It is 54 degrees outside. Inside my home it is 80 degrees. At night, as the outdoors gets cooler, the inside of my home continues to get warmer, at least with the windows closed. It's a relatively safe neighborhood, but not safe enough to leave a downstairs window open. Opening upstairs windows alone hardly makes a dent in the temperature.

Most of the heat comes from thermal mass I presume, meaning the walls and floors and ceilings store the heat from the day and release it all night, much to my sleeping displeasure. I can't sleep at temperatures above 75 degrees. We have some electronics plugged in, but not too much in that department.

As I walk the dog at 5:30 am, many of the neighbors have their windows closed and the air conditioning running. I reiterate that it is 54 degrees outside.

All of the homes in this development were built about five years ago. I'm sure they meet or exceed all the codes for energy use. And yet many of us are running our air conditioning when it is 54 degrees outside.

All we need to solve this problem is a downstairs window that has both a screen (for bugs) and jail bars (for intruders). The trick is to make the jail bars not look like jail bars, so there is some chance the homeowners association would allow them. The jail bars need not be grey vertical bars. They could be a design that adds a cool and funky look to your portal. For example, the barrier against intruders could be a peace sign, or a happy face, or a pine tree, whatever. And it could be whatever color works with your house.

Obviously this sort of solution is only useful in places and seasons where it is hot during the day and cool at night. But that is a lot of places.

Ideally that window, and a few upstairs, would be motorized and on a remote, so you can close them without getting out of bed if it gets too cold inside.

But my real question is this: If it is colder outside than inside, is there any reason you shouldn't run the air conditioning with your upstairs windows open?
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Sep 12, 2008
All you need to do is get one or several window fans and blow the cool air into the house. It works like a charm.
Sep 12, 2008
Your local homo* association probably can't stop you from putting jail bars on the <em>inside</em> of your windows. And if they extend perpendicular to the direction your window opens, they won't impede opening the window.

* - short for "homogeneity", not anything else
Sep 12, 2008
I live in Florida, and nobody opens the windows for any reason, ever. But that doesn't mean we all love A/C. Here are some of the downsides:

1) Meat takes forever to defrost in an air-conditioned kitchen.

2) The windows, chilled by the A/C, frost up with condensation from the humid air outside, rendering them opaque.

3) Snakes are attracted to the heat produced by the A/C compressor motor once the air cools off a bit in the evenings, and are often caught and wrapped around the drive shaft of the motor, causing the motor to burn out.

4) During the winter months, when the A/C isn't running, lizards find their way into your household ductwork, where they eventually die. Two months later, when the temperatures warm up, the stench of their decomposing bodies is piped all over your house.
Sep 12, 2008
In addition to the fans others suggest, you could get a Canadian well to get the cool air in (even when it's hot outside actually)

The Canadian well consists of passing a proportion of fresh air through pipes buried in the ground, before it enters the house. The principle is to make passive use of geothermal energy.

A PVC or baked earth pipe is inserted in the ground at a depth of about 2m. Typically, its diameter will be between 20 and 30 cm, one of its ends is open to outside air, and it is provided with protection against water, insects and rodents. The other end may be fitted with a circulating fan (15 W for 200 m3) and carries air inside the room.

In winter, the soil at this depth is warmer than the outside temperature, and therefore the cold air is preheated as it passes through the pipes. In summer, the soil is colder than the outside temperature, and therefore, the well will make use of the relative coolness of the ground to moderate the temperature of the air input into the residence.
Sep 12, 2008
Wow...they are some really complicated ideas here.

My advice is to buy (and have someone install) a whole house/attic fan. Open the upstairs windows and turn on the fan. It will draw the colder air in and cool down the house. It only needs to be on for a short period of time

An additional bonus to that is it uses significantly less energy than your A/C...especially if you keep the windows open.
Sep 12, 2008
I live in the UK. In my terraced house, I have insulated the loft to exceed standards to keep the house warm during winter. However, we overheat during the summer, and can't leave windows open downstairs for the same reason you mention. We don't even have aircon.

I'm also planning on fitting a tiny window above the conservatory to allow exactly the kind of airflow you suggest, and I'm having problems picking something nice to look at. I think custom wrought ironwork may be the way to go, but it will be relatively expensive.

Having gone into the loft space during the summer, I think we are also absorbing heat through the tiled roof, and I've been wondering what effect it would have if I painted the roof white to affect the albedo, and installed insulation boards against the backside of the tiles. Surely as well as slowing absorption of heat during summer, this would also retard the emission of heat radiation during winter, so it could be a win-win. Of course, local planning laws I wouldn't be allowed to paint the roof white anyway.
Sep 12, 2008
Sounds like you just need something to promote air movement. Consider a whole house fan or an attic fan. The attic fan will pull cold air into your attic, while the whole house fan will cycle the air out of your house.

Also, running the A/C uses a lot less power in the !$%*!$%*!$%*! you describe then, say when it's 120 outside.
Sep 12, 2008
Two words:

Whole-house fan

Er, or is that three words? In any case, from Wikipedia:

A whole-house fan sucks hot air out of a building and forces it into the attic. This displaces the very hot air trapped in the attic (which is pushed out the gable-end or soffit vents). Then, with windows and/or doors open to the outside, the whole-house fan draws cooler outside air into the building to replace the hot air (creating a cooling breeze whilst doing so).

A whole-house fan can significantly lower the temperature in a building very quickly, and is much less expensive to operate than air conditioning. Newer whole house fans are extremely environmentally friendly and energy efficient additions to house cooling systems. On temperate days they can be turned on to circulate rising hot air out of the house while pulling cool air in. Also new models are quieter and smaller than their older counterparts.
+3 Rank Up Rank Down
Sep 12, 2008
3 words: Whole House Fan

this is an energy efficient way to remove the hot air in the house (as a result of thermal mass of the house) and draw in cool fresh outside air.
Sep 12, 2008
Two words: attic fan.

Even with open windows only upstairs, it should draw the hot (risen) air out.

Or you could just stuff your walls with freshly frozen flavorice freezy pops each night. :)
+4 Rank Up Rank Down
Sep 12, 2008
You could do what most of the people in the middle of the country do: open the windows and buy a gun.

: )
+1 Rank Up Rank Down
Sep 12, 2008
Hi Scott,

Yes, the intruders might have ladders.

Instead of installing some new window bars or some type of fan system in each home, have your neighborhood association hire a security patrol. Plus your dog will be helpful. The main point of a guard dog is noise and not physical threat. Then open your windows whenever you want.

Sep 12, 2008
I've worked hard this year to keep AC running at a minimum. Doing the following has dropped my electricity usage 20% this Summer.
- Control sunlight: Keep curtains down during the sunny days, open them and windows at night, closing the downstairs windows when the family goes to bed.
- I have a big fan, that I use on occasion upstairs at night, pointed out to draw out inside air. I only have to use it for about 15 minutes or so to cool the entire upstairs down.
- I run a dehumidifier in the basement (where my office is) when it starts to get stuffy. Thin air moves better.
- I run the fan on my AC/Heater unit all day to keep the air moving. It's cheap to keep that fan going and it keeps the house consistent/amplifies the other things I do.

I should note, I live in farm country, so some nights I can't open the windows due to the fine smell of cow excrement spread on corn fields (I'll take the AC hit rather than smelling that while I sleep).

The "right" invention for you might be a small window/hole that can't let people in, but lets air flow. I like the pipe idea.
Sep 12, 2008
wait, I just had a better idea!

what if you took a bathroom exhaust fan, reversed the flow (outside to in w/flap) and put it on a programmable thermostat? if now() between 01:00 and 07:00 PST and temperature>72 then kick on #fan instead of AC

this is a active/"smart" extension of the "pipe" idea someone threw out combined with a smaller/tactical version of the fan I suggested earlier...
Sep 12, 2008
run the centrail air on fan only, and open all the upstairs windows, you'll be at outside temperature soon enough.
+2 Rank Up Rank Down
Sep 12, 2008
Man, It must suck to live in an area that needs jail bars. No one around here, NH, even locks their doors. Since it's safe we just run a fan in the upstairs windows that exhausts air. We leave few downstairs windows open during the night and close them during the day. This way we never feel the need for air conditioning.

They also make whole house fans that ceiling mount on the second floor ceiling. Then you can just crack a few windows on each floor and draw cool air throughout the house. Someday I'll get one of these so we don't have to lok at the upstairs fan in the window.
Sep 12, 2008
wouldn't one of those fans that sucks (hot) air from upstairs hall into attic do the trick? we have one and let me tell you that thing will move some air like it's its job! the only problems (at least w/ours) are that 1) it's kind of loud so having it kick on at 3 a.m. off a timer or thermostat would make everyone jump out of their bed and 2) it's actually SO powerful that it creates a slight pressure delta you feel in your ears (since it can pump air out a whole lot faster than it bleeds back in) - not painful but noticable...
0 Rank Up Rank Down
Sep 12, 2008
Well, I've actually already been working on a design for this problem. You covered a few key points, and luckily not everything I have in mind for it ;) It's something I want for my own house, I'm sure someone else would to.. so it's to a point I really need to patent it (in which i have to start rereading your blog posts on how to go about that) Better yet, it requires no additional energy... hopefully.

PS: I wish my house was 80 when it was 54 outside. Anything sub 75 and i'm freezing.
Sep 12, 2008
You shouldn't runthe AC with the window open. Part of the AC's job is to dehumidify the house air. The night air is cooler, but probably also more humid.

Windows are not what you need. Pipes are - more exactly, air vents with a diameter of about 3 inches. Those are easy to install with screens and flaps, and are way too small to be a security risk.

Unless they have monkeys.
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Sep 12, 2008
I used to crack open an "air input" window and place a charlie bar (i.e., cheap 2" thick wooden dowel cut to length) so that someone from the outside couldn't open the window any farther than I already had. That way, I could run a fan in my bedroom window to blow the hot air out while !$%*!$% in the cooler air from the other room. You only need one piece of dowel if your windows open from side to side or if you can open the upper sash. If you can only open your lower sash, you can cut two lengths of dowel: one 1-2" long to keep the window from closing and another cut as long as needed to keep the window from opening any farther. I used to wedge the dowel against the jamb so that potential intruders wouldn't actually see it.
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