We have a Vermont kind of summer going on here, the problem is that my house is basically a large solar box. Great for winter, not so great for summer. So AC could be installed but at a premium because of the lack of runspace for ducting.
Then I found some information of what they call Whole House Fans. Basically a rapid venting system that forces hot air out while drawing cool air in from the bottom of the house. It SOUNDS like a good alternative since we meet the criteria of Warm during the day, cooler at night.

Im looking for personal experiences with these fans. How good do they work? Noisy? Etc...

I really dont feel like spending 10, 000 on AC.

SJ

We've got a similar fan in my house, but it's less complicated with only one large intake at one of the upper points in the house, so I'm not sure how much of my experience translates to what you linked. It's pretty loud, but again it looks like a different design than you linked to.

It definitely gets the hot air moving out of the house though, creating noticeable breezes through all the windows. As long as it's cool enough outside, we get significant cooling from the fan. I think it's effectiveness as an AC replacement is all depends on what the climate you're living in. There's no way we could rely solely on the fan during the summer here in the washington d.c. area, but it's great for us in the spring and fall.

Why not use a swampy (evaporative air conditioner). Very similar ducting design but with the added benefit of cooling the air. Most all of the swampies here have a reverse switch that would do the same thing, evacuate your home off hot air.
Your location need to be considered though. Moist climates aren’t the best.


DJ

Try a simple window fan.

They are fairly quiet (about the same as a cheep ceiling fan $30 -$75) and can move 500 - 1000cfm. At that rate the air in a 2400sf house is changed every 20 to 40 minutes. Opening the downstairs, or basement windward windows and the upstairs downwind windows would also create a natural draft. Note: the closer to the ground the intake air comes from the cooler it would be (in most cases). Air at grass level is on average 10 deg cooler that abient. If you water your grass in the evening, and draw your intake air from just above the grass (ie a basement window) then it acts as a natural swamp cooler.

I hear swampies arent as efficient for this climate. We dont really even have the right climate for a heat pump.
But I could see this working pretty well. My wife used to have one in the house she grew up in and didnt flich when I told her the price.

Worth looking into



Window fans wont cut it due to the amount of thermal mass that occupies the top of the house.
Remeber those fans they used to use in the gyms at school? I have one of those in the bedroom. Barely cools the house at all. I did check the eaves of the house and it definitely has enough venting to keep the attic space dry, but it gets hot as hell. Then there is a wall which stands between the attic and the shaft in our bedroom that has a southern window ( which cannot open). That wall has no insulation so it leaches heat right into the bedroom area and gets compunded by the solar radiation.

In the end, its like trying to cool the broiler under a lit stove. You can do it, but there is always a big heat source above it.

I was thinking about a duct there, a duct in our bedroom and one in the kids room and leaving the last one free to vent the attic. That SHOULD make a rapid reduction in thermal mass for the attic, leaving the rest of the house easier to deal with.

Maybe a little more insullation in the attic might help. It's often tax deductible (depending on your state) and helps with the winter bills as well. Window treatments (ie drapes, blinds etc) with a thermal shield work well but can be expensive.

In the end you can't save money spending money. The cheapest solution I know is to plant some shade trees around your place and wait 30 years.

Oh the attic is greatly insulated. We dont get ice dams or anything on out roofs and the snow tends to stay there. I think we have about 18 inches on the floor. But the heat buildup in the summer is just monsterous. The mass of the house gets really warm and then its a bitch to cool it off.

I may have to post a picture so you guys can get an idea of the hothouse effect.

Is the attic positively ventilated?

Sounds like a quiet attic fan. The houses I have lived in have a belt driven 36" fan with louvers in the hall way. It is a bit noisy, but it moves a lot of air. This whole house fan is just adding ducts to slow down the air (so it is quieter). I would bet that both move about the same amount of air.

The house we live in now has a high/low setting. If you turn it on high and do not have enough windows open it make a low tone grown because it is trying to move more air than is available. If you open more windows you can get a good breeze in every room. It cools the house to the outside temp in about 5 minutes.

Check for the volume of air(CFM's- ft^3/min) that it can move, then you can size one of either type.

The two get mentioned in the same breath quite often. The whole house fan usually has a few extra modifications such as doors that close tight and eliminate the need for winterizing. That seems to be the big factor and of course the quiet construction. They usually add a few more amenities like a radio control for speed and tighter construction to reduce vibrations.

BC. our attic is passively ventialted. It has a band of soffit venting which is continuous around the eaves and a roof ridge vent. I have to admit that in the wintertime, Its great. It holds a good deal of heat and makes out bills quite a bit more manageable. But the hot days in the summer are killers. But I have been looking at the actual use of our AC unit. I think If I could vent the house effectively, I could nearly eliminate the AC use. Fine with me because that would save me on electricity. Seems the fans use about a 1/4 of what AC units use.
Im green, but Im cheap too.

I also hear that the large fans are good for removing dust particles etc from a house. Seems that modern houses dont breathe as well as they should and can lead to a buildup of of all kinds of things that can make our lives miserable. I was thinking that after raising some dust when cleaning, just turning on the fan could really be a life saver. Of course the air from outside could be laden with pollen, but I guess thats a chance I will have to take.

Anyone have any thoughts on winterizing these fans? If I put it in, it wont be easy to get to.

SJ

Perhaps these.

If I was going to use the big red fan with the vents I might use these, but I was referring to the 30 inch fans they put in hallways. I have read that a lot of people put foam enclosures on them during the winter. This may be a little impractical for me, as getting to the fan is very similar to breaking out of prison. Possibly an insulated foam "hatch" to cover it.

I’ll rephrase it.

Perhaps something like these. DIY?

Yeah, but they are Australian...I would have to mount them upside down to work...


That said. I do like the idea. Im pretty certain a little PVC and some creative metalwork could develop into something cheap. But the winters are really cold here. I want to make sure Im not damaging my homes ability to hold heat. But you could make a gable ended system with these sticking up through the insulation and just use a gravity flap like they use on tractor exhaust systems.

Biggest thing you can do mainstream: fan-ventilate the attic. A whole house fan is much larger and requires much more to install. The fan I showed is installed in an hour, tops. You need one fan per 1500' ft of attic floor. It runs on the same simple thermostat used in early 15" DIY PJs, which is included with the ~$80 fan. In the winter, you simply shove some insulation in the ~14" hole and throw the switch for the fan. These fans can be located toward the apex of the roof, where the bulk of the house's heat collects. If you really want your house to be cool and save a load of money...paint your roof white or silver. This would decrease heat input into the house by ~80%! Of course, you'd want to paint the roof black by winter's onset! Not practical, but reflective panels and dark panels are...and can be installed strategically over the southern facing roof within an hour's time 2x/year.

To ventilate the house without AC, find your northern and southern exposures. Use window fans drawing air into the northern windows and exhausting out the southern. Place the exhaust fans on the second floor and the input fans on the first. Just 2-4 fans can have a huge effect on household temps.

We have been through the fan and ventilation part already. Thats how I established to the wife that we needed more throughput in order to cool the house. I took more readings on the house last night. Seems like the Attic may not really be part of the equation, but it might come into play for the venting. The ceiling was only a few degrees warmer than the ambient room temp of the second floor. But the drywall inside of the sunshaft we have was quite a bit warmer. Im thinking now that if we could install a window that actually opens at the top of the sunshaft, we could vent the house by simple convection. But I am quite fond of the idea of getting the house cooled off in a matter of moments with a house fan.
Another problem is the actual entrance to the attic, which is a 20" x 20" shaft entrance into a basic sea of insulation. The entrance to this is in our closet. A closet with 8 foot ceilings. Thats why Im leaning towards something that doesnt demand I make a journey through my precious insulation twice a year.

I was joking with the wife last night and told her I was going to put a couple of mushroom fans ( thats what they call roof fans around here) in the window. She just shrugged and said " Well, if you really think it will help."

I think my wife has finally figured out that I should be left to my own thoughts in some areas.

Let me try to whip up a quick diagram of the house.

Any blower system that has over 8" of flex duct will be nice and quiet. (I did A/C in a past life) If you can install a up draft system like in the first post you could also install a evap cooler just the same.

Evaps are fine if you have low humidity but if you don't then a split window A/C might be what you want.

http://cgi.ebay.com/WILLIAMSON-Wall-Mounte...emZ250263016647

You can install this type of system in the hottest room perhaps the MBR and place and exhaust fan at the other end of the house to move the cold air through the house.

The amp draw of a A/C increases with the difference in temp so if the split is only 15deg or so the electric cost wont be so high. They are also vary good at removing humidity which makes you sweat less.

What are your outside temps at night?

We have casement windows in every part of the house...

Our outside temps are very good. An 89 degree day will drop into the low 60's at night so AC isnt really needed. But I have this heat trap of an attic plus an oddly constructed roof structure that lends itself to pockets of warm air which dont go anywhere.

Click to view attachment

Okay. Here's a really quick sketch of the side of the house that faces WEST. Note the glass french doors in red and the large blue trapezoid window. The passthrough into the upper bedroom drafts right up into a sunshaft that faces SOUTH. Worse, the builder didnt install a window that opens so its a bit of an oven in there. Combine that with the heat from the attic in black ( which also continues around the space to the back) and you can see why I'm having heat buildup problems.

Im of the mind now that replacing the upstairs window with one that opens would allow for some serious thermal chiminey effect. But the last guys I talked with about that were scared cause the roof is steep and 40 feet off the ground.

Oh the house sketch isnt to scale. I figure I have about 525 square feet of attic that varies between 2 and 6 feet from the roof. Thats roughly 2100 Cubic Feet of Hot air in the attic alone, not to mention the several hundred in the light shaft.

I'm certain you already thought of this, but would you be able to vent the area above the blue window into the sunshaft, as well as the attic? Then you might want to consider installing a skylight (with a screen to keep critters out) in the sunshaft that you can open (electronically). There is also an option of installing an electronically operated blind that can block the skylight and/or the window in the sunshaft. I know that a blind would defeat the purpose of the skylight/window, but this is what we had to do with our kitchen that had a skylight over the island. It got too bloody hot in the summer.

Actually, I hadnt thought of a skylight since there was a window there already, But thats why I posted here...I like it when I have a lot of options. You just gave me another one...Thanks. If you look at the wall between the area below the sunshaft and the blue window, you will see its actually a window frame that looks out over the lower area, so it would already be vented. But small flow through vents could make the difference in getting that heat pocket out of there.

Still, I had never even considered a skylight in the location opposite the window. Good thinking.

Thats why I love this place. So many clever people and solid thinkers in one area.

Ived lived in sac town california for 8 years, and it would push 100F during the summer months. what seemed to work for us was simply opening up evry window in your house when you go to bed and closing them all and shutting the blinds when you get up. even though it was boiling outside this worked really well. eventusally we got lazy and bought an attic ac system, but it was actually cold in the house when it was freakin hot outside from just rotating your windows.

Well, I shopped some skylights last night and was VERY surprised to see they werent so bad. Prices were in the 3-500 range, so they could be an option.
Until I looked at motorizing them.
Some of the motor kits cost almost twice what the window costs...geesh.

The peak where I would put it, is pretty high up and Im not sure I can reach it with a 10 foot skylight rod.

Still open to suggestions...

DUH!!! DIY the automatic skylight lifter.

Say . . . anyone seen a stray house elf?

Yeah I was thinking a car door electric motor might be just the thing....bzzzzzzzzzzz.....bzzzzzzzzzzz

WAF on this needs to be rather high, however.

So just needs to look good? I recall years ago looking into greenhouse vent lifters which were temperature activated and they were nowhere near $100. But maybe they require excellent counterbalancing or something? What are the commercial lifting units like anyway for that price?

Well, if you look at the type of Skylight I need, you can see it uses a conversion kit called a WCM 140.

Looking this up as a product shows it as a pretty expensive item. 100 dollars more than the window itself.

Yeek!
Wife wants me to pay for an install so Im lookin at over 1000 for a skylight.

Wow! That IS pricey!!! Looks like a no-win situation if you ain't willing to cough up the bucks. That is insane for a motor and controls!!!

The end goal is to cool the house with a little ingenuity...Im hopin other folks will chime in.

Weeelllllllll . . . since you'll be spending your 4th at Home Depot check for this.

Hey just my 2 cents we have a 36" whole house fan and it does move a lot of air, yes you can hear it run but it's not bad I can watch tv in my room right next to the fan in the hall and you dont really have to turn the tv up much at all, one thing to be sure of is plenty of vents on the roof. our's has a plexi cover that we can put on in the winter and it seems to do alright. Depending on how much money you want to spend the whole house fan is the way to go.

Kick-ass review! Real data, imagine...

hmmm...

I've become a "self-proclaimed expert" ( take THAT with a grain of salt) on the art of cooling the house using something other than A/C. Fans work GREAT... but as far as something "quick", A/C is the best, hands down. I will agree with BC on this, removing the heat from the attic space should be a priority and concern #1 as this will reduce heat tranfer into the house as much as possible. An attic fan will keep the majority of heat from transfering into the house, especially upstairs bedrooms. (upstairs bedrooms are the curse as far as comfortable sleeping, IMO) Window fans can be used, and moved (a big plus), during late afternoon and even hours for very effective cooling. Opening and closing windows, in addition to adjusting fan speeds, you are able to adjust the temperature of the house in the moring. (I was able go get my house to 66-68F most mornings by simply adjusting the # and speed of fans during the night... trial-and-error method )

There is not much to do about humitidy however, and this has a much greater effect on how "cool" you might feel, which means we ended up with several A/C windows units, but still ended up costing ~$60/month or so during the hot months (june/july/aug)... not too bad for 4 units (3x6500BTU, 1x15000BTU).

If I ever get to build my own house, it will have (hopefully):

1) Attic Fan
2) Whole house Fan
3) Central Air
4) 2 Types of heating systems (FHA & FHW)
5) Solar / Wind "backfeed" system

I've only just started thinking of this now, but BC brings up a great point, that simply changing the color of a roof would SIGNIFICANTLY change the heat transfer properties of a house... i'll have to poke around a bit and see what options might be available for this... obviously, re-roofing with a different colored shingle is out of the question ! ... I always wanted a sunroom off the larger greatroom for heating/cooling... my next "dream" house would have this too...

[clink, clink...]

good luck, no matter the path you choose...

It would be cool (double entendre intended) is you could get a spray coat for your roof which reflected only IR radiation. The roof would look the same but stay cooler.

***clink***


I had an idea for an invention some many years back; a 'shingle' composed of striated grooves. The striata are linear grooves with a white side and black side. The shingle grooves are oriented so, that when the Sun is highest (Summer) the shingle shows the Sun its white side, but when the Sun dips in fall, the black side of the shingle is in focus. The striations can be quite tiny, allowing the shingle to look "normal" (pfft).

In my first house I had an attic fan. It was great!

My house was small (1300 sq ft), but it did the job. The fan was about 3 ft x 3ft. It made a noticeable breeze. It was a bit noisy, but not irritating. In the evening when the house was hot, I could use it to pull the outside cool air in. This was really nice at night when I went to sleep. [url="http://www.canwesavetheworld.com/whole-house-fan-photo.html"] Here is a link that shows the type of fan I had.


This year, to save $ on air conditioning ($250/month in July & August), I plan to put a similiar fan in my new house (2800 sq ft). The fan will be the same size, 3ft x 3ft. This is a project that I've been wanting to do for the last couple years, as my uncle is giving me that fan for free (he picked it up from a trade show at low cost 10 years ago).

Installing the fan will also help cool the attic, which should help keep all of the bedrooms on the second floor cool.

Cheers!

Fulcrum

I have been thinking about a solar powered one that would only come on when the combination of temps above 70 and sunny are available.

can you offer any suggestions for southeast texas?

we had to get a new roof thanks to hurricane ike so I got a much lighter colored shingle which I think will help..We have a ridge vent but they left the "whirly birds" or wind turbines on the roof as well. I think that may actually be hurting me..I'm thinking about just removing the turbines from their base an putting one of those low profile vents there instead but it would just be for looks..I would probably block them off in the attic to let the air all go to the ridge vents...

I always though it would be neat to fashion an active cooling system that ran the length of your ridge vent and mounted to the top of your attic, forming a seal between the ridge vents and your attic space, which would basically just accelerate the natural process already taking place with the ridge vent.

It would be a neat DIY project! Go find tons of discarded PC fans or something and build a plywood/plastic/etc. long skinny enclosure to fit up against your ridge vent..caulk around it for a good seal....

For texas?

A big assed fan!

well I'm convinced my house doesn't have enough intake on the eaves..the other day we had the windows open and I opened the attic to stow some things away and the updraft was pretty strong. Perhaps I'll just add more vents to the eaves when I go to re-paint the house...

Why do people try to get away with the bare minimum when it comes to cooling? Twice I have purchased dvd players (one dvd, one hd dvd) that would get blazing hot and begin acting up. Both times I had to hack the case up and mount a "real" fan in there instead of the grossly inadequate puny fan or no fan at all.

An even bigger crime..one time by brother in law was living in a rent house that had NO ventilation in the attic! It was crazy hot in their house...The owner of the home wouldn't pay for cooling the place but he would let my brother in law install it (how nice)..so we spent an afternoon cutting the top off the house and installing on of those cheaper aluminum ridge vents. I took some scrap wood and made some rectangular frames and stapled some screen door screen to them and used those as the vents alont the eaves..the difference of course was huge in the house temps.

ok I'll try not to overtake this conversation again..back on topic...

I think the "active ridge vent" idea would be pretty good, but after feeling that strong draft the other day..perhaps just adequate air intake and the laws of nature do the best job.

I got pretty curious about this one: http://www.wholehousefan.com/superfan.html

I mean, it has the word "Super" in it...It must be good.


If you can take advantage of that updraft, you may not even need the fan. A couple of passive vents at the peaks of the roof and just open your attic door when you want to draw in cooler air from downstairs. We use breathable roof vents around here. Makes for a dryer attic. Basically makes the entire peak into a roof vent.

SJ

Hello, all.

I'm new to the forum, signed up to study DIY antenna designs (and built one with great success, thank you!) and have been lurking in other topics since.

I've got a couple thoughts for your cooling problem.

Would it be practical to build a chase up the east-facing outside wall? If so, large vents could be placed in the sun well and the attic and the fan could be placed at ground level. Any fan large enough for whole-house purposes would have negligible losses to the convective force in the chase.

I see the following benefits:

1. Appearance. Only a louvered grate would be visible inside.

2. Maintenance and winterizing would be at ground level.

3. If the chase is well insulated and the exhaust properly winterized, nothing would need to be done at the intake in winter, so no ladders in the house.

As an add-on, consider using "earth-tubes" to supply some of the makeup air. As I understand, you are in a northern climate. 50' or so of 8+" pipe buried below the frost line with a screen at the intake and a small fan exiting into the house will provide natural air conditioning. Some research would be required to determine what size, how many, and how long the tubes would need to be to have the desired effect.

Good luck!

Steve