Log homes and energy efficiency

On a recent road trip around the State of Washington, we stayed at a motel constructed of older style Pan Abode buildings built sometime in the late 50’s. 

The structures seemed in remarkably good condition for their age, but the stresses on these structures are perhaps not what they would be in a wetter area of the state–like west of the mountains–in the Seattle area.  The structures seemed well suited to their hot and dry climate.

What I found interesting was the insulating ability of the 4″ thick walls–or their lack of ability would perhaps be more accurate.

This first picture is of the exterior wall.  The red rectangle corresponds to an area at the interior that will be discussed below.

Pan-abode type building

This next picture is what the wall structure looks like.  You can see the double tongue and group shape with the wall being approximately 4″ thick.

Pan-abode type wall structure

On the interior, with thermal camera, the wall and pillow temperatures show in the next two pictures.

Thermal image Thermal image

In this next picture we see the wall with the pillows moved away from the wall to reveal how the wall was “insulated” by the pillows.  The wall, heated up by the direct sun shining on it at the exterior, could not give up its heat to the interior as readily as the other areas of the wall. Thermal imageThermal image

My understanding is that modern Pan Abode structures are a double-wall type of construction that allows for the installation of insulation inside the walls.  This would certainly be required by modern energy codes for both heating and cooling. 

Regardless, these pictures demonstrate very well how poor 4″ of wood is as insulation (about R-4).  By themselves, it would take exceptionally large logs to meet modern energy efficiency standards.

By Charles Buell, Real Estate Inspections in Seattle

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Reducing the need for air conditioning

Grape arbor sun protectionHow long have we been building houses?  A lot longer than we have been air conditioning houses.

Well we have certainly done things to keep warmer and dryer for thousands if not 100’s of thousands of years–but we have also done things to keep them cooler as well.

As a designer/builder for most of my adult working life, I have marveled at how ignorant we are of how to accomplish keeping warm, dry and cool.

We now have air conditioning systems that allow us to live in places where not too long ago it would have been considered uninhabitable–or at least inhospitable.

We have long had the knowledge to mitigate the use of air conditioning to some degree and yet we simply choose to turn down the knob on the thermostat.

Today I just want to talk about a few “passive” things that can be done to greatly decrease the use of actual mechanical air conditioners.

First and most important is house design and orientation. Obviously if we build a house and make all the south facing walls floor-to-ceiling glass, with no roof overhangs, we can expect to find ourselves inside a solar heated oven. Just providing a roof overhang to prevent the sun from hitting the windows directly can go a long way to turn the oven down a bit. By eliminating ground and other surfaces that might reflect the sun’s rays into the home can also be an improvement.

Even these Native Americans made an attempt at basic principles

Of course reducing the amount of glass itself will make the most difference because then the walls themselves can be better insulated. This brings us to the huge topic of insulation in general. There is nothing like highly effective insulation in the walls and ceilings to keep the heat out of the house. This is not as simple as it may seem because heat is always attempting to move to cold and make balance. When it is 95 degrees outside, all that hot air is just hungry to gobble up our pathetic little bubble of coolness. So our air conditioners have to work their butts off to maintain that bubble of coolness.

While today I do not want to go into how I think houses should be built to eliminate the need for air conditioners altogether in many areas, I want to talk about ways we can deal with adverse conditions in our older homes in passive ways. While these things will not reduce your need for air conditioning in some areas it may greatly reduce the amount they may have to run. It may mean in some hot humid areas you might have to add a dehumidifier to make up for what the AC used to do.

The short story in all of this is to insulate your house as much as practical and use good air sealing type insulation–anything longer and we are into the full fledged novel.

One of the most important things you can do, if you live in an area where the nighttime temperature drops even 20 degrees between daytime and nighttime, is to change the air in the home and lower the thermal loading that has built up in the home during the day. The house is then closed up during the day to keep the nighttime cooling in and then the process simply repeats itself. In an average size house, even a simple window fan in a window on one side of the house and a window open on the opposite side of the house can accomplish this goal.

I cannot stress the importance of roof overhangs to keep the sun out, but in older homes that is not likely going to be possible.

In my own house, built in the early 30’s, the overhangs are insufficient to keep the south facing windows from overheating the house in the summer. So a simple thing I have done is to shade the windows with a grape arbor–the one plant now creates shading of most of my south facing windows and makes an amazing difference, and of course provides grapes in the fall.

Grape arbor sun protection

While we certainly do not get as hot as lots of areas of the country, my house certainly never needs any mechanical air conditioning. The attic has a ton of cellulose fiber insulation, the walls have minimal insulation limited by the 2×4 wall thickness, and we put a fan in an east window at night and open up a west window–on those occasional really hot days.

Before the days of the grape arbor, we use to have to do the fan approach a lot more.

If you have a house with a basement, you can open up a basement window (as the path to the upper fan in the window) and get the benefit of the cooler basement to improve the cooling of the interior space during the nighttime. Accessing the constant ground temperature is another thing that can have a huge impact on minimizing the mechanical cooling needs of the home.

A huge number of homes across America could benefit from this passive approach to improving house comfort and energy efficiency.

By Charles Buell, Real Estate Inspections in Seattle

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Your attic access is smiling?

People love to install pull down stairs as the means of attic access,  Stairs tend to make the attic space more useful as one is not teetering on a step ladder to get things up and down.

Before I go further in this discussion, I want to state that attics are for insulation–not storage or other purposes even though commonly done.  There are numerous problems with using attic space for things other than insulation and this article is NOT about all of those things.

At this time I only want to discuss the pull down stair attic access.

As you can see by this infrared picture, the pull down stairs is staring right at us and gives away the problem.

I am smiling because of how much I am costing you!

The two beady white eyes are all that shows of the zipper seam of the insulating cover between the poor seal of the lid.  This picture is what the lid looks like without the infrared.

Pull down stairs

The foam zipper cover made to improve energy efficiency is a whopping R-3.8 at a cost of around $116.00 from the Big Orange Toolbox.  Modern standards require that attic hatches be insulated to the same level as the rest of the attic.  In other words R-38 to R-49.  Some sort of thick foam cover would be necessary.  And, of course with that much insulation in the attic any storage floor system gets quite complicated.

This next picture is what the R-3.8 foam cover looks like with the infrared camera and with the stairs pulled down.  As you can see, it represents little resistance to heat flow from the warm attic. 

This greatly increases energy consumption due to heat loss in the winter and heat gain in the summer.

Like I started out at the beginning of this conversation, it is best to leave the attic to insulation–and find a better place for the Christmas decorations and stuff your kids will have to deal with when you are gone.

 

Charles Buell, Real Estate Inspections in Seattle