In Blog, Solar for Beginners

Radiant    VS.   The Solar Racking World
Radiant Emblem

Regularly I’ll get a sales call from a solar product supplier asking “what rail do you use?” “Radiant” I say, knowing it is a conversation stopper. They know too well they won’t convince an installer who is committed to quality to be swayed by price. However, late last year I caught up with one of my suppliers for our semi-regular coffee. David is one of the industry’s good guys. I find it a worthwhile meeting to keep my eye on a changing market, and to find ways of be more competitive. It was when I was pushing him on price of panels, that he pushed back.

The Cost

“Mark, I know it’s hard to convince you to go to “Grace” solar rail racking, but let’s run the figures.” David challenged. I cracked open my Macbook and we compared his Grace racking prices with my Radiant prices. The price difference caught me off-guard. On a 6kW tile system, I was paying a huge $450 more for Radiant.  “That’s a lot of cash I could save on an installation” I thought. I brought it up at our next sales meeting.

My Team’s Reaction

“But it’s $450!!” I was playing the devils advocate with my sales team,
“Wouldnt that help with sales if you could drop the price by $450?”.
Nicole put me straight: “Mark, we install quality and our customer generally get that. Radiant doesn’t give 15-year warranty for no reason; we can’t go backwards!”
I was pleased with the response.

I then called one of my electricians, Alex. He’s been with us for seven years: his input counts.

“How much do you like Radiant”. I asked.
“It’s the best Mark, you know that!”
“Is it $450 better” I continued.
“How much do you like roof leaks Mark?” Alex chuckled.
“Seriously, we can’t go back there … can we?” he quivered.

He was right. I write this post to try and explain why.

The Radiant difference

It’s a little hard to explain this with words only, so I jumped on the roof of one of our installations to take some pictures. This is how you install solar on a tile roof:

  1. Remove a tile to expose the truss and batten.

Remove Tile


2. Grind off the tile lug of the upper tile to allow a gap for the tile bracket.

Remove Tile Lug


The traditional tile bracket problem

The problem arises is that all roofs are not the built the same. Batten and tile sizes differ, so tile brackets have to be adjustable to suit. Traditional tile bracket are not adjustable. Here are three common images of three of the most commonly used tile feet on the market.

hopergy tile hook


clenergy tile hook


Grace tile Hook


Notice that these tile brackets are not adjustable in the lower section.

If you end up on a roof installing with a smaller batten and tile profile your job will look like the images below.

Old Foot no adjustment

Old tile foot complete

It is hard to pick in the photos, but tile foot is not flush with the lower tile, creating a larger gap in the tile above. This increases the risk of the tile cracking under weight, and opening the ceiling space up to water ingress. Additionally, if the batten or tile is larger than normal, there will be downward pressure from the tile foot on the tile below.

The Radiant Advantage

The main advantage of the Radiant rail system is the simple adjustable batten height. With this adjustment, we can ensure that the tile sits back down in place, with only the lug missing. The gap is filled with the tile bracket. It also ensures no unnecessary pressure is put on the tile below.

Radiant adjustability

Radiant side adjust

Once the Radiant tile foot is in place, slide the tile back over the tile bracket. The lift of the tile is negligible, so wind will not force rain into the ceiling space.

Radiant tile foot installedRadiant foot, tile back


A better rail system

It’s not just this simple adjustment that make installers adamant that Radiant is better. The full side adjustment allows installing brackets near ridges where it may have not otherwise been possible. If that wasn’t enough, the method of fixing rails to the tile feet and the panels to the rail is redesigned for the better. Forget the old cumbersome keystone in every other rail system, radiant have introduced their own spring loaded method. More than anything, this reduces frustration on the roof. A happy tradesman makes a quality install.

A quality install is the end game.

Mark Cavanagh

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10 Comments on Solar Rail. Why we Choose to Pay for Radiant. Part 1 – Tile Roofs

Devina Rogers said :Guest Report 9 months ago

We use Radiant for all roof types so that our quality systems will last the distance.

    Maria M said :Guest Report 2 years ago

    Hey Mark, An interesting read and I understand why Radiant is the best but in your example it is a tiled roof and may well be the best solution.I have a iron congratulated roof so is me getting a cheaper option like Grace a bad option?

      Mark C said :administrator Report 4 years ago

      Hi Brian, apologies for the delayed reply - COVID has kept me crazy busy with the business. It depends on what roof and what Sunlock gear you are using. For tile roofs, all you are looking for is the adjustability of the bracket both horizontally (for the truss location) and vertically (for the batten hight). Otherwise, Sunlock is a good rail system

        Brian said :Guest Report 4 years ago

        What are your thoughts on Sunlock? Sunlock vs Radiant

        • 5045
        Esmail Attia said :Guest Report 5 years ago

        Hi Mark Why Iove Radiant Railing, some of he reasons 1. The Radiant brackets are aluminium compare with other rail sys is gal. or chrome metals thus avoid 2 dissimilar metals in contacts 2. The tin bracket has a curve at the base that make the bracket screwed down more squarely and upright and adjusrment to move the bracket in/ out for rail straightness otherwise rail curved under side pressure 3.Using the Radiant sys we are able to have the big gap clearance ( Tin or Tile bracket ) of 150mm hence better energy production ( refer to the Power Temp rating , that power decrease every rise of temperature above 25deg C ) 4.The cable management sys is Quick and easy, Its easy to move the PV cable in and out of the clip with a single hand. no cable tie to cut, ( Remember you have a big gap under panels to work with ) 5 The Rail joiner more solid when compare to others Regards Esmail Attia Solar Hybrid Solutions

        • 2196
        Esmail Attia said :Guest Report 5 years ago

        Yes Radiant is the best when there it is available in your local area. In Sydney , we do not have the local distributor for Radiant, So I have to buy from Qld or Mel ( Supply Build ), But cost more money in Transport because a rail of 4 m lenght. I am a small installer in Syd so do not have a financial space to order big stock . In the past there are a few solar warehouses that bring in Radiant but they gave up, so now I turn to NOVA of Hopegy which has some of the features that in Radiant from AC Solar Warehouse.

        • 2196
        Mark C said :administrator Report 6 years ago

        Hi, Good question. With Radiant rail, the exclusion zone is usually about 200mm from the edge of the roof. With other rails it is usually further. Ask for the engineering specifications of the rail you are using. It's often worked out with a formula using the width and height of your house.

          How close to the edge of your roof can your solar panels go? said :Guest Report 6 years ago

          […] one positive review. […]

            Mark Cavanagh said :administrator Report 7 years ago

            Hi Rob, Yeh we don't use the isolator cover from radiant. We use one from ZJ Benny. It's much better. Radiant was looking into changing their cover, but I guess they haven't yet.

              Rob Ketelaars said :Guest Report 7 years ago

              Hi Mark, I am an Electrician myself and just installed a East-North-West orientation solar system using Canandian panels and Enphase micro-inverters. Allthough I did my solar course using Clenergy racking, I used Radiant on my own place only because it is the only brand the wholesaler offered. I found out the hard way that utilising Radiant's roofmount isolator bracket was creating not enough gap between the bottom of the AC isolator and the colourbond corrugated roof. I was surprised that the wholesaler informed me that Radiant was aware of the problem but does not have a solution at the moment for me. I ended up doubling up the base rail for about 100mm to "lift" the isolator bracket up to fit. Just wondering if you have run in to similar problems like this?

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