Saving Money

[Salinas R134]

Hello Guys & Gals, This is my first time doing this-so i hope i do it right. My question is ?Is it true that by wiring a residential home in 12 gauge wire saves more money on the light bill than by wiring a home in 14 gauge? Any respond is greatly appreciated. Thank You

 

[iwire]

In my opinion, all other factors remaining unchanged, larger conductors will result in lower energy consumption.

Would it be a noticeable reduction in the monthly bill for a typical home?

I really do not think so.

 

[iaov]

In my opinion, all other factors remaining unchanged, larger conductors will result in lower energy consumption.

Would it be a noticeable reduction in the monthly bill for a typical home?

I really do not think so.

I agree with you completely on this one Bob.:smile:

 

[SmithBuilt]

In my opinion, all other factors remaining unchanged, larger conductors will result in lower energy consumption.

Would it be a noticeable reduction in the monthly bill for a typical home?

I really do not think so.

What do you base your opinion on?

 

[480sparky]

What do you base your opinion on?

Ohms Law... I?R losess. Larger wire has less line loss for the same load.

I recall a webwite by the copper industry showing the difference in dollars between Code minimum wiring and using one size larger. It was for a large factory, of course, but the principle still applies (on a much smaller scale) to a dwelling.

 

[charlie b]

Is it true that by wiring a residential home in 12 gauge wire saves more money on the light bill than by wiring a home in 14 gauge?

Yes. But it will obviously cost more for the initial installation. Will you save enough on the light bill to offset the cost of the larger wire? No you will not. So if you are looking solely at cost considerations, it is not a good financial decision. If you have other considerations, such as voltage drop in long wires in a large house, it may be worth looking into.

 

[SmithBuilt]

Thanks 480. The payback on the examples they show are faster than I thought.

I really didn't think it would be possible to break even $ wise. Especially in a residential home. But now I know otherwise.

 

[mdshunk]

With the intermittent nature of loads in homes, and the fact that wire lengths are relatively short, it would take an awful long time to realize a payback in resi. You'd be better off with that cash in a money market account or something.

 

[LarryFine]

In my opinion, all other factors remaining unchanged, larger conductors will result in lower energy consumption.

Bob, I have to disagree as far as making such a blanket statement is concerned. Different loads have different reactions to varying voltage. For example, resistive loads will flow more current with lowered voltage drop, increasing power. Motors will use less current, but the power consumed will remain fairly constant.

Electric heat (and maybe air conditioning) may well run for fewer minutes per day with higher voltage making (and using) more power when running, but with "all other factors remaining unchanged", over time the heat generated, and power consumed, will equal the heat loss.

So, it all depends on what the loads do with the extra voltage. At least that's how it seems to me.

 

[LarryFine]

Thanks 480. The payback on the examples they show are faster than I thought.

I really didn't think it would be possible to break even $ wise. Especially in a residential home. But now I know otherwise.

You gotta consider the source of the information.

 

[iwire]

Bob, I have to disagree as far as making such a blanket statement is concerned. Different loads have different reactions to varying voltage.

Larry I know that, but regardless of the load, the wasted power in the supply conductors will still be less with larger conductors even with the reduced current that a resistive load will draw with reduced voltage.

Lets also keep in mind my 'blanket statement' was aimed squarely at the OPs question which was a 'home'.

As far as motors and how they react to reduced voltage it is a crap shoot, many variables come into play. They do not always react in the real world as they tell us in text books.

When they say 'A motor will draw more current with reduced voltage' they are assuming the work produced remains constant. Many times that is untrue.

 

[LarryFine]

Larry I know that, but regardless of the load, the wasted power in the supply conductors will still be less with larger conductors even with the reduced current that a resistive load will draw with reduced voltage.

I dig, but my point is what happens as a result of that reduced loss. With less loss in the supply conductors, what happens due to the higher load-terminal voltage? Is there a net gain or reduction of consumed power? In my opinion, it depends on the load type.

An HVAC system will have to run a bit longer per day to compensate, so there would be savings there, unless the conductors with the waste heat are within the conditioned space, and contribute to heating the building; during AC, that's a negative, and larger conductors are even better.

However, with incandescent bulbs, there's nothing we can do to recap any savings from the reduced voltage drop. We can't use the lights for a few minutes less each day because they're brighter, or use a 95-watt bulb in place of a 100-watt one. 130-volt bulbs might be an exception, though.

Of course, we're talking pennies' worth of differences here, and I believe that any size conductor in a properly-sized circuit is the right choice. I'll keep using #14 wire.

 

[wirenut1980]

The point is that the payback period to recooperate (sp?) the extra money spent on larger wire is going to be on the order of probably 30-50 years, which may be approaching the useful life of the electrical system. So the best you could do is break even. And given the value of money over time, you are really still losing $. And all that is assuming that any I^2*R losses are not negated by load operation.

Like Larry said, that initial extra money spent would be put to better use in a mutual fund or money market.

Edit to add: My statements are keeping with the OP example of a residential application.

 

[iwire]

but my point is what happens as a result of that reduced loss.

I understood your point, I just don't agree. :smile:

IMO there is no instance where using larger supply conductors will not result in less energy usage regardless of the load. I agree that different loads will result in more or less % of savings but it will never swing the other way with larger conductors resulting in higher energy costs.

That said, I will still be using 14 AWG. :smile:

 

[480sparky]

I think you're better off buying Forever stamps @ 42? each now the postal rates are going up....

 

[Tiger Electrical]

I can't help but think of the copper marketing people sitting around asking "How can we sell more copper?" and coming up with energy savings as the answer. This would have been much more believable coming from another group.

Dave

 

[Sharpie]

There are some other things to consider along these lines. If the branch circuit has to travel a long distance it would be the right thing to up-size. Or if you think you might add more lighting over the course of the years, and want to leave the option there to change out the breaker to a 20A.

Just my thoughts.

 

[LarryFine]

I understood your point, I just don't agree. :smile:

Well, allow me (as he cracks his knuckles):

IMO there is no instance where using larger supply conductors will not result in less energy usage regardless of the load. I agree that different loads will result in more or less % of savings but it will never swing the other way with larger conductors resulting in higher energy costs.

Let's take a hypothetical 1200 watt resistive load. With a 120v rating, the resistance should be 12 ohms, and the current 10a.

Now, let's introduce 2 ohms of series supply resistance. Now, the load is 14 ohms, the current is roughly 8.6a, and the total power is 1032w.

The intended load receives 102v, and the line voltage drop is 17.2v. The load's power is 867w, and the line's power loss is 146.2w.

(Numbers don't add up due to rounding.)

The electric meter will run slower with the resistive supply, so, with no compensation for reduced power made, the cost per hour is less with the poorer supply system.

If this was a heating load, there would definitely be a money savings to minimize voltage drop, because the heater would have to run longer in order to deliver the same heating energy.

The loss would be two-fold: the heating element receives less voltage, and has to run longer to deliver a given kw/hr, and the line loss can never be recovered.

However, if this was a lighting load, the lights would be dimmer, but, unless higher-wattage bulbs are used to compensate for reduced voltage (which would exacerbate the problem and require even more current), the power consumption would drop.

Result: larger wire = higher cost.

That said, I will still be using 14 AWG. :smile:

Same here.

 

[iwire]

Result: larger wire = higher cost.

Sure, if we lived on paper. :smile:

But we do not, and to arrive at your conclusions you left out what you did not want.....realiity.

Electric heat will run longer, they might use larger lamps in the fixtures. The most common place to find voltage drop limitations are in energy codes, there is a reason for that, voltage drop will eat watts.

IMO, to answer the question honestly we must compare apples to apples. For the same amount of work produced, all other factors remaining unchanged larger conductors = less energy costs.

Now here is my statement that you first disagreed with.

In my opinion, all other factors remaining unchanged, larger conductors will result in lower energy consumption.

'all other factors remaining unchanged'

Your calculations did change the work produced, certainly the work produced is a factor of the circuit.

 

[brian john]

So that 4/0 I ran for all my branch circuit wiring was a waste, cost me a fortune in boxes and terminations much less all that copper.