Customer reviews

Feedback on operation with two TWINSOLAR 2.0 in a holiday home in Lanzarote:

After extensive consultation meetings with your sales partner Mr Hoffmann, Lanzarote, in December 2009 we decided to have a Grammer Solar installation installed. The living area of our house in Lanzarote is 138m². Mr Hoffmann therefore decided two twin modules would be sufficient and mounted these accordingly.

After now more than a year's experience with the Grammer installation, we are delighted to tell you that we are more than satisfied with the result. Previously when we arrived in the house (used as a holiday home) there was always a musty, damp smell and also a slight growth of mould on the curtains as well as on items of clothing in the wardrobes caused by moisture. As a temporary remedy we purchased a very good dehumidifying device and opened the windows to let the warm fresh air flood into the room. This is all "water under the bridge" thanks to your solar installation! We are currently on the island and have switched on the dehumidifier as a means of testing. After 6 hours, only a coffee cup of water was found in the collection container of the device. A great success, particularly as there is no longer a musty smell and damp, mouldy clothes. The constant, heated fresh air flows through the entire house and is drained off by an additional exhaust air damper. In the then preliminary talk with Mr Hoffmann we were intially somewhat sceptical. This, however, turned out to be unfounded. We wanted to send this note as a positive reference to inform you about our experiences with your solar installation and to thank the company Grammer Solar. Kind regards from the sunny island 

Rudolf J. 23.11. 2010
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TWINSOLAR in an apartment house in Amberg - installation of the system in the course of old building renovation in 2003:

We primarily use the TwinSolar Collectors for heating and ventilation during the changing of the seasons in spring and autumn and require very little additional heating during these periods.
The second greatest advantage of this installation is that it heats as well as ventilates and supports the general ventilation of the house. 

June 2008, H.Schwager, Amberg

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Feedback from Mr. Kurt Miller on the TWINSOLAR 6.0 on a holiday home in Sweden:

We arrived at our home on 23rd April with the sun shining.
We were eager to see the climatic conditions in our typical Swedish summer house (log cabin) with approx. 60m² of living area on the ground floor and a guest room (approx. 7m²) on the first floor. It was generally known to be a mild winter (2007) but with overcast skies quite frequently. According to statements from friends and neighbours, this was also the case in the weeks leading up to our arrival.
The installation data was as follows:

RT: 26 ° C
dt min: 3°
dt max: 6°
The outside temperature was approx. 18° on arrival.
The inside temperature in the inspection/living room was 23 °.
Relat. humidity: 62 %

This was the first pleasant surprise for us.
For me this meant no longer having to frantically fetch and kindle wood to bring all rooms up to a minimum of 20° as quickly as possible. Also, our friends no longer had to start up any electrical and gas heaters before we arrived so that the temperature in the living room and kitchen was at least 15°. The second and most important surprise was the lower humidity in the interior for this time of year. In addition to our material inspections, we were able to feel this instantly:

All drawers in the kitchen, living room and bedroom functioned perfectly i.e. without sticking.
The kitchen cupboard doors could also be opened and closed without jamming.
The wallpaper showed little to no damp creases caused by moisture expansion and the walls were not damp to touch and also not very cold in comparison to the previous year.

July 2008, Kurt Miller

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12 years operating experience with TWINSOLAR 10.0 on the Klostertal Environmental Hut of the German Alpine Club (Deutscher Alpenverein):

We now have 12 years of positive operating experience with TWINSOLAR. The installation has been operating without any problems or servicing since 1999. With the clean mountain air at an altitude of 2.360m, so far only one filter change has been required.

Further observations:   

• No more dampness problems in the hut
• The installation has been functioning perfectly!
• Good indoor climatic conditions in the hut

08.02.2011, Ernst Pfeifer, Designer of the Deutscher Alpenverein DAV and hut manager.

More info on Alpine applications

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30 years of experience with an air collector system by Grammer Solar

In the autumn of 1980, or 30 years ago, 10m² of GRAMMER solar air collectors were installed on the pitched roof of my 150m² terraced house (constructed in 1964) and connected to the warm air central heating using a ventilator and an air pipe. Since then, the solar air ventilator has activated as soon as the collector sensor is 3 K warmer than the living room sensor and deactivated when it is 3 K cooler. If the living room temperature increases 1 degree above the preset 22 °C standard room temperature, the gas burner switches off.
 This has functioned without any problems for 30 years with almost the same result i.e. instead of 2500 m³ / year the natural gas consumption (including 500 m³ consumption for warm water and cooking) is still only 1500 m³ / year.

12.07.2010, H.Barthel, Nürnberg

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8 years of operating experience with 2 x 10 m² TWINSOLAR on the new Traunstein Hut of the German Alpine Club (Deutscher Alpenverein):

Extract from the year book of the DAV Traunstein Section 2007/2008
Conclusions:
The results of the many years of positive experience using Grammer TWINSOLAR ventilation systems on the Traunstein hut are summarised here:   

• Relatively low capital expenditure
• Minimal operating costs (e.g.changing the air filter)
• Simple assembly and air piping
• Stable and practical, almost maintenance-free year-round operation    
• Great improvement in temperature and humidity in physical aspects of construction
• Considerable savings in conventional heating costs    
• The experience illustrated in the 2007/2008 year book can be fully confirmed today (March 2011). We installed further three TWINSOLAR installations on the hut as a result of the positive experiences.

04.03.2011, Alfhart Amberger, Chair of the DAV Traunstein Section

More info on Alpine applications

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Operating experiences with TWINSOLAR 4.0 in the club house of the Gartenbauverein Alsterkanal e.V. in Hamburg

 In our club house, the interior of which is panelled with wood, we were surprised to notice after some time that, upon entering the club house, we were now greeted with a fresh and dry smell in comparison to the cold and damp air. Even the heating energy consumption decreased by up to approx. 40% in comparison to the annual average.

Extract from the website of the Horticulture Association (Gartenbauverein) - Find the whole text here

You can find more information on the projects described above and on further references here.