Frequently asked questions

Here you will find the answers to many frequently asked questions about the Energyroof®. Please contact us if the answer to your question is not listed.

I have a tiled roof – gravel roof – roof terrace; can the Energyroof® also be installed there?

No, these types of covering do not allow enough heat to enter. Also, the main part of the solar rays is blocked so these types of roofs do not allow to be combined with the Energyroof®. Our system is developed for a finish with a strip-shaped roof covering. With the help of the pipe system we extract the heat from the roof covering. This roof covering lies directly on the pipe system. In the case of a finish with tiles, roof gravel or roof terrace tiles there is ventilated/stagnant air between the roof covering and the pipe system. This has large negative effects to the yield of the system.


Can I heat my house with the Energyroof®?

Yes, but not by directly connecting the Energyroof® to the heating system. A heat pump and a storage buffer, for example seasonal thermal storage systems, need to be used for heating. In that case the Energyroof® can function as a performance improver (by approximately 25%) to the heat pump. Furthermore, under floor heating is required because a large radiation surface is required due to the low temperature of the water in the floor.

Can I use the Energyroof® to cool my house?

To cool you can use the under floor heating again, but this time to have cooled water run through it, for example during the night. Heat from the house can be radiated through nocturnal radiation via the Energyroof®.

Can I heat my tap water or swimming pool with the Energyroof®?

Yes, the Energyroof® can directly be connected to a solar boiler to pre-heat tap water. A so-called double separator needs to be installed so that the anti-freeze agent cannot reach the tap water.  Approximately 12 m2 of Energyroof® is sufficient for a house boiler. Swimming pool water can also be pumped directly through the Energyroof® and be heated directly by the sun this way. In this case the use of an anti freeze agent is not even necessary. During the winter period the system needs to be drained to prevent freezing.

I am building a new house; does the Energyroof® contribute to the reduction of the EPC level?

The Technical University Eindhoven (TU/e) did a calculation for the Energyroof® on a reference house. This show that Energyroof® can result in a decrease of the EPC value by 0,14.

Can you send me the different research by TU/e?

This research was very costly and naturally represents a commercial value to us. You can view it in our showroom in Best. Sadly, we cannot send them.

Is the Energyroof® visible from outside and can you walk on it?

Energyroof® is hardly visible, you really need to look well to be able to see whether an Energyroof® was installed. The Energyroof® can certainly be walked on for example for maintenance. However, it cannot be used as a roof terrace.

I have several roof planes available. Can the Energyroof® be installed on every roof plane?

Of course the Energyroof® needs to be fitted as close as possible to the building installation. From the garage at the back of the garden it is difficult and expensive to get the generated heat inside the house for example.

Achieving the highest yield from applying the Energyroof® often requires quite a lot of calculations. Can you do that for us?

If you can tell us how much energy you need (in Joule or Watt) and which application you are considering, we can indicate how much surface of Energyroof® you require to generate that. However, we do charge for the design or drawing of an Energyroof® or installation plan.

Who should I have install the Energyroof® on the building installation?

Any reputable installation company can install the Energyroof®.

The Energyroof® is part of the building installation. Should I install special facilities for it?

In case the Energyroof® will be connected to a solar boiler there are no special facilities required. A heat exchanger (TSA), pressure vessel, filler point, temperature regulator and a circulation pump are required for heating or cooling a building.

Can the Energyroof® freeze during the winter and is the antifreeze poisonous?

Freezing is not possible provided a certain amount of antifreeze is introduced in the pipe system so that there is no risk of freezing until -30 ºC. Although only 0.27 litre anti-freeze agent per m2 is required to protect the roof against freezing, glycol is a substance that should not end up in the environment. It does not need to because the Energyroof® is only filled once and never drained after that. A biologically degradable alternative is also available.

Can the Energyroof® also be used to generate electricity?

This is possible if a combination is made with the so-called photovoltaic roof covering, fitted with flexible solar cells. This combination also provides a higher power yield from the solar cells than if they were installed without the thermal Energyroof®.

Can the Energyroof® be fitted with just a synthetic roof covering or is for example a bitumen roof covering possible as well?

The roof covering needs to be highly absorbent and as thin as possible. Additionally, open fire, as often used in bitumen, is absolutely forbidden. This leads to the choice for synthetic roof covering with a girth of only 1,6 mm. This will be mounted in the base mechanically; the overlaps are welded with a special blow-drier.

How much does an Energyroof® cost?

The required size and therefore the additional investment of the Energyroof® is firstly dependant on the energy requirement of the building where it is installed. Furthermore, size and shape of the roof plane (for example base, required insulation for the desired Rc value, slope, specification) play a role. For a house you need to count on additional costs of approximately €150 per m2. These additional costs are usually recovered within 7 years (excluding subsidy) but shorter periods are also possible. This depends on the combination of applications. The costs for a pressure vessel, a circulation pump, a filler point/draw-off tap and a solar boil or possibly a heat pump still need to be added as well. For a house boiler approximately 12 m2 Energyroof® will suffice. In real estate terms it is better to speak about the return of the Energyroof®: usually more than 10% ROI.

Is the Energyroof® cheaper than solar panels or a flat plate collector?

Yes, with the Energyroof® we turn (part of) the roof into a solar collector. Especially when the life span of a solar panel or a flat plate collector is taken into account, the Energyroof® is a much more economical solution.

Does the government facilitate subsidies?

Every country has it's own schemes; often there are also schemes on a regional level or per council. It is not possible for us to keep track of all the European schemes here.

Is the Energyroof® also applicable to existing houses that want a dormer window for example?

Yes, the company Knipping (the Netherlands) supplies a dormer window fitted with a ready-made Energyroof® system.

What is the life span of the Energyroof®?

The life span of the Energyroof® is probably more than 50 year, for the synthetic roof covering on top you should consider approximately 20 years.

Can I install the Energyroof® myself?

No, you will need a specialist. The members of the NDA are those specialists.

Can the Energyroof® be installed on an existing roof?

Yes, you will have a (local) raising of the roof of 30 mm. Of course existing roof pipe holes should be taken into consideration. The Energyroof® is installed on the existing roof covering.

Should the base have a slope?

We recommend 20mm/per m2 of slope so that rainwater quickly runs of the roof and causes less pollution of the roof. As a result the yield remains optimal.

Should I perform maintenance to the Energyroof®?

You will receive a 10-year guarantee for the Energyroof® for leakage and performance. However, to this end the functioning does need to be checked annually. That is why the Energyroof® always comes with a maintenance agreement.

Are there specification texts available for the Energyroof®?

Certainly, click here for our specification texts.

Does SolarTech International B.V. have general conditions or terms of delivery?

Certainly, our general conditions have been filed with the Chamber of Commerce in Brabant (the Netherlands) under number 50237306.

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