Worth it to redo ducting/moving furnace?

[Ed Ww]

Hello all, I'm new here (as if you can't tell ). I am not a HVAC pro, but a home owner but would like to get some opinions on some plans I had in mind for the future. I am thinking of completely having the ducting and moving the furnace over. I apologize for the long post but think the details are important, so here goes

Details on existing system and house:
The furnace- 80% mid-efficiency Carrier natural gas (58WAV091-14), but its only 5 years old, so it should have plenty of life. House is 1950's with central heat and air, all sheet metal ducting run in the basement parallel the main beam and I believe are original- however here's my (negative) observations so far:

Ducting:
1) The basement already has low ceilings at 7 feet. The HVAC ducts run down the middle of the basement ceiling and underneath that area is 6' 3".

2) The house has reverse flow venting- as in, in most areas the returns are on the exterior walls (uninsulated) and the supply are on the interior walls. The kitchen and bathroom have supply on the wall though. Makes no sense to me why it was done this way originally. I also lost two supply ducts when I had a foyer wall removed, so that area is constantly cold especially next to the front door. When the heater turns off, it seems like it gets cold quick.

3) There are only 2 (one on the furnace/AC itself) supplies on the basement in the ceiling and ZERO returns except the furnace itself. There's a bathroom in the basement that has no ventilation at all. Thus, it's always cold down there.

4) Minor issue but the existing grilles are somewhat noisy- (when I remove them it's quiet), which brings me to:

5) The ducts are an odd size which I read is common for an older house, like 5x8 so it's almost impossible to find grilles for the vents. Which ties along with this- because of their off size, they are placed low on walls, and not the floors, so I have to use them with this ugly baseboard trim.

Furnace:

The furnace and water heater currently vents out a masonry chimney in the middle of the house. Since the house is small, it's taking up valuable room in the kitchen on the floor above and in the basement.

To address these issues:

Furnace:
If I can move the furnace, I can get rid of the chimney, it will allow me to put in more counter space or a wall oven in place. I have a closet I believe I can have run vent pipe up to vent out the roof, it'll just have to be enclosed. I'd also would shrink the utility area and have more space to use as a basement. Which brings me to:

Ducts:
1) Since the furnace will be moved to a corner, having the Supply and return ducting run down one side of the basement wall (without basement windows) instead of the center as you see in most homes. This way, a soffit or wall can be built, I won't lose the vertical space, instead horizontal space which I have much more of. I have consulted one HVAC company so far and they've said the supply and return ducts can be run in a vertical orientation along the side wall. One place tells me 8" high ducting is standard- but are there any "wide and low" ducts?

2) While this is done change the flow to be "correct" with the supply at the exterior walls (I'd specify floor vents) and return in the interior walls. I was told having floor vents would be best as the air will rise up and it "washes" the exterior wall, so this would address the cold feeling when the heat turns off syndrome.

For the basement have the the proper supplies and returns, supplies down low to allow the heat to rise.

3) The proper load calculations and sizing calculations should be done of the ducts.

4) To move the furnace, a professional will have to capture, extend and recharge the line for the condenser, size and run the B-vent etc.

I've talked to one HVAC company so far and they think I can keep the existing furnace. But they'd "plan for putting in a high efficiency furnace" when the 80% unit dies.

I realize this is going to cost a good bit of money as it's basically installing a complete duct system AND paying for installation of the furnace as I'm moving it, but at least the house is small, and only 1 level (plus basement which is fully accessible) and I'll be using the existing furnace. But it will allow me to have better use of the basement without the low ducts in the way and allow more usable space in the kitchen above and basement and more even cooling/heating.

Is this project I'm planning crazy or is this something that is actually done? I've searched around the internet and can't find too many people looking to move their ducts and furnaces. My other thought is to continue with the current setup and use space heaters or gas stoves/fireplaces for additional heat as needed.

Anything else as a homeowner I should be aware of before I sign on the dotted line?

[skippedover]

To my eyes, it appears you have two issues. #1 is that the house is not well balanced and therefore uncomfortable. #2 is that you're trying to gain space in a couple of areas, the basement and the kitchen.

On the face of the plan, it's quite feasible. Relocating the furnace and having a new duct system installed, if designed and installed properly, will result in even temperatures throughout.

Moving the furnace to eliminate the chimney is relatively easy and should work out nicely. Don't hurt yourself removing the old chimney however.

Now come the questions.

Of prime concern to me are the dimensions of the home. The location of the furnace could be more critical if the home is exceptionally long. Furnaces have blowers with limitations and even the best variable speed models will run out of push if they're trying to move the air over very long distances. So the length of the house from end to end is a concern. I generally don't like to run ducts longer than 50-feet. So if your house is 75-feet in the longest dimension, I'd want to put the furnace somewhere in the middle and be blowing less than 50-feet in each direction.

The depth of the home is the other consideration. When installing a main trunk right at the front (or rear) wall of the home, the branch run to the front supplies is measured in inches, while the runs to the back of the house is measured in 10-foot increments. It can get very tricky to get a well balanced system with such an imbalanced trunk. I'm not saying it can't be done but it takes a lot of attention to detail in the design and sometimes can be a daunting task to get it right when there are space considerations. It is for this reason that most duct systems occupy the center of the home and normally run parallel with the main girt or carrying timber in the house.

In summary, as long as the house dimensions are not too big, most of it sounds okay. I'd put some reservations, however, on moving the trunk to one extreme wall.

[tinner73]

you've moved this to the right forum...CFOT has a lot of "know it all" idiots.

these guys here know the business.

fill out your profile

use this................ http://icemeister.net/aop_map.html

[Ed Ww]

Hey Tinner.. Nice to see you! Glad I found this forum been reading it all night, especially the hall of shame part. No I def won't be DIY on this :lol: Did give it a thought but too much involved (can I say that in here?), too much can go wrong.

I've gotta put some thought into this, you're right these guys here are great! Yourself included. I'm gonna type a reply to skippedover but need to do some drawings first.

[Ed Ww]

Skippedover thanks for the reply, quite informative. To answer your questions:

Yes you see correctly of my 2 issues, the chimney taking up space and the uneven heating. The house dimensions are 38' x 26'. Currently the ducting runs down the middle parallel to the main beam. The 26' dimension would be tricky with the 10 foot increments, something I've never thought about.

Another thing I'm kind of kicking myself about is I had the chimney rebuilt only 2 years ago. At the time I was up on the roof putting in a TV antenna and found the chimney disassembled with my bare hands At the time I wasn't thinking about reventing the furnace, but looking back, it was a perfect opportunity. If I do this I've effectively flushed a "good amount of money" down the drain for a new chimney

If I were to keep the position of the furnace- should I bother with getting the ducts reversed? Not sure why in the old days the supply was in the interior walls and the returns were in the outside. At the very least I'd like to get some additional registers put in in the living room to even out the temperatures.

To summarize, seems like I'm down to 3 options:
1) Go all out, get the furnace moved, new B-vent AND new ducting run down the side wall. Including basement registers.

Advantages- head room in basement, maximize space in kitchen and basement, "correct" reverse flow. More even heating/cooling, esp in basement. Since it's a parallel system to the existing ducts, existing system will still work while work is being done.

Disadvantages- cost, it will be the most expensive option. Possibility that back half of house may not condition properly due to uneven load.

2) Use existing ducting, but get new supply vents put in for living room and parts of the basement. Perhaps get the flow reversed.
Advantage: cheaper than new ducts.
Disadvantage: Ducts will still hang low in the ceiling, can't get rid of chimney.

3) Do nothing. Keep the system as is. Use space heaters for living room and get a gas stove/fireplace for the basement.

Advantage: Cheapest option.
Disadvantage: Solves none of the original problems.

[tinner73]

By tinner_73 at 2010-07-15

[Ed Ww]

I'll take some pictures this weekend

[cartercrew]

As it was explained to me some years ago, the returns were put on the perimeter in a heating dominant environment so the furnace would draw the warm air toward the heating load, not from the heating load to the center. Because the perimeter walls and windows are the largest heat loss area, the ducts were most likely laid out to keep the coldest air closest to a return. As long as all of the duct runs are in good condition and adequately sized, I would probably leave them.

[beenthere]

As it was explained to me some years ago, the returns were put on the perimeter in a heating dominant environment so the furnace would draw the warm air toward the heating load, not from the heating load to the center. Because the perimeter walls and windows are the largest heat loss area, the ducts were most likely laid out to keep the coldest air closest to a return. As long as all of the duct runs are in good condition and adequately sized, I would probably leave them.

Its a poor set up like that. My place is like that. Can make you very uncomfortable, when the blower shuts off.

[Ed Ww]

Its a poor set up like that. My place is like that. Can make you very uncomfortable, when the blower shuts off.

Beenthere- I'm curious if your house has a poor setup and you're involved in the HVAC trade, would you not correct redo it?

[Gib's Son]

As it was explained to me some years ago, the returns were put on the perimeter in a heating dominant environment so the furnace would draw the warm air toward the heating load, not from the heating load to the center. Because the perimeter walls and windows are the largest heat loss area, the ducts were most likely laid out to keep the coldest air closest to a return. As long as all of the duct runs are in good condition and adequately sized, I would probably leave them.

Not being disrespectful, but I don't buy that. You want to wash your windows with heated air, it cut's down on drafts. Allot of Hospitals etc. have vav boxes or convectors right bellow the window. A home is really no different. I think Kruegar is the the one that has an auto change over grill that blows air towards the window in heating, and inwards into the building during cooling....pretty cool technology.

As long as you have the right amount of air, proper air distribution methods so you are mixing the room properly it's not going to matter where the return is because your room is at an even temperature....when properly mixed.

[beenthere]

Beenthere- I'm curious if your house has a poor setup and you're involved in the HVAC trade, would you not correct redo it?

Like I really feel like working more when I come home.

So I cheated, and made an adjustment to the supply registers that works ok for me.

If I install the heat pump this year, then I'll almost have to change the supply and returns.

[Ed Ww]

Like I really feel like working more when I come home.

So I cheated, and made an adjustment to the supply registers that works ok for me.

If I install the heat pump this year, then I'll almost have to change the supply and returns.

This reminds me of when I went to the mechanics long ago, and I saw the guy working on my car drive away in this POS that made all this noise. Or, when the Safelite glass repair guy came and the windshield was cracked on HIS truck

[Ed Ww]

OK here's some pictures of what I'm brainstorming:

Here's the said ducts in question, you can see the single supply duct that's supposed to cover ALL of the basement Ceiling is 7 ft already, under ducts is 6'3". (ignore the PA system, I'm a guy in my 20s and throw dance parties )



Here's the opposing wall where I'd like to put the ducts and build it out to hide them. This wall is 38 ft long



This is where I want to put the furnace. It's currently behind the left side of the wall, left of the open door. This way I can house the gas, electric and water lines and HVAC all in a single closet (accounting for combustion needs of course)



Existing furnace and ducts. This shot is the back of the wall you saw in the previous shot. The wall heater I have NOT used as I'm aware its flue slopes down and the insulated wrapping is likely asbestos. If I get the furnace moved, that entire wall would be gone.



Opposite shot of furnace, you can see how it's currently vented. The discoloration in the chimney, should I worry about that? The flue pipe itself is not rusted.



Upstairs in the kitchen, which is small and needs updating. This blank area is where the chimney is and is taking up space for a pantry, counter space or a wall oven.



Living room shot- those are both returns, in the exterior wall.

Here is where 2 supply ducts used to be. You can see how the hardwood floor doesnt exactly match as I had a wall removed there. The closet you see at the top of the shot (missing baseboard trim) is where I'd like to have the new vent run through.



For reference, here's where the 2 supply ducts were...

[Ed Ww]

Here's a crude MSPaint drawing I did of the locations.

Basement existing:




What I want to do:

[Ed Ww]

Upstairs existing: See how it's this big mix of supply and returns all over the place.. the area by the front door is especially cold. The front door is leaky (will be replaced).




What I plan to do it "correctly"




Hope this gives more insight of what I plan.

Another question- for the basement system, the furnace appears to be more than capable of doing 2 floors even with the added ducting- but for the additional basement ducts, can they tap off of "branch" lines going to the upstairs or should they have their own lines tapped into the trunk?

[catmanacman]

looks ok as long as they size the duct correctly.you will need a new load calculation to determine proper duct sizing and i would put in a new 95% properly sized furnace and vent the flue straight out the back wall if possibe

[Ed Ww]

Sounds good. Time to start making some appointments Hope I won't be in too much sticker shock. I'd really like a 95% furnace that can vent out the wall, but from a cost stand point it seems like a waste to toss the 5 year old 80% unit. I can't imagine them having much resale value. Also, currently my monthly winter gas and electric bills are "just less than or around 3 figures" per month (since we can't discuss price here), so they're not terrible.

I don't know the specifics of the Manual J & D but I'd imagine the design/load calculations of today are much better than those that happened in the 1950s. I found this attachment (How to Design a Ducted Distribution System) from a different thread it gives me stuff to look out for. hvac-talk.com/vbb/attachment.php?attachmentid=243851&d=1329065426

I've learned a great deal here. I just don't want to get screwed by the contractor.

[Ed Ww]

Update to this thread, I had a few HVAC contractors come out to look at the system/house. Waited to around this time now that summer is simmering down and it's not heating season yet One company pretty much blew me off and thought while it's possible he didn't really go into too much detail. The second company spent over an hour with me answering questions and making recommendations. I will call some more companies.

I think moving the furnace is out, it will cost more than double what it would cost to just get new ducting run. I also looked into having a zone 2 Honeywell system put in but that too, is not cost effective.

The 2nd company was going to reverse the flow of the house, For the main level- put in floor vents all through out the exterior walls . They would also put one big return duct high in the living room and 1 low small return duct in each bedroom (for a total of 3 small, 1 large on the main level). For the basement, one return duct low in the basement and 5 ceiling vents.

Question- i heard the standard duct boots are the boxy kinds. Is it worth it to get the smooth, round kinds?

Anything else I should be think about or ask the contractor?

[George2]

A couple of ideas for you...........they make oval flue that will fit into a wall cavity (I recommend a 6" stud wall.

From your (existing) register (map) placement, I can see adding some floor supplies here and there and that should do the trick.

Yes, moving the furnace, with all that is involved, would be very expensive.

Is that a wall furnace in the basement? Do you plan on keeping it? That will effect the flue size.