DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (
-   Appliances (
-   -   Why can't they build a smart AC? (

Piedmont 06-21-2010 08:27 AM

Why can't they build a smart AC?
Why can't they build an AC that's aware of what's going on outside?

Why can't they make an AC unit with a feature I can set a temp and it won't go over that temp. However, if outside air temps drop BELOW it, the compressor shuts off and it sucks in outside air and blows it inside (like a window fan). Once outside temps warm up more than inside it then shuts the vent off and then waits to keep my set temp using the compressor. Call the feature "smart cooling". Seems like such a simple energy saving feature to me.

Right now, I wake up at 2AM to see what the temp is outside. Typically it's 65F, so I shut off my AC's and turn on the house fan. In one hour the house fan will cool the house down better than both AC's running all night. Come morning, the house will typically be 62F-67F. I shut off the house fan & windows, turn on my AC's set to 72F, and it will typically be about 3PM before the ac units kick on, some days they don't even kick on. However, getting up at 2AM is not something I enjoy (nor do all the time so I lose out).

Just seems like a simple, smart way to cool. Why cool at night using the compressor when you don't often need to. The AC should be smart enough to automatically use the compressor and recirculate air, or use outside air and just fan.

Scuba_Dave 06-21-2010 08:35 AM

They could build one, more expensive
It would need to check Temp & humidity
You wouldn't want humid air being blown into the house
And since its more $$ it probably would not sell as well
I never run my AC thru the nite....can't sleep
But it doesn't get as hot up here
We use mostly ceiling fans & window fans

NitroNate 06-21-2010 01:37 PM

i imagine it's because it's not universal enough, in other words would be unnecessary in many very hot areas of the country, like where i live. for about 90% of the time the A/C needs to be on from april through october, the outside temp never gets low enough to warrant this feature. manufacturer's would have to be able to mass market something like this and the cost must justify the savings. for that 10% of the time you are talking about, the extra cost and complication would outweigh the overall benefit.

Jacques 06-22-2010 05:55 AM

why don't you put that stuff on a timer or programable thermostat.

Piedmont 06-22-2010 05:10 PM


Originally Posted by Jacques (Post 459669)
why don't you put that stuff on a timer or programable thermostat.

I can't have a timer/programmable thermostat open a window/vent :no:

I think it would be more useful than 10%, I would guess anyone living in hardiness 7 and below would find it a useful feature especially the further away from 7. Most of the country is hardiness 7 or below, but most population dense states (Texas, California, Florida) are not. Maybe 40% of the population of the USA would find it useful & energy efficient.

Maybe electricity is cheap other places, I'm paying $0.22/kWh. I see my Kill-a-watt meter displaying if I continue as I am right now I'm looking at $330 this year for cooling a small ranch in New England using a one year old Energy Efficient AC. If that feature cuts my cooling down by 1/3rd (which I believe is conservative) that's a savings of $110/year. Mileage can vary as you pointed out.

Tom Struble 06-22-2010 05:14 PM


Originally Posted by Piedmont (Post 459944)
I can't have a timer/programmable thermostat open a window/vent :no:.

why not? how do you think green houses are vented..:whistling2:

Red Squirrel 06-22-2010 06:05 PM

That would be cool if they made that. Basically there could be a secondary return with a damper (whole vent and damper would need to be very well insulated) so when the AC is on it would either turn the unit on, or turn this damper on, based on the house temperature, outside temp/humidity.

Jacques 06-23-2010 07:17 AM

this is easily a project for a -competenet-DIY. for instance have a/c's on a timer or a receptcale controlled by a /prog'therm' and a separate temp or time controlled vent [many homes have attic mounted fans that are controlled that way] you could also control your house fan this way, you'd just have to wire the pro/therm on fan only to go on at a certain time or temp.

Marty S. 06-23-2010 05:31 PM

Lots of commercial heat/AC package units have that feature, it's called an economizer. Has a control that senses outdoor temp and humidity and opens a damper to bring in outside air if the parameters are met. More meant for places that need cooling when it's 30-50 degrees out though. Night time temps in the 60's also have humidity levels in the 80-90% range so they will not bring in outside air under those conditions. Even though the temp is cool bringing in humid air adds more load for the system , more $ to run, then just leaving the AC on.

BTW 22 cents a KW is crazy! Ours is closer to 8 cents.

PinkBagGirl 06-23-2010 08:02 PM

Babington style waste oil heater pumps
The cam gear pump works fine for filtered WVO or used motor oil Babington heaters and I have installed it on my Babington style heaters. Ldu Company's stock number is 450516 , The only thing about the cam gear pump is that the fire kind of pulses as the cam gear rotates. If you use the spur gear pump that is LDU's stock number 450512 then you get a steady non-pulsing fire. The WVO pump website is or you can click through to the tools section from the home page at

LDU Company also has other parts that I use for building my waste oil burners, like gear reduction motors. I find it best to turn the pump slower because you really don't need a whole lot of oil dripping on the atomizer ball.

Red Squirrel 06-23-2010 09:05 PM

Out of curiosity, how would one go about adding an outside intake anyway? It would need to be much larger then a typical dryer vent for example. This is a very big hole in an outside wall, that needs to be properly insulated, with a good damper, and also have very good protection against burglars, animals, bugs, and the elements (water, snow, flying debris from wind etc). I'm guessing a serries of grids would need to be used, maybe a pre filter to catch dust particles and so on before they hit the furnace filter. Even having this as a manual setup would be pretty neat. It would be a very quiet way of bringing in outside air and distributing it evenly. Would also be cleaner if you have a good filter system, vs a whole house fan that relies on windows to be open.

gregzoll 06-24-2010 10:42 AM

They actually do make thermostats that use sensors, and also Internet connected ones that use weather info to watch what is going on, track use, make changes, etc. As for a unit to be smart enough, this is where that gray matter up in your noggin comes into play.

All times are GMT -5. The time now is 03:48 PM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

Search Engine Friendly URLs by vBSEO 3.6.1