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Questions tagged [energy-efficiency]

The percentage ratio of energy produced to energy supplied to a system; or a measure of minimum energy required relative to energy actually consumed; or a measure of relative energy consumed to provide the same energy service.

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How to choose between an electric, natural gas, or heat pump clothes dryer?

I will soon be moving into a new home with a very old electric clothes dryer. I expect that before too long it will fail and need replacing. I would like to replace this with a more efficient model. I ...
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1answer
70 views

For overnight heating, is it more efficient to use an electric space heater in a bedroom or a whole house natural gas furnace?

Is it more efficient to heat a bedroom with whole house's forced-air natural-gas burning furnace, or only an electric space heater in the bedroom? For a very location-specific application, electric ...
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1answer
144 views

Are crypto currencies sustainable?

Except generating a different kind of "money value", what is the sustainable value of crypto currencies compared to the energy consumed to generate them? Compared to currencies working with ...
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0answers
52 views

Home efficiency

Please comment on which design is more thermally efficient. They are roughly the same. The apt is 2' shorter on the out (left) as space is not need for stairs. It is a cooler climate with 70" of ...
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2answers
94 views

Does transporting plastic offset the benefits of recycling it?

Apparently China has been processing about half the world's waste until this year, and most of that waste is transported over the ocean in large container ships. Recycling plastic uses less energy and ...
4
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1answer
56 views

Are all Peltier-type stove fans the same?

I'm considering a stove fan to distribute heat from a small wood burner. The prices of commercial Peltier-type stove fans seem to range from £25 to £100. Is there likely to be a significant ...
8
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2answers
164 views

More sustainable pick-me-up: can of coke or cup of tea/coffee?

Question: which has a greater embodied energy: a cup of tea/coffee or a can of Coke (or Pepsi, or other caffeinated soft drink) -- or maybe some other stimulating drink? I have made some estimates of ...
4
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1answer
78 views

How much, if any, does resolution effect the net power consumption of watching online video?

I watch a lot of online video. I'd assume that for example videos on Youtube in 720p use less power than the same videos in 1080p. I think this might be because: more power is used by sending network ...
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3answers
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Newer heat pump vs new space heaters in Seattle winter

I see similar questions to this one, but mine is slightly different, so here goes: I live in Seattle, where the winters are mild, with days in the 40s°F (4-10°C) and nights in the low 30s°F (around -...
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3answers
120 views

Mindset change in developing countries

I've travelled a bit in Africa, Middle East, and Asia. What strikes me, in all of these places, is that often in the most poverty-striken areas, things that people look up to are big cars, and ...
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3answers
82 views

Most cost effective heated flooring?

I am pulling out the carpet in my house. I live in a cold area. I want to heat my flooring, but don't want to spend an arm and a leg doing so. What is the most cost effective and energy efficient ...
4
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1answer
64 views

How much energy am I harvesting?

I've developed a water pump that is powered by a 1 watt solar air pump. In 24 hours it pumps 54 gallons to a height of 30 feet. How much energy have I harvested?
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2answers
178 views

Water heater vs stovetop: most efficient way to heat water using natural gas?

When I am going to boil a pot of water for cooking, will the total energy consumption be less if I start with hot water from the tap? A few considerations: Both the water heater and the stove burn ...
8
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1answer
2k views

How much gas does it take to heat water from 15 to 60 degrees C?

There's a great answer about heating water with electricity, where anyone can easily get an idea how much would it cost to heat water just by applying one's price for kWh. I'm looking for the same ...
3
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1answer
109 views

How much energy would it cost to stabilize 2 tons of water at 70 degrees?

So what I'm trying to figure out is the efficiency of energy usage between heating up 2 tons of water from 5°C to 70°C everyday (during winter) with a certain given time (let's say one hour) and ...
3
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3answers
672 views

Is 3 phase electrical generation more efficient to utilize than single phase?

Is 3 phase power more efficient to generate/use? How difficult or complicated is it going to be to provide balanced single phase load(s) from a 3 phase service? (equipment & controls required) If ...
9
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1answer
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Are building certificates under EU Directive 2002/91/EC, such as EPC, Energieausweis, DPE, directly comparable between EU countries?

Implementing Directive 2002/91/EC, the UK have the Energy Performance Certificate (EPC), Belgium has the Energieprestatiecertificaat (EPC), Germany has Energieausweis, France has Diagnostic de ...
3
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1answer
197 views

How to regulate temperature at home with windows and blinds?

I have windows getting direct morning sunlight on one side of our apartment, and direct evening sunlight on the other side. All windows have (wooden slat) blinds. I was wondering: what is the best ...
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1answer
112 views

What are the incentives for energy companies promoting energy efficiency?

My hydro (electricity) bills always contain helpful hints on conserving energy: do laundry runs in the wee hours, favor LED over incandescent bulbs, etc. I'm sure many at the big-energy corporate ...
7
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2answers
232 views

Anything similar to GravityLight that can be readily purchased?

Ever since it was first mentioned in a popular news site, I've always been interested in GravityLight. But I've never been able to go to a store or a site and just buy it. Is there anything vaguely ...
5
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1answer
100 views

Energy Efficiency vs. Reduced Consumption

Energy efficiency and reduced consumption are not exclusive. But is it possible that we focus too much on the former and not enough on the latter? To expand on my question, I live near a very ...
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0answers
60 views

Permaculture Urban Transition [closed]

In the more realistical and pragmatical way, which are the main steps a set of people in a medium sized urban envinroment, should undertake to convert the city to a permaculture oriented living style? ...
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2answers
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What exactly is Potential Induced Degradation in PV panels?

Can someone explain Potential Induced Degradation? I've been looking over the internet but a lot of the explanations go into too much detail.
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1answer
114 views

Cookware thermal isolation [closed]

We like to waste a lot, particularly, in the kitchen we like to wash the hot water down the tubes, literally, right into the sink. We even heat up much more water than we need: 2 leters of water to ...
14
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3answers
2k views

Are plastic cups more environmental friendly than ceramic mugs?

Many years ago I read that plastic cups, like this: are more environmental friendly than ceramic mugs, like this: This is rather counter-intuitive. If I remember correctly, I believe the argument ...
7
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1answer
359 views

Why isn't STES (Seasonal thermal energy storage) more popular?

I don't understand why STES - or more specifically BTES (Borehole thermal energy storage) - isn't more popular. I understand that is has a high implementation cost; excavation, drilling, evacuated ...
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0answers
142 views

Model for sustainable, free food distribution [closed]

Background Consider the following model intended to sustainably eliminate human involvement in food production: Known Issues The following known problems exist: Friction. The amount of energy lost ...
9
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2answers
139 views

Does it make any difference to charge my electronic devices using an USB port?

I work with a computer and I was wondering if using its USB ports to charge the devices that I use the most (mostly my phone and my e-reader) while working as opposed to charging them using a normal ...
6
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1answer
73 views

Is it possible to calculate energy efficiency of a flat by knowing how much energy was consumed for heating?

During 6 days my heating system consumed 11,4 m3 of natural gas keeping its temperature at 20 degrees of Celsius. No human or other energy source (except for refrigerator) was inside the flat at that ...
5
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1answer
357 views

Electrical usage data logging with wireless data transfer

Does anyone know of a wireless energy usage capture device, that one can attach to an appliance and find out the energy usage? I know that there are certain energy monitors that do the job to some ...
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3answers
4k views

Should I worry about the minimum mark on our kettle?

Our electric kettle for boiling water for tea or coffee has what looks like a minimum mark at 0.8 litres (though on closer inspection it says “mini” rather than “min”!). I try to save energy by ...
6
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4answers
1k views

Which is more energy efficient? Heating ten 1L water separately or one 10L water directly

Just like the title said. In my house, we are very heavy tea drinkers. So my mother tends to boil a lot of water every day. She usually does this with a small amount of water (1-2L) every time she ...
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1answer
139 views

Energy requirements for sustainable food production system

Overview Consider the following system for sustainable food production: The purpose of this system is to provide an environmentally-friendly, semi- (or fully-) automated means to produce food for ...
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3answers
86 views

Fuel efficiency when decelerating on a hill

Another efficiency question from me out of curiosity. Let's say that I am driving at a decent efficiency rate (say 40 MPG) and am coming up on a hill, with no cars immediately behind me or traffic ...
13
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1answer
72 views

Co-firing fossil fuels use in waste incineration

I know from shop talk among previous colleagues that waste incinerators often need natural gas to sustain firing. AFAIK this is mostly because mixed household wastes have a high moisture content, ...
3
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1answer
172 views

Can artificial lighting compete with horizontal agriculture?

Background In Professor Bugbee's presentation, he describes some drawbacks of vertical farming (VF) versus traditional horizontal agriculture. Most of Bugbee's arguments against VF hinge on grow lamp ...
5
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2answers
3k views

Which is more energy efficient, a washing machine express wash, or normal?

My electric washing machine has an express wash button (they seem a common feature) that reduces the washing time by a lot. My first thought would be that using it would save energy because of the ...
2
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2answers
260 views

How feasible would a gas-powered electric-engine based car be?

Would an electric motorized vehicle work if there was a small gas-powered generator to power it instead of batteries? EDIT: The original Chevy Volt was going to have a gas generator to charge the ...
7
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1answer
92 views

How much energy would U.S save if all public illumination use LED?

How much megawatts U.S could save if they used LED for public illumination? Bonus : The math for China which is another big energy consumer in the world. And the math for the humanity as whole. ...
4
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3answers
226 views

How can I more effectively cool my house by managing windows with outdoor temperature changes?

How can I more effectively cool cooling my house by managing windows with outdoor temperature changes? My current strategy I open all my windows when the temperature inside the house is warmer than ...
5
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1answer
115 views

Is the production of hydrogen fuel more efficient than storing the excess solar energy in a battery?

Can energy be stored long enough in batteries so that the cold winter days can go without any shortage in power supply, or should the energy be converted to hydrogen which will be used as a fuel later ...
5
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2answers
542 views

Home owner doesn't care about house having insulation

I'm renting a home with central heating and air conditioning in Oklahoma. It's really hot now (90 inside) so I have the A/C on all day but it's cold at night because the attic has no insulation and ...
5
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3answers
512 views

Best way to store vegetables in the fridge

What is the best way to store fruits and vegetables in the fridge? I currently use plastic food containers like those in this picture, of different sizes. 1) Is it better in terms of energy ...
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3answers
4k views

Most fuel efficient way to run AC in my car?

More of a curiosity question, but I'm trying to figure out the most fuel efficient way to run the AC in my car, assuming I must use AC. I already know when to open windows vs use AC, so I'm looking ...
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4answers
4k views

How much firewood does it take to produce the equivalent of 1kWh of electrical heating?

Let's assume 1kWh of electricity is used to run a fan heater. Heat pumps are more efficient, but have a range of different efficiencies, so perhaps aren't a good base comparison. Assuming a good ...
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1answer
143 views

cost of energy for old crt vs new flatscreen

My parents recently moved and are going through throwing out and replacing a lot of their furniture. They have 3 large old fashioned crt televisions that are quite heavy, and I'm considering ...
5
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2answers
79 views

What's the most energy-efficient temperature to use when cooking?

Should I use low or high temperature to use a stove energy efficiently? If I use low temperatures a lot of energy will be wasted with time, but using high temperature is not energy efficient as well. ...
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3answers
1k views

How to cover an open-top shower, to make it feel warmer while showering

There is a product on the local market in New Zealand called "Showerdome" that is a clear plastic dome that can be attached over the top of most open top showers. Covering the top of a shower reduces ...
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1answer
210 views

Energy saving lamps suggestion

My dining room lights are shown in the pictures. I have two of those fixtures, with 3 bulbs each. 1) On the plastic chandelier it says "MAX 40W", but the lamps that when I first arrived in the flat ...
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2answers
677 views

How much energy costs do portable solar panels save in a house?

Our Houston area HOA does not allow roof top solar panels and I doubt they would survive our hurricanes too. I discovered NRG Energy sells these portable solar panels under their goal zero brand. If ...