Whole House Ventilation Upgrade

[wooferhound]

I have been using Whole House ventilation in place of air conditioning ever since I moved out of my parents house in 1979. It works by basically forcing out the heat that normally builds up in the house from electrical appliances and body heat. This is not cooling the house down but it is keeping the inside temperature from getting any higher than the outside temperature. Well the Box Fan that I was using quit, so I made a new system.

This is my most recent version, which is just fans in a window pulling air through a hood I built that holds a Filter to help keep the bugs and dust out. The new system is a set of three DC 48volt 20w DC fans that I got for $20 when a local electronics dealer that went out of business recently. There is a 4th fan at the top that is a 120vac 20w fan. This system is controlled by the thermostat in the corner on the left side. The box it is mounted to has a relay inside that switches the 120vac power. This thermostat works great in the Spring and Fall when it gets too cold at night for outside air ventilation. The transformer next to the thermostat is powering the 48vdc fans with a rectifier circuit mounted onto the fan housing.

This is a double window and the fans are sealed to the Outside window with the 1/4 inch blue plastic sheets that I cut out. There is a 4 pin XLR connection just to the left of the bottom fan. I can disconnect this to close the inside window without mashing the wires. I can easy take the whole unit out and close all the windows for the Winter cold. I have planted some plants outside that should shade the window, hopefully in 3 or 4 more years of growth, which will help to cool the air at that time. Here is a story about plant cooling.

http://www.fieldlines.com/story/2007/6/5/4912/23050

Until now I had been using a Box Fan to pull the fresh air in. I had Cardboard cut-outs built around the fan to help seal it off and pull more air in. This is a picture of the old fan, without the cardboard sealing. It was much louder than the new fans, pulled in less than half the air, and used twice the watts. For some reason DC fans are extremely more efficient than AC fans, so any vent fans that I use in the future will be operate from DC. Here are some stories from other users that have discovered this.

http://www.fieldlines.com/story/2005/8/27/42713/8716

http://www.fieldlines.com/story/2007/3/10/23942/1876

http://www.fieldlines.com/story/2007/5/1/212155/6372

This is a view from the outside where the hood is. There is a slot on the side that the filter slides in & out of. I made the box the right size to hold the same size filter as my air conditioning unit inside the house so I wouldn't need to remember 2 different filter sizes. I need to change the filter about every 2 months, it gets brown stuff all over it and lots of bugs. Inside the hood I stapled carpet pad to absorb some of the fan noise resonating around in there. I've been using this system for 2 years now and the wife and me love it. We like the fresh air and the LOW electricity bills. In the Spring & Fall, if the house is running a higher temperature than the outside air, the thermostat will cycle and actually maintain a steady temperature inside.

I've written a diary about this before but it's not nearly as informative

http://www.fieldlines.com/story/2005/4/6/2056/94039


W o o f -={(

[pvale]

Woof,

I live in a 2 story house right now, and we just use the upstairs as storage. So I have windows up there open on the south and north sides. I have window fans in both of them, exhausting. Until the weather gets really hot(may just be happening now in MO), it works really well. The hot air rises into the upstairs, and if I leave windows open downstairs, air comes in them and goes out the upstairs windows. It deinately has extended the time until I needed to turn the AC on.

[wooferhound]

 I have a 2 story house also, and the fans are on the ground floor in the laundry room. There are 3bedrooms upstairs and those are the windows that are open. This of course uses the heat rising action. When it gets cold fast outside and the fans are pushing cold air into the hot house, I think the colder air pools on the lower floor because it's to heavy to get pushed upstairs.

My utility bill runs about $100 more if I run the air conditioner instead of the fans.

[zeusmorg]

 Well my scheme is similar, in a way with probably a few differences. I have a whole house attic fan 4'x4' with 1/2 hp motor. The incoming air comes in a window in the basement,which has a standard fiberglass filter in it. Then the cool air coming in the crawlspace through the window is pulled first into the basement and then up throughout the house, most through the standard air ducting, which I open to accommodate this. Then the air is pulled up to the center of the house out the attic and out through a peak roof vent and the original vents under the eaves.

 I have the system on a timer, and it is a 2 speed setup. (high gets a bit noisy) i turn it on at dusk and let it shut of before sunrise. I get a "flywheel effect" during the daytime and rarely ever have to use the two window units I have.

  This type of cooling in the summer was quite common in the 50's to cool down a house before the advent of affordable a/c systems.

 Fortunately part of this system was in place when i purchased the house(the fan) the rest were just improvements at a low cost to increase the cooling. (the filter, duct baffle, and peak vent)

[GeeMac]

I have noticed that builders of new homes are putting fans in the attic access panel and forcing the hot air into the attic to be vented out the roof ventilation system.

[wooferhound]

That's good, because there are many homes built today that require the air conditioning, and are almost impossible to ventilate sensibly.

[phil b]

Good post Wolf!

I think with the price of oil going up daily, we should see new low and mid priced houses with improved ventillation. Bigger houses are using heat pump systems that already save money over regular air conditioning systems.

I remember seeing some of the big mansions made in the 1800's along the gulf coast of the US. They had windows that went from the ceiling to the floor that could be opened and walked through. High ceilings helped vent the heat outside from people and candle lighting. On the smaller side, houses had a big porch on the North side where everyone slept in the summer when the house was too hot.