
This is down the other "L," showing the duct for the kitchen hood fan. The fan motor is remotely mounted and suspended from the roof with chains and springs to isolate noise and vibration. Since it is two floors up from the kitchen, it can't be heard in the kitchen. It can be heard in the spare bedroom, but it's not annoying at all. Once I get the variable rheostat on it, I don't know if it can be heard even upstairs. The other HVAC is the kitchen woodstove chimney and the ERV exhaust from the bath and second bedroom. The attic areas are kind of small, but I've noticed one great thing with spray in foam. It doesn't hurt at all if you bump your head.# posted by gnome-honey @ 12:26 PM 
