Now You’re Washing With Gas

[Michiel] likes to wash his clothes in warm water. Like a lot of machines, his draws from the cold water line and  heats it electrically. Gas is much cheaper than electricity in the Netherlands, so he wanted to be able to heat the water with gas instead. Hot-fill machines already exist, but few models are available and they’re all too expensive.  [Michiel] rolled up his sleeves and hacked his brand new washer into a hot-fill machine.

He started out thinking that he’d just connect the hot water line instead, but that proved to be too hot. He found out it needs to be about 35°C (95°F), so he decided to mix input from the hot and cold lines. Since it’s a shiny new machine, [Michiel] wanted an externally mounted system to keep from voiding  the warranty. He got two solenoid valves from the electronic bay and used a PIC16F to make them dance. He wired up a light switch on a two-panel face and used the blank plate for power and status LEDs.

[Michiel]’s design works like a charm. The machine used to draw 2000W to heat the water, and peak usage now is as low as 200W. He noticed that the washer drew a lot of power in standby mode so he added a solid state relay and a bit more code. Now the electricity to the machine is cut after two hours and [Michiel] saves about €97 per year.

64 thoughts on “Now You’re Washing With Gas

  1. I’ve yet to see a washing machine that doesn’t have hot & cold inputs with internal mixing depending on cycle selection (got my current one off Craigslist for $75, in fact…), they’re neither rare nor pricey. Am I missing something?

          1. In the UK, all washing machines used to have a hot intake, now they only seem to have cold. As long as you keep the temperature low, you can run them from the hot pipe, but it’d be an expensive mistake to get it wrong once.

            Is it some legal thing? In the age of energy-efficiency rating stickers on every white good, why remove the hot-water intake?

      1. Maybe so. As an American, I’ve never seen a motorized washing machine that didn’t have separate hoses for hot and cold water (or if I did, the hoses were hidden behind it so I didn’t notice, and it was at some random hotel in Europe.) On the other hand, most home kitchen dishwashers here seem to take hot and cold water but then heat the hot water electrically to a higher temperature. Dryers might be electric or gas, depending on what you’ve got available, and gas is also much cheaper to operate.

        My grandmother had an old wringer washer (the type where you’re washing your clothes by hand on a washboard and then squeezing the water out with crank-powered rollers), and you could fill that with any temperature of water you had around, but that didn’t count, and by the time I saw it (1960s) I’m pretty sure she’d have had a washing machine for regular use and only kept the wringer around for washing random things.

        1. My dishwasher only takes hot water. Before you run it you’re supposed to do all the handwash-only dishes so that the hot water is as hot as it gets so there will be less of a need to use the electric heating element in the dishwasher.

          1. We have one that we call a “roll up dishwasher” because instead of being permanently installed, you roll it up to the sink and hook it to the faucet using a spigot adapter, then roll it out of the way when done. It also is supposed to only accept hot water, and you are directed to get the water as hot as possible before connecting it.

            We rarely use it except as an extra drying rack for large pots and pans, because it’s such a hassle to operate. We do use it occasionally to sterilize the dog’s food and water bowls though.

    1. In most of the world, washing machines are front loading and combine dryer functionality as well. USA is spoiled — we built our plumbing & gas infrastructure almost entirely in the 20th century.

      1. I tried a front-loading washer the last time I needed to buy one (some German brand, I think Siemens.) It didn’t get the clothes wet enough to get them clean; I returned it for an American top-loader.

          1. Nonsense. It’s a fact that modern washing machines don’t use enough water in either the wash or rinse cycles to clean or rinse properly. This is due to the eco friendly guidelines decreed via Brussels. I live in England, and have been through several washing machines (with hot & cold fill, and cold only), and so appalled by the quality of the wash from modern machines I’m thinking of getting an old twin tub.

  2. I also live in the Netherlands, but I’ve never seen a hotfill machine here, which I have always found very strange.

    My own washing machine still uses cold water, but I do feed my dishwasher hot water at about 60C. It works in both the 55C and 65C programs.

    Electricity is about four times as expensive as gas per unit of energy, so it really is an easy way to save on the energy bill. Besides that, it is of course more efficient to heat water directly, as opposed to converting it to steam, driving a turbine, which drives a generator, going through a series of transformers and power lines, and then just dumping it in a big resistor to heat some water. Quite ridiculous, if you think about it.

  3. Sorry to be a little off-topic here, but is there some reason I can *never* see the main article image on this site until I reload? Everything else shows up first load, but the main article image always is a broken image icon until I refresh. Thought for a while it might have been a way to discourage Adblock, but I’ve had that off on this site for a long time now, and it’s still happening. I think it started with the last big redesign.

    Oh, and yeah, American here, never have I seen a washing machine without hot and cold inputs. Dishwashers, on the other hand, only have a hot water input.

    1. Well what do you know, it seems that having hot water in homes is uncommon in the EU therefore its uncommon to have both to the washer. how wierd. Is this because most of your homes there are 1000 years old or older?

      1. > it seems that having hot water in homes is uncommon in the EU

        not true, I live in Germany and i have never once seen any house that didn’t have hot water. (running in pipes, i’m not talking about kettle and bonfire ;) )

    2. We do have LG and many others and of course you can select washing temperature in all of them…either you can choose between 2 different temperatures (hot/cold program) or you can directly set your desired temp. But is not very common to see hot/cold water inlet hoses.

  4. Ok, all fine, but the last part of washing clothes ie. the rinsing/flushing HAS to be done in a COLD water, otherwise you’re left with a skin-irritating particles of leftover washing powder embedded on your stuff (if you’re from the “washing is done by washing machine, by hand, dafuq?” generation – ask your mother/grandmother etc.). And yes, even those fancy hot/cold connected machines do this last rinsing cycle in cold water. I don’t see any non warranty-voiding method to do it properly without hacking into the “brains” of the machine itself to sense when to stop pouring the 35C into it. IMO: fail, not win, unless you like developing skin allergies and rashes over time.

    1. He have it switch to cold water only after a set time. Measuring the time from start to rinse should not be that difficult.

      Or if he wanted to add some flow sensing he could count the number of times that water was requested by the washer and after so many requests switch to cold.

      If the washer is equipped with an LED telling him what part of the cycle the washer is in, he could use a light sensor that to trigger the hot water to turn off.

      1. Same here. I have programmed the PIC to allow hot water for a fixed amount of time when filling. After filling ( lets say 30 min ) only cold water is supplied so when its time to rinse ( after like 30 min ), it does it without warm water.

        0 min – Activate by switch
        0 min – Supply power and start mixing water
        30 min – Supply only cold water
        60 min – Rinsing starts ( +/- 20 min)\
        120 min – Cut power, and close both valves ( overwrite can be done by switch )

      1. The soap is already dissolved at this point of the wash so that’s not particularly relevant. It would actually be better if the soap precipitated, then you could get it all out instead of just continuously diluting the concentration. But probably the greatest effect is the sudsing, the bouyant soap bubbles which remain floating on the surface no matter how much water pours through the pipes. Lower temperatures result in less suds, meaning the soap will wash out instead of floating on the surface.

    2. I live in the US. I buy only older appliances because they’re more durable/repairable. And every washing machine I, my mother, and grandmother have ever owned had hot water rinses, if that’s what the temperature switch is set to. When repairs were necessary, on the schematics I found a single contactor in the timer responsible for controlling power to the temperature selector switch, which in turn powers one or both solenoids according to its setting; so it’s quite impossible for them to select different temperatures for different cycles.

      A little Googling reveals cold water rinses are a feature of newer washers, forced on consumers to save energy. Leaving some wondering why their new washers leave their clothes poorly rinsed. And shopping around for one of the few high-end washers that still allow you to select rinse temperature, or going back to old washers, or manually repeating a wash cycle (on hot) without detergent to work around the problem with the existing washer.

      So although you’re wrong, I’m glad to have learned yet another reason why my old appliances are better.

    3. “I don’t see any non warranty-voiding method to do it properly without hacking into the “brains” of the machine itself to sense when to stop pouring the 35C into it”

      I do. : )
      I first thought of measuring the current drawn by the machine. This must contain some sort of ‘fingerprint’ which can be identified by the microcontroller.

      1. Um… it is switching 200 watts of power, and is in a enclosed case which will raise the temperature of the SSR possibly requiring it needs to be derated. That also assumes there is never a fault in the machine which could cause a increased current draw. I tried looking for a datasheet for this SSR but couldnt find one.

    1. Perhaps, could it be, that you are wrong? Like perhaps that metal back is heatsink enough on its own, or the massive case itself can shed enough heat?

      And if you were right, could you tell me how much heat it has to dissipate and where/how it originates?

      1. The TRIAC inside the SSR has a when-on main-terminal voltage of somewhere around 1V. In the EU, 200W is less than an amp, so there’s less than 1W of heat dissipated in the TRIAC.

  5. Europe, where American efficiency “gurus” keep claiming is so ahead of us on appliance efficiency, has mostly highly inefficient clothes washers with built in water heating instead of simply using already heated water from the main water heater…

    Some combo washer/dryers are sold here but most of them don’t use heated air, they just tumble the clothes for a long time and blow ambient temperature air through. If you like to keep your house at 60F in the winter, one of those will take a very long time to dry clothes.

    I’ve yet to see a dishwasher with anything but a single hot water connection.

  6. All the talk of not having hot-feed washers in Europe is very strange – I bought my washer/dryer over 15 years ago, and it has both cold & hot feeds. It wasn’t even an expensive model. In fact, it was one of the cheaper ones.

    American washing machines are not ahead of the EU, they’re behind – top loaders are long extinct in the UK, in the same way that gas guzzlers are.

    1. Today, having a washing machine with hot&cold inputs in Europe puts it in another class, which mandates extra eco friendly rules. That is why this feature almost just disappeared overnight in 2008.

      1. Leaving us with electrically-heated washing water, instead of from gas. What a brilliant move that was for the environment!

        This is a bug that needs solving, I’d write to my MEP if I had any idea who he was.

      1. Maybe it has something to do with the fact they use electric boilers in great parts of Germany and France. In France it’s even quite common to use a electric heaters instead of gas. But I live in the Netherlands as well and I would like to see more hot/cold washers in Europe.

    1. I read it the same way, and my mind instantly went to what our friends on the other side of the pond would call petrol. I really had my doubts about the efficiency of this… glad I read the article! (Note: petrol works great for cleaning grease off of metal, but I don’t think it would fare well with fabrics once you put them in the dryer!)

  7. In modern detergent are enzymes (protease) that solves the albumin in the the clothes, Those enzymes are destroyed at higher temperatures, so don’t fill in hotter water than 55°C

    1. modern detergent?
      you mean EUROPEAN cold water only stuff
      very advanced!

      seriously, cold water for washing clothes?
      what planet did you grow up on?
      ive washed fabric before by hand, in a sink,
      using NORMAL (hotwater) CLOTHES SOAP.
      or you will be re-rinseing several times and STILL slimy with soap.
      what kind of crack is being fed to your engineers/politicians?

      what next a law saying all cars have to be driven in reverse?

      the only time ive used a cold water only machine with cold water only detergent was while visiting europe.

      1. the only other time i had ruined clothes was back in warmwash country.
        when i accidentally hit the temp sw. and washed cold.

        cold water puts reeeally gross looking white stains all over.
        the funny kind … impossible-sized … had a good laugh.
        it looked cleaner going in.

        and again,
        extra wash cycles without soap did NOT fix the soap+coldwater stains problem.

  8. It could be just me, but why not use a standardized hot&cold mixer thing that we’ve been using for nearly 20 years to (automatically temperature controlled through the miracle of bi-metals) fill our bathtubs and take showers with?

    I’ve been using a mixer like that on my washing machine (which stands directly behind the wall of my bathroom shower (hence the access to cold & hot water pipes) for over 8 years now.. thats nothing new.. sure, it’s not exacly 35 degrees celcius, but what do I care.. I never wash colder than 40 degrees anyway.

  9. First I would like to explain how the hot inlet works on many machines (that have them). The machine normally expects the hot inlet to be around 60 Celcius (very hot). Thus for washes below 60 Celcius it does not take any water from the hot tap at all, so unless you are using a very hot wash, no water is used from the hot tap.

    Another problem can happen with the hot inlet is that when it is being used, it can take 10 or 20 litres of water before any hot water arrives, if the source of hot water is a long way away from the washing machine. In these cases the machine is already filled at this stage, and so hot water moves towards the machine, but only cool water fills the machine. The hot water that moved towards the machine is wasted, as it sits in the pipes and cools down. This is also true for combi (combination) gas boiler systems. These do not use a reserve hot water tank, instead instantly heat the cold water from cold to hot, in response to a hot tap being turned on. These take a small amount of time to deliver hot water,

    As already said, machines take in water, and then heat it up to a higher temperature if needed. I have never seen a two inlet machine that mixes hot and cold to get a medium temperature. If they have two inlets they use the cold inlet only for washes below 60 Celcius. However generally later on in the cycle they rinse the clothes with cold water only. Adding warm water at this stage is a waste of energy, and as others have said, may not wash away the suds and give a bad result.

    Used valves are easy to get from old washing machines. They are generally mounted exactly where the water inlet is connected and use AC to turn on. On front loading machines they are generally at the very top and easy to access.

    So as others suggested, it would be simplist to use a thermostatic mixer tap, but also to switch over to cold water after a short time to allow rinsing with cold water at the end. If you do not pay for water quantity a way of “running the tap” down a drain until the water gets hot, before starting the machine would ensure the machine only gets hot water from the start. All this could be mounted in an external unit, along with leak detection for an ideal energy saving unit.

    This is a great hack, I often thought about a similar unit, but this guy delivered! I am not sure if the costs savings would be reasonable for a commercial unit, and if the market would be big enough, but the technology would be fairly basic and an ideal DIY install, and could be sold online or in stores.

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