# Electricity use from power tools



## mission76 (Jun 24, 2008)

Does anyone have any clue how much power a basement shop can add to an electricity bill? I know it's a hard question to answer without all the rates, but I'm really just looking for a ballpark amount. I am in the process of buying my own place, and being single..all the bills will fall to me.

Anyway to give you a better idea..I would like to build a basement shop. Nothing spectacular, but believe it or not I have about 5-6k in change that I saved up for 13 years that I'm planning on using for new tools. These tools will be for the most part 220v. Now I'm not using these tools everyday…lets say I'll use them maybe 8 hours a week, normal usuage. My question is, how much of a difference will these tools make on my electric bill? Will it skyrocket or will it be like a 20 dollar difference?


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## pommy (Apr 17, 2008)

simple answer to this question is use hand tools then all you have to worry about is lighting


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## mission76 (Jun 24, 2008)

Haha..yeah I knew that was going to be an answer, and there will be plenty of hand tools in the shop. But every once and awhile I need to break out the table or band saw, or jointer..and would rather not face foreclosure after I find out these tools made my bill jump 100 dollars a month!!


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## SnowyRiver (Nov 14, 2008)

I dont think it will skyrocket. I actually didnt see much difference on my electric bill after installing all of the equipment including the lights. I would think that $10 - $15 a month would be a wild guess. It would of course depend on what your local rates too. The heating in my shop (gas) is where I see the big difference in billing.


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## chrisl (Mar 19, 2008)

Your amps usage will be more telling - that's the measure of how much current you're using. Voltage really isn't that helpful. 220v at 9 amps is the same as 110v at 18amps, it just balances the load on the electric grid better to pull 220.


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## dbhost (Jul 20, 2009)

Negligible. Running my computers at home costs me substantially more than my shop… Except for when I run the electric heater. THEN the shop COSTS ME A LOT…

I have since shoved the electric heater into the attic, and only use my Mr. Heater propane heater…


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## PaulfromVictor (Mar 29, 2009)

I don't think it would add much. As Wayne said, $10-15 is a good estimate for a typical hobbyist in a typical area. I can tell you that in my area the electric utility bumped up the cost for being connected to the grid, and dropped the cost per Killowatt hour. By doing so, there is less incentive to save electricity.

If you want to guestimate the cost, look at your elec bill for the cost per kilowatt hour. A kilowatt hour is the cost of using 1000 watts for 1 hour. So for example if your cost is .10 per KW/hr , a 100 watt light bulb costs 1 cent per hour to use. In theory at least.


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## mission76 (Jun 24, 2008)

Thanks to all..I'm sorry to even ask but as you can see I know nothing about electricity. I always figured that something running with 220v power would cost twice as much as something running at 110v.

Ever since I restarted this little hobby a few years ago, I have been working with small tools in an unheated garage…I always said that when I'm ready to get that house I'm going to build a nice little respectable shop in the basement. Now that the time is getting nearer for the house..I find myself thinking more and more about what I'm building…and getting psyched to build my first real workbench. It would suck to go through all this and then find out i can only stare at the thing because the lighting/tools cost me more than I could afford!!


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## SnowyRiver (Nov 14, 2008)

Actually 220 v draws half the current that 110 does with the same load.


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## Dennisgrosen (Nov 14, 2009)

jaa but if you new ohm´slaw its abaut the same watt inthe end
110v x 2a is the same as 220v x 1a = 220w
and then you can calculate backwards from watt iff nesserery

if you look at the watt a bulp is use per our you just multiply
with the time you use it and multyply it with the kost per K watt

its the same with powertools except that they useing a little extra under start

Dennis


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## SnowyRiver (Nov 14, 2008)

Yep I agree…I dont think you save a whole lot by increasing the voltage. Power is equal to the current times the voltage so one goes up the other has to go down to support the same power.


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## Sawkerf (Dec 31, 2009)

Mission -
It isn't about the rates, it's about the kwh (kilowatt hours) you use - and the usage brackets the power company uses for billing. You'll use a few more kwh's because you have a shop, but probably not much more. At worst, you may have some kwh's in a higher useage bracket which have a higher rate.

When I "went pro" five years ago, there was only a small increase in my monthly electrical consumption although I was in my garage shop all day every day instead of the occasional weekend.


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## Dennisgrosen (Nov 14, 2009)

SnowyRiver 
but there is one great advance on useing higher volt mashinery 
they have usely more power (Horsepower) than if you use 110 v mashines
as I remember


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## Brian024 (Feb 2, 2009)

They won't have more horsepower on 220v than 110v, but the will run more smoothly. With 220v, its not starving for power like it is when you are running 110v, which is why most single phase motor's have capacitors to help when they startup/run under a load. You will use the same power regardless of the voltage.

As far as the "addition" on your power bill, $15 to $20 seems reasonable depending on how much time you are working.


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## a1Jim (Aug 9, 2008)

My shop has it's own power meter and it's bill is about $ 250 a month but I would expect a non commercial shop to use less than that.


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## CharlieM1958 (Nov 7, 2006)

Jim, you should really turn off all those routers when you aren't using them.


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## Dennisgrosen (Nov 14, 2009)

thank´s Brian for correcting me

but in Denmark we have only 220singel and 400 tree fase
and I wasn´t qeit fammiliere with 110v

Dennis


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## toddc (Mar 6, 2007)

I have been using my shop professionally and we have noticed that the bill jumps or drops $30 - $35 per month depending on if I am working in the shop constantly or in the field on a remodel project.

That covers the lights and tools but the heat is natural gas and is additional.


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## Catspaw (Dec 15, 2007)

Also, remember, most of the tools you use aren't on for very long. Unless you're planing rough lumber all the time and whatnot. It's not like you're leaving the table saw running for half the day or something.


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## DanLyke (Feb 8, 2007)

You're billed for electricity by the Kilowatt Hour, often abbreviated kWh. The ballpark I've been using out here in California is $.13/kWh. Some places are cheaper, some are more, some plans and meters vary it by time of day, sometimes it's one price until you've used some amount, then you move to a different tier.

Check your electricity bill. We'll use $.13/kWh for the sake of illustration.

This means that if you run something that draws a thousand Watts for one hour it costs you thirteen cents. This scales: Leave a hundred watt (.1 kW) light bulb on for an hour, that's 1.3 cents ($.013).

My plug-in drill says that it draws 5.4A max, for the purposes of approximation, Watts is roughly Volts x Amps, so this means the drill draws 648 Watts max. Run that drill continuously for one hour under load (because if you just let it run free it won't be drawing nearly that much) and it'll cost just under eight and a half cents (And I'll need a new drill, 'cause it'll burn out).

1800 Watts is roughly 15 Amps, or the most you can draw from a residential 115V circuit. Run that 3¼HP router continuously under load for an hour (say you're cutting molding on the router table) and you're out less than a quarter ($.234) an hour (1800 Watts is 1.8 kilo Watts, 1.8 * $.13 is $.234).


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## mission76 (Jun 24, 2008)

Thanks to all for the replies..and for clarifying how the electric bill is calculated. I will definitly be going ahead with the shop…now to read up on the pro's and con's of basement shops…I imagine it has everything to do with dust collection. Anyone have any thoughts on that?


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## ND2ELK (Jan 25, 2008)

I enjoy working in my shop and I am not very concerned what it cost. I do know that my electric bill did not go up enough to notice a great increase since putting in the shop. I have a 220 saw, cyclone, 12" jointer/planer and a heater. When the shop gets warm I shut the 220 heater off and use a 110 heater to hold the temperature.

God Bless
tom


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## sIKE (Feb 14, 2008)

Don't forget to turn of your dust collector….my called me in for dinner one day. Apparently I hit the button on the remote that turns on/off the dust collector that was in my shop apron pocket when I took it off. I went out he next day and I was like oh snap!


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## cliffton (Dec 18, 2009)

and remember when your calculating how much a tool uses, the HP value is useless. go by how many amps it uses. if it runs on 110/115V circuit the max HP you can have in a tool is ~1.75 HP. also remember that that is a load amperage, if there is no load the amp draw is much less.


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## rcs47 (Oct 31, 2009)

Volt X amps / 1000 = 1kVa or approximately 1kW. Run that for an hour and you get a kWh.

A quick rule of thumb - 1 horsepower ~1 kVa or1 kW

You should look at your residential rate structure. In most of California, we have a Baseline set by the California Public Utilities Comission. If you go over this baseline (something 95% of us do), the amount you pay per kWh goes up. There are tiers as you continue to go up. So, if you are near a tipping point, the new equipment could push your usage from Tier III ($0.219/kWh) into Tier IV ($0.303/kWh) or Tier V ($0.346/kWh).

You will not see a great power draw for a hobby shop unless you plan to have friends working with you. If you have a 3 HP table saw, 2 HP DC plus 2 KW lights running for one hour, that's only 7 kWh. Unless you are in a production shop just assigned to a table saw, when was the last time you stood in front of your table saw pushing wood for an hour? When I worked in my Dad's shop pushing cabinets out the door, I never stood for an hour in front of a saw. It was always just long enough to cut what I needed for the piece I was building.

Check your bills to see if you have a tiered rate structure, or if it's a flat charge per kWh no matter how much you use. I think you will see a larger impact for heating and cooling than the equipment.


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## fredf (Mar 29, 2008)

CessnaPilotBarry "My big draw is my cyclone. It settles into a steady 20a of 220v. Cyclones always run under high load and run for long periods of time. Most of the other tools draw a large start current, and idle most of the time as they wait for a human."

Wow a 5hp dust collector -I thought my 3 was big. Keep in mind it may be a 20a circuit, but it will draw only what it requires . . . . a starting guesstimate is 750 watts / HP. Watts are roughly Volts X Amps, most tools wont draw full current unless under load. cyclones etc are an exception. if you block the input the current is minimum, no air movement no load. Vacuums the same way-ever notice that the vac speeds up when it gets blocked???? if you run a cyclone with the input wide open you can over load it!


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## bob101 (Dec 14, 2008)

My power usage is minimal for my shop and I use it at least 10-30 hours per week, with sometimes multiple people working with lots of tools huming, I barely notice the difference in my power bill.


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## Sawkerf (Dec 31, 2009)

In your basement shop, dust collection is gonna be an absolute necessity. At least one air cleaner will probably be needed as well.


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## stevepeterson (Dec 17, 2009)

My calculations come out to less than $1.10 per hour.

Everything runs through a 50A subpanel with 220V. The biggest load is the dust collector at around 20A (or less) at 220V. The table saw is the largest machine (5HP) but it doesn't run all the time. The lights are always on with a constant load of a few hundred watts.

All combined I figure that it averages out to around 30A at 220V during heavy use times. Lighter use times (when the dust colelctor is not running) would be around 10-20A at 220V. Let's assume that the average load is 25A at 220V = 5500W or 5.5KWh electricity usage per hour. I am in California with a tiered metering plan, so electicity costs around $0.20 per KWh for this additional power. 5.5KWh * $0.20 = $1.10 per hour.

$1.10 per hour * 8 hours per week * 4.5 weeks per month = $39.6 per month. This is a worst case estimate and most likely will be less than this. There may also be offsetting factors, like every hour you are in the shop means one less hour that the TV and lights are on in the house.


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## novice1983 (Sep 9, 2010)

Thanks all for your great, well-thought replies.

I am trying to write an article about saving power in shops as i can find very little on the internet about this.

does anyone have any resources about how reduce power? For example, how to save power on specific devices like a table saw or a cyclone??

Or personal advice?

Thanks.


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## Knothead62 (Apr 17, 2010)

Why not put this question to the engineering folks at the power company? Have the electrical specifications of your power equipment and they can tell you all you need to know.


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## helluvawreck (Jul 21, 2010)

Considering the joy derived from working in a shop and the fact that you can can build useful things for the home and spend less time seeking entertainment elsewhere I would say it's not an issue at all.


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## swirt (Apr 6, 2010)

does anyone have any resources about how reduce power? For example, how to save power on specific devices like a table saw or a cyclone??

1) sharp tools - results in less work (work from an energy standpoint, work done = energy used)
2) thin kerf blades - results in less work needing to be done 
3) turn tools off when done. (sorry that one is obvious)
4) let tools cool - a hot motor wastes more energy than a cool motor
5) clean sawdust from motor casings - sawdust acts like a blanket and keeps the heat in and prevents air from getting through, resulting in a hotter motor.
6) Don't use a power tool when a hand tool will do it faster.
7) 220V as opposed to 110V causes less loss due to heat (wasted energy). Theoretically, yes 220V x 8A is the same as 110V x 16A but when it comes to heat loss in a wire, Energy is related to the square of the current, so keeping current low results in less loss. W=I²Rt (my favorite formula …. my last name) A motor is lots of long wire, so this can be significant.
8) Use corded tools rather than battery powered. The batteries waste more energy in use due to the lower voltage, they waste energy in chemical heat, and they waste it on the charging end too.
9) When you must use extension cords, use the largest gauge you can and shortest cord to reduce energy losses in the wire.
10) When wiring the shop, larger gauge wire (lower number) is more efficient and less dangerous than the thinner stuff. Sadly with the recent rise in the price of copper it makes people more likely to use thinner gauges.


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## pcott (Jul 7, 2009)

I watch my bill like a hawk, and the shop barely makes a dent in it. Mind you, I use hand tools quite a bit, but all the same…


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## novice1983 (Sep 9, 2010)

knothead 62, thats a good idea, I think I will try that. thanks


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## novice1983 (Sep 9, 2010)

Swirt, thanks for all of that. There are some good suggestions there-I like 5, 7, and I like the tip about the extension cords….thanks a lot!


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## novice1983 (Sep 9, 2010)

helluawreck and pcott-I agree, a small shop doesn't make too much difference, but up here in Canada they have cash incentives for reducing power bills by 10% per year--BC is apparently one of the worst and highest power consumers in the world. I'm surprised there isn't more about power saving with tools. If you have a tool for 8 years and can save 10% of its total electricity cost, there must be some savings there-add that up to 5 or 6 tools and it must be a bit of money. A new small tool or something.


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## pcott (Jul 7, 2009)

I live in Victoria, BC, and despite the shenanigans over power billing here, I still saw a negligible increase in my bill. and I'm cheap-I watch my bill like a hawk.


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## dbhost (Jul 20, 2009)

I am in my shop working a LOT, and no big deal. Maybe $20.00 extra a month on HEAVY months not including A/C… That adds up the most…

Honestly, even with the A/C, my computers add FAR more to my bill than my shop will ever think of. And my shop is currently fully 110V. 220 would be nice that's for sure!


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## TheDane (May 15, 2008)

My household electric bill has been averaging about $125 per month … we have electric water heater, dryer, dishwasher, range, 3 refrigerators, pump, and A/C in addition to what I use in the shop. The shop also has electric heat that is used about 4 to 5 months of the year, and the air filtering system run most of the time I am out there. We just installed a new Heat Pump Water Heater … be interesting to see if my bill go down!


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## crank49 (Apr 7, 2010)

A horse power is about 0.75 kw. If you run 5 hp of machines (a 2hp DC, a 1.5hp TS, a 1hp jointer, and 0.5hp DP for example)for 8 hours each for a week that's 8 X 0.75 X 5 = 30 kwh for tools per week. If you have 4 light fixtures with four 4ft tubes each that's 16 tubes of about 35watts ea. = 560watts = about 0.5 kw X 20 hrs a week = 10 kwh for lighting. So we have 30 kwh for tools + 10 kwh for lights = 40 kwh per week. Here in Tennessee that costs about $0.10 per kwh so that would cost $4.00 per week. Doesn't matter if its 120v or 240v or 480v for that matter. A hp is 745 watts, and 1000 watts is a kw.
- Running all those machines for 8 hours per week would be pretty heavy usage for a hobby shop so your cost should be lower than this IMHO.


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