Mike - The house is located in NJ in a climate zone labeled 4. The house is 2800 square feet plus a 1400 square foot unfinished basement. The house will have two HVAC systems.. The first system will run the first floor and is sized to handle the future finished basement.. The other system will be dedicated to second floor... The reason for the hi/lo as per the project manager is that the hot air should come in lower in the room so that it will rise and warm the room.. And then putting the cold air supply higher it will blow out and across the room and then get lower to cool the room.. He also mentioned that by doing this you avoid having a "draft" feel because ceiling vents will blow down onto you vs the wall vents that blow out above your head.. Theoretically what he is saying does make sense, however the placement of these vents sounds very unsightly, and again, not something I have ever seen before.. I have only ever seen floor or ceiling vents.. My thing is that the way he was saying that this setup is more money just doesn't make sense.. I would think that this is the cheapest route since you are running the duct work to the same wall cavity.. This would be compared to running floor and ceiling vents.. Unless I am mistaken that you only get one or the other.. I was under impression that HVAC utilized both floor (heat)and ceiling vents(cooling), however I was reading online and it looks now like you either do floor OR ceiling vents.. With that being said, perhaps the project manager is speaking correctly..

As for system setup goes, they are putting the second floor HVAC system in the attic.. At this point in the build and large part my fault and architect, is that there was never a section put in to have everything run from the basement.. I thought it was weird that many house plans online had an area that was blacked out or had an "X" and my plans did not.. Not being fully knowledgeable on the subject I didn't think anything of it.. Now I realize it was just that putting the system in the attic around here is just common practice so unless its specified differently you just go that route..

"He also mentioned that by doing this you avoid having a "draft" feel because ceiling vents will blow down onto you vs the wall vents that blow out above your head."

Aren't ceiling vents on the second floor going to blow down on you? Are you going to have any ceiling vents directly above any beds? It may be difficult, but see if you can estimate where the beds will be placed in the upstairs bedrooms.

Having two wall where the centers are 6 feet apart is not going to make much a difference. I suppose you can close the low vent in the summer, and the high vent in the winter. But it is not worth it if they are ugly.

What is the efficiency rating of the furnace in the attic? I will bet it is only 80%. This is another reason furnaces should not be installed in attics. The HVAC contractor could install a high efficiency condensing furnace if he has the skills to do it. Most don't want to be bothered.

When we went to make some of the contract decisions I specified energy star rated equipment.. Based on this the furnace should be one of the models with 96% efficiency and the air should be minimum 16 seer..

My parents' house had registers on the wall. Supplies were up high, returns were at floor level. For my own house, some are in the ceiling, some are in the wall.

Get the model numbers of the furnaces, condensers, and coils. Ask for the AHRI number for each system.

I saw a couple of systems where both high and low registers are installed in the walls. They are designed so the upper are opened in hot weather for cooling and the bottom are opened in cold weather for heating.

Hey njdirect134, I am also thinking of building a custom house in NJ. Can you tell me how your experience was? do you have a blog? I am wondering how much it cost etc.

Thanks

Mike

I have something
different - Verano climaconvectors. They do the same job like HVAC but are
silent and look better. I cannot compare it to any of air conditioners I know.
What is more they are still convector heaters – winter they heat, summer – they
cool.

I personally think it makes the wall look silly. And homeowners for the most part dont want to screw around with opening and closing vents a couple times a yr. Being in jersey I quit often see them not being ever adjusted.

a properly designed register and returns will work just fine.