Saving Electricity; Block Heater Timers

[ABMax24]

It's that time of year again when using a blocking heater or "plugging in your car" becomes common place, at least here. If you don't know what either of these things are you can stop reading now.

A block heater is used to warm the engine coolant in the engine block (hence block heater) to aid in cold weather starting, to make the fuel easier to ignite, and also to some extent to warm the oil to make it easier to pump. Block heaters pull hundreds of watts, and this varies by engine size. Generally a small car pulls about 400watts, a mid sized SUV about 600watts, a pickup is around 800 watts, and diesel pickups can be up to 1200 watts. If left plugged in for extended periods this energy consumption quickly adds up, not only wasting energy but significantly adding cost to an electric bill. For example, my F350 with the 6.7 diesel pulls 900watts to run the block heater, if I plugged my truck in when I got home at 6 and left the block heater on until 630 the next morning when I left for work it would consume 11.25kwh of electricity per day, or at my energy cost $2.36/day or about $47.20/month (assuming 5 day/week use).

When to use a block heater? Generally I have found that every vehicle I have ever owned starts reliably down to -25c (-13f), but for this the owners manual should be consulted, -18c (0f) seems to be a common recommendation for block heater use. I push this recommendation a bit, but I also ensure I use quality engine oils for winter that allow good cold flow, and the appropriate viscosity for winter. For instance my 6.7 diesel gets 5w-40 synthetic and my wife's diesel Colorado gets 5w-30 synthetic.

How long to run the block heater? Every vehicle I have ever owned has always started when plugged in for 4hrs prior to startup, even down to -40 and even colder than that. So I use a heavy duty timer to control the block heater, it is plugged into my house outlet and then the extension cord is plugged into the timer. Currently my timer turns on a 3am, and I start my truck at 6:30 for work, giving the block heater 3.5hrs to warm the engine. Running for this period of time uses 3.15kwh of electricity for a daily cost of $0.66 and a monthly cost of $13.20, a savings of $34/month, paying for the timer in the first month.

Obviously this works fine if you use your vehicle on a schedule, if not there are some timers available that can run a "duty cycle" which allows the block heater to run say 30 minutes every hour. Which still reduces consumption, but not to the same extent as above. There are also "smart plugs" available that an be setup to run on a schedule, but can also be programmed remotely through wifi or Bluetooth.

 

[Solarguy3500]

Back when I was in my late teens, I had a 1976 International Scout II as my daily driver in the winter. It had a block heater and in very cold weather, it made all the difference in ease of starting on a cold morning. Sometimes if I forgot to plug it in, I couldn't get the old girl to run, and it wasn't even a diesel. It had the 345 cid gas engine in it.

Never used a timer on it, just plugged it in overnight. I wasn't thinking much about conserving energy back then as it was at my parents house and I wasn't paying the electric bill. Looking back now, I'm sure it would have worked fine on a timer with only a few hours on before trying to start it. That block heater worked really well.

 

[ABMax24]

Back when I was in my late teens, I had a 1976 International Scout II as my daily driver in the winter. It had a block heater and in very cold weather, it made all the difference in ease of starting on a cold morning. Sometimes if I forgot to plug it in, I couldn't get the old girl to run, and it wasn't even a diesel. It had the 345 cid gas engine in it.

Never used a timer on it, just plugged it in overnight. I wasn't thinking much about conserving energy back then as it was at my parents house and I wasn't paying the electric bill. Looking back now, I'm sure it would have worked fine on a timer with only a few hours on before trying to start it. That block heater worked really well.

Lol. My parents weren't so forgiving, between both of them and my brother and I there were 4 vehicles plugged in at the same time, that adds up pretty quick, if we wanted "free" power we had to have timers set to run no more than 4 hours before we left.

 

[DBoon]

ABMax24, you've brought back a fun/fond memory. Many years ago (early 1990s) I was in far northern Vermont and the low temperature reached -34 degrees F overnight. My car wouldn't start the next morning - a battery jump didn't help. I had a spare quart of oil in the trunk, so I was curious if it would flow at these temperatures. It was solid like jello. Ah ha! That is why the engine won't start. Car was towed to a garage where it could warm up and it started in the afternoon. I think it was 10w40 oil, can't remember.

I was in Fort McMurray in January one year. I rented a car to drive from the airport to the Syncrude facility. The car never warmed up and provided real heat, and the seats were hard, like boards, even though they were normal foam. It was -40 degrees F. The car rental company told me not to shut the car engine off for more than an hour.

I get the need for block heaters.

 

[Highbeam]

I also have a timer for the block heater on my 7.3 diesel in a 2000 f350. I monitor engine oil temperature and experimented to find that after 3 hours of 900 watt run time, the engine is getting no warmer so I use a heavy duty lamp timer for those three hours. Now, just because the diesel will start without the block heater doesn’t mean there aren’t benefits to a preheat. It’s much easier on the engine and smoother with less fuel consumption to have some preheat. No long warm up idle period .

Oh and I also use 5-30 synthetic. It’s only slightly more money than regular.

My current issue is four dead glow plugs. It won’t start dependably below freezing without the block heater so no skiing until I get it fixed!

 

[ManitobaSky]

Yep love my old crappie mechanical timer, digital ones don’t like -40. My granddad was old school and always did his chores with a team of horses and stone boat, his running joke when it was cold was that he couldn’t do his chores cause he had forgot to plug the horse in the night before.

 

[Max W]

Have had block heaters but more recently a magnetic slap on oil pan heater got vehicles to turn over faster. Back in the day, and I don’t recommend this especially if you have any oil leak, I have used a pan full of coals from the wood furnace under the oil pan.