A new system?

[ZackN]

Hey Everyone,

Brand new to the forums and brand new to home ownership. Moved into our new house last week and all was well. It wasn't until we started having 105+ degree temperatures (Texas) that I realized we had a problem. Basically, we are lucky if we can keep the temperature at 80 degrees during the day and it takes most of the night to get it back down to where we set it ( 76 degrees ). We have been keeping it on 76 24/7, even trying 78 degrees to see if that changed anything. The unit runs 24/7 and as the day goes on, the temperature continues to rise inside the house.

Here is a quick run down of the house specs.

It is a single story home that was built in 2006. It is just shy of 2000 Sq. Ft. It is brick construction on all sides except the rear of the house, which is siding.

The unit specs are as follows:

Outside Unit: Carrier 38BRC030320

Inside Unit (In Attic): Carrier 58STA070---12112

Correct me if I'm wrong, but is this a 2.5 ton unit?

Temperature of air coming through indoor vents: 69-70 degrees.

Okay, so I've had two separate AC companies come out and take a look. The first one was sent by my home warranty company and the guy spent maybe 10 minutes here and said "Well, your freon was just a tad low, so I guess we'll just see if that works." Obviously, that didn't work so I contacted another company that was recommended to me. The guy came out and spent about 2 1/2 hours checking everything and fixing a kinked air duct in the attic, as well as re-sealing the inside unit as it was blowing a little cool air into the attic. Other than that, he said the unit is running fine.

I'm still having the same issues and both companies mentioned that my unit may be too small for the house. As a first time home buyer and only living in here a week, this is a pretty hard hit. What should I do?

Thank you so much
~Zack

[Mr Bill]

It is a single story home that was built in 2006. It is just shy of 2000 Sq. Ft. 2.5 ton unit? Zack

Zack, the red and the blue will never work in Texas, I have been preaching this here for a long time, but of course you have
your folks here that say it will, and you can bet most of them don't live in Texas. :grin2: http://i99.photobucket.com/albums/l286/mrbillpro/watchdrama8jm.gif

[ZackN]

Zack, the red and the blue will never work in Texas, I have been preaching this here for a long time, but of course you have
your folks here that say it will, and you can bet most of them don't live in Texas. :grin2: http://i99.photobucket.com/albums/l286/mrbillpro/watchdrama8jm.gif

:censored: That is exactly what I was afraid of......I wonder what the likely hood of getting the home warranty company to replace it based on it being undersized? If we were to upgrade, what is the recommended tonnage?

Also, is it possible to just replace the outside unit and keep the inside stuff the way it is? Just purchasing a house has a way of sucking you dry and shelling out $ for a whole new system would kick me right in the gizzard.

[Mr Bill]

:censored: That is exactly what I was afraid of......I wonder what the likely hood of getting the home warranty company to replace it based on it being undersized? If we were to upgrade, what is the recommended tonnage?

Also, is it possible to just replace the outside unit and keep the inside stuff the way it is? .

Answer to blue question....Good luck...but my final answer would be no. :grin2:

Answer to red question.... No, both inside and outside "cooling components" would more than likely have to be changed.

Hey, if you need just to feel better mentally for a while, hang here for a while, and you will have some Pro's tell you that you should be able to cool your home with a 1.5 ton, of course their all snowbirds. :grin2:

[fliks]

Mr Bill is right, that is 800 sq ft/ton. The only way that could work is if you had foam in the walls and attic.Since the duct will be too small that will have to go also. You might be able to add a 1.5 ton system to the existing one? If the existing one is older you would be better just installing a complete system of the correct size.

[ZackN]

That may be a decent idea. The existing one is only 6 years old and the two AC guys said it's in pristine condition. I wonder if just adding another small one would be more cost effective than just upgrading to the appropriate size. Especially if you include energy use, etc.

[SBKold]

A ductless mini split sounds ideal.

[ZackN]

A ductless mini split sounds ideal.

Main thing that concerns me with doing something like this, is the electric bill. Does a system like a ductless mini split or even a portable AC unit use an over abundance of electricity? If my bill is going to go up $50-100 a month, it seems like it would be better just to replace the entire system.

[SBKold]

a ductless mini split would be the most efficient. way over another traditional ducted unit.

You will want it to have a inverter compressor.

[ZackN]

Any idea how much those units would increase an electric bill? I know it's variable, I'd just like a ball park figure.

[tipsrfine]

Look into what you can do to improve your homes thermal envelope. Maybe some air sealing & improved insulation could make the difference. Maybe some more air sealing of the ducts. An HVAC system is supposed to be sized according to the heat load of a home, and how well the home is air sealed & insulated plays a huge role in what that heat load is. There is no reason to accept the notion that the only way to address your air conditioning needs is by increasing the size of the air conditioner; you can also address them by improving the home.

[catmanacman]

Mr Bill is right it ant gona get the job done

[ZackN]

I'm definitely going to take a few measures to increase home efficiency, such as curtains, better seals around the doors, ensuring none of the duct work that is accessible is leaking, using fans, etc.

However, in addition to that, I'm really leaning towards a portable AC unit for the living room (that is where it is the hottest), until I can afford to replace the entire system. Seems like the most reasonable option at this point. Thoughts?

[tipsrfine]

Hey Everyone,

Brand new to the forums and brand new to home ownership. Moved into our new house last week and all was well. It wasn't until we started having 105+ degree temperatures (Texas) that I realized we had a problem. Basically, we are lucky if we can keep the temperature at 80 degrees during the day and it takes most of the night to get it back down to where we set it ( 76 degrees ). We have been keeping it on 76 24/7, even trying 78 degrees to see if that changed anything. The unit runs 24/7 and as the day goes on, the temperature continues to rise inside the house.

Here is a quick run down of the house specs.

It is a single story home that was built in 2006. It is just shy of 2000 Sq. Ft. It is brick construction on all sides except the rear of the house, which is siding.

The unit specs are as follows:

Outside Unit: Carrier 38BRC030320

Inside Unit (In Attic): Carrier 58STA070---12112

Correct me if I'm wrong, but is this a 2.5 ton unit?

Temperature of air coming through indoor vents: 69-70 degrees.

Okay, so I've had two separate AC companies come out and take a look. The first one was sent by my home warranty company and the guy spent maybe 10 minutes here and said "Well, your freon was just a tad low, so I guess we'll just see if that works." Obviously, that didn't work so I contacted another company that was recommended to me. The guy came out and spent about 2 1/2 hours checking everything and fixing a kinked air duct in the attic, as well as re-sealing the inside unit as it was blowing a little cool air into the attic. Other than that, he said the unit is running fine.

I'm still having the same issues and both companies mentioned that my unit may be too small for the house. As a first time home buyer and only living in here a week, this is a pretty hard hit. What should I do?

Thank you so much
~Zack

So the temp of the conditioned area is around 80 degrees and the temp of the supply air is 70 degrees? What is the RH of the home? Whatever the RH of the home is, I wouldn't listen to anybody that tells you your solution is a bigger system. Do a search for someone BPI certified to give you some education about the "Whole House Approach", and stay away from those who tell you "Bigger Is Better" and doesn't know anything about Building Science. Do your own homework on this, because the average HVAC contractor either has not, or doesn't have a business structure to provide you with a "Home Performance" type approach to your comfort & energy reduction needs.

[Mr Bill]

Do your own homework on this, because the average HVAC contractor either has not, or doesn't have a business structure to provide you with a "Home Performance" type approach to your comfort & energy reduction needs.

Any other nice things you can think of to say about the Pro's here? This forum was originally built for Professional techs and you come here and degrade most of them with this attitude. So the "average" HVAC Contractor just SUCKS in your world. What a piece you are, you need to stay over on your energy auditor talk forum, at least us Pro's don't come over there dissing you and your "average" energy auditors. Thanks for your help, but we don't need your kind of help over here, were not perfect like you, most of us are still work in progress. :mad:

[carmon]

he hurt my feelings.....

[Mr Bill]

he hurt my feelings.....

That's because he is here to promote his agenda by slamming all of us that don't totally agree with him, it's called arrogance with no regard for others.

[carmon]

well then..... I will ignore him.....

[Mr Bill]

well then..... I will ignore him.....

Most everything we do in the business world is all about approach. His approach is about like the pizza guy delivering your pizza to your door, and throwing the pizza in your face and asking for his money so he can get. :grin2:

[tipsrfine]

Any other nice things you can think of to say about the Pro's here? This forum was originally built for Professional techs and you come here and degrade most of them with this attitude. So the "average" HVAC Contractor just SUCKS in your world. What a piece you are, you need to stay over on your energy auditor talk forum, at least us Pro's don't come over there dissing you and your "average" energy auditors. Thanks for your help, but we don't need your kind of help over here, were not perfect like you, most of us are still work in progress. :mad:

I wasn't "slamming" anyone. Just pointing out what is true; that the average contractor does not take the "whole house approach". I'm not understanding why the OP has been advised to replace his existing system -and duct system- with a larger system and nobody has bothered to address the fact that he only has a temp difference of 10 degrees between his return air and supply air.

[Mr Bill]

I wasn't "slamming" anyone. Just pointing out what is true; that the average contractor does not take the "whole house approach". I'm not understanding why the OP has been advised to replace his existing system -and duct system- with a larger system and nobody has bothered to address the fact that he only has a temp difference of 10 degrees between his return air and supply air.


Do your own homework on this, because the average HVAC contractor either has not.

Well, yes in a way you were cutting some of the Pro's here by saying "the average HVAC Contractor has not". Words like this create a snowball effect, and also confuses the home owners. You know, we Pro's already have a bad enough reputation from the home owners that stereotype us, I see it in some of their post here everyday. We need all the help we can get, in the way of encouragement, and we also need other folks that are in trades related to ours to work with us, not condemn us. Remember just because you and I might read things one way, the HO can read it just the opposite. I appreciate your participation here, but you just need to work on your approach, there are ways to work together here, were the message still gets out, were there is no harm done. :grin2:

[tipsrfine]

So the temp of the conditioned area is around 80 degrees and the temp of the supply air is 70 degrees? What is the RH of the home? Whatever the RH of the home is, I wouldn't listen to anybody that tells you your solution is a bigger system. Do a search for someone BPI certified to give you some education about the "Whole House Approach", and stay away from those who tell you "Bigger Is Better" and doesn't know anything about Building Science. Do your own homework on this, because the average HVAC contractor either has not, or doesn't have a business structure to provide you with a "Home Performance" type approach to your comfort & energy reduction needs.

Please don't take a quote out of context. The whole quote is simply being informative, not insulting anyone. Do you have any helpful comments to the OP regarding the 10 degree delta T?

[Mr Bill]

Do you have any helpful comments to the OP regarding the 10 degree delta T?

From cyberspace no, but if you want to fly me out yonder, I will be glad to offer my service call for free, how's that? :grin2:

[ZackN]

You'll have to excuse my ignorance, but what is "RH"? Also, so a 10 degree difference is definitely not ideal? What kind of numbers should I be seeing there and what are some things that could be wrong that the HVAC techs I've had out here have not seen?

Thank you all for the replies.

[tipsrfine]

RH is relative humidity. How much of a temp diff you get across your evap coil is largely based on blower speed and how humid the air entering the evap is. The more humid the air is, the more the evap has to work at removing the humidity so how much the air is cooled is reduced. In a properly working system, you may start out with high humidity and a lower temp diff, but as time goes by and the humidity level goes down, the temp diff should go up. A typical temp diff is typical conditions is around 18 to 23 degrees temp diff between the air entering the evap and the air leaving the evap. Some measurements need to be taken to determine why you only have a 10 degree temp difference to determine what is the cause.

[tipsrfine]

RH is relative humidity. How much of a temp diff you get across your evap coil is largely based on blower speed and how humid the air entering the evap is. The more humid the air is, the more the evap has to work at removing the humidity so how much the air is cooled is reduced. In a properly working system, you may start out with high humidity and a lower temp diff, but as time goes by and the humidity level goes down, the temp diff should go up. A typical temp diff is typical conditions is around 18 to 23 degrees temp diff between the air entering the evap and the air leaving the evap. Some measurements need to be taken to determine why you only have a 10 degree temp difference to determine what is the cause. Here is a chart that will give you an idea of what I'm speaking of.
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