A Case for Solar Tubes / Sun Tunnels

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Smpl Mnmlst
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#3357084 25-Mar-2025 05:55

tweake:

most of the time there is still plenty of natural light, the solar tube is just an addon. the same thing can be achieved with led lights for a whole lot less cost especially as your going to have lights there as well. lighting is cheap, heating and cooling is not.

for $2.5k i think you could easily rig up solar panel, lights and sunlight switch (and even battery) and still have change left over.

No, the reason most people would be considering installing a solar tube (or a Velux) is because there is insufficient natural light in an area - otherwise why would they be considering it? In our case, the walk-in wardrobe had no windows and the only natural light came in the door from the bedroom. The en suite had a tall, narrow set of solid louvres which let light in only when they were open (plus what came in the door from the bedroom). Both were dark rooms - the two SolarTubes solved this perfectly and were a game-changer.

The idea of forgoing beautiful natural light from a solar tube or a Velux in favour of a solar panel, LEDs and a sunlight switch rig is unappealing and somewhat ridiculous - even if it is a bit cheaper. It’s not just about money - or thermal efficiency.

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cddt

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#3357091 25-Mar-2025 07:48

+1 vote for some kind of solar tube here. Our house came with three of them, and they're great. Admittedly not lighting a large area but for bathrooms, hallways, etc. they are perfect.

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johno1234

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#3357104 25-Mar-2025 08:50

Our 1964 build house has a plethora of skylights and solar tubes. The natural light is very nice. Much nicer than light from LED or any other style bulb.

However if I was building I would always, always avoid roof penetrations. It is just paying money for trouble.

tweake

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#3357171 25-Mar-2025 10:36

eracode:

No, the reason most people would be considering installing a solar tube (or a Velux) is because there is insufficient natural light in an area - otherwise why would they bother? In our case, the walk-in wardrobe had no window/s and the only natural light came in the door from the bedroom. The en suite had a tall, narrow set of solid louvres which let light in only when they were open (plus what came in the door from the bedroom). Both were dark rooms - the two SolarTubes solved this perfectly and were a game-changer.

The idea of forgoing beautiful natural light from a solar tube or a Velux in favour of a solar panel, LEDs and a sunlight switch rig is unappealing and somewhat ridiculous - even if it is a bit cheaper. It’s not just about money - or thermal efficiency.

a few things to unpack. natural light is not really natural. its filtered by the windows, especially with modern glass, tints and coatings. especially with solar tubes, the light is not anything close to outdoors (mates was very cool white, a warm white led looks far better). really your talking about a natural source ie free instead of paying for power to create light. so really its a question of cost. 2.5k for free light during daylight hours to save 1c of power being used for the couple times a day that room is used.

i wouldn't knock using led's, mains or solar powered. you can achieve far better light spread with multiple lights giving a much better ambient light thats similar to windows (solar tubes are like a single light bulb), you can adjust color spread a bit easier than with solar tube. no issue with insulation and roof leakage. you can run several lights down hallways, bathrooms, closets etc and have them all running off a single solar panel.

quality of lighting all comes down to whats used and how its designed. someone could fake a solar tube and i highly doubt you would even notice.

eracode

Smpl Mnmlst
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#3357205 25-Mar-2025 12:18

Well we’re really getting into the weeds now. The consensus here is that SolarTubes and similar are useful products and work well. Think I’ll just leave it at that and hope that all this is of assistance to the OP.

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tweake

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#3357210 25-Mar-2025 12:51

eracode:

Well we’re really getting into the weeds now. The consensus here is that SolarTubes and similar are useful products and work well. Think I’ll just leave it at that and hope that all this is of assistance to the OP.

20 years ago i would have agreed with you. but today i think you can achieve a better cheaper result with modern tech.

for the op new home, i think the whole idea is antiquated. this comes back to kiwis love affair with "indoor/outdoor flow" trying to make everything lit up like its outdoors. nz homes suffers from excessive windows in the first place. i would prioritize heating/cooling first. lighting is simple and cheap compared to everything else.

elpenguino

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#3357262 25-Mar-2025 13:37

tweake:

a few things to unpack. natural light is not really natural. its filtered by the windows, especially with modern glass, tints and coatings. especially with solar tubes, the light is not anything close to outdoors (mates was very cool white, a warm white led looks far better). really your talking about a natural source ie free instead of paying for power to create light. so really its a question of cost. 2.5k for free light during daylight hours to save 1c of power being used for the couple times a day that room is used.

i wouldn't knock using led's, mains or solar powered. you can achieve far better light spread with multiple lights giving a much better ambient light thats similar to windows (solar tubes are like a single light bulb), you can adjust color spread a bit easier than with solar tube. no issue with insulation and roof leakage. you can run several lights down hallways, bathrooms, closets etc and have them all running off a single solar panel.

quality of lighting all comes down to whats used and how its designed. someone could fake a solar tube and i highly doubt you would even notice.

I take your point - if the top of the tube was not installed and a LED light was installed above the diffuser in the bottom half of the tube, could you tell the difference?

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Handle9

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#3357319 25-Mar-2025 16:35

tweake:

eracode:

Well we’re really getting into the weeds now. The consensus here is that SolarTubes and similar are useful products and work well. Think I’ll just leave it at that and hope that all this is of assistance to the OP.

20 years ago i would have agreed with you. but today i think you can achieve a better cheaper result with modern tech.

for the op new home, i think the whole idea is antiquated. this comes back to kiwis love affair with "indoor/outdoor flow" trying to make everything lit up like its outdoors. nz homes suffers from excessive windows in the first place. i would prioritize heating/cooling first. lighting is simple and cheap compared to everything else.

Just because you want to live in a cave with no natural light and tell yourself LED light is just as good doesn't make it right for other people.

"Excessive windows" is a subjective opinion, not objective fact. Indoor outdoor flow is enabling the way many people want to live in their houses. That is right for them.

johno1234

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#3357320 25-Mar-2025 16:49

Our house would likely meet the criteria for excessive windows but that's just the way we like it. The view makes living here more pleasant. In the winter the low sun floods in and warms the place. In the summer the high sun is blocked by the veranda eaves and it stays cool with a cross breeze.

The problem is the living room in winter evenings. Peaked single glazed glass wall, 3m high ceiling peak and multiple (double glazed) skylights. The living room leaks heat at night time... Am installing a large heat pump ahead of this winter. Too expensive to double glaze and curtains would look weird because of the peaked roof line. I accept the power bill but at least the heat pump is very efficient.

tweake

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#3357427 26-Mar-2025 11:24

Handle9:

"Excessive windows" is a subjective opinion, not objective fact. Indoor outdoor flow is enabling the way many people want to live in their houses. That is right for them.

considering that a common design element is to install fixed slats in front of the window to reduce the light and heat, tells you straight away they have to many windows.

the simple fact people are complaining about overheating homes in summer shows they have to many windows.

the no1 factor is insulation level is window to wall ratio.

"excessive windows" is more fact than opinion.

johno1234

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#3357464 26-Mar-2025 14:21

tweake:

Handle9:

"Excessive windows" is a subjective opinion, not objective fact. Indoor outdoor flow is enabling the way many people want to live in their houses. That is right for them.

considering that a common design element is to install fixed slats in front of the window to reduce the light and heat, tells you straight away they have to many windows.

the simple fact people are complaining about overheating homes in summer shows they have to many windows.

the no1 factor is insulation level is window to wall ratio.

"excessive windows" is more fact than opinion.

Disagree. It says they have too many windows for the design elements of the house (shade, eaves etc).

tweake

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#3357480 26-Mar-2025 15:44

johno1234:

Disagree. It says they have too many windows for the design elements of the house (shade, eaves etc).

fair enough. thats certain the case.

however many homes have gone well past that point. when you have open ceilings or sloping roof line with glass from roof to floor, the gain is huge. add in the 80% windows for the lounge, 70-80% for bedrooms etc, theres barely any wall insulation, the wall insulation value is tiny (its offset by the ceiling insulation). so heat conduction through the walls is high. then there is reflective solar gain, another design issue not helped by ceiling to floor windows. certainly it can be designed for.

but keep in mind they are building fixed wooden battens (and even steel designs) to block the sun from getting to the window instead of doing it the cheap way of just downsizing the window (which reduces the solar gain, increases insulation and reduces cost). thats the mentality.

i've said before if they actually put in solar gain limits, a lot of people will be upset they won't be allowed to have such poorly designed houses anymore. double back to the OP, that means things like solar tubes and skylights will probably disappear.

RunningMan

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#3357485 26-Mar-2025 16:14

tweake:i've said before if they actually put in solar gain limits, a lot of people will be upset they won't be allowed to have such poorly designed houses anymore. double back to the OP, that means things like solar tubes and skylights will probably disappear.

Whilst your priority is clearly solar gain when designing a building, please realise and respect that not everyone shares the same priorities, and they may value the additional light, view, or feelings of openness as opposed to a solar gain figure. It doesn't in any way mean those buildings are poorly designed, as they reflect the requirements of that person. It simply means the priorities are different to yours.

Handle9

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#3357488 26-Mar-2025 16:26

tweake:

Handle9:

"Excessive windows" is a subjective opinion, not objective fact. Indoor outdoor flow is enabling the way many people want to live in their houses. That is right for them.

considering that a common design element is to install fixed slats in front of the window to reduce the light and heat, tells you straight away they have to many windows.

the simple fact people are complaining about overheating homes in summer shows they have to many windows.

the no1 factor is insulation level is window to wall ratio.

"excessive windows" is more fact than opinion.

No it shows that fixating on a single design element is flawed. There is more to the design of a building than a single metric.

tweake

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#3357543 26-Mar-2025 16:47

RunningMan:

Whilst your priority is clearly solar gain when designing a building, please realise and respect that not everyone shares the same priorities, and they may value the additional light, view, or feelings of openness as opposed to a solar gain figure. It doesn't in any way mean those buildings are poorly designed, as they reflect the requirements of that person. It simply means the priorities are different to yours.

<sigh> try telling that to all the people currently complaining about overheating homes. its been in the news multiple times. its a well known problem and even branz has publicly said its a "house design problem". the houses are simply poorly designed and thats from the professionals, not just my personal opinion.

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