The Half Program has proven to be a very good investment - we spent a total of $7,525 for all the energy reduction projects, and we are saving $4,007 per year in energy costs!

The Half Program

Gary Reysa | BuildItSolar

The Half Program
The Half Program has proven to be a very good investment - we spent a total of $7,525 for all the energy reduction projects, and we are saving $4,007 per year in energy costs!
The Half Program

Gary Reysa,

We got started on our energy reduction plan for two reasons: 1) we were getting a bit frustrated over the fact that little was being done in the US to reduce greenhouse gas emissions, and 2) we received our first winter propane bill after moving to Montana (ouch!).   We wanted to see if we, as individuals, could develop a program that would cut our CO2 emissions significantly, and also reduce our energy bills. 

After some thought and a few calculations we decided to see if we could cut our families  energy use and greenhouse gas emissions all the way down to half.    We decided to keep careful track of our progress for energy reductions, greenhouse gas reductions, and for  the dollar costs and savings.  We also wanted to find out if any significant lifestyle changes were needed to make this kind of cut.

We are now two plus years into the program and the results are very encouraging.  The plan and the results are described in detail below, but just as a preview, we have cut our energy use by 49,000 KWH/year and our greenhouse gas emissions by 32,000 lbs/year  of CO2 - achieving our half goals.   Furthermore, the Half Program has proven to be a very good investment - we spent a total of $7,525 for all the energy reduction projects, and we are saving $4,007 per year in energy costs!

The Plan

The goal was to cut our energy use for: 1) space heating, 2) water heating, 3) electricity, and 4) transportation in half.  This covers most of the energy use that we have control over, but does not include energy embedded in the products we buy or air transportation - maybe phase II can tackle these areas.

Our Approach

The first step was to determine our current energy consumption and greenhouse gas emissions.  We used utility bills, fuel bills, and our car gas mileage to estimate our pre Half Plan energy use.  We used the Carbon calculators at and to estimate the CO2 emissions resulting from our energy use.  The two pie charts show the breakdown for our pre Half energy use and CO2 emissions.

We found the totals of 93,000 KWH of energy and 65,000 lbs of CO2 a bit staggering, but I do not think that it is far out of line from the average US family.  Based on these estimates, we set our targets at 47,000 KWH per year energy reduction and 32,000 lbs of CO2 per year greenhouse gas reduction - two years ago, these targets seemed formidable indeed.

Energy Saving Projects:

It is clear from the energy use breakdown that each of the areas of energy use is significant, and needs to be tackled if the overall reduction of one half is to be achieved.  We selected 20 energy saving projects that cover all of our areas of energy use.  They are a mix of energy conservation and solar energy projects.   We chose these projects based on our particular home construction, climate, habits and skills - these are the projects that give us the best payoff in energy saving and greenhouse gas reduction for the money spent.    There is no "one size fits all" set of projects - the list will be different for each family.  If you are interested in pursuing your own Half Plan, see the section on Planning below for help in determining your list of projectsCareful selection of the projects you do is really the key to getting a good return on the money you invest and maximizing your CO2 reductions.  The 4 step plan we used to select our projects is described below.

The Projects

This table shows each of the 20 projects plus a few that we plan to do in the future.  For a detailed description of each project, click on the project name, or go here.


Initial Cost


Cost Saving

10yr Saving







$/10 yrs(1)


GHG lb/yr

Completed Projects:






More Attic Insulation







Crawl Space Insulation







Infiltration Sealing







Duct Sealing







Efficient Lights







Phantom Loads





















Efficient Fridge







Strom Windows







Bubble Wrap Windows







Storm Door







Thermal Shades







Dryer Venting (3)







Electric Mattress Pad







Turn Off







Solar Shop Collector







Direct Gain Collector





















Total Completed














In Work Projects:







"Solar Shed" Home Heater







Solar Water Heater














Total In Work














Future Projects:




























Total Future







(1) The 10 year savings include a 10% per year energy price increase.

(2) For electricity savings, it is assumed that power was generated in a coal plant - true for more than half the power in the US.

(3) Important! - 1) NOT for gas dryers, 2) for dry climates only - details.

I should mention that I am a "Do-It-Yourself" type, and some of the costs are lower because of this, but most of the projects will offer a good return even if hired done.  Again, this is all part of choosing the best set of projects for your circumstances.

A quick look at the table makes it clear that some projects payoff much better than others.  This may be the most important point that this article makes.  For example, we were (and still are) quite interested in doing a solar electric system, but, the fact that it will double our total cost while only accounting for 3.5% of our energy saving made us move this project to the end of the list.  At the other end of the spectrum, some projects cost next to nothing, and yet have very good energy and CO2 savings. 

The energy reduction estimates for each project are conservative, and in some cases you may achieve significantly larger savings for a project than the table indicates.  For example, our heating duct system was already pretty well insulated and sealed, so I claimed only a small fraction of the saving for Duct Sealing than would have resulted if the duct system were in "typical" condition.  See the details for each project.

Going into the project, we were willing to make some lifestyle changes to achieve our goals, but we found that no lifestyle changes were needed.  The next 50% reduction may require some changes, but that's OK.

Here are just a few sample photos of the projects we undertook.


Bubble Wrap Storm Windows

Efficient Lights

Infiltration Sealing

Insulating Shades

And here are a few of the future projects mentioned:

Solar Water Heater

Solar Shed House Heater

Developing Your Half Plan

If you want to pursue your own Half Plan (or ¼ or ¾ plan), here is one way to go about doing it:

Step 1:  Develop a long list of potential energy/CO2 saving projects.   I would error on the side of too many projects - you can always weed out the unworkable ones when you get to step 2.  Go a bit wild - it's important to not limit yourself to just the standard "tip" lists.  The list of projects should take into account your families particular circumstances, housing, climate, transportation needs, and skills.

Here are some good places to look for ideas:

Build It Solar

Look at the Projects page and the Half Plan Projects pages.

This is my site, and while it is aimed at "Do-It-Yourselfers", there is much information for everyone. 

 Utility Audit programs

See if your utility offers and energy audit program - these can be quite good, and some even include blower door tests to check your house for infiltration.

Rocky Mountain Institute

The "Energy Briefs" papers are very good.

Energy Star

Lots of good information on Energy Star rated appliances as well as a wide variety of other energy efficiency subjects.


A generally good source of unbiased advice and ideas.

All of these websites are non-commercial, and are at least trying to give good, unbiased advice.  There are also many good commercial sites (and some bad ones) - just be sure you get confirmation from a good source that their products work as claimed.

Step 2: For each of the projects in the list estimate the cost, energy savings, greenhouse gas reduction, and cost saving per year.

This is probably the most difficult step, but it is also the most important step if you want good value for the money and effort you invest.

Here are some tools that may be helpful:

Insulation Upgrade Calculator

This simple calculator can be used to evaluate insulation upgrades, window improvements, storm windows. …  Any change that involves reducing heat loss by increasing R value.

The "Half Plan" Examples

These example projects each include details the details on how the energy saving was calculated.  The examples cover a wide variety of projects, and can be used as a guide for similar projects you may want to evaluate.

The book "The Carbon Buster's Home Energy Handbook", Godo Stoyke, 2007

A very good book with many concrete examples of energy reduction projects.

Green House Gas Calculators

Infinite Power

My favorite general purpose carbon calculator.

Hybrid Cars dot Com

A good car carbon and fuel cost calculator (not limited to Hybrids).

If you get stuck - contact me

I'll do my best to help or find someone who can.

Step 3: Pick the projects you are going to do, and the order to do them in. In deciding on the order in which to do the projects, you will want to consider the following factors. 

  • How well the project pays off in CO2 savings and dollar savings.  All things being equal, do the ones that offer the shortest payback first.
  • Some projects will interfere with other projects if done to early in the sequence.  For example, you will want to seal up plumbing and electrical penetrations into the attic before you blow in more insulation - else you will find yourself knee deep in new insulation while trying to seal holes.
  • Your budget may limit what you can do right away.  There will be some projects that require very little cash, but are still quite effective in saving energy.  You can do these first, and then fund next round of projects from the savings on the first round.
  • Some projects may just be more interesting to you personally - no harm in moving these up the list.

Step 4: Do the projects.

I bet you could do a couple projects by the end of today that would save a couple thousand KWH of energy per year and a couple tons of CO2 per year.

A Final Note

The Half Plan offers a way to make significant cuts in greenhouse gas emissions with little or no lifestyle change.  And, save money at the same time.

If 100 million US families each reduced greenhouse gas emissions by 20 tons, it would reduce total US green house gas emissions by 25%.

This is not only a significant CO2 reduction, but it is also one of the most cost effective ways for the country to reduce carbon emissions.  The kinds of projects mentioned above not only reduce carbon emissions, but they do it at a cost saving.  In contrast, things like sequestration of coal power plant CO2 emissions will require huge investments and will and will entail significant ongoing costs.  Ref Article

Beyond the Half Plan, it is certainly possible for families to achieve much greater GHG reductions.  Some have reported achieving large reductions by adopting significant lifestyle changes.  While change can be difficult, the reports I have read indicate that that most people who do elect to adopt a simpler lifestyle not only reduce their carbon footprint dramatically, but also live more satisfying and less hectic lives - something to think about.


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