Factors You Should Consider When Selecting a Sun Tunnel.
- 3 days ago
- 5 min read
When most homeowners and body corporates start comparing sun tunnel options, the first thing they look at is the price.
That’s understandable. But the cheapest option is not always the most cost effective option over the life of the installation.
A sun tunnel is a roofing penetration first and a daylighting system second. While factors such as light output, tube efficiency and product warranties are important, the real cost of a poor product choice often doesn’t become apparent until years later.
If a flashing system is unsuitable for the roof, requires excessive maintenance, or develops leaks, the cost of rectification can quickly exceed any initial savings.
This becomes even more important on homes where access equipment such as scaffolding, edge protection, elevated work platforms or specialist roof access systems are required. A repair that might appear minor can become an expensive exercise simply because of the cost of safely reaching the roof.
For this reason, we encourage homeowners to look beyond the purchase price and consider the total life cycle cost of the installation, including maintenance requirements, flashing design, product support and long term reliability.
At Auckland Skylights, we specialise not only in skylight and sun tunnel installations, but also in repairs, replacements and flashing remediation. Having worked on many systems installed by others, we see firsthand product performance over time and which products or flashing systems create additional maintenance.
That experience influences our recommendations. We don’t select a product based on price or claims. We assess the roof type, roof pitch, access requirements, maintenance considerations and long term performance before recommending the most suitable solution.
1. Selecting the Right Size
The first consideration is matching the sun tunnel size to the room being illuminated.
250mm Sun Tunnel for:
● Toilets
● Walk in wardrobes
● Hallways
● Small studies
Typical room size: 3–15m²
A 250mm sun tunnel is excellent for removing darkness and providing comfortable daytime lighting.
400mm Sun Tunnel for:
● Bathrooms
● Bedrooms
● Studies
● Kitchens
● Larger hallways
Typical room size: 12–25m²
This is often the most versatile residential size and provides a significant increase in natural daylight.
600mm Sun Tunnel for:
● Lounges
● Dining rooms
● Open-plan living spaces
Typical room size: 20–40m²
A 600mm tunnel can deliver substantial daylight and often reduces the need for artificial lighting during daylight hours.
700mm Sun Tunnel for:
● Large open plan spaces
● Schools
● Community buildings
● Commercial applications
Typical room size: 40m²+
For very large spaces, multiple smaller tunnels may provide a more even spread of light than one large unit. At this size of skylight it is often the time to consider a glass skylight.
2. How Much Light Is Enough?
Lighting designers measure light using lux as a guide:
● Hallways: 50–100 lux
● Bathrooms: 150–300 lux
● Kitchens: 300–500 lux
● Studies and offices: 300–500 lux
The objective isn’t necessarily to create the brightest room possible. The goal is to provide comfortable, usable natural daylight while reducing reliance on electric lighting during the day.
The right size sun tunnel, correctly positioned, often delivers better results than simply installing the largest unit available.
3. Tunnel Length and Roof Space
Not all installations are the same.
The distance between the roof and ceiling, along with the number of bends required, can significantly affect performance. Certain buildings only a sun tunnel will be able to bring light to dark places.
When assessing a property we consider:
● Ceiling height
● Roof pitch
● Roof cavity depth
● Structural framing
● Services within the roof space
● Number of bends required
● Roof orientation
This helps determine which product and tube configuration will provide the best result.
4. The Flashing System
In our experience, the flashing system is often the most overlooked part of a sun tunnel installation. The flashing is responsible for directing water safely around the roof penetration and preventing leaks.
The brightest sun tunnel on the market can still become a problem if the flashing system is not suited to the roof.
Questions we consider include:
Is the flashing designed specifically for this roof type?
How does it perform during heavy rainfall?
How does it handle leaves and organic debris?
Will it require additional maintenance?
Is the roof pitch suitable?
Different roof types require different flashing solutions.
Tile Roofs
Concrete, metal and asphalt tile roofs frequently utilise under flashing systems.
While these can perform extremely well, there are situations where roof pitch, surrounding vegetation, organic debris or high rainfall can influence long-term performance and maintenance requirements.
Longrun Roofing
Longrun roofing generally requires profile-specific flashings designed to integrate with the roofing profile and safely direct water around the penetration. Selecting the correct flashing from the outset can significantly reduce future maintenance requirements and improve long-term performance.
5. Consider Future Maintenance
Many homeowners focus on the purchase price but overlook maintenance.
Factors that affect maintenance include:
● Roof pitch
● Flashing design
● Tree coverage
● Leaf accumulation
● Moss and lichen growth
● Roof accessibility
The wrong flashing choice can result in increased cleaning, inspections and maintenance over the life of the installation.
The right flashing choice can provide decades of reliable service with minimal intervention.
6. Product Support and Warranty
Natural daylight systems are expected to last many years.
Before selecting a product, consider:
● Warranty coverage
● Availability of replacement parts
● Local support
● Manufacturer reputation
● Performance in NZconditions
These factors become particularly important if repairs or replacement components are required in the future.
7. Installation Experience Matters
Even the best product can perform poorly if installed incorrectly.
Proper installation involves:
● Roof waterproofing
● Flashing integration
● Structural considerations
● Room Décor
● Light placement and distribution
An experienced installer will assess the entire roof system, not simply cut a hole and install a product.
Why Independent Advice Is Important
One of the advantages of working with Auckland Skylights is our Independence.
Our starting point is not:
“Which brand do we sell?”
Instead, we ask:
“What is the best solution for this roof and this room?”
When recommending a sun tunnel, we assess:
● Room size
● Desired light levels
● Roof construction
● Roof pitch
● Ceiling cavity depth
● Tunnel length
● Flashing compatibility
● Maintenance requirements
● Product support and warranty
Different brands have different strengths.
Some provide excellent light output, some offer superior flashing systems for specific roof types, while others may be better suited to longer tunnel runs or challenging installation conditions or differing scope like ventilation.
One advantage of repairing and replacing skylights and sun tunnels every week is getting to see the results years after installation. We see which flashing systems remain watertight, which products handle New Zealand weather well, and which installations become maintenance intensive. Practical experience often tells us more than a glossy product brochure
That experience allows us to recommend solutions based on long term performance rather than simply product specifications. (In a property we owned the sun tunnel had been installed over 30 years and still performed well.)
When selecting a sun tunnel , don’t focus solely on purchase price. All products age and need maintenance. The level of which is impacted by product choice and type of flashing for your style of roof.
The best solution balances:
● Light performance
● Flashing design
● Roof compatibility
● Weatherproofing
● Maintenance requirements
● Product support
● Installation quality
● Long term ownership costs
At Auckland Skylights, we believe every successful installation starts with understanding the roof. By combining independent product advice with decades of installation, repair and flashing experience, we help homeowners select daylighting solutions that not only brighten their homes but continue performing reliably for many years to come.
If you’re considering a sun tunnel, reach out to the team at Auckland Skylights for independent advice on the most suitable product which suits your home and needs.
