Insulate Your Water Heater

[Woodified]

[Bart1080]

Very old thread but here goes for anyone that's interested....yes it makes a BIG difference.

John on this forum (or the old RENOVATE forum) gave a detailed write up of his off grid experience to which I tried the same on 2 electric water tanks - 1 underneath the verandah and 1 inside a shed. I put a 12Kw solar system and timers to only heat up the water during daylight hours to maximize solar utilization. As there is no heating from 4pm in the winter and 7pm in the summer and doesnt switch back on for 17 hours later, the heat loss is quite large....in the winter can be up to 20 degrees or as little as 12 degrees.

Wrapping the tank in batts, tie them in the middle of each batt, fold a couple on top and then wrapping the tank with sisalation/sarking (the foil stuff that goes under tin roofs) makes a massive difference with as little as a 2 degree heat loss over the same measured period. The silisation initially was to make it look a bit nicer rather than looking at fluffy batts sagging over months with 2 sheets cut to pull down across the top (using good quality cloth based duct tape to the side of the tank/sarking so only 4 small corners are exposing the batts)

With a loss of only 2 degrees, the water is still super hot and no noticeable user difference resulting in a happier household but also shorter re-heating times. Obviously a change in habits of long showers and selecting washing times or the amount of washing that is done contributes to a great result. The batts and foil were left overs sitting in the shed waiting for a future use so effectively cost me nothing.

[419]

Interesting. Might try it. The only concern I have is insulwool getting wet and losing insulating properties. Sarking over top should pretty much deal with that.

My last gas bill was just over a grand for two months. Most of this was probably for central heating and the rest for water heating as cooking on the stove top doesn't use much.

In addition to your suggestion about insulating the water heater, I'm thinking about going back to some old basics that got lost in modern streamlined design such as curtain pelmets and sausages across the bottoms of doors.

Recently we had some clown in from some government sponsored scheme to improve sealing the house against draughts, but he couldn't do the internal door between the garage and the house because it wasn't an external door (i.e. he wasn't getting paid for it) despite the fact that I can feel the breeze when the central heating is operating.

I should have ignored Mrs 419's advice that a government scheme staffed by supposed professionals would be better and cheaper than my intention to use up some old sealing strips left over from jobs.

Off topic, but I hope you won't mind if I ask if your 1080 reference is to the rabbit poison.

[Bart1080]

Off topic, but I hope you won't mind if I ask if your 1080 reference is to the rabbit poison.

Yes
I'm lucky that my tanks arn't exposed to the rain.
You could wrap them in a builders plastic over the insulation.
I also lowered the max heating temp to the minimum from memory so it doesnt have to spend more energy heating to a higher temp given how effective the batts insulation are at reducing heat loss AND adjusted the cold water mixing valve (wound it all the way out or in...what ever way it was to turn it off). With the lower max temp, the risk of a burn is very very low and we have no little kids in the house these days....figured why cool the hot water before it gets to the taps/shower up the back of the house when thats what the taps are for.

In regards to you gov scheme to reduce drafts, Dont think much of any Gov scheme that sends so called "experts" to your house. Recently went through the process of putting in a heat pump HWS in the shed. After months of delays, they finally locked in a date. I queried the chap on the phone that I wanted to keep the old tank for an off grid project to which he replied thats fine but all the electricals will be removed and holes drilled in the tank to destroy it from further use (mandated by the Gov). I said forget it, cancelled the appointment and highlighted that its BS to be destroying a perfectly fine HWS...so environmentally friendly to be sending more crap to landfill!! He couldnt get over I was turning down a "FREE" service with an equivalent $4,000 value...to which I replied that its not "free" its mine and the rest of the state tax payers funding this circus with this gov giving away millions yet again.

[419]

Yes

Nice. Rolls off the tongue better than myxomatosis.

I also lowered the max heating temp to the minimum from memory so it doesnt have to spend more energy heating to a higher temp given how effective the batts insulation are at reducing heat loss AND adjusted the cold water mixing valve (wound it all the way out or in...what ever way it was to turn it off). With the lower max temp, the risk of a burn is very very low and we have no little kids in the house these days....figured why cool the hot water before it gets to the taps/shower up the back of the house when thats what the taps are for.

What mystifies me in our house is that the hot water in the en suite pretty much next to the HWS is nowhere near as hot as the hot water in the kitchen which is about another 12 metres further on, and they're coming from the same tank with no other heater in the line for the kitchen.

Here's something I thought of years ago but don't have the skills or interest nor probably the time left to develop any more and do all the submissions etc to government, so I'll throw it out to anyone who has the skills and interest.

All houses waste a ridiculous amount of cold potable water waiting for the hot water to arrive. Prove this by collecting in a container all the cold water that is wasted while waiting for hot.

Thermostats, like those on car radiators that open when the water gets hot enough, are old and simple technology.

It wouldn't be hard to design a recirculating system that returns the cold water to the hot water tank until the hot water starts to flow. The cost of plumbing this in to a new build would be a small fraction of the total plumbing cost.

I did a very, very rough calculation many years ago on how much water this would save in a house multiplied by the number of dwellings, and in Melbourne we'd be getting up to not needing to build another dam for a long time to meet the ever expanding population.

If someone takes this up and convinces government to make such systems mandatory in all new houses, they'll make a fortune and we won't need new dams for quite a while. Or they could just bang their head against a governmental brick wall that is resistant to new ideas.

In regards to you gov scheme to reduce drafts, Dont think much of any Gov scheme that sends so called "experts" to your house. Recently went through the process of putting in a heat pump HWS in the shed. After months of delays, they finally locked in a date. I queried the chap on the phone that I wanted to keep the old tank for an off grid project to which he replied thats fine but all the electricals will be removed and holes drilled in the tank to destroy it from further use (mandated by the Gov). I said forget it, cancelled the appointment and highlighted that its BS to be destroying a perfectly fine HWS...so environmentally friendly to be sending more crap to landfill!! He couldnt get over I was turning down a "FREE" service with an equivalent $4,000 value...to which I replied that its not "free" its mine and the rest of the state tax payers funding this circus with this gov giving away millions yet again.

Problem with a lot of these 'free' government sponsored schemes is that they're not always all that well thought out [hard to believe of governments, I know] and often ensure their failure by jumping on the government money bandwagon, where the scheme is exploited by a sort of 'in person' rather than online scammer. Like the character I had come out to put top hats on exhaust fans in the second bathroom and toilet, but he refused to do it after inspecting the first bathroom and toilet which already had them. I knew that. Which is why I wanted them where they weren't.

[Chief Tiff]

All houses waste a ridiculous amount of cold potable water waiting for the hot water to arrive. Prove this by collecting in a container all the cold water that is wasted while waiting for hot.

Thermostats, like those on car radiators that open when the water gets hot enough, are old and simple technology.

It wouldn't be hard to design a recirculating system that returns the cold water to the hot water tank until the hot water starts to flow. The cost of plumbing this in to a new build would be a small fraction of the total plumbing cost.

Someone did; about 20 years ago it was featured on “New Inventors” or whatever the show was called. The hot water was recirculated until the temperature at the tap reached a pre-set value and only then did it begin to flow.

[JZG]

It wouldn't be hard to design a recirculating system that returns the cold water to the hot water tank until the hot water starts to flow. The cost of plumbing this in to a new build would be a small fraction of the total plumbing cost.

These are available. We looked at them when we were building our house 17 years ago, as we are on tank water, but the system was too expensive for us. I suspect most plumbers aren't comfortable installing them, due to a lack of familiarity.

[rambunctious]

These are available. We looked at them when we were building our house 17 years ago, as we are on tank water, but the system was too expensive for us. I suspect most plumbers aren't comfortable installing them, due to a lack of familiarity.

Hot water circulating systems are not rocket science and have been around since Adam ate the apple.
Used predominately on high rise but not difficult to incorporate in a home build.
Hot supply comes from the tempering valve and runs as close as possible to each fixture/draw off point then at the end of the line it returns to the water heater.
A small circulating pump is used at the tempering valve which can be timed to come on when needed then shut off when not needed.
i.e maybe 1-2 hours morning and night depending on demand.
Of course all pipework needs to be insulated and this plus the return line and pump would be the expensive items not to mention labour

As for insulating water heaters, without a doubt well worth the money and a much better investment than just insulating the valves and pipes at the heater as currently required.
Simplest is a roll of roof insulation with sisilation attached (double wrap for colder climates) usually available on the likes of marketplace and ebay for about $60-$70 for the roll which is usually 18 metres x 1.2 metres.

[ErrolFlynn]

These are available. We looked at them when we were building our house 17 years ago, as we are on tank water, but the system was too expensive for us. I suspect most plumbers aren't comfortable installing them, due to a lack of familiarity.

Seems like a great idea, but I'm not getting it.

I can understand how such a device would work if the hot water tank was one of the old unpressured systems. A pump could force the water back to the tank until the thermostat kicked in.

However, if the hot water tank is under pressure, and it generally is, then how is the cooler water forced back into the tank (that's already under pressure)? I don't see how it's done. Wouldn't the cool water have to go to an unpressured tank?

[Beardy]

Seems like a great idea, but I'm not getting it.

I can understand how such a device would work if the hot water tank was one of the old unpressured systems. A pump could force the water back to the tank until the thermostat kicked in.

However, if the hot water tank is under pressure, and it generally is, then how is the cooler water forced back into the tank (that's already under pressure)? I don't see how it's done. Wouldn't the cool water have to go to an unpressured tank?

The water is already pressurised on the return line as it is a closed system

[ErrolFlynn]

What's this system called? I'd like to study it. Find out how it works. What do I look up? Do you have a link?

[Chief Tiff]

I found the one I saw on TV all those years ago; Enviro water Saver

My dodgy memory got it slightly wrong; what it does is divert the water to a tank or similar while it is waiting for the hot water to arrive at the tap. Think of it more as a drain diverter; instead of sending it down the plughole it diverts it to a storage device.

I guess it would be perfect for tanked water and really good for people with high water bills and low rainfall who have rainwater tanks fitted.

[ErrolFlynn]

Not so cheap at $180, but if access to water is limited (ie off-grid) it may be worth considering.

My initial thought, with a gravity-fed hot water system, of recycling the cool water back into the hot water tank (using a pump) may not be such a good idea. That is, rather than having the cool water go to a holding tank, pumping it back into the hot water tank would only serve to cool the water.

I might eventually be living off-grid. I can see myself getting one of these gadgets. Thanks for the link.

[rambunctious]

What's this system called? I'd like to study it. Find out how it works. What do I look up? Do you have a link?

You are looking for a circulating system design, not recirculating design.
Check out the link for designs or to do your own search, look for hot water circulating design.

hot water circulating design - Search

[Beardy]

Not so cheap at $180, but if access to water is limited (ie off-grid) it may be worth considering.

My initial thought, with a gravity-fed hot water system, of recycling the cool water back into the hot water tank (using a pump) may not be such a good idea. That is, rather than having the cool water go to a holding tank, pumping it back into the hot water tank would only serve to cool the water.

I might eventually be living off-grid. I can see myself getting one of these gadgets. Thanks for the link.

I am thinking it is very cheap at $180.00. You could then send the return line back and T it into the supply line of the hot water service

You could look up Reticulated hot water systems to get you started