Daox's energy use tracking

[Daox]

Well, its been quite some time since the last update here. I'm happy to say that my latest September bill is in and things are looking quite good. My electric use is up over previous years, but I'm using my electric on demand water heater vs my old inefficient gas tank water heater. Also, I've been using the plugin kit for my Prius lately which saps up a little under 2kWh per day but is working out delightfully well for increasing my mileage (tank is at 76 mpg right now after 400 some odd miles).

Also, despite it being colder than any September yet, I have only fired up the furnace once to verify everything is in working order. Besides that, I've just been using good thermal management of the house (close blinds on cloudy days, open them on sunny days) and the attic fan has been working wonders even on days that aren't that sunny. I must say I love that little device. I'm eager to see how well it collects heat in the few months to come since I didn't get to use it a ton last fall.

[strider3700]

how are you calculating the running average in the last column? I like the idea but the math eludes me at the moment

[Daox]

I'm adding all of the entries in the "total energy in kWh" column and dividing it by the sum of the "days on bill" column.

[WD-40]

Hey Daox any chance of getting an updated spreadsheet, I can't figure out that last column either .. thanks

[strider3700]

I figured it out.

my running average calulation is =average(K$23:K42) where column K is the kwh/day. the $ is K$23 is so that the average always starts from row 23 and K42 is because this calculation is in row 42. When I fill down and go to row 43 it looks like =average(K$23:K43) if you don't include the $ then it would have been =average(K24:K43) which is wrong.

The reason I start at row 23 is because I moved and that's the first entry for my current house.

THis is being done in a google docs spreadsheet so excel syntax may be different.

[WD-40]

Thanks strider3700 the same syntax works fine in excel

[Daox]

Its been a while since I updated this. I just got my December bill and wow it was a lot warmer this year than last, and its been the warmest since I moved into the house. Even so, consumption is down a good amount. The closest month I have on record was December of 09 where I used 107 therms of gas vs just 85 this year. Of course my kWh is up due to the electric hot water heater though 472 vs 300 in 09. It seems that adding seal-n-peal to my leaky upstairs windows (planned on doing it every year and always forget) really helps out... imagine that, sealing leaks works well.

In addition to that, I have updated the spreadsheet again to include costs. Its nice to see my actual cost per kWh and therm vs just what the rate is and try to think about the service charges. As you can see, its quite a bit higher than the .12/kWh rate that I thought I was paying. I've attached the spreadsheet if anyone wishes to use it.

[Piwoslaw]

Originally Posted by Daox

The closest month I have on record was December of 09 where I used 107 therms of gas vs just 85 this year. Of course my kWh is up due to the electric hot water heater though 472 vs 300 in 09.

Still, total energy usage is down - 2963 vs 3435 kWh. Good job

Originally Posted by Daox

imagine that, sealing leaks works well.

Who would've thought? The Home Energy Saving Tips really work!

[Daox]

I can't wait to actually get the upstairs INSULATED though. I have a feeling it'll be a sauna up there, but I look forward to it.

[Daox]

I wanted to do a yearly summation / compairison and have been slacking a little. I've added some additional information to my spreadsheet recently so I can track cost of energy usage too. I don't have all the cost data for 2010 in yet, so just ignore that part of it. For individual entries you can see the above post.



As you can see, 2011 was only a little colder (3.5%) than 2010. This gives a good compairison for heating energy use (natural gas in my case). That being said, gas use is down a good 10%.

However, my electric usage has gone up 19% since installing an electric on demand water heater which replaced my old tank style natural gas water heater. However, overall energy usage for heating hot water has been drastically reduced. The old style water heater was estimated around 55% efficient vs the electric's 100%. The cost for hot water therefore has remained about the same.

So, all in all, my energy usage looks to be down about 6.5% from last year. I was hoping to see a larger number, but I really haven't done a ton of work on the house this year so it is to be expected.

Next year we'll be putting up the solar hot water panels as well as finishing up some remodeling and some additional air sealing projects. The effects should be quite sizable and I'm really looking forward to it.