lantern or flat roof light
Lara
4 years ago
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Comments (7)
rinked
4 years ago
Sven
4 years agoRelated Discussions
flat or lantern roof light
Comments (5)I think it depends on what you are looking to achieve by using the rooflight. With various styles of rooflights, it is important to know whether it is about maximising light, air or space (or maybe a combination of more than 1). Can you give more details about where you are looking to install the rooflight?...See MoreFlat roof and lantern or vaulted ceiling with veluxs in a kitchen?
Comments (2)Hi, Too much light at one end of a room eg Bi-fold + Rooflight makes one end of the new space very bright and the other end comparatively dark. The contrast in light and dark within an extended living space can lead to a cave corner or even whole original room being cave like and a bright area in the extension only. In general useful daylight travels twice as far into the room as the top of the window. This is why I nearly always recommend tall glazed gable facing the garden to capture this useful light without. High ceiling heights and tall windows have the same effect. The Georgians know what they were doing....See More6m rear extension double Pitch roof or Flat roof with Lantern
Comments (5)We went through this same decision process with our 6x4m rear extension recently. Eventually we choose a gable with glazed end for several reason. Firstly several friends and comments online made me wonder about the heat and light issues with lanterns. It will also be our main living area when entertaining so noise on a large glass lantern was also a consideration. However worth noting we spoke to several builders and all came back with slightly higher estimates for the gable than the flat roof extension so that might also be a something worth considering (although that did include the glasses end, bifold and skylights). I'm currently researching skylights (that's how I found your post) and were looking at circa £6k for velux and possibly more if we go for frameless bespoke ones. Good luck with your planning....See MoreFlat skylight vs roof lantern
Comments (3)Interesting question, and at least from my point of view, possibly more complex to answer than you may realize ... I suspect, but currently don't either have the time or mathematical rigor to fully model this from first principles, that a lantern will get you more light in a north-facing situation. This is for a combination of reasons: Reflection / Transmission ratios depend on the angle of incidence; steeper (i.e. "head on") means more transmission. Since the panes of a lantern are more-inclined than a flat rooflight (even on a pitched roof), expect more light through. For north-facing windows (i.e. permanently shadowed), it's _ambient_ light that counts - i.e. the more or less even brightness of the blue sky (or, less-bright evenly overcast sky ...). A roof lantern, with panes facing two or four different directions, is again "catching" more ambient light at steeper angles (transmitting it inside). Ambient light (blue sky) is polarized to a strong degree, and reflection/transmission also depends on polarization (strongest: 90 degrees from the Sun, or - "generally northwards"). On some times of the day, ambient sky polarization may be such that a flat rooflight will reflect a larger proportion of light than at others. Again, the differently-oriented panes of a lantern would balance this out more. If indeed your geometry is such that the roof opening would not be in the shadow all day long but receive some sunlight at some hours ... then a pitched-north-facing flat rooflight would be oriented disfavourably at such hours (away from the sun, so getting the light at shallow angles, reflecting much). I'm not a technical consultant for this kind of advice (only have a physics background, which makes me a decent smart-*ss on such questions), and I can't say out of my head if a lantern would give you twice-as-much light in your situation, or only 10%-more-light. And then, the glazing (coated, and how ? double/triple glazing ? water-white glass or ordinary "greenish" float glass?) also plays a role. If you want it quantified, contact a professional. Right-to-light surveys commonly do such calculations (if for a slightly different reason ... how much light do I loose if that five-storey block of flat is being built on my doorstep ...). Also ... an alternative, in some situations, may be an extension with a ridged roof (i.e. two opposite pitches), and then two flat rooflights (facing east/west). Large roof lanterns don't come cheap after all....See MoreLara
4 years ago
kinchif01
4 years agoLara
4 years agoHU-209277437
4 years ago
minipie