Heat Pump Advice

I’m looking at different options to reduce my current water heating bill.
I have a 200l geyser with a 4kW element (set to 55deg) which runs off a timer as follows:

05h15-06h45 and 15h30-19h30

My current daily power usage is approx 18-20kWh.

I am investigating the option of a 5.4kW ITS heat pump which I am told will provide equivalent volume and rate of hot water (up to 60deg) but at a fraction of the power usage as my current geyser and element.

  1. BRAND AND RELIABILITY: are ITS heat pumps reputable and reliable? Any other recommendations?

  2. EFFICIENCY: is the claimed 1,2kW per hour power usage and the claimed 1.5-2hr time to heat water from 20 to 60deg both realistic?

  3. MAINTENANCE: I’ve heard mixed opinions regarding the cost of maintaining heat pumps. Any opinions on maintaining ITS heat pumps?

  4. NOISE: I’ve been told heat pumps are not exactly silent. My geyser is outside my kitchen and it makes practical sense to have the heat pump directly adjacent the geyser. Will this make the kitchen unpleasantly noisy?

  5. INVERTER: with a power usage of 2kW, will I be able to run heat pump off solar and potentially also batteries? I’ve been advised this is not a good idea. any advice?

Any thoughts on all/some of the above heat pump issues would be appreciated.

Ever considered Evacuated Tubes for the geyser?

I’m soon going to install PV panels across much of my roof but don’t necessarily have the space for enough panels to also cater for my current geyser demand.

Apart from space constraints I’m also sensitive to aesthetics and would prefer not to have evacuation tubes on my roof that I personally find pretty ugly.

Your location is a big factor. If you’re in Cape Town then solar is fine for summer but not so great for winter.
I’ve given up on geysers retaining their heat. They lose heat far too rapidly despite better insulation. And if one is spending the money then heat pumps are a good bet!
I’m installing one at the moment…

I have installed the 5.4kW ITS on my 200l geyser a few weeks ago. Note that it starts off using about 1.2kW but ramps up to almost 2kW towards the end of the heating cycle. I don’t think it is a good idea to try and run it off a 2kW inverter. It also isn’t a resistive load, so you should account for start-up inrush as well as maybe a PF of 80%.

That being said, it is awesome. I use much less power, and it really isn’t that loud while running. It was an expensive installation though, copper piping and lagging don’t come cheap.

I can’t comment yet on reliability and what servicing would entail.

Broad strokes of maintenance:

  1. Twice a year clean debris away from the filters (especially on the inlet side of the fan) and the condensor.

  2. Maybe once a year clean the strainer

  3. I had mine regassed after about 9 years. How much gas was actually needed I don’t know, I had didn’t have time to watch the guy. I got him in because the pump was running longer but
    a) it was winter
    b) I later find out I had changed the timer settings so that it could run for longer
    c) he did say to me that the strainer was clogged and restricting water flow - so that was probably the main problem.

Mine is a Kwikpump (Kwikot). It’s clearly well built and the moving parts have given me no problems after 11 years and counting. Hasn’t got noisier either. I like this brand because they’re local, so there will be parts and technical backup for a long time.

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You should not have to do this, it is a closed system like your fridge and all the joints are welded. If you do need to regas, something has sprung a leak that you will have to fix at the same time.

(Aircons have flare joints which can leak from the start or start leaking at any time due to thermal cycling/corrosion etc., so they are a little different in this regard).

The fact that it’s a closed system also makes it a good candidate for a more environmentally friendly refrigerant, like CO₂. That is because CO₂ requires much higher pressures that don’t mix well with flare joints, but it’s also not as friendly from a serviceability viewpoint.

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Shooting from the hip here, I want to say something important. Something a bit like a public announcement. It is somewhat controversial.

Timers don’t save energy consumption.

Well, if you are pedantic, yes they do, a tiny tiny bit, but for the most part, a geyser that was left switched off the whole day, will simply recover all its standing losses within 10-20 minutes the moment you switch it back on. Beyond that, all the consumption is proportional to actual hot water use.

There is one good use for a timer switch: If you have solar power, and you want to prioritise the solar for water heating, then a timer can be used to prevent it from reheating the water until the sun is up.

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I don’t quite agree. Lets say your standing loss is 2.5kWh, you can optimize that to almost 0 if your timer is set exactly to match your consumption. The reason is because the water temperature is not uniform in a heater while it is heating up.

So if you need 100l of hot water, heat only that much and immediately use it after the timer switches off (before the temperature gets a chance to homogenize), your standing loss will be a small fraction of the 2.5kWh. (not 0, but you can approximate it if you want by scaling the 2.5 by half the time it took you to heat the water out of 24h).

This is the lower limit and you have to manage it exactly then, but all other sub-optimal solutions will lie somewhere between this and the upper limit of 2.5kWh.

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I live alone, probably in the minority here, with my use case I believe the geyser timer saves me money on electricity.

I only heat the geyser once per day, ok now in winter sometimes 1.5 times.
Geyserwise runs 2 hours in the morning before I shower, that gives me enough water for a shower, plus doing dishes and such somewhere in a day. In summer there is even enough hot water left for a quick 2 minute rince shower before bed time, but now in winter I switch the geyser on for around 30 minutes before that quick evening shower.

With multiple people in a house this obviously won’t work and I also believe the only thing a geyser timer is good for then is shifting the load to different times.

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When I wanted to get a heatpump 3 years ago and I looked at ITS. Spoke to them and was ready to order after the rep assured me I would be able to install myself. Later he came back and said sorry, I need to use one of their approved dealers…. That was costing a lot more for a standard back to back install. Mine is installed about 6-7 meters high.

I found alliance through fourways Airconditioning and even they gave me the same story. Eventually managed to buy an alliance 5kw unit from Midrand Airconditioning.

I clean the strainer once a year and will be doing it tomorrow but I also have a big blue filter on my municipal line.
It takes longer to heat the water in winter and struggles a bit for the last few degrees. Have mine set at 58 in winter but I do use the geyser element at midday and that’s set at 65.
I can hear when it’s running but it’s about the same as an aircon condenser. Just a slight hum.

The alliance unit is exactly the same as either the kwikot or the heat tech unit. Even manuals are the same.

Don’t forget about the geyser anode replacement. I didn’t do mine for some time and when I opened up the old one a few weeks ago, I only had about 5cm of the center rod left. Everything else was gone.

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Heat pumps are high tech compared to a conventional hot water geyser. (The comments on Hello Peter on this company reveals this deficit)I
I bought a second hand ITS heat pump and took it to them to have it checked… all good!
This small specialised company is run by a clued up bunch of owner managers and workers which I appreciate.
I installed the unit myself following their detailed instructions.
The unit recirculates the hot water on the outlet back to the inlet until the temperature rises enough to improve performance. This is external to the heat pump itself.
ITS - Domestic HP Installation Manual V7.pdf (3.9 MB)

The other interesting feature is the hot water is fed into the top of the geyser. So initially you don’t see an increase in temperature from your thermostat thermometer. It only indicates when the hot water has reached this level in the geyser.

And therein lies the rub, plus you always end your shower with lukewarm water, because an exact match necessarily means you’re digging into that “beginning to cool” layer. Also, because people turn on the geyser a whole hour before bath time, it has ample time to recoup the standing losses of whatever was “saved” during the day.

But I don’t quite disagree with you either. My estimates is based on the average guy who doesn’t want his wife to have a cold shower, and who has a family large enough that the entire tank is consumed at least once a day. When evening comes round, he’s going to turn on the geyser long enough to heat a full tank, and leave some for tomorrow. In this usage pattern, the water consumption dominates the equation.

Anyway, I derailed this conversation a little. I’m a bit pedantic myself :slight_smile: And I have a healthy dislike for people selling timers to unsuspecting customers, promising them hundreds of rands in savings.

It is important to get this part right. There is still a problem with mine, but it doesn’t bother me enough (yet) to fix it, and we get around it by switching the heat pump off when bath time rolls around.

But let me also answer the original question, @RichardvdS , before I veered off on a tangent.

I have an ITS heat pump. I love it, it works well, gives no problems, and saves oodles of money. I can recommend it.

In an area with lots of sunshine, a solar water heater will give you more savings on an annual basis. But whenever winter/the rainy season rolls around, your bill shows a very huge swing. In a perfect world I would have both. But money-wise, that is not a good move.

It is expensive to install. The materials needed for installation, copper piping and lagging, will easily be a third of the total cost.

They prefer (your favorite) 22mm Pex piping so that’s a big saving :sweat_smile:

Yes. The guy arrived with gas and some gauges, and showed me a needle pointing at some number like this was particularly significant. He also gave me a little lecture about only using a torque wrench when putting the strainer back in.

Later on it occurred to me that if there was a loss of gas, simply regassing wasn’t going to solve anything because the gas would leak out again. Yet the heat pump was working better after the service.

As I said, I rather suspect the strainer was the main problem.

There are two reasons I use a timer

  1. Because, as you say, I don’t want the heat pump running through the night and taking charge out of the batteries.
  2. Because our kitchen has become a busy place with an ever expanding range of electrical gadgets in use (“it doesn’t use much”). The heat pump is on the backed up circuits, and we have had a couple of system trips through overloading lately. So because people can’t understand that if you keep turning stuff on, that consumes increasing amounts of power, the next best is to say “the heat pump runs from Xam to Ypm and so you should go easy on the appliances at that time”.

Yesterday I chanced upon a nifty device that shows the total load in amps being pulled through an AC circuit. It has an LED display. So I could put that on the line from the inverter that feeds the essential circuits and say “when that gets to 15 you stop turning stuff on.” But it doesn’t fit in a DB board.

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I was wondering about this. I have noticed that the temperature as per the thermostat doesn’t increase in a linear fashion.

Indeed it often drops when the heat pump turns on. I assume that’s because there’s a sudden surge of cold water past the thermostat.

This is due to the layering of hot water in the geyser. You know this effect in a still swimming pool when the sun has heated up the water but only the water at the surface is way warmer than the deeper water.
So the position of the thermometer in the tank is pivotal to measuring temperature accurately.
(Those who have a vertical geyser are the worst off knowing this)

That was a big sales pitch from ITS when I was looking at their pump. It was a patent pending solution but it’s basically just an off the shelf diverter valve. I have installed the same with my alliance heatpump.

The diverter valve itself can be adjusted to different temperatures but the problem is if you have the return from the pump going to the hot water outlet of the geyser, then you have bursts of hot water. Newer geysers like the kwikots have the renewal energy port and if you use this, then at least the water is mixing in the geyser before it comes to the tap.

I have a daikin tank that has a few outlets so I don’t use the hot water outlet.