Are these registers going to be up high in the wall, or in the ceiling? Do you live in a cold climate? Do you have an attic? Do you have a basement, or crawl space?

I would fur out the whole wall before I did a weird soffit.

Was there no planning ahead of time for the HVAC?

Thank you for the responses! The registers are up somewhat high on the all. I live in Burbank, CA so it can get warm during the summer but not Bakersfield or desert hot. There is no attic except a small attic where the 5 ton is directly behind the register above the doorway.

In a perfect world, I'd love to have one, 4' register in the wall above the doorway and a second 4' register in the living room. Take down the 3rd register. I can then build a soffit on the opposite side of the living room wall where the bedroom is so there's no soffit at all in the living room and kitchen. Would that be enough to heat and cool the 15X37' room?

There was planning that I'd rather not get into, ha.

My first thought is why do you need 5 tons. I completely admit that it is always my first thought on these questions. I just looked up Burbank weather. It doesn't look like you really need heat most of the time - compared to the national average. Your summer is also relatively mild (not compared to Santa Monica perhaps but national).

5 tons is an lot of BTUs for that space. The need for BTUs can be driven quite high with large uncovered windows - particularly facing west. I see no windows in your space so it becomes hard to see why you need so many BTUs. It is never just a simple square footage calculation.

The tendency for HVAC contractors is to oversize and then you need large registers and ducts to move that air.

As a point of comparison, I have 4 tons in 3800 sqft with 35 windows in Raleigh NC which is both way colder and more humid in the summer.

You really need to do calculations to see what size registers you need - no one here can answer that. They look enormous to me. In more modest constuction, we tend to use 4x10 registers - very cheap. The room I am sitting in typing is about 35x20 with 10 foot ceilings. It has 5 registers - but mostly because it is on the coast with a massive SE facing window wall.

Has the HVAC equipment been installed yet? If so take some pictures of that and post it. Both inside and outside equipment.

Most of the time 5 tons of cooling for 1600 Sq ft would be oversized, but there's this kick over the last number of years to put in walls of glass (floor to ceiling) so doing things like that plus really tall ceilings (anything really over 10ft high) can add quite a bit to the load calculation.

@David Cary, we moved last year from a few towns away from the OP. There might not be much humidity, but the heat gain from the CA sun is above anything we have felt in the southeast. The stucco on our house there would be warm to the touch late into the night, even with cooler evening temps. Those towns are also at higher elevation than the coast.

Hi, Jonathan,

Controlling your home's indoor environment involves both conditioning air and distributing it throughout your home, too. Without careful consideration of the distribution part, rooms can be uncomfortable. Don't look to eliminate air supply ducts, but rather to locate them so they are less obtrusive. If there is attic area behind the wall, it may be possible to relocate the ducts to that space. If the attic is an unconditioned space, the insulation may need to be a higher R-value, but it's a trade off worth considering.

I find it a little hard to believe a newly constructed 1600 sq. foot house in Burbank needs 5 tons of cooling. Has the HVAC contractor done a Manual J heating and cooling load calculation? If he has ask him to give you a copy and explain it to you. Also have him explain the calculations on how the duct sizes were calculated for supply and returns. If he doesn't want to give you any information then you should seriously considering hiring another HVAC contractor.

What's the source of heating/cooling?

What's the primary method of distribution, forced air or chilled/hot water?

Does this 5-ton include Domestic Hot Water (DHW)?

SR

Consider consulting with another local HVAC contractor.

I agree with the architect's comment. 5 tons seems too large. I have a 22 year old two story, 1500 sq ft free standing home in SoCal that was built as part of a development. Meaning, mass produced, shoddy and cheap construction, etc. Single pane windows, ten foot ceilings, insulation seemingly lacking in places, leaky. But in a coastal area, not like Burbank's SF Valley setting, so not as hot in summer nor as cold overnight in winter. We do have hot days though. I replaced the HVAC equipment when I bought it - a conscientious load calc said "2 tons" for AC and as I recall, a 40K BTU 80% gas furnace.

The performance of both is excellent. Comfort winter and summer. If the sizing I have isn't right on, then it could be borderline a bit too large. I get long run times when recovering from setbacks (or our absences) and not too frequent on-cycles once the setting is reached. On the hottest of days, it can run for a long time, but that's what to expect with proper sizing.

Good luck - I hope you're able to find someone else to work with.

PS - used to go to Burbank's "Bobs Big Boy" pretty regularly. I think it's gone downhill in recent years but it's a landmark. Also the Smoke House across from Warner Bros. Not haute cuisine but a retro experience these days.

chispa, stucco retains heat because it's essentially a thin layer of concrete and that's a characteristic of that material. Try walking barefoot on your driveway or the sidewalk in the evening of a hot day, the concrete will still be hot. I believe the building technique is to put an air break between an exterior stucco wall and the interior construction. Different from a brick wall, which similarly absorbs heat but is thick to not transmit it to the interior.

fsq, Southern California isn't Quebec. Burbank has mild, typical inland SoCal weather and its single family residential areas are quasi-urban with homes on lots that are probably about 80 x 100 feet. I'm pretty certain most all HVAC systems you'll find, and so what the HVAC contractors know to do, would include either normal split air to air AC with a gas furnace inline, or a conventional split heat pump. Water is heated with water heaters.

None of us are in a position to re-design your HVAC system. It's not a reasonable ask - and we should all be responsible enough to tell you that.

(Re) Designing things on-the-fly is always a terrible way to do things. Always. "This wall is being knocked down" on new construction - unless it's a temporary support - would make me want to get out of this project ASAP if I were involved.

There's no excuse for HVAC ductwork being "tacked on" after the fact. None. The HVAC design may or may not be right, but that's not where the problem starts - and you need to address THAT issue first. If this is a Design / Build job, I'd sit the GC down and tell him that unless there was a soffit in the original drawings that you signed off on, this isn't acceptable - and he needs to figure it out - and you approve the changed design drawings before another nail goes in.

If there was a designer involved, that person needs to be called on the carpet.

Hi everyone, thank you for the responses. Most importantly I found out it is not a 5 ton, I was told the wrong information, it's a 3 ton.

With that information in mind is it possible to remove the 4' register above the doorway and move the register on the right up a foot. This would make the soffit smaller and allow me to move the register in the living room up a foot as well. I'd then have two 4' registers in the 15X37' room. The intake is in the hallway behind the doorway and would be between the two registers which should help move air. Curious what everyone thinks. Thank you!

Re: Elmer J Fudd

“fsq, Southern California isn't Quebec. Burbank has mild, typical inland SoCal weather and its single family residential areas are quasi-urban with homes on lots that are probably about 80 x 100 feet.”

Yes, but until the OP responds we really don’t know very much of anything. The reason for my questions is that if the OP will be using an air-to-water HP for air-conditioning, heating and full capacity Domestic Hot Water (DHW) then even without fully knowing their hot water needs, 5-ton might make sense and might not be too big. We just don’t know.

I guess we know now, he just responded.

A 3 ton is more reasonable, but without a load calculation no one on this forum can comment whether it is the correct size. That being the case, it appears the contractor is using 12 inch flexible duct work. Why such large diameter, why is it flexible, and why does it need to be connected to two 4 foot wide registers spaced 5 feet apart? A typical supply register is 4 X 10 inches. The two 4 foot registers are the equivalent of 10 4 X 10 registers. This seems overkill for 1200 CFM of air in my opinion. Where is the return and will it be a similar size?

Can you post photos of the air handler or gas furnace? I fear there may be more installation surprises.

I’m with Jake. Impossible for us to design for you- where is the gc and or designer. They are responsible. The current situation does not look planned.

Again, we shouldn't be second-guessing any of this based on incomplete information, misinformation from the homeowner, etc. We haven't done a Manual J, we haven't seen a floorplan, determined solar gain, or any other really important info. We are guessing. We are also encouraging a homeowner to be involved in a way that will most certainly muddle roles and responsibilities on a project that's in trouble as it is. This is a setup for failure - and none of us are going to be around when this goes South.

OP: You are asking strangers- who may or may not be qualified- questions that require accurate and complete facts in order to engineer a solution. You have a desired outcome in your head, and you are fishing around on the internet for someone to validate your ideas. Stop it.

Tell the person who is in charge of this project (not the HVAC guy) to figure all of this out and get a qualified HVAC contractor in there.

Your role as the owner is not to design the HVAC - and you put the entire project in jeopardy when you blur roles and responsibilities. The HVAC contractor doesn't work for you, he works for the GC. If I were associated with this job, and you came to me saying that you and your internet buddies have decided how the ductwork should be... I'd tell you exactly where to stick your laptop before I walked off the job.

3 tons is more reasonable though possibly too large with new, better insulated and hopefully tighter than standard construction . Others have suggested remaining questions. Present your questions, I wouldn't worry about doing so as a first step. Good luck.

"if the OP will be using an air-to-water HP for air-conditioning, heating........"

With any knowledge of Southern California and its competitive but often pretty slapdash and price driven HVAC contractor practices, you would have known to assume that air to water equipment was most unlikely to have been involved.

It still goes without saying that we don't have enough information to answer some of the questions. But moving a register a foot or two is generally fine. In tight modern construction, the placement of the registers is not all that important. Mostly you want them near windows because that is where the greatest gain is (and loss too). With shading and low SHGC windows, it isn't as important. It doesn't look like yours are near windows which may be why they have been designed so large - to get the air to the windows?

Larger registers will always be quieter for a given air movement. The noise tolerated probably varies in certain markets and price points.

Pros often get bent out of shape by "internet" knowledge. That often says more about them. That doesn't mean you should go all in claiming to have figured it all out. But, being able to expand your knowledge and ask better informed questions is the goal. There are often local considerations that the contractor knows about or owner expectations in certain markets.

Someone in your area (or your contractor) could answer this - is a Manual D required? I sometimes find the "requirement" does not actually require a decent job. Throw some numbers in a report that an inspector just glances at.

Outside of the equipment being sized properly... I wanted to see a picture of the equipment being used... because?

It might explain why the duct work is as it is? If the equipment is traditional?

Before I call it a Trane Wreck, I want to see the train... if you know what I mean. I use some pun here so if you're a mfg fan boi I appologize for that pun in advance. Personally, I've seen too much in my career... I call it as I see it, but I need to see it first. LOL.