Common questions and answers about our products

1. How many ventilators do I need?

We recommend at least 1 ventilator in each room for an efficient ventilation. If the room is bigger than 22 m2, we recommend 2 ventilators. For larger rooms and premises we recommend installation of one ventilator per 20 m2.
(example: 60 m2 3 ventilators, 80 m2 = 4 ventilators and so on)

2. Can I install your ventilators in existing holes?

Yes, that can easily be done! We have a complete range of pipe sizes 80, 100, 125 that fit most ventilator pipes. We also have cover plates for installation in existing square holes from flap ventilators.

3. We have a holiday home that we visit both in the summer and winter. It feels stuffy when we arrive so it needs to be aired properly. I’m interested in your thermostat-controlled ventilators but there are two temperature ranges, which temperature should I choose? We have a basic heat of approx. 8°C.

The house needs airing and the Velco ventilator takes care of that when you’re not there, but you should not have ventilators that are open all the time. Our recommendation is a ventilator with +5 to +20°C and ventilator size 80 in each room. This will give a well-ventilated house without increased electricity consumption. See our range of fresh air ventilators for holiday homes here.

4. We have self-regulating ventilators in our house, but we’ve noticed that some ventilators are semi-open even when it’s -7°C outside. Shouldn’t they be closed like the other ventilators?

This is to protect your walls from damp. The houses have a so-called over-pressure when it’s cold outside. This is created when cold, incoming air is heated. The air gets an increase in volume then and the increased air volume is pressed out through the Velco ventilator. This prevents the air mass from passing through the wall sections, something that can create damp problems in the walls.

5. I have condensation at the bottom of my windows as soon as it gets cold outside. I understand the need to ventilate, but I can’t afford a ventilation system costing more than SEK 50,000. I welcome any tips. Thank you for any answers.

Your house has far too high humidity indoors and the damp is probably found in the walls. If your house is too tight it means that damp has passed through the walls. We recommend installing fresh air ventilators and to supplement with small fans in the wet areas. The condensation on the windows will disappear almost immediately. The estimated cost is SEK 8,000 to 10,000.

6. Is it suitable to install self-regulating ventilators behind a radiator?

That works splendidly! Remember, the ventilator must have a thermostat bulb +5 to +20. See the model in question here.

7. I have an exhaust air heat pump, can I install self-regulating fresh air ventilators in my house?

Yes, our ventilators can be installed together with exhaust air heat pumps and after FTX ventilation etc. We supplement the ventilators with min discs that minimise closings. (FTX = exhaust/supply/heat exchange system)

8. We are building a new house and our walls are 44 cm thick. Your VTK 125 has a length of 27 cm, can that be installed in the walls?

Yes, there is an extension pipe for the VTK 125. Supplement with 2 extension pipes. See our pipes here.

9. Where in the room should I install the ventilators for best performance?

They should be installed as close to the ceiling as possible and anywhere along the wall. Note that there may be load-bearing beams above windows so it’s better to install at the side of the window. The absolutely best place is in a corner as the so-called over-pressure is highest there. In this way a good natural ventilation is created (air enters and exits through the same ventilator).

10. The house has an extraction fan that is regulated in relation to the outdoor temperature and the wall ventilators are always open. In winter there’s a draught in certain places in the room, can this be eliminated by a Velco ventilator?

Absolutely! If you change to Velco ventilators and add a 4 mm min disc. The ventilator will not close fully then, but regulate with an opening of 16 mm down to 2 mm. With the correct flow setting of the exhaust air fan, cold downdraught is avoided. See our min discs here.

11. My house has manual wall ventilators which can be opened and closed by a lever and a string. Now I’m wondering what’s the point of investing in thermostat-controlled ventilators?

It’s about saving instead of wasting. For optimum energy savings and adequate indoor comfort we should neither over-ventilate or under-ventilate our houses. Taking in cold air is costly, therefore manual ventilators must be monitored, especially in winter. Instead, thermostat-controlled fresh air ventilators regulate the air automatically and complement the daytime heating, which gives a great energy saving. See our range of fresh air ventilators for residential houses here.

12. I work as a consultant and include ventilation in the design of new, small houses and renovation objects, etc. The diameters of your self-regulating ventilators range from 80 mm to 180 mm. Do you have any material for projecting the ventilation?

Yes. If it concerns a permanent dwelling, a temperature bulb -5 to +10°C must be included (see our ventilators for residential houses).

For houses built before the 1950s, we recommend the 80 mm ventilator unless supplementary insulation is provided.

For houses built before 2000, the ventilator size is 100 mm.

For new houses built 2000 and later, we recommend the 125 mm ventilator due to thicker walls and tighter houses. The natural ventilation provided by the ventilators is quite adequate for a good indoor climate. Wet areas must, of course, have a small fan or an exhaust duct for natural ventilation.

We provide a 10-year warranty for our thermostat bulb.

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