Any HVAC techs in the house?

[Sigarms]

Are you indicating that taking return air from a basement is against code in some areas? I'm concerned because I have three basements like that.

Unconditioned space.

If you would of read the last sentence in post 40, I think I spelled it out pretty clearly for you.

 

[kenmac]

Unconditioned space.

If you would of read the last sentence in post 40, I think I spelled it out pretty clearly for you.

That's right. Around my area inspectors define a condition space as any space that is heated and /or cooled with the exception of an area with dirt floors. Any place with dirt floors (whether heated or cooled) is still considered an unconditioned space.

We're talking IAQ here..Why would anyone want to distribute / breath musty unconditioned air throughout their living space ?
Another issue would be taking air from an area close to a gas furnace , W.H., etc, that doesn't have a sealed combustion chamber. You stand a chance of drawing combustion products from the furnace,wh,etc, into the return and distributed throughout the home..

Again, when considering where to locate a return, the air that is circulated throughout your home via return, is the air that you breath. IAQ is what's imporant,along with efficiently.

 

[CADplans]

Are you indicating that taking return air from a basement is against code in some areas? I'm concerned because I have three basements like that.

I do not think it has been mentioned here,,, so I will add the word,,,

Radon,,,

The people that install radon abatement equipment would have you think 90%+ of basements have radon.

If I were gonna move my basement air to the main part of the house,,
I would have some sort of radon detection equipment!! (do they make a radon detector?? )

As we only spend 5% or less of our time in the basement,,
I am not overly concerned about continual monitoring for radon.

 

[dadster4]

Given the new information, 3-1/2 ton should be OK. You said the main return was 20 x 20, what is the actual size of the duct coming from that return? The duct size is what determines how many cfm you will get. You need more return air, but the basement is not the place to get it, see below as to why (LD1 take note). Do you have a closet or dead space that could be used to create a chase to run a 12" - 14" round duct up to the attic, and then to a return in the ceiling or wall of the cathedral area? You need to get more return from the living space on the main floor, and tap into the return drop (24 x 10 min), or increase the return duct size to the furnace from the point the new duct taps in. I know it is a lot of work, but the problem will not be resolved without some modifications.
Basement return: In General Lee's situation a basement return is OK...IF...it is made smaller, preferably run a distance away from the furnace, and supply air is added to the basement of sufficient volume to balance the volume of return air being drawn from that space.
In MOST situations...when a return is cut into a return drop at the furnace, it creates a negative pressure in the basement, which can cause a loss of draft of both the furnace( General Lee has an old oil furnace) and water heater flues, drawing CO into the living space. As Kenmac knows, every situation is different, but relying on the homeowner to remember to cover a basement return is a NOT the way to go!!!
My current home of 3 years has no return duct at all, it draws directly into the air handler in the basement, BUT... I have an all-electric home(like I said, every situation is different) and I have plans to add both supply and return up to the loft in the future (log cabin) when I remodel the first floor bath and have walls opened up.
Another note: You mentioned that you didn't know what blower speeds you had. Check the wires coming out of the blower motor- red=slowest speed(heat), black=high(cooling), white=common, two browns(if you have them)=capacitor(stay connected no matter what speed selected), any others are med-low or med-high.

 

[General Lee]

As to the op....I do t think he has ever specified weather his is conditioned or not. And my apologies for the hijack

My basement is conditioned. There are a couple vents down there off the main trunk line. Maybe "perfectly" conditioned but I wouldn't call it unconditioned.

In the install company's defense, They did inform me keeping my old oil furnace and blower would not allow the system to be at its best efficiency. I did not want to give up my oil heat. I added the heat pump/AC combo in hopes of saving a little bit in oil costs.

 

[General Lee]

Dadster - Throughout the years having a few different HVAC companies out here, it has been mentioned I could use another return in the living space. I realize now adding the second one at the furnace, duct comes up about 4 foot with a 14x20 grill, was a quick band aid to help quiet the system down. Off the top of my head, I don't know the duct size coming off the 20x20 return. I was told my system needs 1400 cfm's and I'm only getting about 1200 off the main return. With the additional 14x20, "I should be close". So yes, return air is a problem in my home.

 

[Sigarms]

Static pressure reading?
CFM's running on the system?
Blower tap setting?
Assuming upflow position?

Model and serial number of outdoor unit?
Model and serial number of indoor blower?
Model and serial numbe of coil?

You would be amazed at the amount of HVAC guys when you ask what their air flow is, they will aways respond with "good".

Oil furnace with heat pumps are becoming more and more of a pain in the butt due to DEO regulations on efficiency ratings (a 14 SEER coil is a lot bigger than a 10 SEER coil), added, you can end up needing a bigger coil for a heat pump over an AC unit.

Here is the reality...

If you have a professional HVAC company propose a HVAC system, they should take speciffic readings on your existing system and document those readings, and address and potential issues with you prior to replacing your system. This way, when they replace your system, they can then compare those same measurments between the new and old system to see what changes were made. A professional company would also give you those readings for your own documentation as well.

Like any business, you have your share of crooks, but a good HVAC company will stand by their work and document everything. This is why some good HVAC companies actaully charge more than the weekend warrior or the guy who sells strictly on price and cuts corners to save on his own end. God forbid men take pride in their work and would like to get paid for it

Ultimately, if there was an issue with the ductwork to begin with, a good HVAC company would of spelled out the issues and relay the information to the end user what the outcome would be if those changes were not made during the retrofit with new equipment, AND have the end user sign off on being informed of those issues.

You can go out to a house and have mis sized ductwork or not enough supplies or returns run, and the end user has lived with it for years and puts up with it. You charge them a pretty penny to change out the system, and all of a sudden their expectations are a lot higher. From the contractors standpoint, this is only CYA.

 

[LD1]

Given the new information, 3-1/2 ton should be OK. You said the main return was 20 x 20, what is the actual size of the duct coming from that return? The duct size is what determines how many cfm you will get. You need more return air, but the basement is not the place to get it, see below as to why (LD1 take note). Do you have a closet or dead space that could be used to create a chase to run a 12" - 14" round duct up to the attic, and then to a return in the ceiling or wall of the cathedral area? You need to get more return from the living space on the main floor, and tap into the return drop (24 x 10 min), or increase the return duct size to the furnace from the point the new duct taps in. I know it is a lot of work, but the problem will not be resolved without some modifications.
Basement return: In General Lee's situation a basement return is OK...IF...it is made smaller, preferably run a distance away from the furnace, and supply air is added to the basement of sufficient volume to balance the volume of return air being drawn from that space.
In MOST situations...when a return is cut into a return drop at the furnace, it creates a negative pressure in the basement, which can cause a loss of draft of both the furnace( General Lee has an old oil furnace) and water heater flues, drawing CO into the living space. As Kenmac knows, every situation is different, but relying on the homeowner to remember to cover a basement return is a NOT the way to go!!!
My current home of 3 years has no return duct at all, it draws directly into the air handler in the basement, BUT... I have an all-electric home(like I said, every situation is different) and I have plans to add both supply and return up to the loft in the future (log cabin) when I remodel the first floor bath and have walls opened up.
Another note: You mentioned that you didn't know what blower speeds you had. Check the wires coming out of the blower motor- red=slowest speed(heat), black=high(cooling), white=common, two browns(if you have them)=capacitor(stay connected no matter what speed selected), any others are med-low or med-high.

What am I taking note of here? My duct work system was designed by one of the best HVAC guys in this area. There is no reason at all for me to NOT pull basement air. And actually foolish if I dont.

No gas or oil burning equipment. All electric. And basement is open to the upstairs via the ~4' wide x ~10' long stairwell opening with just a little short ~42" wall around it. And I have 7 vents downstairs.

My house is no different than a common 2-story house with an open stairwell to the 2nd level. Only difference is my 1st floor.....is sub grade and has 8" poured concrete walls. As a result....it stays considerably cooler than the second level....due to it being sub-grade, and the fact that heat rises.

I know my uncle just had HVAC system installed in his new ~3500sq ft house. His system uses some type of zone controls. Where there are dampers and what not that can control the temp in each individual room. Its a fully finished basement, with a 2-story house on top. IF the upper rooms get above setpoint, and lower rooms are below setpoint, through the brains of the system, it is smart enough to adjust a few dampers, and turn on nothing more than the blower to redistribute the air to satisfy setpoints. Makes for a highly efficient way to heat and cool a house.

Thats the same basic approach I am taking, only on a smaller and more manual scale.

 

[LD1]

My basement is conditioned. There are a couple vents down there off the main trunk line. Maybe "perfectly" conditioned but I wouldn't call it unconditioned.

In the install company's defense, They did inform me keeping my old oil furnace and blower would not allow the system to be at its best efficiency. I did not want to give up my oil heat. I added the heat pump/AC combo in hopes of saving a little bit in oil costs.

If you have supply vents down there, then it is indeed a conditioned space. Now I dont know enough about oil furnace, fumes, etc etc. If it were not for that, I'd say you most certainly would want a return duct down there, at least enough to balance out the supply vents.

 

[newbury]

<snip>
Are you indicating that taking return air from a basement is against code in some areas? I'm concerned because I have three basements like that.

If you would of read the last sentence in post 40, I think I spelled it out pretty clearly for you.

Post 40, last sentence:

I believe what Kenmac is saying in 35 years he has never pulled return air from an unconditioned space (I also believe that is what he meant by "code").

What your beliefs are and what Kenmac writes can be entirely different. He's the one that wrote basement in the first place and as has been demonstrated here many of us have "conditioned" basements.

That's right. Around my area inspectors define a condition space as any space that is heated and /or cooled with the exception of an area with dirt floors. Any place with dirt floors (whether heated or cooled) is still considered an unconditioned space.
<snip>

So just to make it simple, since you have not written that it meets code to draw return air from ANY conditioned space - Are you indicating that taking return air from a basement which is conditioned is against code in some areas?

My main concern is with the constant tightening of inspection regulations which force me to meet new codes. I've a major addition being put on one house which will need a deck added later. I've been told by the inspector that I'm going to have to move a concrete block shed with a concrete floor that has set next to the property line for over 60 years because it does not meet new code before I can get a permit to build the deck.

I'm also concerned if I upgrade my heating unit in Mississippi they will require inspection with new codes and they might require new returns being brought down from above which would cause significant ductwork.