Pump cool air from basement into upper floors?

[101mph]

I live in a 2 story colonial house and when the summer heat comes, we use the AC pretty much every day.

Since the upper floors are still quite warm (especially one room that faces west which is really warm) and the basement gets really cold, I was wondering if there was a way to pump some of the cold air from the basement up to the upper floors without using the AC or furnace fan.

I was thinking about cutting a hole in the existing duct work, getting a fan, and rigging up some duct work from the fan into the house duct work to try and pull the air from the basement and push it up through the house. Basically recirculating this really cold air from the basement and cooling the upper floors of the house with it.

Is this doable? Has anyone else come up with some nifty ideas of taking the cold air from the basement and pushing it through their house?

I'd like to hear some thoughts on this.

Thanks.

 

[Crusarius]

When I lived in AZ my downstairs was always cold while upstairs was always hot.

I taped my downstairs vents to about 10% of full size. The cold air blew upstairs then rolled down the stairs keeping the entire house at the same temperature.

 

[101mph]

When I lived in AZ my downstairs was always cold while upstairs was always hot.

I taped my downstairs vents to about 10% of full size. The cold air blew upstairs then rolled down the stairs keeping the entire house at the same temperature.

I have tried shutting down the vents with the little doors on the vent covers but haven't had much luck. Still quite a bit of air makes it through. Maybe I should try taping them up as you did.

 

[vekster]

more return vents downstairs
less upstairs

 

[nh_yota]

Yeah I don't know if I'd want the rest of my house smelling like my basement.

 

[kwschumm]

more return vents downstairs
less upstairs

This. And it doesn't cost all that much to leave your fan on continuously to keep the air mixing (and filtered).

 

[dave89iroc]

Yeah I don't know if I'd want the rest of my house smelling like my basement.

only at first, after a couple hours and the air has circulated, all the smell is gone



I use a large industrial type fan(I got a couple free ones) at the bottom of the stairs to push the colder air up, it works

 

[gungatim]

my house is a 3 story (walkout basement) with finished basement. In the summer I shut off the basement vents, and the ones in the living room where the t-stat is, fully open everything on the 3rd floor. I also block the return air vents on the middle floor so it pulls evenly from basement and top floor.

if your not setup that way, it's easy to open up the return air to the basement, you just may have to leave the basement door cracked a bit to keep the flow even...

obviously in the winter I do the opposite, close the top floor vents and open the basement...let the heat rise.

 

[Crusarius]

I tried the closing of the vents. that didn't work very well. That is why I used packing tape. couldn't even tell it was there.

 

[zak77]

I do this in my ranch style house and it helps a lot. I dont have FHA heat so i use a box fan at the top of the stairs and i have a return for the air at the other end of the house. I have a hybrid hot water heater with a heat pump so that "air conditions" the basement and i run a dehumidifier to keep humidity around 60-70%. But when the heat gets real high and stays for a while that alone will not keep the house comfortable. I still need to run the ac. I honestly dont think it'll make enough of a difference to not need AC, but it will reduce the workload on the AC.

 

[dsimatt]

I've got a ranch with full basement and a open stairway going down, in the spring for the occasional hot days it might work but as summer wears on it can get up over 70* down there and I don't think i'd want to risk losing what cooler air I have down there since I don't have AC.

 

[101mph]

I'll see if closing off some of the returns will help. I've tried the fan in the basement and blowing air up the stairs thing and it didn't help.

 

[LS6 Tommy]

This. And it doesn't cost all that much to leave your fan on continuously to keep the air mixing (and filtered).

It costs less to leave the fan on.

Tommy

 

[CNGsaves]

I was talking to my HVAC guy to do the same thing. I've got full basement in brick home and it's always cool in basement, compared to upstairs.

He recommended modifying the RETURN ducts so there would be a damper where I could close off trunk going to returns that now are upstairs. Instead, in the summer I'd open a damper where air would come from basement to get circulated in house (either with just running fan portion of the HVAC or while AC was on).

+1 to nearly close Supply vents on lower levels (ie basement, etc) and open up fully the upper floor supply vents in rooms that want to be cool.

 

[sands35]

What everybody else said.

Plant some trees to shade the house, if you can. Poplars grow fast. Maples a bit slower, but will last longer. Oak or Sassafras are good in Michigan too.

Heavy curtains on the windows that see afternoon sun.

I have a dual system, one for up and one for down so I don't have to change the ducts seasonally, but I do run the HVAC fan all the time to move air around. The furnace fan is designed to be run a long time and is relatively efficient at it.

It is a good idea to keep air moving in the basement regardless of what you do, but you may need to look at how damp it is and if that will be a problem. Normally the typical HVAC duct install will have enough bleed air to do that, but YMMV. I do run a dehumidifier in the basement to control humidity in the summer. I also have a bath fan rigged up to evacuate the cat box area in the basement. Keeps air moving down there.

 

[Zeke]

I did this very thing here in CA using just the air in the crawl space — no basement. It knocked a few degrees off until late afternoon but the main thing was keeping a lid on the overall heat gain during the hottest part of the day (2-4 pm). There was no A/C so by 6 pm all the windows were open and fans on.

If you can modify your existing duct system to do this, I think it will help. But it seems like you have an overall balance problem that you might look into.

 

[101mph]

I did close all the vents on the first floor and about 80% closed for the vents on the second floor. I'm definitely getting a lot more air in the one hot room now. I don't know if this will help pull any of the cool basement air up through the house, but I'll give this a go for a while and see how it works out.

We have some hot days coming up so I'll be running the AC again for a while. Maybe it'll be enough just doing this and running the furnace fan more.

Thanks guys.

 

[101mph]

Update - The room is definitely cooler with more air coming up through the vent. But I am not able to run my fan all the time because it seems the way the system is wired, as soon as I turn the fan on, the AC comes on (doesn't matter if I have the system set to "Off" or "Heat" the AC still comes on).

When set to "Auto", the fan only comes on when the AC is on or when the furnace kicks on in the winter (thermostat set to "Heat" then).

I did a little research and it looks like all fans are not created equal and some are not designed to run continuously. Looks like that's the case with my fan.

 

[gregtwojeeps]

Another one of my novels follows for anyone bored, that may relate to why the OP cannot set his fan on "manual or On" and get A/C all the time...

I had the same issue in the tri-level house that we moved from last year. Top floor was too warm and the basement level too cool. Luckily it had a return air duct in the basement, with me just tweaking the air registers closed partially in the basement in the summer, I dropped the top level two degrees.... But, not all was well with my plan....

I had a combo temperature/humidity meter on the wall at my PC desk in the basement. After I set my unit on "fan only" for a few days I noticed the humidity level in the basement kept rising to 55 and 60 % ..... Hmmm, that's odd. The RH outside was reported to be a steady 30 -40 % those days....

So I went in the crawlspace where my air handler was located to check on it. When I killed the power to the unit, water came rushing out of the compartment where the evaporator sat in the unit. With the unit off, I watched as the condensate water trickled out of the evap coil pan and ran in to my condensate pump tank...

So hmmmm, the drain hole in the unit's evaporator compartment was clear, my condensate pump kicked on and pumped the water out when the float switch engaged it... so why did water come rushing out of the unit when I de-powered the unit ?...

So I put the compartment door back on, but left it loose on one corner so that I could open it just a bit. I wanted to peek inside the unit while it was cooling just to see what was going on with the drain water. ..

I powered the air handler back up and heard the condensing unit fire up outside. I waited a while and peeped in to the evap compartment again. ..

Hmmm, I saw as the blower was running the water in the condensate drain tray under the evaporator coil, was not draining at all. It was simply "boiling" in the drain tray from the force of the air being pulled over it. ..

So this meant to me, that as long as I had the fan in the "on" setting and with it running continuously, the condensate water being made from the evaporator, was laying in the drain tray "boiling", not draining adequately and therefore acting as a humidifier while "misting" the supply duct. ...

Therefore, the condensate water really only drains properly ...when the system thermostat is set to "auto" and the fan/blower shuts down as the compressor does, after the room temperature set point is satisfied. .....

This "off" cycle, then allows the condensate water to drain properly without it being pulled up in to the evaporator coil and being made a misting humidifier. jmo

 

[101mph]

Interesting story gregtwojeeps.

I'm not sure why the fan is not continuous, but I think if I want to go any further with this project I may have to contact the guy who installed the system.

This all started because I had this great idea of being able to take the nice cold air that's sitting in the basement, and use that to cool the house without running the AC (yes I'm cheap).

Didn't go as well as I would've liked, but at least I was able to get the one room that was hot as hell cooled down to something reasonable thanks to some of these suggestions.

 

[bczygan]

I cut a hole in the roof and left the attic and basement doors open. Creates a continuous flow of cool air through the house. It's called the chimney effect.hot air rises and draws cooler air up from below. Used throughout the arid equatorial world.

Install a cupola on the roof with louvers or operable windows.

In addition, use trees and shrubs to absorb sunlight and create a cool shade under them. This is then drawn through open windows.

Wrap your house with covered porches to do the same thing.

Install tall double hung windows in high ceiling-ed rooms and open them both top and bottom. Cool air is drawn in the bottom and hot air escapes the top.


Bill

 

[lilredex]

Update - The room is definitely cooler with more air coming up through the vent. But I am not able to run my fan all the time because it seems the way the system is wired, as soon as I turn the fan on, the AC comes on (doesn't matter if I have the system set to "Off" or "Heat" the AC still comes on).

When set to "Auto", the fan only comes on when the AC is on or when the furnace kicks on in the winter (thermostat set to "Heat" then).

I did a little research and it looks like all fans are not created equal and some are not designed to run continuously. Looks like that's the case with my fan.[/QUOTE)

**************************************************

If you look out by your condensing unit, you may see a box that holds what looks like a metal plate (continuity disconnect) for service people to remove and de-energize your cond. unit.

I have a brick bungalow (1000 Sq. Ft.) and run the fan continuously 365 days a year for maximum comfort. We try to store all the cool air possible when the evenings cool off (a rarity).

 

[BD1]

Use box fans to blow the air upstairs, cold drops down so power fan is the best.
Set another fan upstairs to move air being pushed up from below.

 

[wornoutoldman]

Install a whole house fan. You turn it on for 5-30 minutes and cool off the entire house. It will pull the cool air from the basement up to the second floor and push the hot air out of the attic.

 

[DCarr2]

In my old house, we would open the basement windows during the summer, place a floor fan at the bootom of the stairs and blow upwards, then turn on the house fan at night. durring the day, turn off the house fan but leave the basement fan on.

this worked very very well for years and years til I acquired 2 room mates over the course of 3 summers. and they could not, would not understand that you only open windows at night, and you never open the blinds/curtains durring the day

by 3pm the house was an oven

 

[PT Doc]

Install a whole house fan. You turn it on for 5-30 minutes and cool off the entire house. It will pull the cool air from the basement up to the second floor and push the hot air out of the attic.

Should work out well with windows opened in basement.