Heating Season Assessment

This winter's heating season is about finished.  I did my assessment of how changes have affected my home energy use.  In summary:

• Heating consumption reduced about 20%
• Electricity consumption reduced about 130W

Electricity

The Kill a Watt has definitely paid for itself.  I went around doing various measurements and made decisions based on measurements.  There were three surprises to me:

1. The inkjet printer consumes almost 10W when sitting idle.  This is much more than I expected, given its energy star rating.  When I re-read the energy star regulation I found it requires an idle consumption of under 10W, which the printer does just barely meet.  So I changed my habits to turn off the printer whenever I pick up printed results or finish scanning. This is not much extra work.  If I forget, it doesn't matter much, I just turn it off when I notice. 
2. Ethernet hubs consume 10-15W.  That was more than I expected.  I did some re-cabling and built one crossover cable to eliminate the need for one hub.
3. My wireless telephone consumes 20W.  I haven't replaced it yet.  I could replace it and the remote with a DECT phone that consumes 5W.  This would save $15/yr and cost about $60.  My delay makes me a typical consumer.  An ROI of 25% does not inspire a purchase.

No surprise was the benefit from consolidating an internal server and the need to put TV and DVD on a powerstrip for an easy on/off.  Doing all this has a net savings of about 130W based on electricity bills.  This is a savings of $200/yr.

I have already shifted lights to CFLs, so it's getting harder to cut much more without some substantial changes.  The next thing that I could do is replace an old PC (233 MHz Pentium) that acts as my general proxy server for scrubbing ads, filtering traffic, email fetching, etc.  It's a matter of lots of software reconfiguring.  I don't feel like putting in all that time to save about $50/yr.

Heating

This was based on degree days and oil usage in gallons.  I saved about 20% through two major steps:

1. An aggressive effort with caulk and plastic to weatherstrip and seal windows, etc.  Having done all that I also got enough improvement that I have figured out remaining things to tackle.
2. A questionable mechanical thermostat was replaced with an electronic setback thermostat.  I think the old one was not working properly.  The automatic setback didn't seem to be effective.  The new one definitely works. 

Short of major home construction changes like opening up walls to re-insulate, I probably won't get more than another 10%.  From an ROI perspective I've gotten most of the easy changes.  The heating system is already measured at 85% system efficiency.  That's as high as you get with heating oil and normal systems.