Sharing a solar geyser between main house and freestanding cottage

[Ockie]

No ways.
I had a kexin 16lpm geyser put in, for R4718.

The piping was there already, granted, but that's definitely not 3k worth.

Oh ok. I thought the install of a gas geyser was hectically expensive.

 

[Sinbad]

Oh ok. I thought the install of a gas geyser was hectically expensive.

I'll give you the name of my dude if you like.
He did a 20lpm forced induction Atlas for me as well, along with about 25m of copper gas piping, new high pressure and low pressure regulator, isolation valves etc, for under 12k

 

[Ockie]

I'll give you the name of my dude if you like.
He did a 20lpm forced induction Atlas for me as well, along with about 25m of copper gas piping, new high pressure and low pressure regulator, isolation valves etc, for under 12k

Sounds like a plan....but first need to see what route we going to go

 

[Ockie]

I'll give you the name of my dude if you like.
He did a 20lpm forced induction Atlas for me as well, along with about 25m of copper gas piping, new high pressure and low pressure regulator, isolation valves etc, for under 12k

Meneer, how much gas do you use on your gas geyser roughly?

 

[Sinbad]

Meneer, how much gas do you use on your gas geyser roughly?

It varies.
The 20lpm is actually in series with a solar geyser, so when the solar is hot it hardly uses any gas.
We also have a gas fireplace on the same installation.
1st 48 kilo cylinder lasted 8 months.
2nd lasted 5 months (over winter)
Nearly finished the third, 4 months now, but i think there was a little leak where it was connected (I could smell gas near the cylinders).

 

[Ockie]

It varies.
The 20lpm is actually in series with a solar geyser, so when the solar is hot it hardly uses any gas.
We also have a gas fireplace on the same installation.
1st 48 kilo cylinder lasted 8 months.
2nd lasted 5 months (over winter)
Nearly finished the third, 4 months now, but i think there was a little leak where it was connected (I could smell gas near the cylinders).

Ok, so one person on a small 10lpm gas geyser really should give you a long time on a bottle then? We both shower once a day (but will each have our own gas geyser) .. on weekends I might shower twice a day.

 

[Sinbad]

Ok, so one person on a small 10lpm gas geyser really should give you a long time on a bottle then? We both shower once a day (but will each have our own gas geyser) .. on weekends I might shower twice a day.

May I suggest you go higher than 10lpm. The cost increment from 10 to 12 or 16 isn't much, and 10lpm makes for a fairly frustrating shower. But yeah, it will last you a good long time.

 

[Ockie]

May I suggest you go higher than 10lpm. The cost increment from 10 to 12 or 16 isn't much, and 10lpm makes for a fairly frustrating shower. But yeah, it will last you a good long time.

Oh ok. Ja, I dont want to scramble for water in the shower like a little hamster trying to wash its face. So will go for a bigger one then

 

[Ockie]

Sinbad ... sorry meneer to be a pain. Would your guy be able to come out for example and give a quote on how much we looking at for the installations so that we can make a informed decision? Would not mind paying him for a call out or something?

 

[Sinbad]

Sinbad ... sorry meneer to be a pain. Would your guy be able to come out for example and give a quote on how much we looking at for the installations so that we can make a informed decision? Would not mind paying him for a call out or something?

Yup he'll do that for you. But you can't call him till after he's connected my gas stove!

 

[Ockie]

Yup he'll do that for you. But you can't call him till after he's connected my gas stove!

rofl. Dankie meneer.

 

[richjdavies]

To use an example an insulated Kwikot 150L geyser uses roughly:
2.3 kWh/day 'standing loss' (Energy used to maintain heat lost if no hot water is used)

Sorry to resurrect an older part of the thread --> a 150L geyser with Standing Loss of 2.3kWh that makes it pretty near the 'worst allowable' standing loss of 2.59kwh/24-hours -- anything worse would be illegal I think? By comparison an A-rated geyser (by SANS 151) as below would be more like 0.86kWh/day

The formula shown gives you Watts - so you need to multiple by 24 and divide by 1000 to get kWh in a day.

We've gone through this in another thread, but despite the 'my bottle lasts 8 months' it may be the change of geyser rather than the fuel that's really making the difference.
19kg of gas costs around R400 - so ultimately you're paying around R20/kg
If properly burned 1kg of gas gives around 10.6kWh of heat
So you're effectively paying R1.88/kWh of heat if you burn 100% of the gas with no other losses.
Just think if you replaced the gas 'element' with an electric one you'd only be paying R1.50ish from Eskom

The only saving grace is that Gas Geysers (in SA anyway) tend to be 'combi' boilers - meaning they boil the water immediately, rather than storing and wasting energy in standing losses. But you can get electric heaters that do the same thing -- although the flow rate would likely be lower.

Ultimately like you've pointed out - the 'saving' all depends on your hot-water consumption. There are no free lunches - you have to get the heat from somewhere to heat your water... although that somewhere can be gas or electric (or solar or 'stealing from outside' - i.e. heat-pump)
After the standing losses, what matters is how much you are using. I expect many people who have changed to gas have also done something to their shower flow rate or time to get the vast majority of savings claimed, either that or they've broken the laws of physics!

 

[Ockie]

Sorry to resurrect an older part of the thread --> a 150L geyser with Standing Loss of 2.3kWh that makes it pretty near the 'worst allowable' standing loss of 2.59kwh/24-hours -- anything worse would be illegal I think? By comparison an A-rated geyser (by SANS 151) as below would be more like 0.86kWh/day
View attachment 231948
The formula shown gives you Watts - so you need to multiple by 24 and divide by 1000 to get kWh in a day.

We've gone through this in another thread, but despite the 'my bottle lasts 8 months' it may be the change of geyser rather than the fuel that's really making the difference.
19kg of gas costs around R400 - so ultimately you're paying around R20/kg
If properly burned 1kg of gas gives around 10.6kWh of heat
So you're effectively paying R1.88/kWh of heat if you burn 100% of the gas with no other losses.
Just think if you replaced the gas 'element' with an electric one you'd only be paying R1.50ish from Eskom

The only saving grace is that Gas Geysers (in SA anyway) tend to be 'combi' boilers - meaning they boil the water immediately, rather than storing and wasting energy in standing losses. But you can get electric heaters that do the same thing -- although the flow rate would likely be lower.

Ultimately like you've pointed out - the 'saving' all depends on your hot-water consumption. There are no free lunches - you have to get the heat from somewhere to heat your water... although that somewhere can be gas or electric (or solar or 'stealing from outside' - i.e. heat-pump)
After the standing losses, what matters is how much you are using. I expect many people who have changed to gas have also done something to their shower flow rate or time to get the vast majority of savings claimed, either that or they've broken the laws of physics!

So what are you saying? Gas geyser works out more expensive than electric?

 

[Sinbad]

Sorry to resurrect an older part of the thread --> a 150L geyser with Standing Loss of 2.3kWh that makes it pretty near the 'worst allowable' standing loss of 2.59kwh/24-hours -- anything worse would be illegal I think? By comparison an A-rated geyser (by SANS 151) as below would be more like 0.86kWh/day
View attachment 231948
The formula shown gives you Watts - so you need to multiple by 24 and divide by 1000 to get kWh in a day.

We've gone through this in another thread, but despite the 'my bottle lasts 8 months' it may be the change of geyser rather than the fuel that's really making the difference.
19kg of gas costs around R400 - so ultimately you're paying around R20/kg
If properly burned 1kg of gas gives around 10.6kWh of heat
So you're effectively paying R1.88/kWh of heat if you burn 100% of the gas with no other losses.
Just think if you replaced the gas 'element' with an electric one you'd only be paying R1.50ish from Eskom

The only saving grace is that Gas Geysers (in SA anyway) tend to be 'combi' boilers - meaning they boil the water immediately, rather than storing and wasting energy in standing losses. But you can get electric heaters that do the same thing -- although the flow rate would likely be lower.

Ultimately like you've pointed out - the 'saving' all depends on your hot-water consumption. There are no free lunches - you have to get the heat from somewhere to heat your water... although that somewhere can be gas or electric (or solar or 'stealing from outside' - i.e. heat-pump)
After the standing losses, what matters is how much you are using. I expect many people who have changed to gas have also done something to their shower flow rate or time to get the vast majority of savings claimed, either that or they've broken the laws of physics!

I've never claimed that my gas geyser costs less than an electric one. However, I do believe it's more efficient due to the lack of stored heat leaking out (standing loss), and the on-demand nature also means I never have to worry about running out of hot water if all three of us in the house decide to bath or shower straight after each other. Flow rate is a very good point. To raise 20 litres of minute of water by 30 degrees will require 42 kilowatts... No electrical on-demand heater can come close to that unless you have a direct line to Koeberg!

 

[desiganp]

Ultimately like you've pointed out - the 'saving' all depends on your hot-water consumption. I expect many people who have changed to gas have also done something to their shower flow rate or time to get the vast majority of savings claimed, either that or they've broken the laws of physics!

Take an 8L gas geyser which uses 1.2kg gas/hour. 19kg/1.2kg = 16 hours usage.

16 x 60 mins = 780 minutes usage

780/15 minutes total shower (conservative) usage for 2 people once daily (7.5 mins each) = 52 days = +/-R315 (price of 19kg on the coast).

To me that works out much cheaper than the cost of running an electric geyser for 52 days.

 

[mmacleod]

Sorry to resurrect an older part of the thread --> a 150L geyser with Standing Loss of 2.3kWh that makes it pretty near the 'worst allowable' standing loss of 2.59kwh/24-hours -- anything worse would be illegal I think? By comparison an A-rated geyser (by SANS 151) as below would be more like 0.86kWh/day

LOL, well I did say Kwikot

They are one of the most common geysers in the country though which is why I picked them as the example geyser, consider it a 'worst case' scenario.
My example was to show how 2 geysers is not necessarily that much worse than 1 geyser though, nothing to do with gas
For a gas vs electric comparison you may want to pick a better geyser as you show above.

Not going to get into a gas vs electric debate, I don't personally like gas for anything so I just steer clear of it

 

[Ockie]

I don't personally like gas for anything so I just steer clear of it

Rouxenator, is that you?