New House Hot Water System

[JonnieB]

I am planning the building of a small 3 BR 2 BA bungalow style home for 2 people. I need advice on the appropriate hot water system for the house...either a single large water heater piped to the hotwater outlets in the bathrooms and kitchen or small (under-counter) heaters at each hot water point. the two bathrooms will have one wash basin each and one a combined bathtub/shower unit and the other only a shower. there will also be hotwater at the kitchen sink.

again there are only two people living in the house and not much hot water is required. i only use hot water for showers during the "winter" season (Dec.-Feb.). The rest of the year, I just use ambient temp water for showering. I do use hot water at the basin for shaving and hand-washing. hot water is also used for dishwashing in the kitchen.

is it more cost effective and energy efficient to have a single larger water heater tank constantly heated and piped to the several outlets or is it better to install small individual heater tanks in the basins and shower water heater units?

also, from a safety standpoint, is one better than the other (assuming the grounding is done properly in either instalation)?

Thanks in advance for any comments.

[CGW]

I would stick with the under sink type, I wonted to put a fairly elaborate hot water system in (Thai standards) but simply struggled to find anybody capable of carrying out the work.

Given your needs single units, will be adequate and certainly cheaper to run and install.

Cheers

[GuestHouse]

I'd put a solar heater in, one unit will provide hot water for the whole house. Installation costs are higher, but there are no running costs.

The cost of electricity is going only one way.

[elkangorito]

I'd put a solar heater in, one unit will provide hot water for the whole house. Installation costs are higher, but there are no running costs.

The cost of electricity is going only one way.

I agree with GuestHouse entirely but bear in mind that a good solar hot water system has a storage tank. The heated water should be circulated through this tank by convection (pay special attention to height of tank compared to water outlets) or by a small circulating pump (Grundfos specially make hot water circulating pumps...about 300 to 500 watts energy consumption. These pumps run continuously).

http://www.grundfos.com

Because you have only 2 people in your household, I would go for an instantaneous hot water heater ('under the sink' type) but ensure that it is VFD controlled & not thermostat controlled. More expensive running costs compared to that of a solar system but cheaper installation costs (as previously stated by an earlier poster).

Thermostat controlled instantaneous hot water units switch off the heating element when the water flow is reduced or it has reached temperature. This leads to 'hot/cold/hot/cold' showers. VFD units (Variable Frequency Drive) variably reduce the heat that the heating element produces thus eliminating the 'hot/cold/hot/cold' shower syndrome (the heating element only switches off if the flow of water is reduced below a safe 'temperature' threshold).

Also & based upon a 10 minute maximum shower time, most people use about 200 litres of water during a shower unless a water saving shower rose is used. To figure out how much water is used, use a bucket that holds a known quantity of water (ie 4 litres), take it to the shower, hold the bucket under the shower, turn on the water & after 1 minute, turn off the water. Multiply how much water is in the bucket by the average shower time that your family uses. This will give you the approximate amount of water used in a shower, in this time period. This will help to correctly size your solar hot water tank. For example, you have 2 people in your household. Each person uses 150 litres of water during a shower. Assume that 50% of the water used, is hot water. Therefore a 250 litre hot water tank is required if 2 people need to shower immediately after each other (not forgetting that cold water is introduced in to the tank as hot water is used & therefore the overall water temp will decrease).

[jomama]

I just ran across a guy the other day who is importing solar hot water heating units from Israel. Cost is about 50,000 baht with solar panels and a tank that sits under the roof and gavity feeds hot water to the house. He said one can locate the tank anywhere, but would then require a pump.

In my house we already have an electric tank that feeds hot water to several rooms; I'm thinking to see if I can use that tank as the solar tank too, and set it so that if solar hot water runs out or its not been sunny enough, the eletric unit will heat water.

If you want his contact info, PM me.

Cheers

[chownah]

If you get a circulating pump on a solar system you do not want it to run continuously...you want it to turn off whenever the collector is a lower temperature than the water in the storage tank....for instance at night!!!!...otherwise you will be circulating hot water to the collector and it wil be being cooled instead of heated.

A properly designed solar hot water system will maintain a relatively constant temperature as you draw off the hot water...a poorly designed system will be constantly losing temperature while you use it.

Chownah

[JonnieB]

Thanks for the replies.

I think for my needs, it seems to be the consensus that individual instant heaters are the way to go. Solar is of course free after instalation costs but I worry about ongoing maintenance issues and finding competent service techs when needed.

The individual units seem fairly inexpensive to buy and run and technically simple.

Can anyone give any reccos on brands. I saw some nice Fagor units at my local Home Pro. The man said they have a bigger flow-thru volume than most other models (and it did have a much bigger shower-head than all the others).

[chownah]

I recommend gas over electric. In many/most places you will get voltage drop whenever the shower is used if you go electric and obviously this is not a problem with gas. Also I've never seen an electric unit that got water as hot as my gas unit and living here in the north that's important since it gets really chilly here in the cold season and many electric heaters really don't do the job here in the cold season. I've got a National gas heater and it works fine....Ecolux makes some also and I've heard one good comment about them and no bad ones.

[lopburi3]

That may be the difference between the north and Bangkok but I had several National gas heaters and they were overkill here. Believe they had four flames and had to kill three to keep the temperature below scalding most of the year. Very happy to have made the change to electric.

A warning if you do go gas to make sure to provide good ventilation, air flow.

[bcross2001]

I recommend gas over electric. In many/most places you will get voltage drop whenever the shower is used if you go electric and obviously this is not a problem with gas. Also I've never seen an electric unit that got water as hot as my gas unit and living here in the north that's important since it gets really chilly here in the cold season and many electric heaters really don't do the job here in the cold season. I've got a National gas heater and it works fine....Ecolux makes some also and I've heard one good comment about them and no bad ones.

Hello - what is difference in cost to heat say 100 liter of water with electric as opposed to gas??

Barry

[chownah]

A tank of gas costs about 275 baht here. We only heat water for showering. It lasts my wife and I for two months even in the cold season and maybe 3 months otherwise....don't know about the cost of electricity but one kilowatt hour is about 860 kiloCalories and one kiloCalorie will heat one litre of water 1 degree C. Maybe you can estimate from that..or a water heater running at 3000 watts for 20 minutes will consume one kilowatt hour...I think a kilowatt hour costs about 5 baht more or less....it varies depending on where you live.

At any rate, in our budget the cost of natural gas for showering is minor. I was surprised when I discovered that it takes more gas to cook our food than to shower.

By the way, the National heater that we bought is really only suitable as a shower and wouldn't be practical for a basin or kitchen sink.

Chownah

Edited June 27, 2006 by chownah

[bcross2001]

A tank of gas costs about 275 baht here. We only heat water for showering. It lasts my wife and I for two months even in the cold season and maybe 3 months otherwise....don't know about the cost of electricity but one kilowatt hour is about 860 kiloCalories and one kiloCalorie will heat one litre of water 1 degree C. Maybe you can estimate from that..or a water heater running at 3000 watts for 20 minutes will consume one kilowatt hour...I think a kilowatt hour costs about 5 baht more or less....it varies depending on where you live.

At any rate, in our budget the cost of natural gas for showering is minor. I was surprised when I discovered that it takes more gas to cook our food than to shower.

By the way, the National heater that we bought is really only suitable as a shower and wouldn't be practical for a basin or kitchen sink.

Chownah

Thanks Chownah for the information - that deing said and done what size's of gas water heaters are available (does anyone know) do they have say 100 plus liter gas water heaters like they do in China?

And what would the cost of these be like - it is apparent that gas is cheaper then electricity - but are there family size tanks available.

Reggards

Barry

[lopburi3]

I believe we were talking about instantaneous type water heater (I know I was) rather than the tank type. Most homes are not plumbed for hot water so only have at point of use. Home Pro type place may have the type heater you seek but in the past they have mostly been used for hotels (who were able to import duty free) so you may pay a premium.

[chownah]

My National is a shower unit. I know that Ecolux makes an on demand (instantaneous) gas heater that you can plumb into a distribution system and then have hot water where ever you want....you can not do this with my shower unit because you need to start the flame manually each time you start it up and turn it off each time you stop using it....the Ecolux unit evidentally starts up and shuts down automatically. Hot water tanks are available...at least in some places because I've seen them at a local hardware store (in the north) but all the ones I've seen are very small by western standards. It was strange because when I asked them why to use a tank style they said it used less electricity...but...in the US the usual wisdom is that the point of use/on demand (instantaneous) water heaters are more efficient....go figure!

Chownah

Edited June 27, 2006 by chownah

[staccyy]

Anybody knows the difference in cost from a "good" electric one VS a good Gas. I live way out in the sticks have to drive over 5 hours to find the gas type. thanks!

[chownah]

Gas water heates cost appreciably more...if you need to save money short term then electric is the way to go...low watt off brand water heaters are really cheap and they are likely to last a long time as long as you don't break off the knobs which tend to be flimsy on all cheap appliances. I have never seen a really cheap gas hot water heater....except for the fact that you can easily heat water on the gas cook stove in which case no additional investment of capital is needed at all for your bath!!

[Gary A]

I replaced an electric Electrolux 3500 watt unit with a Panasonic 3500 watt unit. The Electrolux worked fine but the water on/off was controlled with a valve. The Panasonic turns on the electricity and the water with the push of a button. I think the Panasonic was a little less than 5,000 baht. I wouldn't have the patience to have to light a gas burner every time I wanted to take a shower. I do have a 500 liter water tank on a three meter high tower that pre-heats from the sun. Unfortunately three meters high does not make enough pressure to activate the switch in the shower heater so I still have to use the water pump.

One other thing I learned when I was renting is that the low, medium and high cheapie heaters are a pain in the butt. Low was too cold and medium was too hot. I had to use low and adjust the water volume to a trickle get it comfortable. The better heaters use a thermostat control and the water temperature stays the same regardless of the water temperature coming in.

[lopburi3]

The gas heaters use a spark generator to ignite so just like using a stove.

As for the button control on some heaters they may be fine until the start to fail; and they do fail. Then you have leaking water. I have three such units and all now run with a control valve rather than use the button on unit. I do run higher pressure than most people, with a Grundfoss pump but had troubles even before when using a normal 30 PSI range pump. I also prefer to keep my wet hands of the heater. I know it is plastic but still prefer to not touch it when having a shower.

[svenivan]

I have an Ecolux gasheater in our new house. We had the same in the rented house and were happy with it.

It costs 5-6000 bath and it starts automatic when I turn the waterknob. I had to replace the batteri after 6 month.

We are happy with it.

[JAS21]

I have an Ecolux gasheater in our new house. We had the same in the rented house and were happy with it.

It costs 5-6000 bath and it starts automatic when I turn the waterknob. I had to replace the batteri after 6 month.

We are happy with it.

We have a new house in BK. Individual heater in our bathroom. Wired up for the other two showers but no heater installed and not likely to be either.

We never use the heater. Find that the outside water tank gets warm enough (from the sun) to just take any chill off. In fact sometimes too warm.

I find I need warm (hot) shower in the UK..but not here.........

I dont know any Thais who like a warm or hot shower.

[chownah]

In the north you will find lots of Thais who appreciate a warm shower during the cold weather months.

Who do you think buys all of those shower water heaters you see for sale in all of those stores?

Edited July 16, 2006 by chownah

[TBWG]

I recommend gas over electric. In many/most places you will get voltage drop whenever the shower is used if you go electric and obviously this is not a problem with gas. Also I've never seen an electric unit that got water as hot as my gas unit and living here in the north that's important since it gets really chilly here in the cold season and many electric heaters really don't do the job here in the cold season. I've got a National gas heater and it works fine....Ecolux makes some also and I've heard one good comment about them and no bad ones.

Is this what you are talking about? sourced from for sale section of TV website.

Paloma Gas Water Heater

Brand new never used-still in box

Highest Quality

Made in Japan

PH-5RFE

If purchased on website (japan) price is 11,200 baht

Are they easy to install? just put a "T" piece in the blue plastic cold water supply? and attach up to kitchen cooker gas bottle?

Comments appreciated if you have one or have installed same.

Thanks

TBWG

[chownah]

Paloma is famous in the US as a premium on demand hot water heater...at least thier commercial units were considered to be rugged and reliable a number of years ago....I always thought they were Italian made....I wonder if they have maintained their commercial unit standards in designing this consumer type shower unit? I think that your description of installation is approximately correct...of course you should follow the manufacturors instructions.....do instructions come with the unit?...one would assume so but it would probably be good if you could determine this before purchase.

[lopburi3]

I changed to electric about 15 years ago and used a National model but yes - you connect a water supply to the bottom input and have a hose/shower from the bottom output. A gas line is also connected at the bottom. I used a dedicated small tank and a copper gas line to second story where it was located.