Saturday, October 8, 2011

Retrovent fitting 2

3 October 2011: Second lot of photos of the Retrovent fitting.
Retrovent front panel fitted, and just that bit of wire to tidy up, and add the switches to a location inside the cupboard. Darren in thoughtful pose. The Top hole is the extractor and the larger finned hole is a low-speed plenum. The fins can be rotated to give a direction.
Tidying up on the outside, a mastic surround to the outlet. The wall is about 10mm thicker than expected. The vents nearest the wall are the outlet, pointing downwards and outwards. The intake is the extended portion, in clear air away from the outlet.

This would be a lot better in a house using GAS as the cooking medium, because the main emissions are CO2 and Water Vapour - both of which need clearing. We are using an electric induction hob that produces a minimum of heat. None at all actually, it's done with a magnetic field in the saucepans.
    We do not have an extractor because it wasn't possible to drill through the wall directly above the hob. We have a filtering recirculator. I hope this device will be more useful when it gets much colder and the humidity of cooking needs clearing.


  1. Hi David.
    I was very interested in the Retrovent but you don't seem to have put any post up since the installation. I would be interested to know how its performing.

  2. Hmmm.... I hoped you wouldn't ask. I guess its too early in the year for it yet - i know that the idea is that you replace the air with warmed air and leave it on all the time, but when we are not cooking, I actually rely on incidental gains as part of our heating strategy, e.g. heat from the fan assisted oven. So, if we are cooking using water on the hob, it is definitely ON. half an hour after cooking, I can't see the point so it goes off. We do NOT use GAS, so we don't have a problem of combustion emissions in a tight airspace. So I hope it might be useful in winter when cooking is happening and one would normally open the water and let v cold air in to reduce condensation.

  3. Hi Dave,

    do you have further news on this? I am thinking of buying a retrovent (or HR25H) next weekend while in the UK.

    I was wondering about the efficiency at moderately high flow rates? Does the incoming air feel cold? I am quite sceptical about the performance at higher rates given the small surface area of the heat exchanger. The documentation reports "maximal performance", but this would be hard to interpret when the in/out flow is inbalanced.

    How is the noise level of the unit? I have no choice but installing it in my bedroom (might add a timer if it's too loud).

    Many thanks,


    PS do you know (site in German)? A 90% efficient balanced rotational vent with 80-200m3/h. Only thing is: it is rather expensive at 2000 euro, and a rather large industrial looking thing to have hanging from your wall.

  4. Damiaan, are you in a hot or cold climate? We do use this Retrovent, in fact, no matter how hot or humid or crowded it has been, we haven't needed to open the kitchen window once during the winter. the retrovent is variable speed depending on humidity. so it runs quieter when things are settled.
    I couldn't see us using this Oekelufter - apart from its massive size, it has to fit into a large single glazed pane of glass and we don't have one of those!
    the air coming in feels cold, but thats because it is moving, but its probably about 18º when what is being sucked out is 21º. We can hear it. I think the sucking rate is about the same as the blowing rate, otherwise there would be a net loss, either of which would be wrong.
    The retrovent as currently sold is a complete package (unless you have a qualified installer). i.e. you order one, they send a guy to you, and the deal is complete. A couple of hours, and it is all done, including making good.

  5. Hi. Have just brought two of the Retrovent fans. I haven't been able to find anyone but yourself that has spoken about them online and I have a couple of questions. I am planning to use one of them in a dining/living room that is semi-open plan with the kitchen. In the kitchen we have a wood burner. Do you think that the retrovent will draw the warmer kitchen air through into the dining/living. I imagine a normal extractor fan would do just that, but I'm wondering if the retrovent would have the same effect because it also inputs air.

    Second question. I have brought mine from a firm called just fans. Couldn't find anywhere else that sold them. There was no mention made of qualified installers needed. I'm hoping a qualified electrician can do the job with the instruction included. Do you think this is OK? Apart from anything else we're miles from anywhere.

    Anyway. Thanks for the informative blog, and any advice very gratefully received.

    1. Hi, the Retrovent is made by Envirovent and when I wanted one, I enquired of them. Didnt seem to be an alternative soucre. i wasnt given the option of installing it myself. It was provided as a package deal, the guy turned up, did a wonderfully tidy job and it was all done by lunchtime. Perhaps I could have done it myself, but if it only saved £100, I prefer to have it done by a fast expert, and no anxiety for me. I think it would only work if it balanced the pressures (it is variable speed), otherwise, it would be much less efficient, either blowing hot air out of the house or cold air in. We dont leave it on all the time, we turn it on only during cooking time, or when many people are in the house. My wife cant stand any sort of noise, its a wonder our fridge is allowed to exist. One of the reasons I got it is that it has a better separation of the airflows than other products.

  6. PS

    I have a 3rd question, which has only occurred to me since making the purchase. It may be a stupid one, but what prevents the air being sucked out of the building being the same air that was just sucked in. That is suddenly worrying me a little, although I'm hopeful there is a reason why that would not be the case.


    1. Normally you need to use the fan to avoid cooking smells and condensation. This is the biggest risk in the Winter, while in summer, its not a problem if you can just open the window. But you wouldnt want to do this in winter. During the most recent winter, we NEVER ONCE had to open the window to refresh the air or clear cooking smells. The Retrovent dealt with everything.


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