Small electric boiler? Featured

I think it may depend on what the (worst case) goal of the solution needs to cover?

If it includes actually *needing* a bowl full of washing-up temperature water several times a day than anything 'instant' is going to have to be pretty powerful, as is any local water store, if not either quite high capacity or high power (for reasonable recovery time).

I've no idea how powerful our balanced flu combi-boiler-sized multipoint water heater is but even that would take quite a time to fill a basin with hot water (mainly the time taken to get the hot water to the basin) and a fair time to fill even a corner bath, as does the combi boiler in daughters flat (where you start the bath running then go and do something else for a good time).

When having baths at Mums years ago with a big HW cylinder you could run a bath pretty quickly (all be it only one without waiting ages).

And if you were suggesting filling a kettle with hot water from any such hot water source, I'm not sure what advantage that would be other than saving time?

There isn't anything much more efficient than a kettle (the element in direct contact with what it's heating in a reasonably insulated (plastic?) container) and so likely more efficient than heating and storing the water to use later or from an instant heater (unless gas because of the potentially cheaper energy costs).

If you are talking of washing crockery, depending on how much and how heavy the soiling (baked on stuff that might appreciate being soaked), I wonder if Jeff could test / vouch for how practical it might be to wash a plate under the instant hand washer?

Cheers, T i m

Thanks Tim, very informative. Youve certainly added to our list of needed considerations. I like the "back to simplicity" kettle idea.

ISTR the problems arise the moment that you have to put in a pressure reducing valve. I don't see a maximum rated mains pressure on that one.

Our VH water supply is roughly 4bar going on 5bar at night in winter. The water heaters are rated 3.5 bar maximum working pressure. (hidden in the small print somewhere)

Once you need a NRV, expansion chamber and pressure reducer to install them it becomes quite a complicated installation under the sink space.

and the cost about doubles.

Owain

You are more than welcome.

I think it's one of those things that can sort of answer themselves, when you get a feel for how much energy it takes to get water to the temperature you need for your particular task.

And that (without us realising it possibly) can provide a fairly good indicator of how much energy over what sort of time it's likely to take any solution to get a known quantity of water up to the desired temperature (or 'science' as it's called). ;-)

eg, Say you found you needed a whole 3kW / 2l kettle of water to make enough washing up temperature water and that took 2 minutes to boil, then it's likely to take any 3kW water heater around that time (likely longer) to get that volume of water to that temperature.

Even the biggest / most powerful burner on the hob generally takes quite a while to get 2l pot of water to the boil, especially if you are watching it. ;-)

Cheers, T i m

Well for my mate in the shop and us at home for the hand basin, as instant as possible hot water, hot enough to wash hands is about all we need. Eg, he doesn't do much washing up (just rinses his cup now and again) as he brings sarnies in from home in a Tupperware box (trying to eat hot food when running a retail shop on you own isn't easy).

Oh, sure but see above.

For us we would retain the Multipoint hot water supply so would still have continuous hot water there if we could efficiently consume the initial cold (like when running a bath).

That's my main bugbear, especially when it's not been run for a while.

True, but I also feel guilty about wasting perfectly good drinking quality water (even though we aren't on a meter). ;-(

If it was the smaller (3kW) one and you could get easy access to both the water supply (above the sink) and electricity (I have on the other side of the wall) then if use alongside any existing solution, should give you the best of both worlds?

Given we now have and are enjoying quite a bit of home automation now (automatic lights in the hall, landing and kitchen), I think I might like the idea of an 'automatic' hand wash water heater, subject to being able to use the existing taps without triggering it etc.

Cheers, T i m

The cheapest way is to boil a kettle. A kettleful of boiling water is enough for washing up/hand washing clothes, once diluted with cold.

if your water comes from Hardham then a lot of their water is now sucked in from the adjacent river Arun. They built a new inlet and piped it under the A29 to get to Hardham treatment works.

I managed like for quite a while after ripping out the Baxi Bermuda back boiler, and just used the immersion heater on a Smiths wired-in timer for larger quantities.

So you might just as well investigate a Quooker

A Lirpa Loof ?

There is always the option of an induction hob too. Just heat up a (non-electric) kettle on it, unless you already have a gas hob which is just as fast. Failing that get a 3Kw kettle before the EU ban them.

Yes, I do end up doing that. Crazy really :-)

Yes me too. I'm not sure it's 'waste' exactly (doesn't it just go round again?!), but whatever, it grates.

Not sure the over-sink is what I'd want, but I have space and a 13A socket under the sink - I'll give it some thought.

I was wondering about feeding an instant electric heater from a hot water supply.

This might sound strange, but hot water supplies aren't always hot:

- there's the leg of cooler water before the hot water comes through

- in a tank system the boiler may not have run recently and the water be lukewarm

- the storage temperature may be lower than you would want for washing dishes

Is there any reason not to feed such a heater from say a 30-60C supply?

Theo

Yes, I believe it does (7 times or so before getting back to the sea?), but I'm guessing it must 'cost' per loop and I just think how grateful some would be for fresh water on tap like that. [1]

I agree, unless it could be fitted where it was un intrusive from a general usage of the basin and conventional taps POV.

I think the 'under sink' solution brings a whole extra set of issues but I agree, if you have the space, don't mind the cost and work of ticking all the boxes ... one in-line with any existing hot water supply as to reduce the warm up time / energy usage (assuming a gas instant hot water feed and the inline system ok with a hot feed [1]).

Cheers, T i m

Coincidentally I have referenced such an idea elsewhere and belive someone here is already (successfully) doing such a thing.

I set the temperature on our Multipoint to not be too hot (for hands) when running at full temperature but there may be a slight conflict of interest between the temp required at the basin and the sink (the sink maybe wanting it hotter for heavy soiled crockery / cookware if we CBA to use the dishwasher).

A mate has a very long house with the indirect HW tank in the middle of the building and the main bathroom at one end. I'm guessing it could be ~20m between the two and with those stupid 'waterfall' type taps it takes *ages* [1] to get hot water at the basins especially if it's not been used for a while.

Cheers, T i m

The other two bathrooms are nearer the HW cylinder and he has Quooker taps in the kitchen and utility room. ;-)

Funnily enough I'd been thinking about that myself. I am sure it would work very well - I never use a bowl for washing up anyway, just a thin stream of hot water from the kitchen sink tap and a sponge/scourer pad with some washing-up liquid on it. The extra force of the instant-heater spray should shift food residue on the plate far more efficiently than the stream of water I use. In any case, isn't that how dishwashers work

- by spraying hot water onto the soiled crockery, pans, and cutlery?

On a somewhat unrelated, or perhaps related, matter the problem of hard water was raised earlier. Does anyone know why the heated parts don't seem to suffer much from furring up, but spray heads and shower heads do. Is it just that when they are switched off the calcium and magnesium salts in the water are deposited when the water evaporates?

Oh well, at least it should cut down the flooding on the Pulborough Levels!