Ducts to floor in basement remodel

[Christheheatingdude]

Interesting points there. However in my experience, ceiling registers do not move the heat to the floor, or even close. Most diffusers spread the patern across the cieling, and that is where the heat stays. By using low wall registers and returns, you are getting a circulation across the cold floor. And trying to keep the warmth where the people are. I am not a scientist by any means, I just know what my customers seem to like best.



[Edited by Christheheatingdude on 12-27-2005 at 08:57 PM]

[atphvac]

For a basement IF i were putting low supplies I would also put low returns. Here is a thought, Is it better to install a system with longer duct runs which increase friction loss, duct thermal losses and possibly increase static pressure, or is it better to get the air out of the ductwork as quickly and with as little equivilent duct length as possible so it can deliver the btus to the space?

[beenthere]

If the supplies are in the ceiling, still put the returns low.

The warm air will not go across the floor if its being blown down from a ceiling reg.

Although your right about the static pressure loss, your suppose to design that it is minimal.

[coolmen]

CEILING REGISTERS AND MOST DEFINITELY LOW RETURN.HAS WORK FOR MY CUSTOMERS FOR MANY YEARS WITH GOOD RESULTS.ADDING EXTRA COST (MATERIALS AND LABER) TO LOCATE NEAR THE FLOOR CAN IMPROVE A BIT.

[jdew1920]

Thanks all for the feedback.

I guess the easiest thing for me to do is to keep the registers in the ceiling and just drop the return to the floor.

I had a new Rheem modulating furnace installed last spring and I have noticed that it rarely runs at the higher speeds - usually only when the program changes temp setting up (like in the morning). So normally the heat just flows slowly (trickles)out of the supply registers - would this still be better flowing out of the ceiling or down low? My intuition tells me if it comes out down low it will immediatly float upward (since low air-flow) and this may allow a nice circulating flow to set up. if they're in the ceiling it seems like it would just sit up at the ceiling. Then again, what do I know.

[beenthere]

You'll be better off with the supplies low also with a mod.

[jdew1920]

Finally getting around to actually doing this. I think I have decided to run the supplies down toward the floor on the outside walls (will be insulated) and then put the return(s) low as well but adjacent to a column towards the center of the space. There is one return down there now but instead of one large one I may use two smaller ones).

Based on what I've seen in my basement with the Rheem mod furnace is that you can stand directly below one of the registers and not even know it is blowing warm air. It just flows very slowly out of the registers and seams to stay at the ceiling level. Near the ceiling (7' high) is about 4 degrees warmer than at 2' off the floor. I think I'll be better off with them near the floor.

Any last pieces of advice or input?

Thanks

[atphvac]

Since first reading this thread I did some more research. Typical supply duct velocity at the register is 300 to 600 feet per minute. We design systems with ceiling heat registers for about 600 fpm (we use zoning systems for basements which increase velocity)and the register we typically use is a 10"x6" Hart and Cooley 831 which at that face velocity has a throw of 14 feet. Even when the face velocity drops to 400 fpm the throw is still 9 feet. I think simple design and register selection is why some guys think it works better in the ceiling while some feel it is better close to the floor. My register in the ceiling works better for us simply because of the design and register selection. With low supply air velocity you are probably making the right choice by going low with the duct.

[deejoe]

[QUOTE]Originally posted by jdew1920
[B]Thanks all for the feedback.

I guess the easiest thing for me to do is to keep the registers in the ceiling and just drop the return to the floor.
------------------------------------------------------
Answer; yes, the easiest way out may be at the ceiling, but the BEST WAY is to take them down to near floor level.Afterall the floor level is where you are when sitting/standing.
Most installers don't bother taking them down to the floor level because it takes more time $$ and $$ material.
But YOU can DO IT RIGHT and take BOTH supply and return down to the floor level (just above the Baseboard.)

[jdew1920]

Thanks for the confirmation of my final decision. But one final thing - finished area will be about 900 sf in one open area. I now have one return in the basement, is there any advantage or disadvantage of having two smaller returns spaced apart vs one large one towards the middle of the area?

[beenthere]

I'd put in 2, if there is any chance you might wall off an area in another couple years.

[jdew1920]

Beenthere - we've already walled off some areas for storage so I don't think we'll be walling off any other areas. I was just wondering if it would help air circulation to have two separate ones spaced apart on each side of the basement or if just one larger one in the middle would be just as good.

Thanks

[beenthere]

My personal preference would be 2, but 1 will work.