Hot Water - What do you think?

Steve

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Ok, so I'm going through the design phase of my house build.
Our builder has a standard inclusion of a instantaneous gas hot water system but I'm looking to change that if i can find a better way....

I'm trying to find the most economical means of generating hot water both from a environmental impact point of view and also to my hip pocket. I do like gas and the instantaneous-ness-ness of it is great but we wont have town gas supply so it will be bottled gas and although I haven't researched the prices of that system and resupply, I'm sure there has to be a better way. Also, it will cost every time I use hot water regardless if the sun is shining or not!
The only other gas appliance in the house will probably be the stove top so getting the gas bought in is probably going to happen anyway but if its only for the stove it will last a really long time.

So I'm thinking either solar hot water system or an electric hot water system that will utilise my solar power (that I'm getting regardless of the hot water system I choose). Or I guess I could stay with the gas option.
I'm leaning towards the elec hot water and solar panels.

What do you think?
What would be cheaper to run long term?
Do you see any problems with either method?
Can I run the elec hot water system during the day (using the sun power) and will it maintain heat throughout the night? (dont like cold showers! :() I've never had elec hot water but I've heard they normally run early morning so they stay hot all day.

I do need to get on the net and google away but I'd love to hear your thoughts. :)
 
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stevo

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I'm not sure what you mean by "run the electric hot water system during the day using the sun power". Are you going Off-grid?

If you're On-grid, then I tend to view solar panels as a completely separate part if you're still "on-grid". You're not using your own sun generated electricity, you're using grid power and being charged for it. You're only selling your solar generated electricity to your electricity supplier so you'd have to check how much you're going to be paid for it and how long will it take to pay for the initial cost of the system and will you make any over the next 20 years?

My neighbour has a good set up for hot water, but it was expensive. I'm not sure of the technical brand name, but it's a evacuated tube heat exchange solar hot water system on the roof with a booster tank in the house. He says he hasn't had to turn on the booster tank yet. I think the whole system was around $6000 though.

Electricity isn't the greatest to use for heating and cooling, and gas would be very effective, but! Electricity could end up being a cheaper option depending on your gas costs. Mark could give some ideas of gas costs.

sounds exciting!

PS... you'd also have to consider what new technologies are coming, like better off-grid systems. If you're getting a On-grid system then you might want to make sure your solar regulator/inverter can connect to batteries in the future, otherwise you may have to buy a new one in 5 years, but.. who knows, they may be cheaper then anyway.
 
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Letsgokate

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I think what Steve is saying Stevo is that if the Electric hot water is heating during the day it will use the power he is generating from his solar panels. We use the washer, dryer, cooking etc as much as possible during daylight hours to use the power we generate from our solar. My understanding is that if there is a shortfall in the power you used and what you generate you will be charged the difference.

As to the question, personally go solar. If you are thinking you might do it at some point down the track at time of building will be the cheapest, might be a stretch financially but you won't have a cheaper time to do it. We currently have gas hot water as that is what came with the place, the stove/oven is also gas. We are renovating the kitchen, and are taking out the oven/stove and have an induction cooktop to put it, which is supposed to be very good and convection microwaves. Again taking advantage of having solar. When the gas hot water goes we will then look at solar. Have you thought about going induction etc why have a gas stove?

Have had this discussion with Mark re the gas bottles. First we have lived in houses with gas hot water either on continuous town supply or bottles that are rented. We found that having gas bottles and paying the rental worked out cheaper. We have also had electric hot water and found it good. Currently we have hooked up 2 9kg gas bottles, and sat them on a shelf off the house. As said this will just be for hot water, we have found this to work out significantly cheaper than hiring the big gas bottles paying the rental etc. Yes it does mean we have to fill the gas bottles ourselves, but we have several and make sure one is always full and ready to go. We then fill 2 at a time.

Cost point of view comparing our bills here, based on our last service charge of 2x45kg bottles last Jan which was $72 and had gone up $6 on the previous year, so I'd expect around $80 which of course is every year. This pays for the 2x9kg gas bottles with plenty of change, nearly buys 3. Our camping trailer takes 9kg as does the BBQ, so we can move them around and also saves the bottles on the trailer just sitting there getting older while it's not being used. So for us it works out. Of course we save that $80 and more every year. At the local camping store it cost us 9kg for $19, BCF $19.95. Last time we got a 45kg filled was March last year @$143 which is $3.18 per kg x 9 = $25.60 for a 9kg of gas.

Discussion on filling your own gas bottles etc is here

Good luck, let us know which way you go.
 
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stevo

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I think what Steve is saying Stevo is that if the Electric hot water is heating during the day it will use the power he is generating from his solar panels. We use the washer, dryer, cooking etc as much as possible during daylight hours to use the power we generate from our solar. My understanding is that if there is a shortfall in the power you used and what you generate you will be charged the difference..
ahh yeah ok.. I may have been confused :oops:
 

Ash

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If your solar panels are going to generate more than 2kWh more than what you currently use, you'll find the existing panels sufficing for your electricity bill. The biggest drain of electricity is the hot water, followed by A/C, fridge and high power kitchen appliances (kettle, toaster, stove, etc). Each modality has its pros and cons. I like the idea of a solar hot water system that drains less power from the grid and again saves you more in the end.
 
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Mark

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My sister and brother in-law have a solar hot water system on their new acreage and it seems to serve them fine although when we stay over it doesn't take long for the hot water to run out and that's very inconvenient to be honest - you'd think these systems would be better by now. I don't know much about solar hot water systems but my preference would be solar power with some sort of backup system where it switches to gas when/if the hot water runs out. Either that, or a HUGE solar system storage tank so I know I have plenty of hot water when the rellies visit or everyone just needs a good long shower without playing the game "I'm in the shower first" every time we get back from the beach with me ending up with a cold one... (that's a shower not a beer)...

We have a gas hot water system and on average we need to replace a 45kg cylinder about every 3-4 months - our last replacement was in April and it cost $139.50 (gas prices have come down slightly in the last 6 months) - that's with a family of 4 and none of us are frugal in the shower :) Of course, we also use gas on our cooktop so it's not all used on hot water but by geez it's hard to beat gas hot water because it's always there when ya want it, no need for a storage tank so it takes up little space, and nothing much goes wrong with them - our last Bosch was still going ok after 16 years and we've got a Rinnai now which is excellent.

I was mulling over (still am) doing what Kate has done and buying my own 9kg gas bottles to save money but I haven't quite decided yet simply on the grounds of convenience... we'll see.

On a different note, if you do a lot of clothes washing, especially in hot water, getting a front loader that heats it's own water will save on costs also. I know many people just use cold water but we like to use at least warm on our work clothes or kids footy stuff and it all adds up if it's coming out of your hot water system.

This is a good thread @Steve and I reckon there's a lot of people wondering what system they should go with both money wise, environmentally, and also effectiveness. It'll be very interesting to see what you end up going with!
 
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firm351

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Personally i would be going with a gas boosted solar system rather than an electric system.

Something like this,
http://www.rinnai.com.au/hot-water/solar-hot-water-systems/prestige-range/


We have a continuous flow gas hot water system at our place and we are on bottled gas, we use a 45 kg bottle roughly every 60 days or so for a family of 5.
i love the continuous flow set ups, with a wife a 3 daughters i still get a hot shower every day.
 
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Ash

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A backup is always good in a hot water system. The problem is hot water tanks are between 300-400L , and take long to reheat once empty. So being boosted by gas means it is instant backup hot water. Electric backup is clearly not so easy to manage but a battery hookup may ensure restocked hot water in the tank is continuously being heated.
 

Steve

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A backup is always good in a hot water system.
It's a good point @Ash and something that keeps bringing my thoughts back to having gas in the set up somewhere.
I know there's a home show coming up in August in Brisbane and I'm sure there will be all sorts of 'experts' pushing their products but maybe I can find someone there who will tell me straight and have data to back it up. It's so hard these days to find definitive answers to questions of running costs as there are always different scenarios and situations.

I found one website (australian) last night that quoted some figures comparing PV powered elec water verses solar hot water. If I can find it again I'll add the link to this thread.

I'm really appreciating everyones thoughts. All good advice.
More thinking to be done....:dunno:
 
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Letsgokate

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Mark made the point that when he visits his sister they run out of hot water. Valid point, National Parks that have solar showers always run out of hot water BUT they are providing showers for a large number of people. So it depends on how many in your family currently living in your house, house many visitors do you often get etc. Everyone situation is different so there is no one solution. For us it's just the 2 of us :) family live close so know no one has the need to stay. I think it is a valid point to have a backup if you have solar especially if you have a large family.

We have a camping trailer that has 12/240v hot water unit. Many van's also have the same hot water. For us that would be our back up as we can run it on 12v off the batteries, 240v off the mains or generator power and it can also be run on 240v off our inverter. I wonder if something like this could be incorporated into a house as a backup only. You can also get diesel hot water for vans/campers.
 
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AzaleaHill

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If you go with the solar electric option (heat the water during the day with solar generated electricity and use it evenings and mornings) be sure to add another R10 or R20 of insulation to the tank. The as-bought insulation is seldom enough.
 

ClissAT

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That's a good point, Azalea.
I find if there are very bad westerlies at my place in winter & they blow directly onto the electric hot water tank, the wind actually reduces the temperature of the water reaching the shower head.
I even thought of boxing the tank in with pellet timber & wrapping the pipes in something.
 

AzaleaHill

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Here in the USA many hardware stores carry foam tubes that are use to install around hot water pipes. They usually come in 4' lenghts. Easy to cut to fit and slip on a pipe.
I don't know how common they are in your country.
 

ClissAT

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Down south much more common than here in the sub tropics or tropical areas.
But people who want to save every cent possible on power will go to extraordinarily expensive ends to do so.
 
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Raymondo

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Bring back the old Rayburn style slow combustion stoves with a water jacket at the back of the fire box , connect to a normal hot water storage tank , even in summer a small fire and close the dampers down will heat your water, just need a supply of wood. If you have a property start growing your own firewood , wattles are quick and short life cycle so could fit the bill depends where you live, we plant nut trees and wait some years for them to fruit why not use foresight and plant a firewood species. I am well aware not everyone has this capability but for those who do , why not? Cheers Raymondo