One with a fridge in it, or one of the dessicant wheel based ones?
Given the temperature of our house, I'm tempted by the latter, despite the additional running costs, but does anybody have any experience of them? Eg do they carry on working?
OK, not MUCH experience, but I am in the middle of an experiment...
I've got two. One for the house which is a Meaco DD8L desiccant-wheel machine. At full bore it uses 800 watts (as measured, spec lies and says 650w), but that heat comes back as heat in the dry air, typically
3 degC above room temp. What I have found is that I can sit and desk-work at 19 deg if the air is below 60% RH, but if the air RH rises to 70% then I want it at 20-21 for comfort. This means that I can turn down the oil-fired heating zones by 2 degrees. Not yet sure how that will work out in practice, and I didn't write the spreadsheet yet!The second machine, a Meaco 20L (350 Watts), which is a compressor type, is on-order for the Church, a small Wesleyan chapel, which we Orthodox rent, but it gets very damp as it is not heated during the week. I chose the Compressor type as we don't need the heat, just the drying. Time will tell on which works best where.
Meaco's site seemed helpful, and the delivery was quick.
After three years of using a compressor-type DH in my garage, I've just gone over in the last week to a dessicant-wheel type:
I put the new desiccant DH in the garage, and set it on High mode (high fan speed). It started reducing the humidity almost immediately, dropping it by 1 percent an hour until it got down to 53 percent (well below mould-growth level).
It has now been raining solidly for two days, and because I've been running the new machine intermittently (it was off all last night) the humidity is back up to 67 percent, just below mould-growth level (which I believe is 68 percent). I've got it in high mode again, but as it seems to reduce the humidity by 1 percent per hour, and not having it on raises the level by the same amount, I can see it struggling today to lower the present level.
The reason for intermittent use is the running cost, according to the manual between 300 and 600W depending on mode, roughly borne out by the energy monitor here. At this rate energy consumption is going to be in the 5kWh per day for High mode running for 8 hours, or effectively a near 50 percent increase in household consumption - potentially expensive.
Against this is set the cost of running the compressor DH (about 250W) and the potential for damage to the stuff stored in the garage (electronic gear, books and other paperwork, and a motorcycle).
I have yet to find the most economical mode for the new DH, or what pattern of usage, would lower the running costs, but it's going to involve £££, the only question being how much.
Terry Fields
While we're on the subject, what's the smallest decent (compressor I assume) wall mounted with drain option device one can buy?
I'm after one for a 2m2 drying cupboard, ambient temperature probably upto
30C as the HW tank will be there (though well lagged along with the pipes).Cheers,
Tim
There are two things to bear in mind here. Firstly, this is an extreme case where the garage is already at high humidity and retains that due to a damp winter climate. Secondly, I haven't been able to try out the various drying modes - the manual is slightly unclear about how the modes operate, at least one of them is supposed to shut off when the target humidity is reached (factory set at 55 - 60 RH). Due to the extreme conditions there hasn't been an opportunity to test the device fully or work out how best to use it.
I have every suspicion that in a domestic setting this machine would easily control the humidity levels. I'd have to say that as far as I can judge it's far superior to the fridge type at getting water-vapour out of the atmosphere. In 'quiet' mode the fan noise is hardly intrusive, and in 'low' mode is supposed to run at max power until the target humidity is reached, when the fan then runs at very low speed with the dehumidfying process turned off apart from monitoring the ambient level.
Nope..leccy consumption was 3400 kWh per annum, until I got this dehumidifier ;-)
Terry Fields
In the interests if DIYers, I suffered the rain and took the energy monitor over to the garage, taking the opportunity while there to empty the DH water tank (it has a continuous drain facility, but I need 4m of 12mm ID hose to reach the drain just outside the garage door).
There are three operating modes: Low, Quiet, and High.
Low and Quiet are factory set at a target RH of 55-60 percent.
High is factory set at 45-50RH.
Low runs at high fan speed until the target RH is met, then runs at low speed.
Quiet runs at low fan speed (possibly all the time).
Low and Quiet run at ~300W.
High runs the fan at the same speed as Low initially does, but also takes an extra 300W. I'm unsure where this extra power is going.
There is a 'Laundry' mode that adds heat to the output air stream, but I didn't try that. There's a 2-4-8-off timer, an ioniser (~20W), and a Swing mode that directs the output air stream to the front, to the top, or swings 150 degrees between the two limits (wattage unsure). In all it's quite sophisticated, and very smart for the home environment.
So, I think I'm running this device in the most economical mode, which is about 300W, rather less than I initially feared. I suspect I'm going to run it on the 8-hour timer once a day, and monitor the humidity swing in the garage. If I can keep it under 65 percent, I think that will limit any deterioration of the items stored there.
If anyone else has experience of dessicant dehumidifiers, I'd like to hear their opinions of this type of device.
Terry Fields
I wonder if just running it for the E7 hours would be enough?
Chris
Ah! You've given me an idea.
I first thought that your suggestion wasn't viable, as it needs a button push to start it, but I could put it on a timer as the unit remembers its settings during a power cut and automatically starts again on power up.
The unit has struggled mightily today, but it's got the humidity down to 62 percent, and the good news is that it's stopped raining and there's a fine day in prospect tomorrow.
Terry Fields
I think you have found the problem with that type of unit. My compressor one doesn't even need to run continuously to cope with today's weather. It doesn't work well in the cold, but raising the temp by a couple of degrees reduces the RH a lot at low temps and that is easy to do.
The latest dessicant units supposedly perform better than the old, the DD8L is indeed better from a quick test I did re XDry and Ruby Dry units. They all draw 650-800W in full power mode, using a peltier effect unit to condense & heater to evaporate - so are in effect fan heaters.
The problem is, they are all pretty darn noisy. Sleeping with one with likely to be a noisy experience, but you can remove them from the bed and put them on the landing which might be a little quieter although not much.
Best compressor unit - and supposedly quieter - is the Mitsubish EV dehumidifiers, they run =A3300-350 which is a fair lot more than a dessicant unit at =A3150 or so. The Mitsubishi is about 250W and so cheaper to run, very reliable, made in Japan.
If you have gas heating, I could say what is the point in paying =A3100 a winter for a dessicant running cost when you could probably do =A333 a winter for compressor, using 3x cheaper gas to elevate the temperature. Worse, running at night re cheap-rate may be impossible due to noise - they are really quite noisy due to limited air outlet volume (cue new design 2013).
Cheapest way of solving excess humidity is often a bit more ventilation and a bit more heat. You can buy a =A360 fan made by ? someone? which runs every 4 8 12 24hrs for 6-23mins. It pulls humid air out of the room preventing humidity buildup. Obviously they make humidity controlled fans but never had much success with those (lack of airflow through them for sensing?). Absolutely stop drying on radiators unless you stick an extractor fan in the same room, because mould will simply take off if the house is "a bit damp & lacking in heating".
The problem with the cheap dehumidifiers is the bearings can fail in the drum-fan motor, which then sits there and smokes the plastic through the house causing very considerable smoke damage. Most AC motors have a bimetallic cutout which turns the power on & off when the motor stops and when current draw is the peak stall current, but this does not stop very high temperatures being reached hence the chance of fire (lint/fluff) or melting plastic smoke causing damage. So whilst the cheap =A389 units are good, if you go on holiday stick a smoke detector with relay module inline. I know of one local narrow boat owner and a distant home owner who found out just how much damage smoke can do. Literally the entire house was smoke damaged. Tumble dryers tend to set fire to the lint. Dehumidifiers just smoke.
Dehumidifiers are not cheap not run for a whole winter - tackle kitchen & bathroom extractors, and drying washing. You also really need one on each floor or even in certain rooms, they do not "dehumidify the entire house" very well. Good for open plan flats or single floor levels - except for the noise of course.
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