Another central A/C question

[HoleshotHolset]

Measuring with my infrared thermometer... the cold air outlet grilles in the ceiling are measuring in the 50°F range... doesn't this sound a bit 'warm'?



This is with the system on for at least an hour... ~75°F ambient temps.



It takes the system quite a while to cool down ~1000 sq. ft. - so the relatively 'warm' cold air outlet might have something to do with it.



Since this is a leased property - I will most likely get the pleasure of dealing with the management and having them probably tell me that if the system can bring the apartment down to the temperature I set... then everything's OK.



Matt

 

[mgoncalves]

There's nothing wrong there.

 

[TowPro]

when you say outlet grills in the ceeling are we talking about an RV air conditioner?



25 colder outlet then inlet is about it. If it is an RV ac, you have a lot of loss through the ducts.



I added this new cover on my RV that I can open vents right at the AC. This really helps for cooling down the camper in the hot sun.



When my 30' camper is in direct 90deg sunlite, I am lucky to get it down to 80 inside. Then I got that new Ac cover that has the vents and my problem of "hot camper" went away.

 

[HoleshotHolset]

50°F is cold enough for household central A/C? Wow, I expected much cooler temps than that... especially when compared to what comes out of some cars' vents... and even A/C units hung off your casement windows.



No camper here... just a small apartment.



Matt

 

[TowPro]

They are worried more about the difference between the inlet and outlet temps. 25deg difference is average.



In my home, I have the return air inlet for my AC in the basement. this way the cold air is blown up to the up stairs of the house, and it returns down a 6' sprial stair case, and all the way through the basement back to the cold air return



This way it dehumidifies the basement, and the basement air temp helps to cool the air some before it goes back through the AC. this gives me a around a 45 deg temp at the outlets.

 

[mgoncalves]

Matt,

The idea is to have a long cycle time, to give it a chance to remove more humidity.



TowPro,

What you really want is a return air vent at the hottest, and highest location in the house. If your only return is in the basement, you are only pulling in cold air to the A/C. The idea is to cool down the hot air, which makes the ENTIRE house roughly the same temp, and more comfortable than a cold basement and hot second story.





Matt

 

[jponder]

You are already running ac in wisconsin? I hope to make it to mid may before i turn it on and I'm in atlanta

 

[HoleshotHolset]

I think the system has the long cycle time thing taken care of... I was just curious about the outlet temps, they seemed a little warm.



It was 80°F outside on Friday... Saturday approached mid-70's. The ceiling fan just wasn't cutting it.



Matt

 

[TowPro]

I here what your saying, and it makes sense.

I guess I forgot to explain my house is 2 floors on the back, and 1 on the front built into a hill (so is my garage).



the way I have it the AC blows air up to the top floor, which pressurizes the house (house is pretty air tight) enough the air is forced down through a 6'x6' opening that has a sprial stair case in it, then the air passes through the downstars (there is a 24" x 12" vent above the door in the downstars so the air can pass through) into the area where the AC inlet is at. If your in the stairs area, you can see the air movment with a candle flame.



the AC is a 3 ton self contained unit that sits outside with a 12" inlet and outlet (like seen on double wide mobile homes). The AC outlet is connected to the heat duct system, the inlet connects to a small inlet duct I built so I can keep 2 -16"x25" filters in front of it.



Works good. Top house stays cool, AC is big enough the house will hold 75 even when its 100 outside, it keeps the basement (downstars) dry. Plus the hot air being forced from the top house into the basement keeps the basement warmer then if the AC was not running.

Originally posted by mgoncalves

.



TowPro,

What you really want is a return air vent at the hottest, and highest location in the house. If your only return is in the basement, you are only pulling in cold air to the A/C. The idea is to cool down the hot air, which makes the ENTIRE house roughly the same temp, and more comfortable than a cold basement and hot second story.





Matt