Half Plan Update for 2013

I'm not keeping the charts up anymore just because its quite a bit of work to do, but we remain very committed to the Half Program and continue to make improvements in energy use. As mentioned before, we have exceeded the goal of cutting our energy and carbon emissions by half.

So, this is a sort of verbal update on activities of late to try to get further down the energy curve.  The way it turns out, maybe we should have adopted one quarter instead of one half as the target :) See also updates 2010.

I'd be very interested in hearing from people on the Half Plan.  To me, its the most important material on the Build-It-Solar, but it does not get a whole lot of traffic.   Any ideas?  contact Gary...

For all the details on the Half Plan...


Space Heating

We did make some changes to the space heating setup this year. Our house came with two propane furnaces -- one that does the main part of the house and the other that does a bedroom area. In some stroke of bad karma, both furnaces went out at nearly the same time.

We had the main house furnace replaced by a local contractor. The new furnace is a Trane 95% efficient propane furnace. This was a REALLY expensive change, and I suspect that the energy saving will not be huge in that the old furnace was a pretty efficient condensing furnace.

The new furnace is nicer to live with in that it has a variable flow gas valve and blower, and most of the time it runs on a low enough speed that you can't tell its there. We also cut the furnace size down from 100K BTU per hour to 80K BTU per hour -- this should increase run times and make it more efficient. Our old furnace would normally only run for about 6 minutes before shutting down. With the improvements we have made to the thermal envelope, the 80K furnace has no trouble at all keeping up with the load even at -22F.

Due to an oversight on my part, one feature we did not get on the new furnace was an ECM motor on the furnace blower. This would have been a really worthwhile electricity saving.

The bedroom furnace was not replaced. We are instead using the solar heating system that serves that part of the house, and have added a backup heating system for when the solar is not enough.

I expect that this will save us a worthwhile amount of propane because we are making better use of the solar heating, and because the furnace was not setup to heat the area in a very efficient way. We will know when we have the yearly tank fill up in July.

We are still thinking about adding a wood burner and also of making our front porch that faces about 20 degrees south of west into a sunspace that would add some nice "outside" space and do some space heating.


We finally got rid of our DISH DVR that used 53 watts 24/7 365 days a year. It used 460 KWH a year -- this is literally more than our fridge uses!

The replacement is a Direct TV DVR that uses 18 watts. So, a 66% saving, and the new DVR also shuts down after 4 hours on non-use (but this appears to happen only occasionally).

So, this should be good for a saving on the electric bill of at least 300 KWH per year.

More on this here...

We have also replaced a few more lesser used lights with LEDs.

So, we continue to make small reductions in electricity use. We plan to increase the size of the PV array sometime in the next couple years.


We traded in the 2004 Prius back in 2010 for a new Prius. There was really nothing wrong with the old one, but the dealer made us an offer that seemed too good to pass up. The new one has heated seats -- nice for Montana :)

Its hard to overemphasize what a big item the Prius has been in the program.  Its the project with the largest single energy and carbon reduction, and it has been a serious money saver as well -- hard to do better than that.

There is a lot of activity in the cleaner cars area, and we will give a lot of thought to what the Prius replacement is going to be. A plug in hybrid might make sense for us in that we could expand the PV array to cover its energy use for local trips, while still keeping the ability to do longer road trips on gasoline.


Gary February 22, 2014