Quite often people frame their results and observations in a context or scenario that may not apply to you. Its always very subjective.

Anyway, it all depends on the ambient temps and how long the car has been off.

I suggest you also buy a timer to control the power to the car. Simply because if you leave it on for too long you'll waste electricity and you'll get diminishing returns. If you don't leave it on long enough then you will not see much benefit.

For example, in the winter I have the power on for no more than 6-8 hours before unplugging and driving off. In the summer months I only need two hours.

Cheers;

MSantos

Thanks so much. I'll get the timer tomorrow and see what works best through trial and error as far as time goes.

I was going mad thinking this thing was broken, you have at least saved my sanity and my blood pressure is slowly returning to normal.

Here are my results after 1 week with the block heater. I am in Sacramento, CA, so we don't get snow (although it felt like it should have this winter). This has been a colder than normal winter here with temps in the 30s in the AM. I waited too long to get the block heater this winter, but i'll probably use it year round like others here.

Explaining the chart:
Date: (Obvious)
Temp: Temp as stated on display of HCH. I used this temp to keep as consistent as possible. I did notice that the temp gauge was reading about 4 to 5 deg F warmer than it actually was according to weather.com.
Miles: Morning commute miles to my AM job - 7-8 miles with 9 traffic lights and 4 stop signs which can include dropping my daughter off at school (en route) which adds 3 stop signs. If this column is blank, it means I did something other than the normal morning commute.
MPG: Morning commute MPG. If this column is blank, it means I did something other than the normal morning commute.
School: If I brought my daughter to school.
Heater: Time block heater was plugged in (timer set from 4-8am, usually leave 7-7:30am).
Day Miles: Total miles driven for the day (including morning commute)
Day MPG: Total MPG for the day.

All numbers are taken from the HCH display. I reset Trip B every morning and use the numbers from there. The block heater was installed on 2/8/08. I knew I was getting it so I started the daily log on 1/25/08. I did not drive on 1/27 or 2/3 (both are Sundays). I got the block heater for the morning commute since it is so short and kills my mpg with all the lights and stop signs. With the sub-60 temps since November, I noticed a loss of about 4-7mpg per tank (43-45 instead of 48-51) which equates for me to losing about 80 miles per tank!



As you can see for last week, my morning commute MPG is up from 4-8mpg! The 42mpg and 46mpg on 1/29 and 2/5 were going in a different direction to other places with less lights and stop signs. When I start the car the temp shows the normal 1 bar which means nothing, but after about 1/2 mile it shows 3-4 bars, and I can AS after about 1 mile (instead of 4 miles with sub 60 morning temps). Having the MPG up by 4-8mpg helps the rest of the day mpg average because I'm not fighting to get from the 30's to the 50's, but from the 40's to the 50's. Plus if you notice the day mpg since 2/8, all but 1 are 45+mpg whereas prior most are 44mpg or less.

I'm assuming the higher temps in the AM for last week are because of the block heater affecting the display temp. While it was warmer during the day last week than in previous weeks, the mornings have still been in the low 40's.

Another good thing to come of this is I shaved 1 mile off my morning commute (notice the first 2 days show 8.2 and the rest show 7.2) by finding a cut-through road when bringing my daughter to school.

Hopefully this information helps someone decide whether to have it installed or not. Any questions feel free to ask.

AJ

AJ

Looks like there was a shift for the better - want to go back to NO heater to see if it follows?

Seems like you went from using 7/35 gal (say 6/30 gal) down to 7/42 gal (say 5/30 gal) or a 1/30 gal savings or $3/30 or $0.10 savings per morning or startup. Also saving wear on the engine.