"Winter" hot water heater.

[CGW]

It's starting to cool off "up North" now, I never realised prior to moving up here how inefficient the water heaters are when cold!

In the summer, water heater is barely required, the winter is a different story, still have hot water but just a good sized trickle from shower if you don't want to freeze, one thing I enjoy is a decent shower, especially when its cool!

What are the options for "upgrading" without ripping down walls for rewiring? current "instant" heater is 8kw, which serves bath, shower and sinks.

 

If your a "southern softy" & never ventured "up North" you wont comprehend - why! ???? 

[Kwasaki]

We have a 7kw shower unit which get too hot If set to high even under extra power from the water pump,  power shower. ????

Never saw the point of water heaters in Thailand. 

 

Edited September 25, 2020 by Kwasaki

[Oldie]

I would say it is hard to give you a reasonable answer if you don't write anything about the existing wiring. 

[CGW]

55 minutes ago, Oldie said:

I would say it is hard to give you a reasonable answer if you don't write anything about the existing wiring. 

All I know is it handles 8kw and its copper & has '2 x 4" on the outer insulation. ???? 

[CGW]

1 hour ago, Kwasaki said:

Never saw the point of water heaters in Thailand. 

Thanks, there had to be at least one stating this, obviously we have a difference of opinion. ???? 

[Oldie]

6 minutes ago, CGW said:

All I know is it handles 8kw and its copper & has '2 x 4" on the outer insulation. ???? 

If your cable have 4 mm2 then this is not enough for 8kW already. At least if you want a correct installation. So a stronger water heater with this cable is a problem. You can take a water heater with a tank. But it needs more energy and has other disadvantages.

[trucking]

15 hours ago, Kwasaki said:

We have a 7kw shower unit which get too hot If set to high even under extra power from the water pump,  power shower. ????

Never saw the point of water heaters in Thailand. 

 

We've never had one as rarely need it even though we live northish.

 

However, on days where it gets down to 15-17 and a cold shower is a bit too bracing we just boil up a big pot of water on the stove ( about 5 minutes ) then mix it with cold water in the bathroom galamang. Low tech but actually prefer a big cascade of water to a shower. In any event , only need to do this about 10 days a year

[chickenslegs]

Seems that you need to "warm up" the water before it reaches the shower unit.

Something like this would do it (there are larger sizes if needed) ...

https://www.homepro.co.th/p/1104418

You would only need to use it in the cold season.

[CGW]

16 minutes ago, chickenslegs said:

Seems that you need to "warm up" the water before it reaches the shower unit.

That would work, but difficult to retrofit! would have to reroute water piping and would need another power supply, worthy of some thought - thanks.

 

Water to the house is cool! doesn't travel far, no other houses around, goes into a smallish stainless tank that is painted matt black which helps a little.

[chickenslegs]

2 hours ago, CGW said:

That would work, but difficult to retrofit! would have to reroute water piping and would need another power supply, worthy of some thought - thanks.

 

Water to the house is cool! doesn't travel far, no other houses around, goes into a smallish stainless tank that is painted matt black which helps a little.

Could you fit an immersion heater to that SS tank and set its thermostat to just take the cold edge off the water.

https://th.rs-online.com/web/p/water-heater-elements/7904811?cm_mmc=TH-PLA-DS3A-_-google-_-PLA_TH_EN_Catch_All-_-Fusion-_-7904811&matchtype=&pla-366797395160&gclid=EAIaIQobChMI3tqhk_-D7AIVUyUrCh1EdQzdEAQYAyABEgJvZPD_BwE&gclsrc=aw.ds

This is just an example, larger ones may be available.

Edited September 25, 2020 by chickenslegs

[Crossy]

Can you measure your supply voltage when the 8kW heater is operating? Power is a square-law against voltage the actual power of your heater may be well down.

 

Without re-wiring  / re-plumbing your options are limited, you could go for an LPG heater, but be aware of ventilation.

 

[CGW]

51 minutes ago, chickenslegs said:

Could you fit an immersion heater to that SS tank and set its thermostat to just take the cold edge off the water.

Tank also feeds toilets, kitchen etc, so not really. It holds enough water for 24 hours normal inside household usage.

 

45 minutes ago, Crossy said:

Can you measure your supply voltage when the 8kW heater is operating? Power is a square-law against voltage the actual power of your heater may be well down.

It drop's ~20v, (Note. heater is placed in one of the most inhospitable and cramped places in Thailand - or I'm old?)

I can live with what I have, but do enjoy a hot powerful shower, (I have no hesitation spending money on myself ???? within reason!) 

Not interested in ripping tiles off the wall for plumbing though, bathroom sits under a flat concrete roof that is filled with insulation so running power cables not practical or easy either. Gas not an option, too many negatives.

I was hoping there might now be a "alternative" heater, new to the market, looks like that is all it is - hope.

[Crossy]

2 minutes ago, CGW said:

I was hoping there might now be a "alternative" heater, new to the market, looks like that is all it is - hope.

 

Not wishing to coin a phrase but "You cannae change the laws of physics Jim", 8kW (or about 6kW with your volt drop) will impart the same energy to the water (and hence the same delta-t) whatever the heater "technology".

 

'Tis how it is I'm afraid.

[CGW]

5 minutes ago, Crossy said:

 

Not wishing to coin a phrase but "You cannae change the laws of physics Jim", 8kW (or about 6kW with your volt drop) will impart the same energy to the water (and hence the same delta-t) whatever the heater "technology".

 

'Tis how it is I'm afraid.

Yes, I get your point ???? 

But! if the energy could be used more efficiently, though it appears we haven't found a way of doing that yet.

My initial thought were that there was possibly a "storage" type of water heater that would be more efficient, I have seen the smaller ones but never looked into them, if you had a "reasonable" volume of water sat at a higher temperature, the colder water would take less heating/power - if that makes sense.

[Crossy]

5 minutes ago, CGW said:

Yes, I get your point ???? 

But! if the energy could be used more efficiently, though it appears we haven't found a way of doing that yet.

My initial thought were that there was possibly a "storage" type of water heater that would be more efficient, I have seen the smaller ones but never looked into them, if you had a "reasonable" volume of water sat at a higher temperature, the colder water would take less heating/power - if that makes sense.

 

One of the few electrical appliances that's nearly 100% efficient is a heater, pretty well all of the energy supplied to any appliance, your computer included, ends up as heat.

 

Storage water heaters use less power (and therefore provide less stress to the supply infrastructure) over a longer period to heat the water, it's still the same amount of energy used (they're not cheaper to run).

[Lacessit]

Er - how do you know the element on the water heater is not stuffed?

[sometimewoodworker]

3 hours ago, CGW said:

Yes, I get your point ???? 

But! if the energy could be used more efficiently, though it appears we haven't found a way of doing that yet.

My initial thought were that there was possibly a "storage" type of water heater that would be more efficient, I have seen the smaller ones but never looked into them, if you had a "reasonable" volume of water sat at a higher temperature, the colder water would take less heating/power - if that makes sense.

A storage water heater will overcome the problem of not being able to raise the temperature water enough because you live too far north. Though a teenage girl can easily defeat even that ???? 

 

8 hours ago, CGW said:

I never realised prior to moving up here how inefficient the water heaters are when cold!

The water heaters are not inefficient, it is whoever thought that they can raise the water temperature by 10 ~ 20 or more degrees with a high flow shower and put in a 3kw or 6kw unit. 

[CGW]

3 hours ago, Lacessit said:

Er - how do you know the element on the water heater is not stuffed?

Got that one covered! exactly what I thought my first year up here! so i bought a new one - result = exactly the same ???? 

it works great in the summer ???? 

[CGW]

12 minutes ago, sometimewoodworker said:

The water heaters are not inefficient, it is whoever thought that they can raise the water temperature by 10 ~ 20 or more degrees with a high flow shower and put in a 3kw or 6kw unit. 

Yes - incredibly stupid of me, after 23 years in Thailand at that time, I only put in an 8 kw unit thinking it would be more than ample, sure you had that one covered. I never realised how cool the water got up here! ???? 

[sometimewoodworker]

37 minutes ago, CGW said:

Yes - incredibly stupid of me, after 23 years in Thailand at that time, I only put in an 8 kw unit thinking it would be more than ample, sure you had that one covered. I never realised how cool the water got up here! ???? 

There are a few choices, get a gas water heater, they can put in the delta v you need.

 

Buy or install a solar water heating system to feed your heater so that the rise in temperature isn’t so much.

 

Add another water heater in series with your current one.

Put a black painted water tank on the roof and only shower at around 2 O’clock pm, that was something I learned to do about 30 years ago when staying in economy places in Chang Mae or further north.

 

Learn the fun art of cat washing so there is not too much water to cool you down.

 

Get used to having a not freezing cold trickle of water in the cold season.

 

Move south where cold water is about 20^oC

 

But I wouldn’t say stupid, just poorly informed.

[CGW]

23 minutes ago, sometimewoodworker said:

Add another water heater in series with your current one.

As I said earlier, this is about adding an extra dimension of comfort to my life, not essential, not going to tear the house to pieces for the sake of an extra ~10 psi when I shower, wife has her own bathroom and never complains so what I have is quite adequate.

 

It just so happens I do have a spare water heater! I'm guessing wiring them in series would pull more juice? be quite do-able if it was feasible?

[Crossy]

8 hours ago, CGW said:

It just so happens I do have a spare water heater! I'm guessing wiring them in series would pull more juice? be quite do-able if it was feasible?

 

Plumbing two heaters in series will reduce the flow rate so you may need to up your pump pressure. Try it without power first just to check you have the flow you want.

 

Also, you are already on the limit of your existing wiring so your second heater will need to be supplied somehow. 

 

Also is the "spare" a multipoint (like your existing unit) or a "shower" heater?

[Mama Noodle]

Pretty surprised 8kw isn’t enough for a scorching shower. 
 

Ive got one, and on the cooler days of the year when the water tank is cold, I might have to reduce the flow a little but that’s it. 

[JWRC]

I have a 50lt Hot water storage unit Thermostat controlled, however I don't leave it on all the time. At this time of year I turn it on 3 times a week for about 1 hour, December it might be 1 1/2 hours During the hot season, about once a week to give it a boost. It goes to 2 bathrooms and the kitchen. Installed this about 17 years ago after being totally disappointed with individual wall type HWS. It is bliss, always piping hot water, especially for washing up,  This was installed after the house was built, but no problem running the pipes and plugging in to the Electricity,

[sometimewoodworker]

8 hours ago, CGW said:

It just so happens I do have a spare water heater! I'm guessing wiring them in series would pull more juice? be quite do-able if it was feasible?

Put them in series was referring to the water supply not the electrical supply.

 

so cold to the first, slightly warm to the second, lobster cooking temperature to you. ???? 

 

electrical supply, once confirmed you’ve still got the pressure, as @Crossy has said has to be done in the conventional manner, as does fitting in the shower room.

 

The big advantage of this is that you can set up the second heater on a plastic stool with no power to it first and your cost is tiny as you just need a couple of extra water hoses to test for pressure.

Don’t forget that some heaters have restrictions built in with things like a rubber washer with a small hole and/or a plastic rod in the shower pipe, so you probably want to take those out for your test.

[sometimewoodworker]

46 minutes ago, Mama Noodle said:

Pretty surprised 8kw isn’t enough for a scorching shower. 
 

Ive got one, and on the cooler days of the year when the water tank is cold, I might have to reduce the flow a little but that’s it. 

What is the temperature of the water in the tank? 
because a water heater can increase only so many degrees at full flow. So if your water is at 5C you will have a very different experience than if it’s a 20C

[Mama Noodle]

33 minutes ago, sometimewoodworker said:

What is the temperature of the water in the tank? 
because a water heater can increase only so many degrees at full flow. So if your water is at 5C you will have a very different experience than if it’s a 20C

It’ll be whatever the ambient outside temps are. It doesn’t get 5C here. Coldest nights are probably 18ish, and that’s pretty rare.

 

Sure if it’s 5C out the heater is gonna struggle. 
 

8kw is a massive power draw, so if that’s not enough then alternative heating sources should be looked at (like gas). 
 

Or get a restrictive shower head. 

[sometimewoodworker]

1 hour ago, Mama Noodle said:

It’ll be whatever the ambient outside temps are. It doesn’t get 5C here. Coldest nights are probably 18ish, and that’s pretty rare.

That is quite possibly what tripped up CGW, as however long you’ve been in Thailand unless you’ve spent some time in the cold season in the north and at high ish altitudes you completely forget that there are night time temperatures into the single digits, possibly even negative, for part of the year. 
We regularly go into the low double or high single digits for a few days/weeks in the cold season and having got an expensive bedroom AC I was surprised and happy to see that it has a heating (via heat pump so not expensive) setting.

[Lacessit]

Just wondering if another solution is a solar water panel on the roof, to prewarm the water before it gets to the 8KW heater.

[Mama Noodle]

18 minutes ago, Lacessit said:

Just wondering if another solution is a solar water panel on the roof, to prewarm the water before it gets to the 8KW heater.

 

Cost would be overbearing, plus unless you install some sort of bypass, it'll be nuclear in the summertime.