Increasing air flow in vents, cold air in basement -) PowerZoning

16 years ago

Hi,

We saw these PowerZoning guys at a home show in Denver, CO and they were talking about increasing the efficiency of home A/C & Heaters.

They came to the house for an estimate, here is what they offer/did:

He turned on the fan in the furnace via the thermostat, he then selected the room farthest from the furnace and placed a small "contraption" that measured air flow out of the vent, the reading was 370. We went downstairs and he removed the bottom door of the furnace (the one you remove to replace the filter) and wedged it in so that the safety switch was still activated so that fan would still work. We went back upstairs and the little contraption sitting on the vent was now reading 520-530.

He said the jump in the number was due to the fact that the fan in the furnace now had more air coming into it and was less restricted. He went on to explain that by adding an additional cold air return in our unfinished basement (10 feet away from the furnace, he said it had to be away from the water heater due to safety and fumes) the furnace fan would not only be more efficient and blow more air but that in the summer we could just run the fan and not the AC until the upstairs temperature reached the temperature of the basement, if we still wanted it colder we would have to run the AC. He kept saying that we have a lot of cold air in the unfinished part of the basement (800sq.ft.) and we should use it to cool the house in the summer and not just waste it.

OKÂhere what it all includes:

- install 10 feet of ducting

- cut a whole in the furnace to attach the new duct

- lifetime washable filter for the new return

Cost: $800

SoÂdoes all of this make sense and should it help cool the house? I am not a HVAC guy, so to me it makes sense and the numbers according to that contraption he placed on the vent sure indicate more air was coming out of the registersÂwhich sounds like a good thing.

Not sure about the cost, what do you think? Sure seems like the material would not add up to that much and it is mostly labor and buying "there idea".

I look forward to hearing from you.

Thanks,

Mitch

Sort by:Oldest

Comments (9)

User
16 years ago
Two words: Radon & Mold

Regards
Chris
mitchel
Original Author
16 years ago
Radon...we have an alarm and it never went off so I am cautiosuly assuming we do not have a radon problem.

Mold...to tell you the truth I have no idea abou that, I have not heard of mold problems in Colorado but then again you never know.

Besides possible radon and mold problems....does what they offer make sense to increase the air flow?

I just never thought I had great air flow. Does anyone have a good way to check for leaks in the venting/tubes in the basement other than with your hand? I was thinking of using something that made smoke like an incense and run it along all the venting in the basement.

Someone else mentiond insulating around all the venting...what do you think?

Thanks,

Mitch
Related Discussions
Vents blow cold air at end of heat cycle, normal?
Q
Comments (6)
"We don't have a furnace, we have a boiler." You saved me the trouble sue of explaining that! OK, what you have is an aqua stat that controls the fan in your air handler. When the t stat calls for heat either a pump comes on or a zone valve opens downstairs and allows 180 degree water to flow through the coil in your air handler. On the hot water pipe that leaves the coil should be a thermostat attached to this pipe. When it senses the water is hot enough going back to the boiler it brings on the blower. That thermostat, known as an aqua stat should be set at 140 degrees. Thats the temperature the fan comes on. The fan off setting is usually 100 degrees. Yours is probably set to low. Check the aquastat settings, there may be 2 settings (on and off) or there may be just 1 and a differential. If its that one set it at 140 with a 40 degree differential. The nice thing about a system like yours is you can fine tune them. If 100 degrees feels to cool you can tweek it up a few degrees to find something more to your liking. You don't have to worry about overheating the equipment. Just don't adjust the two settings to close together or else the blower my cycle on and off to ofter before the t room stat is satisfied
...See More
Air flow/hall thermostat problem
Q
Comments (8)
You have one air handler/heat pump that is served with two returns in the same hallway? It seems like your base problem is that you have inadequate return air flow. With supplies elsewhere and the returns in the hall, you need to have air flow from ALL the rooms into the hallway where the returns are. The typical low cost way too do this is undercutting the doors. Alternative methods are to install jump ducts (transfer grilles, transfer grills, transfer grates,...) in the walls or through the attic space. Ideally, you have a return in each room, but that is costly. The door undercutting is often subverted by later carpet or flooring installation. If you have pressure differentials like you describe, opening one door is not going to work very well. You pressurize the rooms with the doors closed and depressurize the hallway or what ever room the returns are in. What happens then? Air blows right out of your house from the pressurized rooms, into the attic, past leaks around the windows and wherever there is a little crack or hole. In the room where there is negative pressure, outside air gets sucked in, from the attic,.... The sucking air in from a hot/humid outdoors sometimes results in condensation and wood rot. For now, leave all your doors open. Maybe later undercut them to an area equal to the supply grill size in that room or install grills, jump ducts or transfer ducts.
...See More
Old, large cold air return vents are consuming our AC too fast. HELP!
Q
Comments (3)
It sounds like your home had floor furnaces at one point. The large return air grilles sound like old openings for floor furnaces, used a long time ago. Where to start? First, your system should have filters somewhere in the return duct or inside the air handler or furnace. I would look really good to make sure you haven't missed something. I've seen filters placed in really weird places. Sometimes filters aren't found for years. By then they're pretty stopped up. As far as the return grilles being large, the larger the better! One thing that kills your system and your energy efficiency is duct work that's just too small. Modern systems are made to run with very little static pressure in the ducts, around 1/2 inch. That's not much, so I wouldn't worry about the large ducts. The filters are another story. You really need a filter in your return duct somewhere. If there's not one, i would install filtration. Usually the cheapy filters work best as they cause the smallest pressure drop in the duct. You mentioned the refrigerant leaking out. If you have a refrigerant leak it should be repaired. That stuff ain't cheap. Besides it's illegal for a technician to keep adding without repairing the leak. If someone is having to add refrigerant, you definitely have a leak, no question about it. If the service provider you called did not look at your duct work, did not tell you your system had a leak, and did not offer sound recommendations, please ditch them and find someone qualified. As far as your system coming on and off every ten minutes or so, that's called "short cycling" and isn't good for your system, your energy costs, or your comfort. It sounds almost like your system is either too large for your home or you have massive air infiltration. Either way, this needs to be addressed. Really, I would recommend you find a good service provider in your area that can be trusted to offer technically correct advice. I usually find it best to ask friends, co-workers, or other family who they use and trust. In the meantime, you may want to check out a couple of articles I've written dealing with heat loads and your comfort. Here's one HERE if you would like to read it. Let me know if there are specific things I can help with. I'll be happy to help if possible.
...See More
Vaulted Ceiling created air flow issue
Q
Comments (6)
On the down side creating the vaulted ceiling increased the cubic footage of space you are cooling, which might be significant depending on how big a percentage this is of your total space. It also may have made your house less efficient by eliminating the insulating effect of the closed-in space you opened, perhaps an attic. On the plus side a vaulted ceiling can help with cooling because the warmest air rises over your head where you do not feel it. The room can feel chilly in winter for the same reason. A ceiling fan would likely raise the temperature of the air you feel because it will stir the air up so you lose the advantage of the vaulted ceiling for cooling. (The warmest air won't be over your head anymore.) Of course any fan can promote greater comfort by keeping the air moving, but in this room I'd put it on or near the floor. By the Fujitsu unit I assume you are referring to a mini-split. They'll keep you cool for certain but they're costly, and I would not be putting money into a whole new system until you have the problem with your main system addressed. When that system's working right you can see where you are and make some decisions. Also consider blinds for the windows letting in all of that sun. Something you can open all the way up for the view when the sun isn't coming in, but close to keep the room cool when the sun shines from that direction.
...See More
mr_havac
16 years ago
Did they check the static pressure in your duct system? Of course not, they probably don't even know what that is. Did they calculate just how much air that particular room requires? Probably not. You want more air, just increase the system blower speed, but more air is not always a good thing. Did they happen to use sling psychrometer to check the humidity level of that basement air they want to dump into the living space? Of course not. Because if they did all of that and understood what the were doing and why they woud come to realize what they are trying to sell is nothing but garbage. Don't get suckered in.
dumbswede
16 years ago
I personally believe that common sense is the most powerful tool a person can use. Given that, what is the primary concern with trying to manage the temperature of the air in your home? Assuming that the air has been heated or cooled by a forced air device, then it has to be moved. If you improve air flow, then that's a good thing. A basement that is humid, full of radon, and moldy, definitely needs some air movement. Radon is a relatively new danger that is addressed by improving ventilation. $800 doesn't sound so bad if you can go back upstairs and feel the improvement at the same duct. Humidity will be taken care of both by heating and cooling, and the mold should go away unless there is some other mitigating circumstance. Sounds to me like they proved that they could improve air flow with an almost 30% increase. What's not to like?
Larry
bob_brown
16 years ago
Filters add to the restriction of air flow. This is called static pressure. 30% increased air flow tells me that your system does not have enough return air. This is a problem with many houses. Installers just do it, and don't do any design or load calculations. While we talk about these important issues, many installers say yea, but I know what I am doing, and proceed without any planning. One early thing I learned was the Manual J type of calculations does not always work as expected. The answers you get are not what you expect. In order to get the sale, the Man J is many times rejected as a waste of time. In existing installations, the Man J may not be needed, the Man D is overlooked. The Man D is the design of the system. This is one area, that does not generate any money for a service call, but can help troubleshoot a difficult problem. The time spent with any calculation is never appreciated by the home owner, and the work is seldom paid for.
mitchel
Original Author
16 years ago
Thanks everyone for the comments. I think I will get a HVAC person to come by and inspect the whole system. Shame on me for never getting the system checked out once in a while, its been 11 years since it was installed.

I called the original company who is pretty big here in the Denver,CO area and they told me that if I feel cold air coming from the vents..the AC is working fine and that I should not bother scheduling a service call. That sounded pretty lame.

Anyone want to recommend a good HVAC company in the Denver area?

Thanks,

Mitch
chapnc
16 years ago
They're selling snake oil. There are so manys thing wrong with this proposal.

First off, why do you feel you're not getting enough airflow? Is the room they used for their demo hard to heat or cool? If the existing 370 cfm is enough to keep that room comfortable, then there is no reason to pay money to increase the airflow. "More" is not always better.

Your air handling system was designed to move air as an enclosed system. OF COURSE it's gonna move more air if you rig it to operate with the fan cover door opened. But again, more is not always better. I'll bet you could stand in that back room and *hear* the air rushing and whistling out of that vent after they took the blower door off. Your system should be set up to move the required amount of air as quietly as possible.

You're also risking damage to the blower by making such a drastic change to the static pressure. The fan is designed to work against some amount of resistance. Lessen or remove that resistance and you could burn your fan motor out.

A return in the basement is going to bring extra humidty and musty odors into your home. The air conditioning unit would have to work harder to remove the extra humidity. It could actually cost *more* money to operate. And if the unit was not capable of removing the extra humidity, you end up with damp air in your living quarters. This results in a cold, clammy feel that makes you feel uncomfortable.

If you have some rooms that are hard to heat or cool, have a reputable HVAC company *calculate* how much air needs to go to each room. It's not a guessing game, and more is not always better.

I noticed that you called the original installers and they blew you off. Forget them, they don't sound very professional. Try asking some of your neighbors for referrals, or check something like "craig's list". There has to be a reputable company in your area.
chapnc
16 years ago
Oh yeah, I forgot to ask:

Did they mention what the effect will be during the *heating* season?

You're gonna have to pay to heat all that nice cold air being sucked in from the basement. Doesn't sound so appealing now, does it?
andrelaplume2
16 years ago
I did notice recently when I changed my pleated $10 filter that while the filter was out for an hour or so (had to run to HD for a new one) The amount of air in my bedroom dramaticllay increased. (My bdrm is furthest from the unit and sometimes a bit warm for my likeing) Not having the filter in place made of more air moving thru the bedrm. I am actually thinking of downgrading my fliter to a $4 one, maybe that will act as a compromise between my allergies and getting a bit more flow to the bedroom.

Increasing air flow in vents, cold air in basement -) PowerZoning

Comments (9)

User

mitchel
Original Author

Related Discussions

mr_havac

dumbswede

bob_brown

mitchel
Original Author

chapnc

chapnc

andrelaplume2

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Increasing air flow in vents, cold air in basement -) PowerZoning

Comments (9)

User

mitchelOriginal Author

Related Discussions

mr_havac

dumbswede

bob_brown

mitchelOriginal Author

chapnc

chapnc

andrelaplume2

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

mitchel
Original Author

mitchel
Original Author