KHRV150/12RH
When I took hold of the box from the courier, I wondered what could justify a cost for such a light parcel. And when I opened the box and looked at the contents, I thought it all the more so. For considerably less money, one could buy a dehumidifier; on the other hand, I have seen passive air-brick filters with a vapour-permeable membrane for sale for £90. Nevertheless, having fitted the unit and its transformer-sensor unit, I believe you simply have to forget about the cost and enjoy its benefits.
I fitted the unit in my kitchen, having removed an inadequate standard fan, which I never used. Instead, I had previously used an Ebac Powerpac 21 dehumidifier. It did its job slowly and reasonably effectively, although it felt like a battle that could never be won To get a feel for how rapidly the humid air in the kitchen could be cleared, one only had to open the back door and watch the humidity meter drop almost like a brick. The dehumidifier could take two hours or more to achieve the same result., if it ever did
I had known about heat-recovery ventilation for a few years and finally decided to try it. Having removed the old fan, I very carefully stitch-drilled the brickwork to open up the holes. The ventilator unit is cleverly designed; for example, the front panel is spring loaded allowing the panel to sit flush with the wall whilst the body of the unit slopes very slightly downwards to the outer wall so any water drains out. Unless you cut the power to the unit, it runs all the time; when seemingly off, it is silently running in trickle mode, and when on, it is in boost mode - either automatically selected by the sensor unit, or manually selected by the user using the pull cord. There is a fuse in the sensor unit, which is in the factory-set position of a fast trickle and one has the option to move it into the slow-trickle fuse-holder. This is what I did and and most happy with the slow trickle: it silently brings in fresh air without making the room cold. I have to admit I was skeptical about this, expecting to come down to a cold kitchen in the morning, but not a bit of it.
The unit has now operated in cold but dry wintry weather and also in cold and wet wintry weather and, much to my pleasant surprise, especially in the wet weather, the unit performs extremely well, far surpassing my expectations. It took only a couple of adjustments of the thumb-wheel to set the unit so it wasn't too sensitive or too insensitive. Now as soon as a pan starts to boil, the fan comes on. If there is so much cooking that the kitchen heats up by a couple of degrees, the control unit can turn the fan off for a while until the humidity increases yet further; this is just the nature of the temperature characteristics of the humidity sensor. This is easily pre-empted by pulling the boost cord after the fan comes on; the boost cord is a manual over-ride and the fan will stay on until the cord is pulled a second time My thumb-wheel is set to 58 and I expect that as the warmer weather comes along I may need to tweak it to a slightly higher setting to avoid it coming on too frequently. But as someone who prefers to have as much manual control as possible over devices, the thumb-wheel gives total control of the humidity setting at which the ventilation unit switches on, and I don't expect to have to alter it more than twice a year to the optimum position for the ambient temperature.
I used to think the dehumidifier was reasonably effective at reducing moisture in the kitchen, but this heat-recovery ventilator has set this into perspective. It has also freed up floor space and is a lot quieter; I'm also sure that there will be a noticeable saving in electricity, too.; there has been no need to run the cooker hood since I fitted the ventilator, and the rest of the house, including the bedroom is less humid, so there has been much less need to run the dehumidifier in that room. The adjoining lounge is now much dryer than it had been beforehand. It was very satisfying installing the ventilator and its control unit, and it has been even more satisfying seeing its benefits, including not coming down to wet windows in the morning after drying washing overnight. It's also worth mentioning that the staff at Kair were exceptionally helpful both before I bought the unit, answering my various questions and setting my mind at rest, and also duting the fitting of the unit when I wanted to seek clarification of a couple of points.
My wife is delighted with the unit and it will take a long time for her to get over its novelty and all the more so for having the dehumidifier out of the way. In short, I cannot fault this heat-recovery ventilator in any way, and I wish I'd installed one years ago.