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View Full Version : How many ton of air do i need for my house.


Mylle
05-10-2002, 01:10 AM
I have a 1400sqf house in southern california. it gets up to 110degrees in the summer.

how many ton of air do i need to cool this house down minimum??

thanks guys

Mylle

GooberPHX420
05-10-2002, 01:13 AM
Id say 2-3. I suggest a 3 ton tho, just to be safe, better to have excessive power than not enough. I have a 1407 sqft house and ours is 2.5 ton I think...

I recommend TRANE also, they have really good, quiet and efficient units. My old brother installs them, he is really proud of them...

Mylle
05-10-2002, 01:18 AM
cool. my buddy has his own airconditioning company. he sais that with my current heater, 3 ton would be the max that could push out. he will do it all for $2000 if i help him install it. thats everything included. if i go with 3.5 or 4 ton i vil have to spend another $700 on a new heater and probably 300-500 more for the extra ton. if 3 is enough i will go with that.

Is there some kinda calculator you can use?? like 1ton per 500sqf??

mylle

MichaelD
05-10-2002, 01:33 AM
Bump for an interesting thread. I'd like to know, too.

thomsbrain
05-10-2002, 02:39 AM
what does "ton" mean in this case? i don't know anything about a/c.

PsychoAndy
05-10-2002, 02:41 AM
<< what does "ton" mean in this case? i don't know anything about a/c. >>



tonnage is a measurement of the cooling capacity in an AC unit. theoretically, the requirements vary from sq. footage space to window size, to what direction your home faces (if you have lots of sunlight during sunrise and sunset you'll get more heat), et al.

you should consult with a local AC company, they would know best

Jerboy
05-10-2002, 02:44 AM
<< I have a 1400sqf house in southern california. it gets up to 110degrees in the summer.

how many ton of air do i need to cool this house down minimum??

thanks guys

Mylle >>



Call a contractor and have them do the measurements and the estimate. They can tell you what kind of system you need.

I recommend Rheem/Ruud, because they use a scroll compressor instead of the standard piston type. It is much quieter and supposedly somewhat more efficient.




<< cool. my buddy has his own airconditioning company. he sais that with my current heater, 3 ton would be the max that could push out. he will do it all for $2000 if i help him install it. thats everything included. if i go with 3.5 or 4 ton i vil have to spend another $700 on a new heater and probably 300-500 more for the extra ton. if 3 is enough i will go with that.

Is there some kinda calculator you can use?? like 1ton per 500sqf??

mylle >>



Not really. There are too many variables. Humidity, temperature difference between inside and outside, house insulation performance, window surface area, window insulation perf, sunlight, heat producing appliances, etc.


In hot Souther Cali where power is expensive, cutting down excessive heatsoure definitely saves power and keeps your room from getting hotter. Turn off your monitor when it doesn't need to be on(if you don't have EnergyStar model) and consider using fluorescent luminaires. A/C can carry 1.5 to 2x the heat relative to it's input wattage. If it can carry 1.5x and you have 500W worth of computers and lights on, you waste 833W(500 to power comps and lights, 333 to carry it's heat out). at 10cents/kWh, it will cost you 8.3cents/hr. It doesn't sound like much, but at 10hrs/day usage, it adds up to $25 a month.

bizmark
05-10-2002, 03:46 AM
<< cool. my buddy has his own airconditioning company. he sais that with my current heater, 3 ton would be the max that could push out. he will do it all for $2000 if i help him install it. thats everything included. if i go with 3.5 or 4 ton i vil have to spend another $700 on a new heater and probably 300-500 more for the extra ton. if 3 is enough i will go with that.

Is there some kinda calculator you can use?? like 1ton per 500sqf??

mylle >>



In SoCal would you really need another, newer heater? I mean, does it really get that cold there?

amnesiac
05-10-2002, 03:59 AM
<< In SoCal would you really need another, newer heater? I mean, does it really get that cold there? >>



You'd be surprised. We had a 50 degree day a couple months ago. I've heard reports of weather once going into the 40's. Brr.

bizmark
05-10-2002, 04:13 AM
<<

<< In SoCal would you really need another, newer heater? I mean, does it really get that cold there? >>



You'd be surprised. We had a 50 degree day a couple months ago. I've heard reports of weather once going into the 40's. Brr. >>



LOL @ the SoCal Wussies! :D

<---is secretly jealous

Mylle
05-10-2002, 10:19 AM
i would need a newer and more powerfull heater to push around more than 3 ton of air.

EagleKeeper
05-10-2002, 12:14 PM
You can replace the Compressor without having to replace the fan unit. Depending on age.
If you get too powerful of a unit, it does not remove the humidity from the air easily enough and actually does less work for a higher cost.

Check your insulation levels.
Adding additional bats in the roof and blowing in some in the walls will help alot.
Check that the attic/roof area is vented, add an exhaust fan to help draw out heat that is trapped.

Doggiedog
05-10-2002, 12:22 PM
I thought AC power was measured in BTUs?

CPA
05-10-2002, 12:24 PM
What's the SEER rating on that 3 ton unit? the higher the SEER rating, the more efficient. 10 is the lowest and 17 is the highest, I believe.

05-10-2002, 12:26 PM
<< You'd be surprised. We had a 50 degree day a couple months ago. I've heard reports of weather once going into the 40's. Brr. >>


You need a heater for THAT?
The heat from monitors and computers would suffice.
:)

sharkeeper
05-10-2002, 12:42 PM
A ton is 12,000 BTU/H.

The original metric came from how much power it takes to make a ton of ice in 24 hours.

A 5 ton unit (large for residential) would be 60,000 btu/hour. Most makes have a two number system in the model number that denotes the size. For example a 18 would indicate a 1 1/2 ton unit, 36 would indicate a 3 ton unit and so on.

SEER (Seasonal Energy Efficiency Ratio) is a measure of the units efficiency. Higher SEER's translate into lower utility bills.



<< You'd be surprised. We had a 50 degree day a couple months ago. I've heard reports of weather once going into the 40's. Brr. >>




Brr????! What???! You MUST be kidding, right?

I guess you could never work here (http://www.pmel.noaa.gov/npole/images/noaa.jpg). :P


Cheers!

cthulhu
05-10-2002, 01:07 PM
I just replaced the ac (compressor, blower, all new copper tubing) and heater in my house not two weeks ago. We also laid down some more insulation and installed whirly birds - attic vents.

I live in southern Louisianna so ac is a must. My house is 1200 sq ft plus change. I helped a friend of mine replace a 2.5 ton with a 3 ton unit. My house is nice and cool. My old ac (about 10-15 yrs old) was not a high efficiency unit and IMO not big enough to properly cool my house. If I had wanted to go bigger (more tonnage), I would have needed to change my duct work.

From what I understand you can increase the size of the compressor without having to increase the size of the blower. But, if you increase the size of the blower then you have to increase the size of the compressor. I could be wrong.

The seer rating goes from 10 - 17.

MooseKnuckle
05-10-2002, 09:00 PM
I'm no expert, but here are some tips:

To properly size the unit you should figure this using heat load calculations. There is a lot to consider, such as existing insulation, types of windows and doors, square footage and exterior temperatures.

To get an approximate size of BTU's needed, use the formula below.

1. Figure your square footage.

2. Divide by 600

3. Multiply by 12,000

This gives you your amount of BTU's needed.

1 Ton = 12,000 BTU's

dartworth
05-10-2002, 09:35 PM
<< cool. my buddy has his own airconditioning company. he sais that with my current heater, 3 ton would be the max that could push out. he will do it all for $2000 if i help him install it. thats everything included. if i go with 3.5 or 4 ton i vil have to spend another $700 on a new heater and probably 300-500 more for the extra ton. if 3 is enough i will go with that.

Is there some kinda calculator you can use?? like 1ton per 500sqf??

mylle >>




Shouldn't your buddy be able to tell you how much tonage you need...after all that is his job, correct?


BTW...If you price a condenser and a A coil for your furnace, a 2.5/3 ton unit shouldn't be more than $750-1000. Just something to think about.

me4get
05-11-2002, 12:36 AM
http://hvac-talk.com
Go here and download Hvac-calc. You need to do a load calculation to find out how big a system you need.

Jerboy
05-11-2002, 01:52 AM
<< You can replace the Compressor without having to replace the fan unit. Depending on age.
If you get too powerful of a unit, it does not remove the humidity from the air easily enough and actually does less work for a higher cost. >>



You shouldn't replace compressor in an A/C outside unit other than replacing a failed compressor with an identical replacement. A/C work the best as a matching system. In order to achieve maximum efficiency you need to replace the whole outside unit and the condenser which goes inside your furnace unit. I don't know if it is necessary to replace the two refrigerant lines running between furnace and outside unit. Workmanship has alot to do with performance and reliability of an A/C. If refrigerant lines weren't flushed out properly, welded poorly or not evacuated sufficiently prior to activation can hurt performance as well as reliability.




<< A ton is 12,000 BTU/H.

The original metric came from how much power it takes to make a ton of ice in 24 hours.

A 5 ton unit (large for residential) would be 60,000 btu/hour. Most makes have a two number system in the model number that denotes the size. For example a 18 would indicate a 1 1/2 ton unit, 36 would indicate a 3 ton unit and so on.

SEER (Seasonal Energy Efficiency Ratio) is a measure of the units efficiency. Higher SEER's translate into lower utility bills. >>



Don't you guys LOVE how we have so many different units?


1 ton=3.5kW cooling power.

bizmark
05-11-2002, 02:46 PM
Originally posted by: Mylle
i would need a newer and more powerfull heater to push around more than 3 ton of air.

Right, but your house isn't getting any bigger, is it? And 3 tons was enough to warm your house in the winter before, right? I don't know anything about this stuff -- do you have to have your A/C and heater of matching capacities? Because the A/C obviously gets a LOT more use than the heater -- it's turned on for a longer part of the year, and works harder during that time.