How does the SolarVenti work from a technical point of view?
The system is free to run and is not connected to the main electricity supply. It is supplied with electricity via a solar cell.

When the sun shines it warms up the air in the absorber and the integrated solar cell produces electricity for the built-in fan which blows the heated air into the house.

Fresh air from outside is sucked / pulled in through a perforated back plate and a 2 mm layer of felt. The air velocity is so low that only extremely small amounts of dust, pollen etc. are drawn into the system.

When the system is running, air flow remains inside the panel. When the system is switched off, it cools itself down – even if there is bright sunshine. The heat rises inside the solar panel and exits via the felt and the back plate (open construction).

What is SolarVenti´s primary purpose?
The main task is to dehumidify and ventilate the house. The aim is to improve the quality of the air and lower humidity. This makes the house better to live in and the air easier to warm up. In many cases, SolarVenti will result in significant savings in heating bills.

When a house is continuously ventilated with dry, warm air, the risk of damp, rot and mould will be reduced in the long term.
Many years of experience and use of the system have proven that SolarVenti reduces humidity significantly.
In practice, SolarVenti’s dehumidification/ventilation eliminates condensation on windows and doors which could cause them to bind.

Furniture, cupboards and duvets no longer feel and smell damp as there is no longer damp in the house.

And you can leave coffee, flour and salt in your holiday home without worrying about it forming lumps or going bad.

The SolarVenti system is an additional heat source, but it also an indirect source of extra warmth. It provides a supply of air which is warmer than the air already in the building. However, dehumidification provides an indirect source of heat: The heat supplied by the main energy source (central heating, wood-burning stove etc.) will be more efficient and distribution quicker when the air is not damp.

And a completely dry house makes better use of the heat from the sun through the windows than a damp house does.

Can the system keep the house frost-free?
At our latitude, temperatures must be extreme before the system is not able to keep the house frost-free. However, we cannot guarantee that the system will keep the house frost-free. We also export to Greenland where temperatures of 45 degrees centigrade below zero are not uncommon. The situation is quite different here.

There is also a great difference in the way in which houses are insulated and there are other crucial factors. For example, the way in which the air circulates differs from house to house. It is also of significant importance that the system has the right dimensions and is positioned correctly. The system must also have enough time/sun to ensure thorough dehumidification. Once the system has had sufficient time to dehumidify existing damp in walls, floors, ceilings and inventory, and the house is thoroughly dry, it will be a lot easier to keep the building frost-free.

Can dust get into the house or into the system?
No, the air is filtered through the felt. The felt cannot get clogged as the air is drawn into the absorber through the whole of the rear of the panel.

A special filter can be used if you wish to filter the air more.

SolarVenti blows new air in. Where does the air come out again?
The air will automatically be drawn to the places where it is easiest to get out, e.g. to vents in kitchens and bathrooms or other vents and openings in the house. If possible, let the air blow directly into the most important room and open the doors to other rooms. You should be aware that a chimney damper in a chimney which is not in use will create an outlet for the air in the room. (There are further details in the answer to the question: “What happens when the system blows warm air into the house?”)

Can I switch off the system if the summer is hot?
All models can be switched off. They all have a built-in on/off switch. A supplementary regulator enables you to adjust air flow and temperature on the larger systems if the people in the building are close to the air injection duct. The small systems can only be adjusted using the air injection vent on the ceiling or the wall. All systems have a switch so that they can be switched off completely.

In addition, most of the systems – apart from the SV3 – are supplied with a variable electronic regulator so that you can turn down the air flow. When the air flow is turned down. the temperature of the injection air will increase.

What would happen if the system was switched off for several days?
The SolarVenti dehumidifies a house over a period of time. During cloudy periods nothing will happen. When the sun shines again, the limited amount of damp which has accumulated in the meantime (and which you will probably not even notice) will be extracted relatively quickly.

Why is there visible condensation on the inside of the top Lexan plastic layer of my SolarVenti solar air collector?
Once the SolarVenti has been installed, there will be visible condensation on the Lexan plastic finishing coat on the inside of the solar air collector at regular intervals. This is quite normal and will in no way damage the system.

When the warm air in the solar panel meets the cold air – or at any rate colder air – outside the panel, the condensation will become visible. When two extremes in temperature meet, condensation will appear at the “dewpoint” which, in this case, is on the top Lexan plastic layer of the solar air collector.

Therefore, condensation will be most common when the solar air collector starts up after an idle period (short or long) due to cloudy weather. This is when the difference in temperature between the warm air in the panel and the cold air outside will be greatest. You can avoid the visible condensation by switching off the solar air collector for an hour or two depending on the weather conditions. When the panel cools down the condensation will disappear.

Is there a risk that smoke from my neighbor’s chimney will be injected into the house instead of fresh air?
“A good indoor climate comes from outdoors”: Fresh air is only available from outside; but polluted air also comes from the outside. So, of course, it is possible to draw the smoke from your neighbor’s chimney into your living room but it could also come in through an open window if the wind is blowing the "wrong way".

The position of the SolarVenti determines which type of air you will draw into the house.
The SolarVenti “breathes” – takes in air – through the multitude of small holes on the panel. If the air intake is placed where the air is normally clean, the injected air will also be clean. In general, the cleanest and driest air will be at the top of the house. In practice, this means that you should not install the SolarVenti close to the ground.

You should concentrate on finding a position in which the solar panel can face south and where there is as little pollution as possible from wood-burning stoves, extractor fans etc.

Should the indoor air injection duct from an SolarVenti solar air collector be mounted on the ceiling, at the top of a wall, in the middle of a wall or at the bottom of a wall?
Most people would say that it should be at floor-level. However, it appears that it is irrelevant whether it is on the ceiling or on the top, bottom or middle of the wall. The volume of injected air is of much more importance to the result.

Can SolarVenti produce cool air for ventilation?
Yes, it is easy to extend the system so that it blows cool air into the building. This requires an extra fan on the north side of the building and a room thermostat which switches between the fans.

Can the system alleviate allergies?
We believe that the system must have an effect in relation to allergies and asthma. It dehumidifies and has a drying effect, which creates the worst possible conditions for fungus and mould. Also, the air the system blows through the building will usually be very clean. The only possible downside is the fact that the system may draw in pollen from outdoors. However, the air velocity of the injection air is so low that it would only draw in very small amounts of dust and pollen and, apart from that, the fresh air is drawn in through a perforated back plate and 2mm of special felt.

Many customers have told our installation engineers that they have noticed an improvement in allergic rashes and asthma after installation of a SolarVenti. In some cases, the symptoms have disappeared altogether.

The air is not quite as warm as promised in the brochure?
If the system is under one year old, it will often blow in more air than expected. This results in lower temperatures and is due to the fact that the solar cell produces an extraordinary amount of electricity to begin with. After approximately one year, the solar cell’s electricity production will stabilize at the specified level.

The extra amount of air to begin with is usually an advantage as it dehumidifies the house more quickly. If you want warmer air, you can adjust the temperature by turning down the damper at the air injection duct, or by turning down the electronic regulator if the system has one.

SolarVenti only runs when the sun is shining. What does this mean?.
When the sun shines, the air is warmed up and this is what produces the dehumidifying and warming effect. Otherwise, the system would just inject the air from outside directly into the house.

Frost and sun often go together. The sun tends to shine on really cold days. On a frosty, clear day almost all of the moisture will lie just above, and very close to, the ground. Therefore, all of the air above this is very dry and suitable for injection into the house.

Is there a draught from the air injection duct in the wall after installation?
No, if the solar air collector panel and the pipe through the wall are mounted correctly, there will be no draught through the air injection hole when the fan is not working at night.