We're moving house soon, and will need a tumble dryer. This will be on an outside wall, but it's a fairly thick stone wall and there's no hole for a vent. We've only ever had a vented dryer and knwo little of other types.
So I have to choose between making a hole or buying a condenser type dryer.
All I've read says that condensing dryers are less energy efficient than vented dryers, but I don't really understand why - a vented dryer blows heated air outside after all.
Any insights?
I've been happy with condenser washer/dryers for 30+ years, if you're worried about efficiency you could look at heat-pump models.
How is the vapour condensed? Heat pump? Cold water (from the mains - requiring water and a drain) or air? The latter is the simplest, but you get a build up of fluff which can catch fire - like the Whirlpool ones. (I don't know whether they have sorted out the problems.)
How much have you got to spend? We recently bought a heat-pump tumble dryer. The efficiency is so much greater than our previous vented dryer, that we figure it'll pay for itself in a couple of years. OK we have 3 kids, my wife is disabled and I am working all day, so we have a lot of washing to dry and don't have much chance to get it out on the line, so we probably make more use of the dryer than others might.
Mine uses an occasional trickle of water during drying, which (being a washer too) just goes out the normal drain.
Unlike a dedicated dryer, I have literally never had to clean a build-up of fluff from anywhere, it gets washed away.
Make a hole for the vent using a Core Drill bit such as:
A condenser is about 20% less efficient than vented, apparently:
I've had it about 10 years and it failed once, a year or so ago. £5 part fixed it. Otherwise works fine.
But doesn't the heat used remain indoors as opposed to being squirted out through a hole to outside? Thus, especially during colder weather which is when one uses the tumble dryer, all the heat from the condenser dryer helps warm the house whereas just about all the heat from a vented dryer is lost.
Andy Burns submitted this idea :
I am surprised that works - we also have a washer dryer, but never use the dry fuction now. The actual heating elements are inside a duct, through which the air is circulated, but there is no flow of water in the duct to wash any fluff away - it just collects there and I could imagine it catching fire. The duct also has the coll water around it, to achieve the condensing.
A couple of years ago we bought the cheapest available heat-pump model, Beko brand, made in Turkey. It works, but rather slower than our old vented model, as it takes 1.5 to 2 hours to dry a load of washing, especially if cottons.
One problem is the condensate. It has an internal tank that you have to empty at intervals else the machine simply stalls till you do this. We found that this needed emptying far too often, sometimes twice per laundry load. The solution is to switch the condensate output into to an external drain for which they provide very basic instructions and a pipe. Fortunately I had one used by the washing machine that could be connected up without too much difficulty.
Other drawbacks of the Beko: the instructions manual is exceptionally poor, perhaps translated from Turkish into English via Chinese? But that hardly explains the omission of lots of important bits of information like what all the symbols are on the display. The machine also has a beep that tells you it is finished - so quiet that impossible to hear from any distance, certainly from another room, and so really rather pointless. But Beko were a lot cheaper than the competing brands, and so far it's worked provided you always use it on the "super extra dry" setting, so I'd give it a qualified recommendation.
I suppose there's energy loss from forcing the humid air through the condenser, but no, I don't get why it's more inefficient. Even after taking into account gains from heating the room.
Chris Green has brought this to us :
Well I am surprise that a condenser is less efficient. A condenser just ciculates the heated air and dries it. Vented, by contrast is a total heat loss system.
It depends on how bigger picture you look at. A condenser will use more energy since it needs to run a cooling capability to condense the hot water vapour. So in that sense "less efficient" since it will use more energy for the same load of washing.
However the vented drier will lob most of the energy used outside, whereas the condenser will keep it all in the building.
So in winter when you are also heating your home, that's say 4kWh for the vented drier per load, and little reduction in the home heating load, or 5kWh for a condenser, and a 5kWh reduction in heating demand.
So it might cost you 20 odd pence more per load, but you get to reduce your heating energy requirement by 5kWh. So if that is from cheaper gas, probably not much in it. If its a more expensive source of heat, then you will be a bit better off with a condenser overall.
So in your case I would go with the condenser, and not tit about core boring the thick stone wall (and that is speaking as someone with a core drill and set of cores!)
Or, build yourself a time machine, go back to 1980 and buy a White Knight gas tumbler dryer. Still going strong? ;-)
Tim
We bought a Zanussi heat pump dryer two years ago, it was about £350. It's been fine since.
It starts by saying it'll take either 1h34 or 2h44 to dry (always one of those times), but those numbers are bogus - it starts drying and then adjusts the drying time down appropriately as things dry. It takes account of the weight and the dampness to adjust the runtime. It probably does take
1.5-2h on average. It takes about 1kWh per load.
The tank is probably good for two loads - we don't need to empty it every time, although we do to avoid the risk of freezing as it's in an unheated space. It's probably safer for us to keep the tank than a pipe that might freeze up.
It beeps, but it's behind several closed doors so inaudible for that reason. You'd know about it if it was in the kitchen.
The symbols seem fine to me.
I wouldn't go back to a regular dryer where I'd worry about the bills, nor to air drying things in the house (a humidity trap).
Theo
Ours is a Beko too (DPHR8PB561W). We only used the tank once (it got about half full), simply because I wasn't ready to modify the pipework behind the washing machine, until the next day.
I don't remember what the manual is like, but the machine itself is just labelled up in English, with only the drying and sound symbols normally displayed (and yes the beep is quiet).
We mainly use Mix and sometimes Cottons (cupboard dry) or Night.
Well I guess if its pumping the damp air outside, then there is one less stage to the drying process, that is only just one fan one assumes. Condensing ones I have to assume have to remove the water from the air, so it has to be some kind of fridge type system or else it will make the whole house into a sauna!. I've often wondered if that is the case, or do they just keep it and pump the water thought yet another pipe into the drain?
Brian
Exactly!
Nothing as complicated as a fridge, Just a trickle of cold water (presumably over a metal plate?) so the hot air condenses there
The condensed water, along with the trickle of cold, go down the drain, easy enough when it's a washer dryer.
No such luxury with just a dryer. It appears to rely on the difference between room and hot humid air temperature to do its stuff. So maybe a colder room will be more efficient.
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