Simple AC tips to help keep your cool this summer

[Bugeater]

*

[Predarat]

I have had an argument with my co workers for some time, but I think its a bad idea to keep flipping the damn temp controll up and down all day long. Maybe flipping it up and down a few times a day is OK, but all day long, up, down, up, down in my opinion will break the damn thing. Its not my $$ so I probably should take the IDGF mode, but still.

[Dave Lane]

Originally Posted by Bugeater

Well that goes against everything I've been taught, which is a fan with x amount of power can move y amount of air through a z size duct, and anything else would require breaking the laws of physics.

AC units normally only move a fraction of the air through a pipe it is capable of. Of course my scenario might part your hair as you walked by the duct but the amount of air flowing through a duct is nowhere near what its capable of.

[Hammock Parties]

I recently found out that planting big trees around your house for shade can make a huge difference. Had no idea.

[Stewie]

Originally Posted by Dave Lane

AC units normally only move a fraction of the air through a pipe it is capable of.

What? A/C units move no air.

[Bugeater]

Originally Posted by Dave Lane

AC units normally only move a fraction of the air through a pipe it is capable of. Of course my scenario might part your hair as you walked by the duct but the amount of air flowing through a duct is nowhere near what its capable of.

You're right that it's not the size of the duct that limits the amount of air moving through it. The speed of the fan is what does that.

[Bugeater]

Originally Posted by Red 5

I recently found out that planting big trees around your house for shade can make a huge difference. Had no idea.

Well yeah, the problem with that is you can't plant big trees. You have to plant small ones and wait for the damn things to grow.

[ChiefsrGood]

Been having some AC issues. Excuse my explanation I don't know much about this stuff. Last summer our AC worked fine. Now this summer has been a mess. When I originally turned it on for the summer the fan wasn't working... so I got someone to come over and they got the fan running and the ac worked fine for awhile. I left town for a week so I shut it off and when I got back home and turned it on again it blew warm air...so I had someone come over again and they got it running fine again. And when I say fine I mean the AC blew constantly and never shut off but the house was cool atleast. Well eventually it started to blow warm/very weak again and I noticed the lines were freezing inside and outside the house. So I shut off the ac, ran the fan to let them thaw out and changed the filter. The pipes still froze up after I turned the ac on again. So I said screw it and got a totally new AC unit. However the vents upstairs work very poorly and one of them that previously worked good just totally quit blowing. So the thermostat is set on 74 and it stays about 75 degrees upstairs and runs constantly and it feels like it's 65 or so in the basement. Going to be a nice energy bill.

[Dave Lane]

Probably low on freon. Sometimes it doesnt get the inside cool enough and ends up freezing up. Call Bug he'll get you going or if you are here in KC I've got a guy thats good and pretty cheap.

[Chief Roundup]

Originally Posted by Dave Lane

Not true. If you think of it in simplistic terms imagine a 5 ton AC unit that has to cool 3000 sq ft. Now imagine all ducts are closed off but one 500 sq foot room (with the thermostat there). It will cool that room much quicker and cycle off much faster (other considerations of wear and tear aside for the moment).

Now is it safe and is it worth the savings is an entirely different argument but all things being equal smaller sq footage = energy savings.

No this will not work like you are thinking at all.
Blower are sized by the size of the system that they are put into.
If you have a 5 ton Air Handler it has a motor and a blower wheel sized to move 2000 cfm's of air. If you restrict or block off half of the registers in your home it will make the blower slow down because it can't move that air. Then that air becomes a restriction. When the blower slows down it won't even be able to pull half of the normal amount of air. Also when you do this and it can't move enough air across the coil and that will cause the coil to freeze up. Along with all of this you are making that motor work hard pulling more amps, costing your more energy, as well as the motor uses that air to keep itself cool.

[Chief Roundup]

Originally Posted by Dave Lane

AC units normally only move a fraction of the air through a pipe it is capable of. Of course my scenario might part your hair as you walked by the duct but the amount of air flowing through a duct is nowhere near what its capable of.

Well there again if the duct work is sized properly for the system by the installer then there won't be much of a fraction left over. If someone oversizes duct you will not get much air flow into your home. And your effenciency is no good.
And it won't "part your hair" if you close off that extreme amount because the blower will not be able to move that much anymore.

[Chief Roundup]

Originally Posted by Bugeater

You're right that it's not the size of the duct that limits the amount of air moving through it. The speed of the fan is what does that.

This is not true. Duct is like a water line you are only going to get so much air through it.
Meaning you can't hook a piece of 10" duct right off the plenum box of a 5 ton unit and think it will blow just fine. 10" duct will not move that much air. The speed of the blower motor is ony in rpm's that the motor will turn. The speed will only affect the fps that the air will travel. Not the volume of air.

[Chief Roundup]

Originally Posted by ChiefsrGood

Been having some AC issues. Excuse my explanation I don't know much about this stuff. Last summer our AC worked fine. Now this summer has been a mess. When I originally turned it on for the summer the fan wasn't working... so I got someone to come over and they got the fan running and the ac worked fine for awhile. I left town for a week so I shut it off and when I got back home and turned it on again it blew warm air...so I had someone come over again and they got it running fine again. And when I say fine I mean the AC blew constantly and never shut off but the house was cool atleast. Well eventually it started to blow warm/very weak again and I noticed the lines were freezing inside and outside the house. So I shut off the ac, ran the fan to let them thaw out and changed the filter. The pipes still froze up after I turned the ac on again. So I said screw it and got a totally new AC unit. However the vents upstairs work very poorly and one of them that previously worked good just totally quit blowing. So the thermostat is set on 74 and it stays about 75 degrees upstairs and runs constantly and it feels like it's 65 or so in the basement. Going to be a nice energy bill.

Sounds like on the first part of your story your evaperator, indoor coil, might of been dirty and or low of refrigerant.
If you have duct that is lined, insulated on the inside, you may have a piece of insulation that has come off or lose and it blocking the air from getting to the piece of duct that feeds that register.
Did you have a split system or a package unit?
Also you have to watch a lot of these companies. I know some that will sell you what they have in stock rather than get you the same sized unit as what they replaced.
If you had a 3 ton system. Did they replace it with a 2 ton unit? You will lose a lot of air that way.

[Bugeater]

Originally Posted by Chief Roundup

This is not true. Duct is like a water line you are only going to get so much air through it.
Meaning you can't hook a piece of 10" duct right off the plenum box of a 5 ton unit and think it will blow just fine. 10" duct will not move that much air. The speed of the blower motor is ony in rpm's that the motor will turn. The speed will only affect the fps that the air will travel. Not the volume of air.

Ah, we're starting to get into things that are covered in the installation class, and I haven't taken that yet. But a higher speed fan would screw up your temp drop over the coil so it wouldn't necessarily cool any faster anyway.

[Bugeater]

Originally Posted by Dave Lane

Probably low on freon. Sometimes it doesnt get the inside cool enough and ends up freezing up. Call Bug he'll get you going or if you are here in KC I've got a guy thats good and pretty cheap.

I'm in Omaha, eight hours round trip travel time would make that service call pretty expensive.

[Chief Roundup]

Originally Posted by Bugeater

Ah, we're starting to get into things that are covered in the installation class, and I haven't taken that yet. But a higher speed fan would screw up your temp drop over the coil so it wouldn't necessarily cool any faster anyway.

This is true.