Hi all!

Hope the people in the know can help me out here... Sorry about the long post, but it is a lot of money and I don't want to have regrets.

TL:DR - reliability, running cost and cost of long term ownership (won't be moving homes in 10+++ years). What would you choose between IHP Geyser and a new Electric Geyser with vacuum tube convert?

I have been really convinced for a while I want a IHP Geyser, mostly my wife is allergic to anything on the house roof. She has now in the last week before I pulled the trigger changed her mind and approved the vacuum tubes (but not a full geyser on the roof).

My VERY old 150l geyser finally burst (taking some belonings with it) - replacing this alone without anything else would have been an advantage already. I'm taking the time to move it outside. I was about to pay for a 200l IHP, but now had to research how the vacuum tubes stack up. Due to having to replace the geyser, etc... The total cost of both systems are basically the same.

We are currently a family of 4, with the in-laws visiting 3 days a week. Shower/bath schedule is basically:

• 4 showers at night, 2 baths for the kids

• 2 showers in the mornings (shower temperature less important — just shouldn’t be ice cold).

My goals are basically:

• Lower electricity costs

• Smart app/wifi control for if I want to boost/switch on/monitor if needed

• Lower in general running costs

• Even though I have the lump sum now, I want to save as much money going forward as possible

• Wear and tear and parts failure should be avoided. Longer life span is preferred

• I want to eventually do a solar carport or so - but that is possibly a 3 - 5 year + plan

My current thinking and research of the alternative:

Electric geyser with vacuum tube convert:

• New 200l electric geyser mounted outside

• 20 vacuum tubes convert

• Any recommendations for high quality companies to do both the electric geyser install and convert in Pretoria?

• Full solar geyser on the roof isn't an option

• Solar seems to have lower running cost long term

• Would plan on upgrading the GeyserWise Max to the wifi add on for smart app etc

• Fewer moving parts

• Flat roof so orientation isn't a problem

• No sun = no heating

• Extended power failures still mean hot water

• Not sure how much heat the tubes actually generate in the winter

IHP geyser

• Installed in the courtyard on a slab

• Not dependent on sun availability.

• Always heats when needed, not only during daylight.

• Efficient daytime heating using excess solar for when I finally go solar (solar carport to avoid the "nothing on roof" limitation from the wife).

• Annual maintenance is an extra running cost

• Wifi/app

• No power = no hot water

Now to my question:

• Any great providers you know of in Pretoria area for the electric geyser work and convert?

• Anybody that either went IHP or vacuum tubes and have regrets?

• What would end up actually costing less to own in Pretoria? (hot summers, no freezing risk, etc)

• Long term reliability of the systems?

• Unexpected maintenance I need to account for?

• Real world performance of these systems in the winter?

Thanks

I have a heat pump that's plumbed into a normal geyser. Works very well for me, heats up water to 60degrees. The cost is way cheaper than heating water with the geyser. Maintenance is about R500 each year.

I also have solar panels and have setup my system to switch on the geyser when I have excess solar power. This increases the water temp to 70 degrees.

Water takes a bit longer to heat up during winter but that's expected because of lower ambient temperature.

I have not used solar vacuum tubes and don't know anything about then.

Edited February 19Feb 19 by phidz
Added

I was one of the first people in South Africa to install a "vacuum tube" water heater (cannot remember exactly, but some 25-27 years ago...). They worked too well! Without any control (no "on/off"), they over-heated the water on a clear summer day, and I cannot tell you haw many PT valves I had to replace over the next number of years. As a "boer maak 'n plan", I ended up removing some vacuum tubes as the seasons progressed from early spring to summer to late autumn, removing six or seven of the twelve tubes during the warmest months. This worked, but removing and replacing tubes was quite a mission, and I finally abandoned this system some 10 years ago (running my geyser fully from my solar system as part of the daily load, and totally off-grid since the end of last year).

Unless modern evacuated tube solar water heaters have been improved by the addition of motors to rotate the tubes to- or away from the sun as water temperature demands, or unless one could install a cover that could shade the tubes automatically once a set water temperature is achieved, I would not recommend using such a system. You will do much better IMHO with a heat pump, and/or by just increasing your PV yield by installing an additional solar panel or two to provide more electricity for use by your geyser/heat pump.

I have a heat pump and PV. In fact I had a heat pump before I had PV.

I got the heat pump because the geyser was not near the north facing roof, so the installer recommended a heat pump.

This has the advantage that you note: I still get hot water on not-so-sunny days. It also has lower power demands than a regular geyser element, so I can run it on the backed up side of my solar system. This means that during load shedding I always had hot water.

My heat pump is not integrated with the geyser. There may be advantages to this. If (when) my geyser goes pop then it's a straight forward replacement.

The pump has been in service now about 13.5 years.

The situation: We are two adults, nobody else in the house. We have set routines. I run the pump twice a day: 6:00 for one hour and then 12:00 for three hours (that's the window I give it to run in, it doesn't run for 3 hours).

I have a blanket (Isotherm) on the geyser and cladding on the hot water pipes. After the midday run my wife is able to take a hot shower at 9, even 10 in the evening.

This is now a good combination for me. I am heating water free, gratis and for nothing. Every day. I prefer it to solar water heating. At our previous address I had a solar geyser. One problem was that it would overheat in the summer and a pop-off valve would let lots of water out. That didn't make me happy. Also water temperature varied across seasons - pleasant but not hot in the winter, too hot in the summer. Sure I can mix some cold water in, but I could see a situation where a person, especially a kid, could get caught by surprise. Now I have a pretty constant temperature throughout the year, the pump won't heat past 60 degrees. With the solar, to get the most bang for no bucks, you have to fit in with its schedule - so showers in the afternoon and early evening.

I run my pump twice during the day. I don't run it at night. If I did then it would draw from the battery, but then so would a geyser element (and more current and for longer).

We also have got into the habit of short showers once a day. That gives whatever water heating system we have less work to do.

Edited March 6Mar 6 by Bobster.
Too/two

For what it’s worth, we’ve been running a 150L electric geyser with a roof-mounted vacuum tube collector for the last four years, and I’ve been seriously impressed. I swapped the standard breaker for a wifi power monitoring smart breaker to get better control. We’re a family of 4, and we mostly shower.

The geyser is off by default (electric element) and only triggers under two specific conditions:

1. Excess Solar: It kicks in once the batteries are fully charged and there’s surplus power.

2. Scheduled: It runs daily at 16:00 to ensure we're ready for the evening.

It automatically shuts off the moment it hits the set temperature. The above is the sweet spot I have found, to not sacrifice hot water, but also to allow the sun to heat it nicely, and not unnecessarily send it electricity.

In four years, we’ve never run out of hot water. To give you an idea of the efficiency: from February 1st to now, it has only used 9kWh (mostly during rainy spells). Over the last 12 months, the geyser used 800kWh out of a total 10,900kWh consumed.

That said, I’ve just bought a new property that uses a heat pump. I’ll be switching over in March, and honestly, I’m skeptical it’ll be as efficient as this vacuum tube setup. But let’s see how it performs.

On 2026/03/03 at 3:44 PM, Pho3niX90 said:

That said, I’ve just bought a new property that uses a heat pump. I’ll be switching over in March, and honestly, I’m skeptical it’ll be as efficient as this vacuum tube setup. But let’s see how it performs.

Please let us know.

Never had solar tubes but I would imagine the current wave of geyser controllers making use of solar panels is better than the tube solar geysers. There is zero maintenance and they make use of your existing thermostat so no chance of overheating anything. Panels last basically 3 decades and the controllers are fanless and simple so no moving parts means less likely for something to break. A new controller is anywhere from 3 to 6k depending on what you want.

I have had my controller since August last year and have the AC input to it coming from my inverter as backup. It has worked very well and it has run as a standalone system since then. So far, rain/clouds etc haven't affected it much, even though I must say it will obviously depend on how much hot water you go through. In terms of long-term running costs, I think this is by far the cheapest option out there for heating a geyser.

Edited March 6Mar 6 by Denns

On 2026/03/05 at 5:10 PM, Bobster. said:

Please let us know.

Still extremely early to tell. But findings are as follows.

Last month (March) usage with the VAC geyer = 27kWh
This month thusfar (1-7 April), with the 3.6HD ITS = 23.77kWh

So, heatpump consumes 4x more than my previous VAC Geyser, perhaps in winter they would be equal.

Also, my previous VAC Geyeser was roof mounted, so cooled fast.

Edited April 7Apr 7 by Pho3niX90

3 hours ago, Pho3niX90 said:

Still extremely early to tell. But findings are as follows.

Last month (March) usage with the VAC geyer = 27kWh
This month thusfar (1-7 April), with the 3.6HD ITS = 23.77kWh

So, heatpump consumes 4x more than my previous VAC Geyser, perhaps in winter they would be equal.

Also, my previous VAC Geyeser was roof mounted, so cooled fast.

Thanks. I have no solar geyser to compare against, but since I put in some CBI smart controllers I can track my heat pump. We used 46.63 kWH for the month of January, 46.92 in February, and 65.87 in March. Hmmm.... I need to try and factor in weather to see why the big increase in March. So on a bad month we are using about 2kWh a day to heat electricity - still double what you report with the VAC.

Our situation: Two adults, each showering once per day. Dishwasher does its own heating, washing machine is always run on cold cycles. Geyser is clad with isotherm, and all hot water pipes between the geyser and walls are similarly clad. The pump runs twice a day. First run is 6:00 to 7:00 in the morning. Second time the timer switches on at 12:00 and off at 15:00, but the pump will not run for all of that (typically 15 to 20 minutes in the summer) and may not start at 12:00 on the dot.

On 2026/04/07 at 4:41 PM, Bobster. said:

Thanks. I have no solar geyser to compare against, but since I put in some CBI smart controllers I can track my heat pump. We used 46.63 kWH for the month of January, 46.92 in February, and 65.87 in March. Hmmm.... I need to try and factor in weather to see why the big increase in March. So on a bad month we are using about 2kWh a day to heat electricity - still double what you report with the VAC.

Our situation: Two adults, each showering once per day. Dishwasher does its own heating, washing machine is always run on cold cycles. Geyser is clad with isotherm, and all hot water pipes between the geyser and walls are similarly clad. The pump runs twice a day. First run is 6:00 to 7:00 in the morning. Second time the timer switches on at 12:00 and off at 15:00, but the pump will not run for all of that (typically 15 to 20 minutes in the summer) and may not start at 12:00 on the dot.

Here is a bit of an update on my usage thusfar for this month.

Heatpump is on 114kWh thusfar, same timeframe last year for the VAC was 75kWh (closer apples to apples), and for last month the VAC was 27kWh (More sunny, 1 - 25th)

Major difference being, the heatpump has no schedule and just keeps water warm permanently. The VAC was also on a schedule similiar to yours. (6:00 in the morning, 16:00 later again).

I will probably add the same schedule for the next week to see if it makes a difference. I am not entirely sure what my current geyer/tank's standing losses are during 24hrs, I should probably pop up into the ceiling to check the rating.