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Micro heaters cut 87% off my electric heat bill

richsoil.com

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Re: Micro heaters cut 87% off my electric heat bill

#201

Post by leni536 »

abelsson wrote: post #193
leni536 wrote: post #187

Earlier quoted context omitted.

How can heating be any less efficient than 100%? I get that engines can be less efficient than 100% since the remaining energy is dissipated as heat and heat is the not desired energy in that case. What happens with the remaining energy if you heat with less than 100% efficiency? Does it start to rotate things?

Heating can be more than 100% efficient. Before you go "what, lol, no" - let me clarify. Obviously it can't be even 100% thermodynamically efficient, but a heat pump for example can generate 3-4 kW of heat from 1 kW of power. The rest of the energy comes from the environment obviously, but naively assuming that the 100% efficient power-into-heat is the best you can do is not true.

Are there any efficient electric heating systems for a household based on a thermodynamic cycle with the environment?

I think the most electric heating systems I have seen are using the rather bruteforce and inefficient (only near 100%) method. The basic principle that they heat a resistor and something quickly transfers the heat away so the resistor doesn't burn out and/or your house doesn't catch on fire.

An other fun method to increase the "efficiency" of electric heating would be heating with bitcoin miners. It wouldn't make the heating more efficient in the sense it would cost the same energy but at least you could get some of your money back spent on heating.

Re: Micro heaters cut 87% off my electric heat bill

#202

Post by Nano2rad »

byuu wrote: post #111
dredmorbius wrote: post #67

OK, Paul Wheaton simply doesn't know what he's talking about: "I think that this does produce some savings, but not as much as you might think. If you set your thermostat to a constant 70, the heater works a little at a time throughout the day. If you drop it to 50 at night or in the middle of the day, the heater stops working, but then when the time comes to warm the house again, the heater has to work at full power…

His article on CFLs ( http://www.richsoil.com/CFL-fluorescent-light-bulbs.jsp ) is very cringe-worthy as well. As part of his argument, he references a report he heard of claiming that kids gained 20 IQ points by switching back to incandescent bulbs. Seriously.

CFL light's spectrum is narrow compared to incandescent light

Re: Micro heaters cut 87% off my electric heat bill

#203

Post by abelsson »

leni536 wrote: post #201
abelsson wrote: post #193

Earlier quoted context omitted.

Heating can be more than 100% efficient. Before you go "what, lol, no" - let me clarify. Obviously it can't be even 100% thermodynamically efficient, but a heat pump for example can generate 3-4 kW of heat from 1 kW of power. The rest of the energy comes from the environment obviously, but naively assuming that the 100% efficient power-into-heat is the best you can do is not true.

Are there any efficient electric heating systems for a household based on a thermodynamic cycle with the environment? I think the most electric heating systems I have seen are using the rather bruteforce and inefficient (only near 100%) method. The basic principle that they heat a resistor and something quickly transfers the heat away so the resistor doesn't burn out and/or your house doesn't catch on fire. An other…

I'm not quite sure what you mean your first question, but I think heat pumps using air, ground or water as heat reservoirs would qualify. They are in common household use at least where I am located, and have a input-power-to-heat efficiency of up to 400% (the Carnot cycle imposes a limit of roughly 7-10x depending on which exact scenario you calculate)

Here's an example of one manufacturer and products: http://www.nibe.eu/Domestic-heatingcooling/Airwater-heat-pum...

Re: Micro heaters cut 87% off my electric heat bill

#204

Post by stinos »

netnichols wrote: post #195
stinos wrote: post #182

Earlier quoted context omitted.

tricky Well, it is mainly a matter of installing a proper ventilation system. So improving energy efficiency of heating for existing houses with lesser insulation is very useful. it is, but it can never reach the levels of energy savings coming form decent insulation (where decent means: German standards for instance)

My German apartment has drafty, unsealed wooden window frames, and the window in the kitchen is a single large sheet of glass. We have to hang a rug over that window in the winter, as it feels like you've left a freezer door open if you get within 3 feet of it. But the walls are indeed very thick!

I don't speak German so I cannot look it up, but my guess is these standards are for new buildings or buildings that are being renovated (and probably the numbers are different for private and commercial buildings as well, which is a shame), and owners of an existing building cannot be forced to adhere to the standard. Thickness of walls is of course related to insulation, but it isn't everything; for example 20cm of typical insulation still has a much lower U-value then a concrete wall of 100cm thick.

Re: Micro heaters cut 87% off my electric heat bill

#205

Post by dredmorbius »

personZ wrote: post #100
ams6110 wrote: post #85

Earlier quoted context omitted.

I agree with all your theory. I thought the same thing. Then I went out and bought a programable thermostat, set it quite low overnight and during the day, and warmer from 5-8 AM and 5-8 PM. My heating bill was higher than just maintaining 68-70 all the time. And that's not even counting the $100 I spent on the thermostat (now on a shelf in the garage, I put the old manual one back in its place).

From a thermal energy perspective this simply isn't possible. However , some systems do lead to this because of flaws in the the implementation. My ground heat pump, for instance, has a backup electric heat system that it will automatically, and unavoidably, utilize if it hasn't reached the target temperature within a set, relatively short period of time. So in my very well insulated home I do indeed see significant…

I'd go with the resistance back-up heat argument here as well.

Re: Micro heaters cut 87% off my electric heat bill

#206

Post by mangecoeur »

ams6110 wrote: post #91
mangecoeur wrote: post #28

Earlier quoted context omitted.

Wrong. Does plenty to save energy. Reasons: - for half the year, you don't heat but you still light, so you automatically gain savings for that whole period. (also if you have air conditioning, in summer you heat the house with lights then have to cool the air again) - Lights are on the ceiling. Hot air rises. Therefore heat coming from lights does almost nothing to improve your thermal comfort. - If you are heating…

What's the energy cost of making a CFL bulb vs. an incandescent? Also since in practice they don't last a lot longer, and are annoyingly dim for the first few minutes, and are considered an hazardous waste when you need to dispose of them, why does it make sense to replace a $0.50 bulb that has none of those issues with a $5.00 bulb that does?

Not sure what you are doing to your CFLs to make them not last longer than incandescent bulbs. I think i've had maybe one CFL break, and that was an early model. LEDs are of course much much more reliable and will most likely outlive you, though personally I don't like this obsession with trying to cram them into traditional light socket formats - I'd like to see something a bit more innovative. They work particularly well as spotlight replacements and ikea have a nice range of innovative designs that don't cram the LEDs too close (which causes heat buildup and reduces efficiency).

Re: Micro heaters cut 87% off my electric heat bill

#208

Post by raverbashing »

Nursie wrote: post #200
raverbashing wrote: post #5

Yes Most people want "summer inside the house" which is absurdly wasteful Of course, it sucks when changing clothes or taking a shower, but there are ways of heating locally.

I want summer inside the house. It may be wasteful, but that's what I want. I don't ever want to step out of the shower in the morning and shiver again, I find this deeply unpleasant. I also don't want to have to wear thick woollen clothes around the house. In pursuit of this I actually moved to Australia for a while, but it turns out I missed the temperate climate and UK culture (also my family, I guess...) So when…

All I can say is: I understand you.

But yeah, improving isolation, having a bathroom heater, using heat pumps instead of electrical heaters are better than just cranking up the heat and paying the bill.

Re: Micro heaters cut 87% off my electric heat bill

#209

Post by roel_v »

leni536 wrote: post #187
roel_v wrote: post #115

Earlier quoted context omitted.

Sure, if you have shitty insulation. The proper strategy is to have good insulation, and then to have the heat on constantly using a CV system at low temperatures, because heating constantly with water of 30 degrees (C, that is) is much more energy efficient than heating in peaks with much warmer water (60, 70, 90 even 20 years ago). So yes, in houses with crap insulation warming constantly is less efficient. However…

How can heating be any less efficient than 100%? I get that engines can be less efficient than 100% since the remaining energy is dissipated as heat and heat is the not desired energy in that case. What happens with the remaining energy if you heat with less than 100% efficiency? Does it start to rotate things?

'Efficient' not in the thermodynamic sense, but in the sense that you need to put in x % less energy to have the same comfort level (i.e, have the house at a comfortable temperature at the times you need it).

And to add another use of 'efficient' to the mix, just to keep things interesting ;) , when people say 'heating a house with a CV (water) based system powered by natural gas is more efficient than using electricity', what they mean is that A) electricity is generated from other sources and there are losses in the conversion/transport/etc, whereas for gas that's not so; and B) that it's just much cheaper. So yeah, sorry for the confusion, but in energy use land, 'efficient' is a highly overloaded word.

Re: Micro heaters cut 87% off my electric heat bill

#210

Post by roel_v »

jtheory wrote: post #128
roel_v wrote: post #120

Earlier quoted context omitted.

But you can't power a computer on PV. I don't think anyone who knows something about energy efficient heating suggests PV to warm a house electrically, it's too inefficient.

Not my comment you're responding to, but it's not talking about PV for heating (that'd be kind of ridiculous, honestly). Systems for heating water/air using solar can be quite inexpensive as well; converting light to heat is rather easier than converting it to electricity. E.g., I've seen cheap pool-heating systems that just pump the water through wide flattened black pipes exposed to the sun and send it back into th…

Yeah my second sentence was a non sequitur, but my point was: you can only do a little with solar/water heating. Yes heating a pool is one of those things, but that's a very niche application. This thread is about heating a house, or at least about being comfortable in one, and solar/water is just not a viable technology for that in the vast majority of cases.
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