Hot water for new house - two separate tanks?

[kitjohnson]

I'm planning a new build house for just two people to live in in Sai Mai, Bangkok. Water pressure here is bad, so I think that means we'll need a water tank. The in-laws who live nearby don't have one, and the shower often reduces to just a trickle.

We take cold showers most of the year, so just getting individual electric water heaters for each shower will take us through the cold months. But we're thinking about getting a bath (jacuzzi-style with jets), and I don't relish the thought of heating up all that water with an electric heater.

One thought I had was to have two separate outdoor water tanks. One would be shaded as much as possible to give cooler water, and the other would be in direct sun, perhaps painted black and with other modifications to keep it as hot as possible. I only ever would take baths in the evening, after it's had all day to get hot.

I just wonder if this adds significantly to the complication of plumbing. Most Thai houses just have cold water, but if we had two tanks then would we want to run two pipes into all the bathrooms?

I've spent an hour reading through threads on these topics, and a lot of people say the expense of a proper solar hot water system may not in some cases be worth it, as the initial outlay is high. The systems seem to have been designed for maximum efficiency - much more than is needed for the climate of Bangkok. Particularly since we are only two people and won't be using much hot water except for this bath.

[OLDMANHARRY]

Hi Kit

I had been looking for a hot water system for a long time for my shed, you can get small electric systems,there find for a shower , and there is sola Pang ,thou I wanted instant gas bottle Lpg there is nothing like this in Thailand so I brought it over from Australia a DUX 26L 50 I picked it up new on gumtree $400 payed for extra baggage $ 80 ,didn't get touched at Phuket airport , now I use it for my spa, and bathroom works great , gas bottle 375 Baht that's nothing.

Now for your water pump go for Mitsubishi demand pump that's what I use model 205 or 255 is heaps 5000 baht at homepro check out the septic tanks 1000lt is 7000 baht I use two and a make shift leech drain so far it works good.

Water tanks are,well I believe cheap 10000 baht for 3000lt tank I just brought 3 5000lt cosmos tanks for 17000 baht each for rain water this season.

Always run two pipes hot/cold even if you don't use it cheap as chips.

I hope this helps

Harry

[sipi]

Be careful storing warm water. It could become an environment for legionnaires disease.

[bankruatsteve]

If you just want hot water for a spa, there are so many solar systems from cheap and simple to deluxe you should check out. Storing hot water in a large tank just doesn't sound good for many reasons.

[bark]

I know many people who built or bought the spa bath tubs. They never use them and most cost 60-100,000 bt.

You will spend most of your life in Thailand trying to kept cool.

Good luck.

[straylight]

Solar panel and tank on roof.

[SOUTHERNSTAR]

Why put your tanks above ground? Firstly your cold water becomes hot. Secondly in drought years like this year above ground tanks can become useless when water pressure fall the tanks dont fill up. According to me its better to have an underground tank. At present all our neighbors with above ground tanks have to buy tanker water while our municipal water is still ok. On the bath tub/jaccuzi issue I believe that you will use it not more than once a month and in the end the cost and bother to maintain it is not worth it. Rather use that money to entertain the gf or wife on a regular basis, the result will be the same.

[Khon Kaen Dave]

Legionella is respiratory,it is most dangerous when inhaled,e.g in a shower room.There was a big problem in London years ago when a lot of elderly people living in a block of flats were subject to the constant change of temperature in the cooling towers.

personally,i have never heard of anybody who has died of Legionella here,but i suppose it happens.

[chilli42]

I am no expert but maybe you are over thinking this a bit. We have one large tank that we keep in a shaded area - some kind of fiber/plastic material. It is filled by a strong/good quality pump. And water pressure is also supported by a pump. To heat we use the electric wall units. We have a household of six and a Jacuzzi tub. Works perfectly ... cool water, hot water, tub.

[chilli42]

Why put your tanks above ground? Firstly your cold water becomes hot. Secondly in drought years like this year above ground tanks can become useless when water pressure fall the tanks dont fill up. According to me its better to have an underground tank. At present all our neighbors with above ground tanks have to buy tanker water while our municipal water is still ok. On the bath tub/jaccuzi issue I believe that you will use it not more than once a month and in the end the cost and bother to maintain it is not worth it. Rather use that money to entertain the gf or wife on a regular basis, the result will be the same.

A good point. We had underground tanks but the tree roots broke into them and we had to replace. So be mindful of this issue when placing tanks.

[Anon999]

I am no expert but maybe you are over thinking this a bit. We have one large tank that we keep in a shaded area - some kind of fiber/plastic material. It is filled by a strong/good quality pump. And water pressure is also supported by a pump. To heat we use the electric wall units. We have a household of six and a Jacuzzi tub. Works perfectly ... cool water, hot water, tub.

Sounds as though you are sucking water direct from the main supply like many Thais do which is illegal. We have 4 tanks, an underground tank that the pump takes the water from an above ground tank that is filled from the main and acts as a header tank, keeping the underground tank topped another tank in the roof space and a hot water tank on the first floor in an airing cupboard that is electrically heated. All the taps are mixers. Should there be an electrical failure or the underground tank becomes empty we can switch a valve over to allow gravity to supply water for a shower in the downstairs bathroom and for the washing machine, etc.

[kitjohnson]

Good to hear a mixed bunch of replies here. My preference is to keep things simple, so use the electric heater that comes with the jacuzzi, but I also really like the sound of Arjen's DIY set-up.

Then there is the question of "Do I actually want a jacuzzi?" I just set-up this poll to see what proportion of people have a jacuzzi actually use it.

[rapom]

Heating water in a tank, even when it is painted black will not work.

The sun here has a power from nearly 1.000 watt/square meter. In BKK maybe 950 Watt. Maximum the half from your tank will be exposed to direct sunlight. Most heating from the water will happen by air temperature. Not by sun radiation.

The simplest solution will be to run a few meter of PE tube. Connected to your tank, but lower then your tank. When the PE tube is filled with water, water will circulate, and heat up the water in your tank. To increase efficiency, isolate your tank and ad a valve what has to be closed when there is no sun (or use a solenoid what closes when water temperature in tank is higher then water temperature in PE tube)

And yes, you must admit a double tubing system.

I made a system similar as described above, a bit more advanced. It supplies our house already 12 years from very hot water. Even on days without sun, and even after several days without sun.

The investment was high, but I.am.sure I have earned it back. But never made the right calculations.

I have to disagree somewhat to your second sentence. We live NE of Surin and our home does not have a hot water heater. Most days, we fill our bath water basin in the morning and bathe at night, when it is at room temperature. When the weather is cooler, I have 3 thirty liter black plastic trash cans with lids that are used to supply hotter water. I sit them near the SW corner of our house, about one foot from the wall which is painted white. I fill them to about 4 inches from the top and put the lid on. They are exposed to the sunlight all day. When it is bath time,we carry two of them inside to bathe. I have never measured the temperature, but the water has to be at least 37 C, when the air temperature was only in the 20's for the day. Also, in your third sentence, I believe something is missing. Are you referring to using a looped piping system that uses thermal hydronics to heat your water. If PE piping if exposed to sunlight,the water in the tank will never get as hot as the piping. The water in the tank will always be cooler.

[thailand49]

You can first place electric water heater for showering they can run you 4.000 Baht and up depending on the power of the unit then there are units I paid I believe 8,000 for the unit to fill my bathtub with hot water. You need to ask the guy which type of unit you need for the Tub. Even a guy at HomePro can point you in the right direction. It is a nice idea but I was no exception after it was put in, I think I used it twice in ten years. As noted using the sun to warm your water? You been watching too many "Green books" wait up and smell the coffee. What you think you are Paul Bunyan? As for the water pressure is low you need a pump not a tank!

Edited May 10, 2016 by thailand49