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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.

15
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1answer
139 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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2answers
55 views

Does air duct cleaning increase heating efficiency?

I recently moved into an older house with a natural gas-burning forced hot air furnace. There are no records of the ducts being cleaned, and based on the layer of black grime I can see, they are quite ...
2
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3answers
175 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 ...
2
votes
1answer
128 views

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

I'm trying to figure out the efficiency of energy usage between heating up 2 tons of water from 5°C to 70°C everyday (during winter) within a certain given time (let's say one hour) and stabilizing 2 ...
6
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3answers
6k views

How can I estimate the gas usage of a pilot light?

Can anyone provide a method to estimate the gas flow rate to sustain a pilot light, using just the apparent size (flame width and length) and reasonable assumptions for things like gas line pressure? ...
0
votes
2answers
130 views

Is hydrogen a good way of storing energy from excess hydroelectric generation? [closed]

Referring to hydro electricity generation, a lot of what we produce is wasted as the buyer buys only the minimum generation. What would be the appropriate measure to use that excess energy? Is ...
0
votes
1answer
67 views

What level of light intensity (lumens) do you need across a solar panel in order to obtain 15% energy efficiency?

What level of light intensity (lumens) do you need across a solar panel in order to obtain an incident-light to energy-output efficiency of 15%?
7
votes
2answers
142 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 ...
2
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2answers
91 views

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 ...
5
votes
1answer
155 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 ...
5
votes
3answers
196 views

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 -...
5
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2answers
591 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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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 ...
9
votes
1answer
52 views

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 ...
1
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3answers
131 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 ...
8
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2answers
181 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
votes
1answer
61 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 ...
12
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5answers
387 views

Lowering the heating thermostat at night: is it really worth it?

I've heard some very conflicting information regarding the effect of lowering the house heating thermostat at night. On one hand there are academic papers (such as Thermostat strategies impact on ...
8
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3answers
2k views

What is the relationship between permaculture and sustainability?

What is the relationship between permaculture and sustainability? What are sound reasons why both urban and rural permaculture takes us further down the road to sustainability? Are there real-world ...
4
votes
1answer
109 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 ...
4
votes
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 ...
9
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4answers
2k views

How to measure the energy output of a thermal solar hot water system?

I have a (thermal) solar hot water system with electric heating, and I'd like to be able to measure the amount of energy provided by just the solar heating. The system is set up like this: Water ...
2
votes
3answers
83 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
votes
1answer
65 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?
9
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5answers
2k views

How can I measure the moisture content of my firewood to ensure good efficiency and clean burning?

It's clear that firewood that hasn't been well dried is more polluting and less energy efficient, hence the existence of various schemes to ensure firewood suppliers provide dry wood. Is there a way ...
6
votes
2answers
212 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 ...
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 ...
3
votes
3answers
769 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 ...
8
votes
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 ...
13
votes
6answers
4k views

What is the relationship between energy efficiency and sustainability?

What are the sound reasons (let's put aside the unsound reasons) why increasing energy efficiency takes us further down the road to sustainability? Are there real-world circumstances whereby ...
16
votes
5answers
21k views

Is it practical to use an infrared space heater along with a heat pump system?

We live in a house that has a heat pump system, for AC and heat, with a second-stage heating coil for aux/emergency heat. It frequently gets down to below 30 degrees in our climate, at which point ...
7
votes
1answer
93 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. ...
3
votes
1answer
247 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 ...
11
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3answers
825 views

Use waste heat of electrical appliances in place of traditional heating?

Does it make sense to keep electrical appliances turned on, or at least not turned off, during the winter as a partial replacement for traditional heating? I'm thinking in particular of computers, ...
7
votes
2answers
266 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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2answers
71 views

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.
12
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3answers
219 views

Options to suggest to landlord for cost savings via renewable energy?

I have a landlord who is very interested in saving money. I wanted to suggest options to her to help her save money while reducing environmental footsteps. However she is not motivated to save the ...
5
votes
1answer
102 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 ...
2
votes
0answers
62 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? ...
8
votes
1answer
178 views

Is the energy used to manufacture and install solar panels in proper balance with the energy output from them? [duplicate]

From mining/harvesting materials to altering them into useful manufacturing materials to making actual products, and then packaging them and shipping them to retail stores, or directly to customers, ...
-1
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1answer
117 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 ...
22
votes
4answers
771 views

What form of electrical lighting has the smallest energy-footprint?

We all know that when it comes to household electrical lighting, LED lights consume the least amount of energy for a given amount of light, followed by fluorescent tubes, halogens, and Edison-age ...
13
votes
1answer
78 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, ...
7
votes
1answer
403 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 ...
6
votes
1answer
74 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 ...
1
vote
0answers
163 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
votes
2answers
143 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 ...
21
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4answers
137k views

Leaving the oven door open for heat - bad idea?

I've heard before that it's a bad idea to use an oven to heat your house, because it's inefficient and carries the risk of carbon monoxide poisoning. But what about leaving the oven door open after I'...
4
votes
1answer
156 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 ...
3
votes
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 ...