View Full Version : What would you do with this mess
04-29-2011, 09:12 PM
The HVAC in this 6 BR 4 BA country house is, to put it mildly, a mess...
Wood furnace and gas furnace, selectable by closing and opening the respective flap in their output plenums (there is a 16" flex duct behind the two furnaces connecting the gas furnace's intake to the common return duct), and an a/c coil in the gas furnace. Despite the surface rust, actually looks worse than it is, the wood furnace is in good shape and does a nice job of heating the downstairs. A/C is an old Carrier unit but also keeps the 1st floor cool. The bedroom at the far end of the duct is not getting enough air (too cold in the winter and too hot in the summer).
There are so many things wrong I can't list them all, such as undersized flex ducts with severe bends, a "creative" return system with three small grilles in strange locations, which also uses one of the joist spaces as a return duct (with a piece of styrofoam board tacked across the bottom), and you can't even see the attempt to heat/cool a large open area upstairs with ONE 6" duct. Fortunately the three upstairs BRs and three of the four BAs have individual baseboard heaters.
What would you do with this mess... the HVAC is accessible in the half-basement as you can see in the pics, but the crawl space is very tight. I was thinking of simplifying the bundle-of-snakes return to one large filter/grille with a short, direct connection to the return duct.
04-29-2011, 09:15 PM
sometimes it's best to just start over
04-29-2011, 09:20 PM
Yep. Starting over is the best advice anyone will give you.
04-29-2011, 09:40 PM
It looks like a clusterf**k to me. My advice is to plan on spending some $$$ and make sure you find somebody who knows what they are doing. DO NOT go with the lowest bidder on this one. You will regret it.
04-29-2011, 09:46 PM
Fair enough... I've already had one pro in who recommended not only redoing the ducts, but also replacing the existing, rarely-used "Ultra 80" with a downdraft gas furnace connected in series with the wood furnace (i.e. output of the gas furnace blowing into the intake of the wood furnace). This would eliminate the plenum switching system and "Y" return duct, but then would require the gas furnace to heat all the cast iron of the (cold) wood furnace...
The existing gas furnace may not be the most efficient one made, but it's in good shape and only used to keep the house at 50-55F when I'm away on business in the winter. Wood is very inexpensive in rural MO (about $20/ton for "cut ends", sawmill pieces) and a 1.5 ton flatbed load will heat the house for a very long time even in the dead of winter.
So my inclination is to have the ducts properly redone, while keeping the existing furnaces. Do you think it is appropriate to have several returns on the ground floor, or would one large one (at the end of the central hallway) be satisfactory?
04-30-2011, 09:08 AM
The existing gas furnace may not be the most efficient one made, but it's in good shape and only used to keep the house at 50-55F when I'm away on business in the winter. Is that the unit to the left? not sure about good shape but again can only see the outside
So my inclination is to have the ducts properly redone, while keeping the existing furnaces. Start completely over..if you insist on still using wood I would think they have better more efficient wood furnaces on the market that would save you the number of cords you use per season.
04-30-2011, 09:31 AM
That looks nasty. "Starting over" are the first two words that leaped into my mind.
You might also want to consider ways to help your house hold its heat in better so it doesn't require you burn as much wood. While wood is a cheap fuel source where you live, it's also a dirty fuel source.
04-30-2011, 10:20 AM
The duct work is a huge mess and needs to be completely torn out. Right now I don't think new furnaces are in the budget though :(
Not to hijack my own thread, but wood is actually a carbon-neutral source of heat. Think it through - where does the mass of a tree come from? Not 1 in 100 people know the answer off the top of their head ;) It's not from the dirt or the fertilizer...
Wood is about 50% cellulose and 50% lignin, (both containing C, H, and O). It's easy to figure out that the H and O come from water. But the C came from CO2 in the atmosphere, so it's being released for new trees and plants to capture again.
Yes, I know that the pyrolysis of lignin emits organic compounds... but oil and gas aren't "perfect" (releasing only CO2 and water) either... and the majority of electricity is generated by coal-fired (40%) and natural gas (25%) power plants!
Can someone please address the issue of multiple small returns vs. one big one? thanks :callpro:
04-30-2011, 12:23 PM
04-30-2011, 01:33 PM
To answer your question regarding returns, More returns will improve comfort and prevent problems when doors are closed. A central return can work if it is located in an area which is common to the majority of the supply air. Closed doors, bathrooms, kitchens and laundry areas need to be looked at closely.
04-30-2011, 05:44 PM
This house is a strange conglomeration that, as best as I can tell, was built in several stages. The kitchen, living room and dining room are open (there are French doors to the living room but I never close them). In fact, since there are only two people living here, the doors stay open pretty much everywhere including the bathrooms. Laundry is out in a room off the garage which is unheated anyway.
It seems so much simpler to put a single large grille and duct return at the end of the hallway. Not only that, it's a straight shot to the return trunk, easily accessible in the basement, and would only require a small amount of room in the back of the MBR walk-in closet.
The second floor could use a properly sized supply, and return, but there is no simple way to get one up there and I really don't need central heat/air upstairs anyway (it's just a hobby/play area where I keep my ham shack and 14 video arcade games).
Can anyone recommend a good HVAC contractor near West Plains, MO?
04-30-2011, 06:46 PM
Time for an energy audit.
Or you could do the poke n hope, that's a dance where go with the improvements that "sound" best and hope...
04-30-2011, 06:54 PM
Whatever gets "poked", it has to work better than the mess you see in the pictures!
What exactly is an "energy audit" and would a good tech perform one before recommending duct changes?
04-30-2011, 08:37 PM
Not sure where you are. But a real energy audit is not done by a lot of companies. They are very good. It just requires a large expense in equipment and most people aren't going to want to pay for them. It just really depends on what your business model is. It will tell you a lot about your house and ways to reduce energy consumption. We don't do them and most in our area don't. But there are a lot that do as well. There are even companies that just do energy audits and don't even deal with hvac.
04-30-2011, 09:55 PM
Bpi.org. Zip code.
Given the complexity of your challenges try to find someone with both heating professional and envelope certifications.
05-01-2011, 07:46 AM
1...Cry. 2... Contact bank for loan. 3... Then have it removed and relpaced after careful evaluation to suit your needs. (heat -cool -hot water)
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