Petrochemicals

Interests me whether hard surfaces between the foam in the first layer would be beneficial. Foam is used in sound studios to stop resonance and reflection on hard surfaces that are there to stop the transmission of sound through. If you think of a microphone, it has the foam on it to stop wind noise, not the transmission of sound.

There seems to be a much energy going missing anyway, even if the exhaust is hot, I'd start there

Anyone would think Id touched a nerve, has something been going on for a while?

That's not beyond reason but it would mean throwing away 200 quids worth of semi flex. I would not need to put round 200mm throughout would I just on the main supply duct? Or does that need to be bigger? This is a mid 70s build house that they put a hot air heater system on. The heating system was replaced due to it being hideously in efficient but the space remains to stick in whatever duct work is nececerry. Part of the reason for putting in the mvhr unit wat that there where 2 double air bricks and a single in the house all installed in the kitchen, the rest of the house was obviously vented at sometime by the hot air system, but since that has been removed the rooms can get stuffy, especially the down stairs living room which has no chimney effect on it at all. It had to be a ventilation system, so I thought why not a mvhr unit, get rid of the kitchen extractor and toilet fan and get rid of the cold pooling and condensation along with the fresh air input.

Like that yes, a bit more heavy duty, it works for me to a degree, it goes straight into the unit and is bent at a weird 90 angle insulating the outflow from the machine, it enables a low flow rate to be inaudible for night time, the extracts are now noisier than the inputs. It isn't perfect but much better than the straight through silencer, I'm not sure that did anything really. Tell me more of your silencing solutions please as the boost level is still a bit noisy over the TV(supply side) when it is switched on for after dinner extract.

As far as I can tell yes as they call the ashp an"inverter" in the wall units. But I do not know how easy it would be integrating it into an existing system that does hot water.

I did not know mvhr reverse exchanged it of the outside air was warmer than required, I though the Auto bypass thing just shunted the air past the heat exchanger.

Thanks for the replies, split unit it is. Just seems like a bother you can't just stick a small one on and utilise the ductwork.

Its worth a shot, other wise the mvhr is being switched off in the heat and I'll stick with the portable., it does however mean getting water to the loft. It is just to trim the heat from the incoming air for those few days.

That did alarm me, the fact that new air is coming in at outdoor temperature, last summer that would have been 500m3 per hour of 39c air, on boost or 100m3 on normal. I've a portable air con that does a similar, splitting the interior air half and half, it seemed to work, but there is a cut off point, if the out air is 16 the room is 26 any hotter than 36 and it is not doing anything. At the moment

Yep, read it all, cheers! lockquote widblockquote widglockquote widlockquote widget

Not sure what you mean, would it not just go across the top of the unit?

Imagine all of those ducts where extracts and you had additionally 2 large or very large in the case of your ground floor imput vents in your hall/ landing, maybe in the far far side in your living room. It seems that you would get the fresh air and the extracted air would have far less distance to travel.

The best silencer I have found is a flexible one from a cannabis garden shop, bent around, it works much better than the straight one. I come to believe bends in the duct work are good, not bad, I think flexible ducting must be pretty good at sound attenuation too. But I followed the manufacturers advice, rigid for as far as was reasonable then semi rigid, it transmits sound like shouting down a long stiff pipe.

For a heatwave of a few days a year I cannot really see condensation being a major problem, plus once it leaves the chiller bit it is only going to get warmer, condensation on the outside but in the temperature and relative humidity it will be it will quickly dissappear. The bacteria et al build up takes time, wood gets wet but as it dries the bacteria dissappear, thus meaning the wood does not rot, the problem is wood that is consistently above 20 percent water, most wood is above 10 percent water at any time.