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View Full Version : What size of air conditioner


mzp
Apr 8, 2008, 12:25 PM
Hello,
My house is about 1350 sqf + about 450 sqf basement in Denver, CO.
What size of central air conditioner should I install? Any brands that are reliable/recommended? What else should I look for when installing air-conditioner? If somebody can recommend a reliable contractor that in the area would be great as well.
Thanks,
Mark

hvac1000
Apr 8, 2008, 12:47 PM
Hello,
my house is about 1350 sqf + about 450 sqf basement in Denver, CO.
What size of central air conditioner should I install? Any brands that are reliable/recommended? What else should I look for when installing air-conditioner? If somebody can recommend a reliable contractor that in the area would be great as well.
Thanks,
Mark


Here is a real easy chart to use. Just follow the directions.

Note if this chart does not help you then I suggest you call a local HVAC contractor in your area. The reason is A/C is not only sized for the SQF but by normal outside temperatures in your area, and window size etc. There is a lot more to sizing a A/C unit than you may think.

coolmen
Apr 11, 2008, 05:10 AM
Keep in mind that from the curb, step backwards 12 feet and measure this will enhance the cooling effienceny

Cletus the HillBilly
Apr 15, 2008, 08:32 PM
Buy a two stage compressor and a variable speed air handling unit, that will increase eff.
You want a professional to size the unit, they'll do the work for you, my guess off the cuff is a 2.5 ~ 3 ton unit depending on how cold you want to stay in summer

garyschiemann69
May 2, 2008, 08:34 PM
Hello,
my house is about 1350 sqf + about 450 sqf basement in Denver, CO.
What size of central air conditioner should I install? Any brands that are reliable/recommended? What else should I look for when installing air-conditioner? If somebody can recommend a reliable contractor that in the area would be great as well.
Thanks,
Mark
Hi a 2.5 tonne would be ideal!

pieceagle
May 14, 2008, 06:17 AM
Call Contractors in your area most will give free est. if they do not measure your rooms,windows, doors and so on I'd stay away from them. If the unit is to big it will not take the moisture from your house and you could end up with mold problems. If it's to small it may not cool during the hottest days. You can size the same identical house and turn it 180% and end up with 2 different size A/C units.
Do not use the guessing game.
Big investment you want it right!

Johnold
Jul 9, 2009, 01:42 PM
Hi I'm new here, I just moved into my first home in FL and I had to replace my condenser and handler from a 10 to a 13 sier unit cause we had a good deal on a that new 13 sier unit and we had it replaced and all done about 3 months ago. My how is 1500 sq feet.

The handler is in the garage cause I guess that house the newer houses here in FL have them. Anyway, I noticed lately that there's been a spot on the one side of duct work the handler is attatched too and today I went out in the garage and there was it was still here but darker. I'm not expert but I figured it could either be mildew or a little early hint of mold. Is this possible for mold or "spotting" like this to happen OUTSIDE of the duct work? I thought it's usually INSIDE. I went up there with a tooth brush, gloves and a mildew remover product and scrubbed it a bit and cleaned it up a little better and lightened it up. I dried it with paper towels and then put a fan pointed at the handler and to dry that area faster. My question is, is this possible? Is this what I think it is? Can this stuff form outside of a duct work? I don't understand cause this is a newer system that was just installed. The AC guy DID tell us that we shouldn't set it up at TOO low of a temp cause it's a pretty BIG system for out square footage we have. We've been keeping the temp at 75 degrees since the install. Today I put it to 78 degrees and I think I'ma leave it there from now on. I think that 75 degrees is TOO much for such a big system to be at in the HOT HOT HOT summer days of FL. I felt the duct work that this "mold" or "mildew" was growing on at it was cold to the touch. My be too much for a handler being in a garage right? What do you think? Thanks for any info or answers and sorry for sucha long first post. Thanks.

Johnold
Jul 9, 2009, 01:44 PM
Man, sorry for the poor typing and spelling.

siberianair
Jul 9, 2009, 03:50 PM
I love that ac guys are experts in mold, mildew, and other things not related to our field. Persoanlly I would call someone who deal with mold and mildew. I own an hvac company and I always recommend others to do that. We are not experts in this and if we provide wrong information it can cost us because we told a customer something was safe that wasn't and vice versa.

hvac1000
Jul 9, 2009, 05:16 PM
Usually a 10% mix of bleach to 90% water will kill any visible mold or mildue BUT that does not mean you got it all. Any place moisture is present mold will grow and in this case your duct might not be insulated well enough allowing mold to form on the cool moist surfaces. Many years ago it was just part of the HVAC guys job to kill any visible mold in the system using the mix above but it is not 1950/60 anymore and there are specialists who due such work. They also take a sample of mold to see what kind it is. Most mold is harmless but there are a few that can be a hazzard to your health and mental well being.

Next time it forms I would call and find out from a mold pro exactly what kind you have and have it taken care of professionally. Also correct the conditions that allow it to start and it will not come back.

Johnold
Jul 10, 2009, 06:50 PM
. Also correct the conditions that allow it to start and it will not come back.

Thanks guys. I Cleaned up that little visible dark spot of whatever it was the day I posted about it. I turned the A/C from 75 to 78 degrees and I noticed that there's little to NO visible condensation on the PVC outlet pipe that's on the handler and none on the handler unit itself. I've been keeping an eye on that spot and it hasn't gotten worse or come back. Granted it's only been a couple days but it seems that the area might sweating less now. I think it was all due to the constant 75 degrees that it was set at plus the fact that the handler is in the garage. I seen the installer do pretty much the whole job. I kind of helped out a bit so I kept an eye and seen his work. I remember him insulating the inner part of the ducts before he moved the handler in the middle between the left and right ducts where the handler goes and I remember seeing him wearing latex gloves while smearing some insulator putty paste stuff with his hands on BOTH inside and outside of the ducts AFTER using LOTS of that metal looking A/C tape. He looked like he did a thorough job. He took his time with the whole install. It took him a week to do everything. So to have see this dark spot had me at a shock. But the installer told me that the handler might sweat quite a bit if we have it on a low temp with it being in the HOT garage. He told me that I should at some point install an exhaust fan for the garage to keep it at a more COOLER temp. He said it would put less stress on the Handler and coils and keep it from sweating so much at a low temp setting on the thermostat.

pieceagle
Jul 14, 2009, 07:26 PM
Again there is no more guess work with heating and cooling systems. Today's houses are built a lot tighter than 30 years ago. If you size your home you must know your insulation value in the ceiling, floor,and walls. Is the basement above or below ground. Are windows single pane, double pane or triple pane are they clear, low e or high e. What windows and walls face north, east, south or west. How many people live in the house. These and many more things are considered when sizing a unit. If your installer installed a unit that will not get rid of the lattin heat. You will not be getting rid of the moisture out of your house. This could cause big problems. You can not install an A/C because it is cheap . Sorry :)