Cheap warehouse dehumidifiers?

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Skolink

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#489665 5-Jul-2011 14:22

Since we have diverged from dehumidifiers already, I may as well ask if anyone has insulated their heat transfer kit? The ducting is marked R0.6, pathetic compared to the minimum R3.2 for ceiling insulation, especially considering it will be carrying very hot air from the fire, so the rate of heat is probably considerable. I have some cheap thermometers on order from DealExtreme to confirm this.

The most practical way I can think of is to use Bradford Gold ceiling insulation blankets (1.2m x10m) draped along the length of the ducting, ensuring it is tucked in around the bottom. I am expecting it to be expensive though - anyone have industry contacts in Christchurch? There must be heaps of insulation going to the dump from demolished buildings, such a waste.

Skolink

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#489673 5-Jul-2011 14:57

Bradford Gold R2.8 1200mm x 10m blankets are $130 from The Insulation Warehouse, and I would need three. $390 would buy a fair amount of extra firewood or power, but I suspect payback will be only about 3 years. Will post back my findings once the thermometers arrive.

jaymz

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#489702 5-Jul-2011 16:03

Skolink: Since we have diverged from dehumidifiers already, I may as well ask if anyone has insulated their heat transfer kit? The ducting is marked R0.6, pathetic compared to the minimum R3.2 for ceiling insulation, especially considering it will be carrying very hot air from the fire, so the rate of heat is probably considerable. I have some cheap thermometers on order from DealExtreme to confirm this.

The most practical way I can think of is to use Bradford Gold ceiling insulation blankets (1.2m x10m) draped along the length of the ducting, ensuring it is tucked in around the bottom. I am expecting it to be expensive though - anyone have industry contacts in Christchurch? There must be heaps of insulation going to the dump from demolished buildings, such a waste.

If i was you i would try run it under your existing insulation, that way any heat loss from the ducts will be put against the celling which can only help warm the rest of the house. plus it saves the cost of buying more insulation

simonpeter2011

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#490773 7-Jul-2011 20:19

I totally rate the delonghi ones.. quiet, worth the price and they really work.

Skolink

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#490949 8-Jul-2011 10:02

jaymz:
If i was you i would try run it under your existing insulation, that way any heat loss from the ducts will be put against the celling which can only help warm the rest of the house. plus it saves the cost of buying more insulation

Not a bad suggestion however the insulation is fitted between the ceiling joists, and the ducting does not run parallel to the joists. Also the fan is suspended from the rafters for noise isolation, so I'll have to wrap the ducting in that region.

A demoltion company sells recovered insulation for $3/sqm, so I'm waiting for them to get some in (should be heaps soon).

I took some measurements of the air temperature, 28.8°C at the inlet, 27.5°C at the outlet, outdoor temperature 5.5°C, so not as much of a drop as I was expecting. Maybe it was a bit warmer in the ceiling space. I have now ordered a wireless temperature sensor from Dealextreme, so when that arrives I'll be able to measure that too. Fan spec says 253L/s (free-air) at full speed, but I only had it on medium speed, so who knows what the flow is - 1/2 that?

richms

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#491023 8-Jul-2011 12:26

I found that as soon as the sun is down, or it is very windy that the roofspace very closely copies the outdoor temperature, but more data is always good.

Which one did you order from DX?

Richard rich.ms

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Skolink

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#491136 8-Jul-2011 15:31

Thermometers I am using are SKU 15553 - great value.
I have ordered SKU 34582 - no outdoor humidity, but fairly cheap.

richms

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#491295 8-Jul-2011 23:03

Ok, just be aware that the outdoor sensor for those wireless ones which are the same as the ones I got to make the tweet-a-temperature are very very very slow to respond as the sensor is enclosed in the case rather than out in the open.

Richard rich.ms

timmmay

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#492866 13-Jul-2011 13:36

Jaxson: Good luck with your insurance too if downlights are found to be at fault for a fire and you've not adhered to the minimum insulation distances.

As above on the duct heater. You spend heaps sealing and insulating a home against draughts and then pay to force cold air into you house, ducted right past the insulation. It's a draught you pay to have!

Pros and cons though, as you need ventilation most at night as everything is locked up tight, but ventilation then will be cold as.

Yeah it's pretty crazy, I turn mine off at night so it's not forcing in cold air, I figure having it on during the day will clear out the moisture.

My ducting is insulated for a meter or so, it runs under the insulation I have, I figure that might help a bit.

Jaxson

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#492932 13-Jul-2011 16:01

Heat transfer wise (as Skolink mentions) you're creating one room under positive pressure and one under negative pressure.

I mention this cos it pays to remember that you can't really just heat one room and not expect to have this spill into the hallway and back to where it started. The lounge (typically) will be sucking air from anywhere it can get it, front door, windows, hallway, roof space via light fittings etc. It will be losing heat up the heat transfer system and also via the new air coming in, draughts, from potentially colder locations.

Likewise at the other end, the room will now be under positive pressure, forcing air out of the room wherever possible. These systems work really well when you're trying to take hot air (from a really hot room), send it to the far ends of the house and let it filter back through to the lounge again.

Skolink

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#492938 13-Jul-2011 16:12

Jaxson: Heat transfer wise (as Skolink mentions) you're creating one room under positive pressure and one under negative pressure.

I mention this cos it pays to remember that you can't really just heat one room and not expect to have this spill into the hallway and back to where it started. The lounge (typically) will be sucking air from anywhere it can get it, front door, windows, hallway, roof space via light fittings etc. It will be losing heat up the heat transfer system and also via the new air coming in, draughts, from potentially colder locations.

Likewise at the other end, the room will now be under positive pressure, forcing air out of the room wherever possible. These systems work really well when you're trying to take hot air (from a really hot room), send it to the far ends of the house and let it filter back through to the lounge again.

Agreed, especially in our house with old wooden window frames. That is why I keep all the doors open, except when the kids are asleep and we need to contain the noise from the TV. You can feel the cool draught at floor level coming from the other end of the house (when the doors are open).

Slightly counter-intuitive, but the destination room actually feels warmer when its door is shut, because the hot air cannot exit via the top of the door way, but fills the room instead. Of course this probably results in greater heat loss overall.

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richms

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#497211 23-Jul-2011 21:32

Red stamp dehumidifier is dead or something.

Put it in the junkroom with the leak that is always damp this morning. came in this afternoon and there was only a few mm of water in it. Strange, its usually full by now.

Anyway, instead of putting the water in the collection vessel, its going into the bottom of the dehumidifier and then out the bottom onto the carpet. So now I have a giant wet spot on the carpet in the middle of the room.

Before this crap it was working really well. It seems that no water comes out the little hole over the collection vessel, which is also where the hose pushes on to make it drained. It was sitting level on the floor and today isnt that cold so I dont see that it would have dropped ice to block the drain like my old one used to sometimes.

edit: opened it and found a dirty great moth jamming up the exit hole, there is hope for it yet.

Richard rich.ms

timmmay

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#497239 23-Jul-2011 23:47

Hahahaha, there's a bug!

(sorry, not really funny, i'm a software developer)

richms

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#497242 23-Jul-2011 23:53

Actually I had it running post moth removal and it still let water thru to under it, although there was more in the vessel this time. I have dried the whole bottom half of it off with paper towels and if it gets any water on it at all then somethings clearly screwed with it. Not sure where it could be going thru, Mitht run it with the lid off in the junkroom since there is no worries of cats in there with the door to it closed and see if I can see how the hell the water is missing the funnel to the drain.

When it was working fine it was great, so I dont really want to have to return it since it worked well and was by far the cheapest dehumidifier around. im guessing something may have moved etc inside it but really dont know.

Richard rich.ms

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