LED Lighting

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#625332 15-May-2012 10:26

Skolink:
timmmay: Downlights are a really bad plan for energy efficiency. They let so much heat out the power saved by using LED over incandescent is almost irrelevant. If you put eight downlights in a room, even sealed downlights, you'll need to put 2-3 times more heat into the room to keep it a comfortable temperature. That's up to triple the energy costs.

You weren't exagerating. I've only just come across these measurements done?on?behalf of?EECA.

Except that under the table it says that it is lighting and heating. Seems they are also factoring in the cost of running the lamps in those figures.

Richard rich.ms

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#625334 15-May-2012 10:28

richms: Except that under the table it says that it is lighting and heating. Seems they are also factoring in the cost of running the lamps in those figures.

I'm not sure what your point is. The energy consumption of a light is irrelevant compared with requiring for example the 287% more heat required to keep a room up to temperature. That could be the difference between a heat pump consuming 1kw and consuming 2.8kw. Saving 0.04kw doesn't even make a dent in that equation.

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#625341 15-May-2012 10:31

Down lights look good for sure , but they dont stack up for any other reason. install one and you are fighting physics from then on ....

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#625392 15-May-2012 11:45

What about replacing with something like

http://ledstuff.co.nz/product_info.php?cPath=26&products_id=208

Anyone have any idea how those would perform as far as keeping the heat where it should be?

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#625413 15-May-2012 12:15

Nety: What about replacing with something like

http://ledstuff.co.nz/product_info.php?cPath=26&products_id=208

Anyone have any idea how those would perform as far as keeping the heat where it should be?

No, that doesn't address the issue, as you can't insulate over it. It's slightly better than open units, but take a look at that consumer report for details.

See this thread for the best options available (Fozz lighting).

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#625487 15-May-2012 14:44

Thanks for the link. Looks like Lighting Direct are currently updating the web site so not info currently.

timmmay

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#625492 15-May-2012 14:49

http://www.fozzlighting.com/

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#625521 15-May-2012 15:19

Heaps of the lighting industry retailers are running around totally confused with what these changes in what can be installed domestically mean for them and what they sell so perhaps give them a few weeks to get their act sorted.

Richard rich.ms

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#625561 15-May-2012 16:36

richms:
Skolink:
timmmay: Downlights are a really bad plan for energy efficiency. They let so much heat out the power saved by using LED over incandescent is almost irrelevant. If you put eight downlights in a room, even sealed downlights, you'll need to put 2-3 times more heat into the room to keep it a comfortable temperature. That's up to triple the energy costs.

You weren't exagerating. I've only just come across these measurements done?on?behalf of?EECA.

Except that under the table it says that it is lighting and heating. Seems they are also factoring in the cost of running the lamps in those figures.

If you make a perfect seal for your whole house you will 1) get mould and 2) suffocate. You and your house need to breath.

CA is closed abutted, but closed is still up to 5% open and is what the report says is performing well. That is what we have throughout our home, about 40 of them. During the night the house cools down only 2-3 degrees, unless there is strong wind so we get a draft through the internal access garage and under the internal door. Last night I've placed a towel in front of the door to stop the draft (builders cut the door too short) and this morning the temperature was the same as yesterday despite all the strong wind and rain. Our fridge puts out enough heat to keep the temperature constant through the night.

Sure, in Winter you need more heating, but in summer you need less cooling. There are arguments for different situations. It depends a lot on your home construction and some reports are for brand new homes, some are for old (thermal) leaky homes.

Did you know if your home is under the flight path near an airport then for code compliance you need a DVS installed. This is because for noise control you tend to keep your windows closed so your home does not breath so you need extra ventilation. Again, your home needs to breath and some ventilation is required, just not too much.

You can never have enough Volvos!

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#625618 15-May-2012 18:08

I have a DVS type unit installed, I only have it run during the day when I'm not here, but I do think they're valuable.

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#625762 15-May-2012 21:30

timmmay:
Nety: What about replacing with something like

http://ledstuff.co.nz/product_info.php?cPath=26&products_id=208

Anyone have any idea how those would perform as far as keeping the heat where it should be?

No, that doesn't address the issue, as you can't insulate over it. It's slightly better than open units, but take a look at that consumer report for details.

That light is completely sealed, preventing any flow of air. The only heat escaping would be via conduction through the glass and then the heatsink. It would go a long way to preventing heat loss. The article doesn't specifically say, but the Consumer testing seems to be with downlight fittings that are not completely sealed (up to 5% gap).
I can't believe that sealed downlights with close-abutted insulation would lead to a 171% to 284% increase in heating required.

timmmay

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#625775 15-May-2012 21:41

Just because you can't believe it that doesn't make it wrong. I trust objective scientific tests over a feeling.

The R value of an insulated wall is about R2. An insulated ceiling, up to R3.2. Glass is R0.1 or so, and heat seems to go through gaps. Taking the fireplace out of my kitchen, which had a small hole and no insulation, led to a 3-4 degree increase in the temperature of the room on a cold day without adding any heating.

richms

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#625778 15-May-2012 21:43

Skolink:
timmmay:
Nety: What about replacing with something like

http://ledstuff.co.nz/product_info.php?cPath=26&products_id=208

Anyone have any idea how those would perform as far as keeping the heat where it should be?

No, that doesn't address the issue, as you can't insulate over it. It's slightly better than open units, but take a look at that consumer report for details.

That light is completely sealed, preventing any flow of air. The only heat escaping would be via conduction through the glass and then the heatsink. It would go a long way to preventing heat loss. The article doesn't specifically say, but the Consumer testing seems to be with downlight fittings that are not completely sealed (up to 5% gap).
I can't believe that sealed downlights with close-abutted insulation would lead to a 171% to 284% increase in heating required.

They dont say that, they say that is the increase in energy with the lighting, and I see they didnt test many options of a single light. If its a small area then the change in energy for heating would not be as much of a change of the total energy.

I have 3 pretty open downlights in the bedroom here and stuff all insulation in the roof and even with a 11 degree difference as they tested a 700 watt heater is more than able to keep up with any losses. I in no way believe that blocking up my downlights would drop my heating requirements to 200 watts or so.

Richard rich.ms

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#625788 15-May-2012 21:48

How do you heat your house with a 700 watt heater? Is it super new? New houses seem to retainer heat better than old houses, even with downlights.

I have an 8kw heat pump and a 6kw heat pump. On really cold days (say 5 degrees) the smaller one can only just keep the place up to 20 degrees, though the new one should do better. Heating a house with 700 watts seems... well impossible with my place.

One thing I noticed with my place is I have a lowered ceiling, and while I can insulate above each room, I can't insulated above the walls easily.

richms

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#625810 15-May-2012 22:15

timmmay: How do you heat your house with a 700 watt heater? Is it super new? New houses seem to retainer heat better than old houses, even with downlights.

I have an 8kw heat pump and a 6kw heat pump. On really cold days (say 5 degrees) the smaller one can only just keep the place up to 20 degrees, though the new one should do better. Heating a house with 700 watts seems... well impossible with my place.

One thing I noticed with my place is I have a lowered ceiling, and while I can insulate above each room, I can't insulated above the walls easily.

I heat a room with it. No way I would heat the entire house even if I could since I can only be in one room at a time.

Not new, upstairs is a 80s addon with only a token effort to insulate the cieling with some fluffy stuff stuck onto some foil with some batts over the top in parts away from where I was wanting to put more wires thru.

Best thing to keep it warm was to go along all the gaps in the ugly 80's tounge and groove cieling with no more gaps before painting it. could feel the draft before I did that and if it was really windy and I had a window open you could see the insulation move.

Richard rich.ms

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