A Case for Solar Tubes / Sun Tunnels

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FineWine

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#319111 23-Mar-2025 14:22

We have an 8m x 4m = 32sq/m dining lounge area. The dining area is in a type of alcove opening into the lounge area (plan below). The lounge has patio ranch sliders and a half height window which outside, 3m away, is a large very bountiful orange tree. Light is also coming in from the open kitchen area.

The darkest area is the dining area, but the lounge area can also be dark unless it is a bright cloudless day. We always need the light on in the dining area when doing anything at the table. Also on in the lounge area on a cloudy day.

We are looking at getting a solar light tube, one or two, installed/fitted. The ones I have investigated have a diffuser size of 250mm to 500mm. The first installer stated their 350mm diffusers had a light spread of 2.4m radius. Taking this into account, we feel just one 500mm diffuser should be sufficient. Placed approximately on the border of the dining and lounge area, where the red star is in the above plan. Allowing for roof hips, ridges and valleys of course.

In the Tauranga area, there really are only two companies that install. SolarTube and Suntrenz.

First quote - SolarTube

(each tube)

$2400 x 1 350mm diffuser
$2530 x 1 with light fitting 350mm diffuser

Less March only sales discount $100 for one and less $300 for two

2nd quote - Suntrenz

Still awaiting Scope & Quote

Any forum members who have experience with solar/sun tube installations and your opinions overall are greatly appreciated.

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#3356537 23-Mar-2025 14:37

mates had some in their old place. there where okish in small rooms. had one in the bathroom and one in the small kitchen. its an improvement but its still not good. frankly their "2.4m" is overrated.

what i don't like is they are a hole in the insulation and also a leakage point in the roof.

frankly i would look at spending that money on solar panels and led lights.

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richms

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#3356546 23-Mar-2025 15:34

I cant make the case for them to stack up. Additional roof penetrations means more leak risk, removed insualtion for the hole, no way to shut if off in the day time and the end result is a light that constantly changes with clouds going by.

What you spend on them vs running a 20-30 watt LED downlight in its place which you need to have anyway for night time, and I see no value in the solartube.

Then you have a protrusion from the roof you have to work around for any solar installation, and the panel that it displaces would more than cover the running costs of any light you use instead of the solar tube.

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mdf

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#3356623 23-Mar-2025 18:03

I've got a Velux Solar Tube and my mother installed one on the strength of mine, both in hallways. Do a great job of brightening things up and the light is natural so very nice. Obviously hallway is a different scenario to dining and yes the point about roof penetrations is a valid concern. But I would do it again in the right circumstances.

eracode

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#3356630 23-Mar-2025 18:55

We had two SolarTubes installed in an en-suite bathroom and a walk-in wardrobe in our new home ten years ago, after we had moved in. They work perfectly and literally brilliantly and have been faultless. They capture large amounts of light and even subtle light on a clear night, brighter with a moon.

We too were concerned about the roof penetrations but, before we accepted the quote, the installer guy showed us exactly what they were going to do and how it would work - flashings etc. We were happy with the explanation.

Big fans and can totally recommend them.

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RunningMan

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#3356633 23-Mar-2025 19:19

+1 for natural light rather than having the lights on. Don't know what your budget is and house construction, but the other alternative would be a Velux roof window. Depending on the ceiling you might be able to open it up to roof height and make a feature of it.

eracode

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#3356639 23-Mar-2025 20:20

RunningMan:

+1 for natural light rather than having the lights on. Don't know what your budget is and house construction, but the other alternative would be a Velux roof window. Depending on the ceiling you might be able to open it up to roof height and make a feature of it.

The OP asked specifically about SolarTubes and although I recommended them above, if there’s any chance of using Velux roof windows, I would run with Velux rather than SolarTube. We’ve had Velux in a couple of homes and they are really great. The two products are not necessarily direct alternatives to each other - apples and pears and horses for courses.

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tweake

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#3356651 23-Mar-2025 20:49

talk about overheating houses (on the news tonight), roof windows add to the problem. sure you get a lot more light, but you gain a lot of heat in summer and its a really big hole in the thickest insulation in the most critical location. on a new home you would have to check you would still pass the insulation standards.

eracode

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#3356652 23-Mar-2025 20:52

tweake:

talk about overheating houses (on the news tonight), roof windows add to the problem. sure you get a lot more light, but you gain a lot of heat in summer and its a really big hole in the thickest insulation in the most critical location. on a new home you would have to check you would still pass the insulation standards.

Velux windows are double-glazed and can be ordered with various types of shades, blinds etc.

There’s also models that can be opened to provide ventilation and let heat out. The opening models can also allow for cleaning the outside glass from inside the house - because they can rotate almost right around.

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neb

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#3356653 23-Mar-2025 20:53

We had a solar tube put in during the Casa de Cowboy redo, a Solatube 160DS at 250mm with built-in light for night use. The amount of light it brings in is amazing, even at dusk when it's almost dark outside there's still a glow coming from it, and during the day it's lit up as bright as day. Really glad we didn't bother with a second one in the hallway since the light from the stairwell is enough for that.

tweake

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#3356696 23-Mar-2025 21:23

eracode:

Velux windows are double-glazed and can be ordered with various types of shades, blinds etc.

There’s also models that can be opened to provide ventilation and let heat out. The opening models can also allow for cleaning the outside glass from inside the house - because they can rotate almost right around.

double glazing is not even remotely close to the insulation value of ceiling insulation. even triple glazing doesn't come close. hence why you would need to recalc the insulation specs for the home. plus having shades/blinds defeats the whole point of having it in the first place. putting windows in for light then having to cover them up to keep the heat out is pointless. funny thing thats actually a thing kiwis already do. many "modern style" homes have big windows with timber strapping across the front of them to shade the windows. spending extra money to make a home worse.

eracode

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#3356698 23-Mar-2025 21:36

tweake:

double glazing is not even remotely close to the insulation value of ceiling insulation. even triple glazing doesn't come close. hence why you would need to recalc the insulation specs for the home. plus having shades/blinds defeats the whole point of having it in the first place. putting windows in for light then having to cover them up to keep the heat out is pointless. funny thing thats actually a thing kiwis already do. many "modern style" homes have big windows with timber strapping across the front of them to shade the windows. spending extra money to make a home worse.

I didn’t say double-glazing was a solution to perceived insulation issues - was just pointing out that's how they come.

Having blinds or shades doesn’t mean they have to be drawn all the time. They can be drawn, if wanted or necessary, at certain times of the day - the rest of the time they let in the wanted light that was the very reason the windows were installed for. Blinds certainly do not “defeat the whole point” of having Velux-type windows.

Many people who love their Velux windows probably don’t have the blind option - and if they do, maybe never need to use them.

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elpenguino

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#3356775 23-Mar-2025 23:56

That's the advantage of the solar tube vs roof window. The tube is a /diffused indirect light. A roof window in a North facing roof would be terrible for glare and fading everything underneath it, but if your room was on the North side, you might not be having this discussion in the first place.

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Handle9

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#3356803 24-Mar-2025 08:35

eracode:

tweake:

double glazing is not even remotely close to the insulation value of ceiling insulation. even triple glazing doesn't come close. hence why you would need to recalc the insulation specs for the home. plus having shades/blinds defeats the whole point of having it in the first place. putting windows in for light then having to cover them up to keep the heat out is pointless. funny thing thats actually a thing kiwis already do. many "modern style" homes have big windows with timber strapping across the front of them to shade the windows. spending extra money to make a home worse.

I didn’t say double-glazing was a solution to perceived insulation issues - was just pointing out that's how they come.

Having blinds or shades doesn’t mean they have to be drawn all the time. They can be drawn, if wanted or necessary, at certain times of the day - the rest of the time they let in the wanted light that was the very reason the windows were installed for. Blinds certainly do not “defeat the whole point” of having Velux-type windows.

Many people who love their Velux windows probably don’t have the blind option - and if they do, maybe never need to use them.

it’s a compromise like everything else in a building. Given the choice between abundant natural light while sacrificing some thermal performance I’ll take the natural light and eat the energy costs. Natural light has a significant impact on my mood and happiness.

Other people feel differently and that’s all good.

raytaylor

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#3356835 24-Mar-2025 10:02

We had one installed in our hallway a few years ago.
Its not very bright - its like having a childrens night light on the ceiling.
If walking through you wouldnt bother turning on the light but if you were sitting at a table then you still would.

Instead I recommend just getting a window skylight which we also had in the lounge of the same house. They let in 20x more light than a solar tube.

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tweake

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#3356908 24-Mar-2025 15:12

Handle9:

it’s a compromise like everything else in a building. Given the choice between abundant natural light while sacrificing some thermal performance I’ll take the natural light and eat the energy costs. Natural light has a significant impact on my mood and happiness.

Other people feel differently and that’s all good.

i'd agree with that. i'm the opposite.

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.

the comment above about the light changing due to clouds etc is quite true. its not like the scattered light from windows.

mates one had frosted glass. it gave a very white light, closer to a white light bulb than natural light. that may vary with brand etc.

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