Comments on Home Efficiency Blog: Best Way to Boil Water

Yes you are right Larry, gas stove is more efficie...

2010-07-30T23:16:44.178-04:00

Yes you are right Larry, gas stove is more efficient than electric one, but again you need to take gas from the ground. It would be interesting to test efficiency of the induction stoves, they should perform better than any other.

Take-home message: there is nothing "clean" about ...

2010-07-21T08:47:23.131-04:00

Take-home message: there is nothing "clean" about electricity per se. Think not of white, humming appliances powered by wind turbines but of coal toxins going up chimneys, strip mines, vast landscapes drowned by hydroelectric dams, and ever-accumulating nuclear waste. All these lovely visions should be kept in mind, too, when discussing all-electric cars. A gasoline-powered hybrid

The original analysis is far too naive. As earlie...

2010-07-11T11:46:28.570-04:00

The original analysis is far too naive. As earlier commenters point out, the only meaningful comparison is not raw BTU consumption at the point of use but the net consequences, energetic and otherwise, of providing the desired energy service by one means vs. another. Electricity is well-transferred at the point of use (by stovetop coil or microwave) but, in a typical thermal power plant --

Hi Energy Savers, I'd like to add my thoughts and...

2010-06-28T06:26:32.063-04:00

Hi Energy Savers,

I'd like to add my thoughts and observations that gives the advantage to using a microwave over a kettle or pot on stove, especially for heating small amounts of water and also larger soup or stew dishes.

1. Unlike your findings, my microwave ("Panasonic 1200 watt High Power" "inverter") boils 1 cup of water (starting temp 55 degrees

amazing

2010-05-31T13:20:39.613-04:00

amazing

Re: loss of heat from microwaved liquids versus st...

2010-05-12T17:53:43.923-04:00

Re: loss of heat from microwaved liquids versus stovetop boiled. Thank you Luke. However, it seems to me that if you don't stir a microwaved liquid, there might be cooler spots that take the heat from hotspots, thus accelerating cooling.

Very nice touch from you, I admire your dedication...

2010-05-12T04:23:25.382-04:00

Very nice touch from you, I admire your dedication...

Anonymous, the short answer is no. Thermodynamica...

2010-05-10T10:08:43.808-04:00

Anonymous, the short answer is no. Thermodynamically, the mechanism for heating makes no difference on how fast the liquid loses heat. BUT, the container plays a big role in the rate of heat loss. For instance, if you pour the hot liquid (regardless of heat source) into a room-temperature container, the liquid immediately starts to lose heat as it warms the new container. I'll explore this

I have a question: Do micowaved liquids lose heat ...

2010-05-09T19:01:41.315-04:00

I have a question: Do micowaved liquids lose heat any faster than those heated on the stovetop?

Good question. I used a medium pot with a lid. The...

2010-05-05T07:13:57.863-04:00

Good question. I used a medium pot with a lid. The pot was sized such that the stove element was slightly smaller than the base of the pot
benz
Home Design

It is a lovely and interesting experiment that you...

2010-05-02T15:27:40.786-04:00

It is a lovely and interesting experiment that you carried and the results are mind blowing.I always thought micro oven was the best of all.

Burning gas on a stove may use less fossil fuel th...

2010-03-31T10:50:02.621-04:00

Burning gas on a stove may use less fossil fuel than burning it to generate electricity but why burn it at all?
Buy your electricity from a company that only buys from renewable generators like wind turbines and photo voltaics. And uses a higher percentage of your bill to invest in new renewable generation than any other company. (In U.K. Try Ecotrcity or Good Energy).
If you use a

In case anyone is checking the math on the Josh Ma...

2010-03-23T12:38:59.373-04:00

In case anyone is checking the math on the Josh Mac comment. It looks like I missed a decimal point.

The bottom line is that for Josh's case we should be comparing 0.72 cents with his gas range to 1.01 cent for an electric kettle boiling 3 c of water. Gas wins (but not by a huge margin).

Griff, Great comment! Good point about more full...

2010-03-23T12:27:29.960-04:00

Griff,
Great comment! Good point about more fully accounting for the heat pump energy. We'll dive into home heating and cooling in a future post.

To be clear, I'm all for cooking with gas. As Greg's test revealed, it's efficiency can rival even the electric kettle... especially when we look at coal power plant losses.
This post was intended more than

WOW, what a cool thread. I want to weigh in. Lu...

2010-03-23T12:05:31.397-04:00

WOW, what a cool thread. I want to weigh in.

Luke - It's worth considering that at $15/mcf natural gas costs $.05/kwh, and burns much more nicely than coal and other fossil fuels used for electricity generation. If you heat with it, it's actually more efficient (in terms of net heat/unit of energy) than your air-source heat pump because of the 30% conversion efficiency for

Anonymous, Sorry for the delay. This is an inter...

2010-03-11T11:38:48.362-05:00

Anonymous,
Sorry for the delay. This is an interesting way to frame heat loss from the stove. The answer in my opinion is "kind of." Here's my thinking:
- Compared to a proper heater, the stove tends to be an inefficient way to heat a space. For instance, heat pumps can introduce MUCH more heat per unit energy than the stove top. An air source heat pump can provide

Consider that the lower gas stove efficiency will ...

2010-02-28T17:08:01.675-05:00

Consider that the lower gas stove efficiency will mean heating the house, that in winter can be considered fully used heat, not waste. Isn'it?

Josh, I'm with you up to the 305 Wh figure. Then...

2010-02-23T13:43:33.940-05:00

Josh,
I'm with you up to the 305 Wh figure. Then, I'm not following. Please correct where I've gone wrong:
12,500 BTU/hr * 5min / 60 min = 1042 Btu
1042 BTU * 1 cf / 1028 BTU = 1.01 cubic feet
1.01 cf * 1 ccf / 100 cf = 0.01ccf
0.01 ccf * 72c / ccf = 72 cents

3C in the electric kettle required 81 Wh.
81 Wh * 1kwh / 1000Wh * 13 cents / kwh =

I clocked my gas range doing 3c water in 5 minutes...

2010-02-23T12:26:23.033-05:00

I clocked my gas range doing 3c water in 5 minutes on a 12.5k BTU burner. Doing the math puts that at 305 Wh. Incidentally, gas costs 72c/CCF here, so that means my water cost almost a penny to boil. Electricity is about 13c/kWh net, so that would have been 2.3c--over 230% more expensive.

Maybe next time I'll put a lid on it.

Good question. If you're referring to an inducti...

2009-12-08T15:44:21.117-05:00

Good question.
If you're referring to an induction stove top, the performance should be about 20% better (20% less energy) than that of a conventional electric stove. We don't have an induction stove handy for testing, but theoretically it would even out perform the electric kettle, especially with large volumes.
If you're asking about a halogen stove though, the results

Any idea on how this data would change with the ne...

2009-12-08T14:56:43.114-05:00

Any idea on how this data would change with the new glass cooktops?

Hi, Great test! I can add that a drip brewer can ...

2009-11-30T02:53:50.409-05:00

Hi,

Great test! I can add that a drip brewer can be even more efficient than the electric kettle. I have tested it to check how to do our morning coffee http://urge4lessenergy.blogspot.com/2009/11/most-efficient-way-to-boil-water.html

Svein*

I always heated my cup of water in microwave becau...

2009-11-13T14:13:04.041-05:00

I always heated my cup of water in microwave because it was the most convenient and quickest (2.5min). I knew it wasn't the most efficient way, but since the difference is very small to really care about. I really enjoy reading your articles. I started a similar blog of my own at smartenergypractice.com

Kaat, Good question. I used a medium pot with a l...

2009-11-11T14:38:12.996-05:00

Kaat,
Good question. I used a medium pot with a lid. The pot was sized such that the stove element was slightly smaller than the base of the pot (i.e. the pot completely covered the element). A tea kettle would probably have performed even better.

What did you use for kettle on your stove top? A p...

2009-11-11T13:58:03.494-05:00

What did you use for kettle on your stove top? A pan with or without lid, or an old-fashioned teakettle? Thanks!