Condensation

Fitting insulation should go hand in hand with fitting a vapour barrier.

Mike

Duncan,

Research heat pump dryers with care. They take a bit (a lot) longer than through air flow types and can leave thicker material (folds at waistbands, pleats, etc) damp, while the rest is quite dry. Maintenance (cleaning the fluff off the fins was less easy on some machines than others and difficult at best,reportedly - but with so many that don't even know what a dip stick is in a carcengine, that is hardly surprising! Some of the 'reduced leccy use' claims are not quite as impressive as those which 'Which' reported.

We bought a Siemens iG500 heat pump clothes drier 3 years ago and it's been pretty darned good. It is clearly a lot more efficient than a standard, "throw it out the window" drier. We operate it indoors (without any ducting obviously) and the only byproduct is water that goes directly into the drain ia the drain hose. Efficient, as in there is little noticeable heat generated by it (it barely gets warm), nor are we piping massive volumes of saturated steam outside that we have generated at great cost. By condensing that vapour, the machine recovers most of the energy used to drive it out of the clothing.

It's also got a pretty effective humidistat that can tell how dry the clothes are and will terminate the cycle when the selected degree of dryness has been achieved.

It's easy to be cynical about energy ratings but that heat energy usage relates directly to energy bills.

Murray

I'm way ahead of you . My clothes drier is fusion powered.

FWIW, I use a cold & draughty garage with no insulation. Yes it's cold in winter so I use electric heating. And yes, it's expensive, I suppose, but compared to the rest of the electric bill (all-electric bungalow, storage heaters, frozen wife..., plus coal fire) it's actually peanuts.

I've tried the WD40 route (smelly and messy) for the lathe, and eventually ended up using a pair of Self Regulating 10W heaters from RS Components.. With these, the lathe never has that bone chilling numbing feel in winter and never gets condensation. The downside is that the heaters run at 38W which, although higher than 2 x 10W is actually within spec.

I've also fitted one of them to my milling machine, but not to the drilling machine or the grinder, neither of which suffer from condensation. It probably also helps that I keep both lathe and mill covered by a cloth cover and a plastic cover on top.

I have some experience of dehumidifiers and like others here, the darn things needed emptying frequently. Interestingly, the previous house (also all-electric with storage heaters) suffered badly from condensation. The present bungalow is a lot better. I put it down to the open fire drawing lots of air through the building hence getting rid of the damp air.

Regards,

Peter G. Shaw

Cavity wall insulation doesn't cause condensation - it allows rainwater to bridge the cavity which in turn is only a problem if you have a lot of rainwater being blown onto the face of the outer wall so that it soaks through. There are places where this is prevalent but they are a very small proportion. Any other source of water in a cavity would have to be due to a fault in the building construction. Looking at many of the photos of the damage allegedly cause by such insulation, the mould looks more typical of poor ventilation and high humidity.

Often the retrofitting of double glazing results in excessively sealed rooms. Beforehand, the original relatively leaky frames resulted in a healthy draught, while on new builds the building regs actually require a minimum level of ventilation. But there seems to be a vibrant new scam industry akin to ambulance chasers / PPI / personal accident claims types that are having a fine time, living high on the hog as a result. There was a very active company on Facebook recently that was stoking up a fine following.

Thinking as an engineer, would you like to suggest otherwise how insulation actually causes condensation?

Murray,

I as see things, as long as the workshop is heated above the dew point then condensation will not occur. Very cold air is often low humidity so it can absorb moisture and heating would be a waste except for personal comfort. One of the problems is the introduction of a breathing person into the workshop when it is very cold. I run a dehumidifier through the winter months but as pointed out it does nothing when it's very cold but providing you don't introduce warm wet air to the workshop you will not get condensation. The worst scenario that I get is a very cold spell that makes everything very cold and then a warm wet wind comes in, the workshop can look like it has been hosed. I think a heater with a dew point control may be very economical but can you get one?

Mike

Edited By Mike Poole on 31/10/2017 15:40:15

Murray,

All i know is that the damp has disappeared completely since it was removed last year, they are removing it from 100`s of properties in our area and thousands country wide. It was removed through the cavity wall insulation compensation scheme. I found out that it should never have been put in areas such as west coast of cumbria that gets loads of wind driven rain.

The cavity wall companies promoted by the big energy companies just put it in any house that said yes , they`re initial surveys of suitability were a joke. I think we were the only house on our road that refused to get it in.

I dont want to get into the argument of damp v condensation but yes most of it was caused by wind driven rain penetrating through the render ,outer brickwork and across the soaking wet cavity wall cotton wool stuff.

It took 2 whole days to remove it from the house, which was done free of charge but they never got the promised compensation for replastering etc.

Edited By mark smith 20 on 31/10/2017 15:41:34

No argument then - apart from the terminology ie not condensation. This free of charge compensation thing is also driving quite a few charlatans who are blindly chasing the money - just like the original installers...

Murray

That's an interesting observation. In places like The Deep South, you get very high humidity and cool nights which can result in significant condensation. In a previous job, we used to ship battery chargers in plastic bags that were stored in new golf karts awaiting shipment to the dealers. There was a continual problem with "water in bag" which was an inexplicable(?) puddle of water in the bag, despite it being completely shielded from any possibility of rain ingress. The bags were sealed with a cable tie but it wasn't sensible to completely seal (weld) them closed, as you may have needed to be able to get back in.

I was able to reproduce this in a "fully sealed" product. Of course, you can't fully seal anything with an internal cavity over the life of a product (8 years in this case), so we had a breathable membrane (Goretex fabric) which prevents liquid ingress but allows air (at normal humidity) to pass. By heating and cooling the product in a climatic chamber, we were able to create a noticeable puddle of water inside it. It drew moist warm air in as it cooled, which then condensed. When it warmed up next day, the expelled air would be at a lower temperature / humidity, so overall, water would accumulate inside.

You can buy humidistats due to the need for bathroom fans that clear the moisture after showering etc. But it sounds as if a timer is often more effective. No experience myself, as I went for timer fans.

Murray

Mick.

Do both. I did years ago and have had absolutely no rust or comfort problems ever since.

Mike.