HVAC for finishing basement

ossrocks · 12-09-2009, 01:54 AM

My basement has a few heater vents equally spread out around the basement. I'm in the beginning stages of finishing the basement and every time I look up at the duct work I wonder how to deal with it. I'm wondering if I need to have the original installers come give me their advice. (System is about 5 years old)

1. Should I keep the existing vents in the ceiling and extend them down to either the drywall or drop tile ceiling or plan on bringing these down to the baseboard like everywhere else in the house?

2. Do I need to work in cold air returns? Today, there is no cold air return in the basement. How does this impact humidity? Seemed odd to me.

3. I'm assuming if I just extend existing vents I'm not impacting the initial design/load. Is this wrong if I'm adding walls to the basement? It seems as if each room would have one vent in the end.

4. I'm adding a wall around my water heater and furnace but it'll be a nice sized utility room. How do I figure out if I need to address combustion air and is it as easy as just adding vents into a neighboring room? The furnace is not high-efficiency and exhausts via the roof.

Thanks!

**beenthere** · 12-09-2009, 05:56 AM

You will need combustion air intake. Unless one room is the whole basement, its doubtful it would be big enough. You will probably need to add a intake from the outside.

You will need to add returns.

You don't have to extend the supplies to the floor. If your registers are able to direct the air flow to the floor.
If they can not. Then either your supplies, or returns must be low near the floor.

ossrocks · 12-09-2009, 11:13 AM

Quote:

Originally Posted by beenthere

You will need combustion air intake. Unless one room is the whole basement, its doubtful it would be big enough. You will probably need to add a intake from the outside.

You will need to add returns.

You don't have to extend the supplies to the floor. If your registers are able to direct the air flow to the floor.
If they can not. Then either your supplies, or returns must be low near the floor.

Thanks! Great info.

When bringing in combustion air from outside I'm assuming you mean from the exterior of the house. If so, is there a vent solution that only opens when taking in air? If you meant by creating cross ventilation to another room, even better. The utility room will be about 9x13' so no, it won't be the whole basement. This is an area I know little about and greatly appreciate the info.

**beenthere** · 12-09-2009, 01:15 PM

http://www.hoyme.com/

It interlocks with the furnace. But you may need to get a control system add on for the water heater.

This would be for bringing in outside air.