Midcoast Green Collaborative Forum

April 10, 2009

Sustainability Post #43 – Maintenance.

Filed under: Conversation, Philosophy — Tags: , , — Topher @ 10:33 am

[From a discussion on making a house maintenance free, and a comment that humans were the weak link in ensuring energy efficiency]

To my mind, the STRONGEST link is the human. Humans are the best multi-purpose machine yet devised on this planet. By orders of magnitude. An empty house, even without any need to accommodate humans and their needs, is doomed to die in short order. A house loved by humans can potentially last as long as that love lasts.

One of the characteristics of humans is that they get better through practice and repetition. Having a house which needs periodic maintenance trains and encourages the humans to look after it. If a house makes no demands on its humans, they will come to ignore it, and it is doomed. Furthermore, the next house those humans occupy is also in for a hard time.

For example, look at the houses around you, some will be wood, and need paint, some will be mostly ‘maintenance-free’ siding plus some painted trim. Count the percentage of wooden houses which need paint, and compare to the percentage of sided houses which need paint. If your experiences matches mine, the latter will be a larger number, and the condition will be worse.


January 15, 2009

Sustainability Post #40 – Blowing In Insulation

Filed under: Information — Tags: , , — Topher @ 1:17 pm

I am often asked what energy improvements homeowners can make themselves. I am now here to tell you that blowing cellulose insulation into your walls is one of those things. While blowing insulation into an attic is a common do it yourself project, this is a job which is often recommended for professionals only, but Mainers are skilled and resourceful people and if I and my sweetie can do it, so can others. This is not intended as a how-to, but rather as an inspirational article.

Infrared picture of house, before

Here is a picture of our house, taken with an infrared camera (one of the tools we use for energy audits). One of the things you will notice is that the windows ‘have ears’, as my sweetie put it. That is, there are warmer patches visible around the top and bottom of each window. This is an indication that the insulation is lacking in those areas. The exact reason for that is related to the unusual way my walls were constructed, something called a Larsen Truss (invented by Jim Larsen). The walls are about a foot thick and contain a lot of insulation. However, when the house was built the insulation contractor failed to fill some areas, particularly around the windows. When I turned the infrared camera on those areas the problem of cold spots my sweetie complained about, became immediately obvious. With all these picture cold is black, then purple, and orange, with yellow and white being the hottest. The temperature in the upper corner is for the spot where the cross hairs are, and the temperature scale is at the bottom. Exact temperatures aren’t important here, we are looking at relative differences.

For other houses the problem may be different. Old houses probably started life with no insulation in the walls. If nothing has been added since, then they are prime candidates for this technique. All the empty space in the walls will need to be filled with insulation.

tud bay missing insulation

Here is a picture of one of the places where I could use some more insulation (taken from the inside). As you can see there is a large space here, more than can be explained by settling. So, the job is to fill that space with insulation. Insulation can be blown in from the outside, or from the inside. The choice comes down to which will be easier to get to, and easier to patch once done. For me, the interior is not painted yet, so going from inside was an easy decision.

Blowing cellulose insulation is a messy dusty job. So the first thing was to cover as much of our stuff as possible, since it all needed to be moved away from the walls to gain access, We moved it to the center of the room and draped it with cloth, and plastic sheets. I also got my respirators out; dust masks are only marginally useful, respirators with filters are recommended. Safety glasses, and grubby clothes are also a necessity. I also planned on us eating out of the house for a few days. I cut the holes in the wall with a 1 inch hole saw in an electric drill.

We rented an insulation blowing machine at a local rental place. The insulation was acquired at a home improvement store (which often rent or lend blowing machines as well). The machine is heavy, so I was lucky to have a neighbor to help move it into place. Sane people would be doing this job on a calm spring or fall day and will have the machine outside. Being the dead of winter, I put it inside. It came with fifty feet of hose, a nozzle for the walls, and a remote switch to control it. The bag label provides some advice on how much insulation is needed to acheive a given R-value for 1000 square feet, but since I didn’t really know how much space I had, I just took a wild guess. And then went back later for as much again.

Stud bay after filling with insulation

I ran the hose and remote switch, my sweetie filled the hopper with cellulose from the bag, and tried to keep the hoseand remote cord from getting too tangled. It would have been much harder or impossible with only one person. The machine had a control to set the air-insulation mix, I found that full open was the best setting for me. The main trick was knowing when the cavity was filled. If I left the blower running too long, the nozzle filled up and needed to be cleaned out (having a short dowel to hand helped take care of this). It took an awareness of the sound from the walls as well as sound of the blower on the machine to know when the space was full. After I had gotten about a quarter of the job done, I was able to get each bay filled with few issues. Here is the same wall as the previous picture, only this time properly filled with insulation. The holes were then filled with spray foam insulation to get a nice vapor seal. The extra was sliced off flush with the wall. Subsequently they will be patched over probably with drywall compound.

The mess can be kept to a minimum by making sure that the nozzle remains in the wall until the blower has come to a complete stop. Removing a little before, or if it seems clogged can end up splewing dusty insulation everywhere. The insulation contains borates to retard fire and pests, and it is not something you want up your nose.

Infrared picture of house, after

Here is a picture of the house after all the work was done. Note that there are still some places that didn’t get fixed (under the center windows for instance) do to accessibility issues. On the whole though the entire house is mostly a uniform color. Since the camera adjusts to a given temperature range, this is the appropriate result. The fact the temperature is 17 degrees lower on the after picture is just an indication that it was colder outside that night.

The whole project (not including prep and clean up) took about 10 hours (spread over two days) and we put 13 bales of cellulose insulation into the walls, which the chart on the package says would be enough to do 722 square feet of 2 x 4 walls (to achieve R-13). For this house, we took perhaps 180 square feet of area from around R-2 (no insulation) to R-45. This should amount to 12 Million BTUs saved every year, equivalent to about 85 gallons of fuel oil. At today’s price of $2.47 per gallon, that amounts to 210 dollars. The cost of the project was as follows:

Blower Rental 1 weekend $55.00 $55.00
Cellulose insulation 13 bags $11.30 / bag (including tax) $146.87
Spray Insulation 1 can $10.30 / can (including tax) $10.30
Total $212.17

So, a simple payback of about 1 year. That is, I could have bought oil this year, or for the same money made this fix, and saved this amount every year from now on. Of course, all situations are unique, so another house would get different results, however for houses without insulation in the walls, this is almost certainly a huge win.

Infrared picture of front door

Next Project

This picture highlights my next project. This is my wooden front door, complete with storm door. As you can tell it is warmer than the (admittedly high-efficiency) window right next to it. It is therefore losing a lot of heat.

August 17, 2008

Home Performance Technician Classes

Filed under: Information — Tags: , — Topher @ 11:34 am

Richard Burbank, who came to the last MGC meeting is teaching a number of courses for energy efficiency professionals.  Details available at: http://www.evergreenbuildingscience.com/

July 17, 2008

What we can do, to help people get ready for winter.

Filed under: Conversation, Question — Tags: — Topher @ 3:16 pm

This is a continuation of a discussion started in email.

The question is what can we as individuals and as a group do, to help people who are likely to be hard hit by recent increases in the price of heating fuel?

July 2, 2008

Sustainabilty Post #23 — How Much Insulation?

Filed under: Information — Tags: , , — Topher @ 10:50 am

Last week after our  talk on insulation, I sat down to write a post here about what the optimal amount of insulation in a house should be.  Given the recent prices of heating fuels, I thought the speaker undervalued the benefits of insulation.

After a week, and some forays into the world of economics that I would have been happy to skip, I finally have this web page which tries to tell you how much insulation is most economical.  It takes values for fuel type, and price, insulation type, and price (price is divided into fixed costs and variable costs based on thickness of application), mortgage interest (or opportunity cost if no mortgage), and several other things, and computes the optimal amount of insulation, free of any building constraints.

So, how is this useful, you ask, given that there are always building constraints?  Well here are some examples:

1) Your attic,  it is the one place in many house which is free from building constraints.  You can put as much insulation up there as you want.  So, how much is that?  Say, your attic is 26′ by 40′ (1040 square feet), you live in midcoast Maine with around 7500 heating degree days, burn #2 fuel oil at $4.40 / gallon, have a high efficiency boiler at 87%, you think that oil price increases will continue on the current line from 1946 – May 2008 of 2.81% per year,  you are on a fixed income, you can get a 30 year home equity loan for 6.00% to do home improvements, plan to put fiberglass batts perpendicular to the rafters (and existing insulation), which should improve the whole wall factor to 90%, the current insulation is R-20, and the contractor say it will cost $900 (total) for labor, and 10 cents (per square foot) for each inch of thickness.  How much insulation should you add?   19 more inches.  Given that fiberglass only comes in specific thicknesses, this probably means a 6 inch batt and a 12 inch batt.

2) You are building a new house, and are wondering about whether to do 2 x 4 construction, or 2 x 6 on 24″ centers for the walls with dense pack cellulose (both including 1″ foam insulation on the outside).  Using the same economic characteristics as the previous example, and 2000 square feet of wall surface, The whole wall calculator (follow the link on that factor) says that 2 x 4, 16″ on center with 1″ foam outside, has a whole wall factor of 87%, and 2 x 6, 24″ on center with 1″ foam outside has a whole factor of 77%.  And you could discuss that with your builder to see which is cheaper in the long run.  However, there is a problem.  The calculator is telling you that you want 20-22 inches of cellulose in those 2×4 or 2×6 walls.  Oops.  Maybe you should throw out the idea of using old fashioned stick framing altogether.  Perhaps look into double walls or Larsen trusses.

3) You are looking at oil prices and think they are going to track the last five years growth rather than the last 50 years.  That is 36% increases every year.  You are prepared to live under a mound of insulation if you have to, and are planning on buying the newest 97% efficient boiler.    The calculator returns 0, which means you exceeded the limit of 200 inches of insulation.   The solution to your problem is not insulation, but rather ceasing to use oil altogether.

* * *

There are websites (such as this one) which give recommendations for how much insulation you should have.  I have found a couple of problems with them. First, the assume status quo in terms of building construction techniques.  They recommend R-19 for wall because that is what fits in a standard 2×6 wall.  Second, they have embedded assumptions about the price of fuel, and the rate of increase of said, as well mortgage rates and other things.  These assumptions are all hidden and there is no way to change them without going through governmental committees.  Hopefully this site will provide insight into those issues.

It shold be noted that this software is in beta test, and there could be bugs, and it could change without warning.

June 6, 2008

Sustainability Post #15 — Comparing Fuels

Filed under: Information — Tags: , , — Topher @ 2:29 pm

I often get asked to compare different heating systems, using different fuels, at various efficiencies. This is often done in search of the ‘Magic Bullet’ to save lots of money on home heating. The latest miracle cure is the geothermal heat pump (actually, a ground source heat pump). Now, there is no magic bullet, but it is possible that a change in heating source could save you money. Before you do that though, you should do everything you can to lower the heat loss of the house.

If you want compare fuels for yourself, I have created a web page which you can input you possible choices, their efficiencies (note: COP times 100% gives efficiency for heat pumps), and current or expected prices. Hit the ‘compute’ button, and you get the prices for a uniform Million BTUs. Don’t worry if you don’t understand what that means, just look at the prices and pick the lowest one. The URL is:


— Topher

May 18, 2008

Sustainability Post #6 — Window screens.

Filed under: Information — Tags: , , — Topher @ 10:00 pm

Do you leave the screens in you windows and storm windows during the winter. We have been telling clients to remove them, but didn’t have a number for amount of energy saved. Searching the web, I found nothing, so I decided to do a little testing of my own.

First, I got a light meter and one of my screens (black fiberglass, standard spacing). The light meter read 75 foot-candles in my test location (out of direct sunlight), and 50 foot-candles with the screen over it.

Next, I placed three pieces of dark soapstone (12″ x 12″ x 1/2″ tiles) near a window facing south, on a sunny March day around noon. One piece was placed in the shade, one in direct sunlight (through the window), and one with the screen in the window. I came back and measured the temperatures of the three stones with an infrared thermometer from a distance of about 1 foot. The shaded stone measured 76.7ºF, the one in the screened window 88.7ºF, and the one in the unscreened window 96.7ºF.

From this it would appear that leaving screens in windows or storms during the winter block about 30-40% of the heat that would otherwise enter through the windows. Audits have the amount of heat obtained from passive solar through windows ranging from 10-25% of the fuel based heating. So, window screens represent somewhere between 3-10% of total fuel.

If you have screens on the outside of your windows or in your storms, bring them in for the winter.

— Topher

Blog at WordPress.com.