Frequently asked questions

COAX is particularly ideal for all types of cabins, holiday homes, annexes, boathouses, lightweight houses, camping, awning tents, boats, hot dog stands and other kiosks. Treetop cabins of every kind in the rental cabin segment have also had a COAX water heater fitted for various draw-off points. You need a minimum of 16A 230V power supply. COAX is supplied for all types of power supply, three-phase 230 and 400 volt. COAX is supplied for everything from an ordinary 16A single-phase fused circuit and upwards. The heater is mounted on the wall anywhere and projects only 5–8 cm from the wall, so it takes up minimal space. No tank, no tank issues, no maintenance, no draining and so on.

COAX gives hot water immediately, the moment you arrive, plenty of water without anything having been stored in advance. You also have hot water for everyone if you have visitors. And you get fresh hot water every time you draw it. COAX water heaters also use exactly the power needed for the short time water is being drawn. The heater is compact and can be placed advantageously, closer to the draw-off points, which in turn means the temperature and volume can be preset to the flow rate in l/min and water temperature you want. Modern water-saving tap nozzles can therefore also be used while still getting hot water quickly at the taps. This makes the consumption of water, electricity and drainage more precise. Easy installation, close by, with today's reinforced and flexible hoses, with ordinary half-inch pipe threads on the inlet and outlet.

If you want to drain a cabin of water for the winter, the heater should not be touched. It drains itself as the pipes are drained, by siphoning.

COAX is used today in offices, workshops, warehouses, shops, hotels and industry, avoiding long pipe runs, wash troughs, shower facilities, pump houses and so on. The solution can easily be scaled to suit requirements, in both large and smaller buildings. COAX is known for operational reliability and is completely maintenance-free. Since there is no tank, both the space required and the heat loss are reduced, with no risk of low oxygen content, aggressive hot water or bacterial growth, while at the same time achieving an energy-efficient installation.

Absolutely. COAX three-phase models are made for homes and flats as well as cabins large and small. For the shower, kitchen, washbasin, bidet, bathroom and utility room. It gives you fresh hot water, which is particularly beneficial for showering, where atomised water "aerosols" are easily breathed into the lungs. As is well known, storage in tanks and/or long runs of lukewarm hot water pipes can lead to a build-up of dangerous bacteria and serious illness. A hot water supply with no need for a large conventional water heater tucked away, which also means unnecessarily long hot water pipes from cellars and storerooms. With the COAX solution the water is heated right where and when it is needed, at the right temperature and flow rate. Choose a model according to the needs and the electrical supply of the building in question. Many manage well with a single heater. COAX is happy to help you decide on the number, 1, 2 or 3 units, and on placement, based on experience. Check your main fuses and what electrical supply is available in the fuse box. Volts: 230V 400V. Phases: single-phase three-phase. Amp rating. Feel free to get in touch, fill in the form or send an ordinary email: post@coax.no or call 97732838 /Rune.

It depends on the power output and the incoming water temperature. In winter the water comes in at 5 to 8 degrees, in summer around 12. An 18 kW heater gives around 7 litres per minute at 40 degrees in winter, and closer to 9 in summer. A modern shower head uses 6 to 9 litres. We always size for winter.

Power output is not consumption. 18 kW in a four-minute shower is 1.2 kWh, roughly the same as that shower costs with a tank. The difference is that the tank carries on using electricity for the 23 hours and 56 minutes you are not showering.

COAX has a typical efficiency of up to 98 %, which means that the energy is used to heat the water, and only for what you use, and at the correct desired temperature, there and then. You can easily feel on the outside of a COAX heater that it does not raise the temperature, which tells you that it is energy efficient By comparison, conventional hot water tanks have considerable heat loss, heating 2 or 300 litres up to an unnecessarily high temperature. It is apparently now meant to be at least 80 degrees, which must have been kept on at that for at least 4 hours to be sure that the water in the tank does not have unnecessarily many bacteria on board. the whole room, the tank and pipe runs. around the clock. IF you wanted heating in that room, you should rather use more favourable solutions for it, such as underfloor heating.

Since 2022 the grid rent has included a capacity component set by your three highest hours in the month. A ten-minute shower is 3 kWh in that hour, not 18. What can push you up a tier is showering while the car is charging and the oven is on. We will tell you how large a heater you need, and how large you do not need.

How much electricity, water and space you save with a COAX heater compared with a tank heater will vary. It can be a great deal, depending on what and how you compare.

For a coax water heater it is simple. You just multiply the rated wattage of the heater by the time hot water is drawn. Which is only the seconds and minutes it is switched on. For example: Kitchen 30 sec., Shower 4 min., Hand wash 10 sec. These are measured as average user times in Norway.

In contrast to a conventional hot water tank, which keeps the water hot and consumes electricity around the clock, as the water in the tank now has to be at least 80 degrees. With COAX this standby consumption is eliminated. How much you save depends on your usage pattern and where it is used. There is particularly much to gain where use is varied, such as in a cabin, and where there is a long distance to a central tank, in an outbuilding with a relatively cool room temperature. If a 200 l tank is used in a cabin, for example, and you empty that tank when you head home from the cabin, you pour 200 litres of 90 degree hot water straight down the drain every time. And you have to use 14 kW to heat it up again on your next visit. You do not do that with COAX water heaters. It is switched off the whole time, and is only switched on for the seconds and minutes hot water is drawn, and at the right temperature and jet size. If it is simply drained together with the pipe run to avoid frost, there is only a couple of cups of water inside it.

By comparison, with a COAX water heater you can, first of all, take your shower the moment you arrive, and using only 250 watts per minute for five minutes, for example, that is just 1,2 kWh.

Use our Consumption calculator to work out how much you can save, or get in touch if you need help assessing the solution.

COAX heats the water directly, there and then, as it passes through the heater past the heating elements, so you get hot water quickly if the heater is fitted close to the tap point. A COAX water heater can be, because COAX water heaters are compact. Only 8 cm thick, out from the wall. If the heater is in the same room, you can see on a display that it starts counting the degrees upwards straight away. It does take a few seconds to heat up the element housing, pipes and tap fitting. And pipe lengths to the tap point can vary. COAX has now also been fitted with an advanced and gentle soft start, which gives several benefits. It does take a few extra seconds to start up, but it also preserves the heating element, which has not burnt out in the past 15 years. It also means the heater can cut in at a lower flow rate than before, and gives virtually no noticeable interference in the mains. With a conventional hot water tank, the water is often too hot straight out of the tank, a scalding hazard, so cold water has to be mixed in at the tank as well, and it often has to heat up long pipe runs from cellars or storerooms to the tap points. This can mean a long wait at the tap in many places. With COAX you avoid this, and save time, electricity and water.

We offer single-phase models for smaller needs and three-phase models for larger installations. Have a look at the website, where there is a needs assessment you can fill in and send to us, or state the place of use, requirements and so on in an ordinary email and send it to us: post@coax.no Tel: 97732838

And do actually check how many litres per minute l/min the shower you use today delivers! A full bucket in one minute means about 9 litres per minute, we say. Half a bucket per minute we say is 5 litres per minute. If the tap is set on the flow side so that the bucket reaches 3/4 full in one minute, we say that is 7 l/min.

Use the bucket method to work out the right model based on your consumption. Do get in touch if you would like help assessing which solution suits you best.

It depends on the main fuse. With 25 A single-phase, our smallest model (5,5 kW) is enough for a kitchen tap and a basin, provided the electrician fits a 32 A circuit. With 32 to 40 A you also get a single shower. With 16 A there is not enough power output for anything other than a basin, and in that case we do not recommend a flow-through heater. Send us a photo of your consumer unit and we will tell you what is possible.

The requirements depend on the model and the power output you want. Our single-phase models run on 230 V and need a dedicated circuit of at least 32 A (the smallest model draws around 24 A). The three-phase models run on 230 V or 400 V with circuits from 3×20 to 3×40 A. With a 16 A main fuse, a flow-through heater is the wrong product, and we will tell you that before you buy. It is important to confirm capacity and main fuse with a qualified electrician before installation, so that you get full performance without overloading.

No. For safety reasons, the installation must be carried out by an authorised electrician and plumber. Correct installation ensures the right pressure, optimal temperature and safe operation. If you wish, we can recommend approved professionals in your area.

The price of installation varies depending on placement, the existing electrical system and the pipework. The cost is usually lower than installing a conventional hot water tank, since the system is smaller and simpler to connect. Contact us for a no-obligation quote from one of our partners.

COAX is very compact and projects only 5 to 10 cm from the wall. That makes it ideal for small bathrooms, cabins, boats and other places with limited space. You can mount it close to the tap point for fast response and minimal heat loss and water consumption. You can also choose a smaller model/power output if it is close by, so that nozzles can be used.

A Coax water heater has no requirement for a concrete floor, tiled walls or a floor drain. It can be mounted almost anywhere, including lying down or upside down.

A common misunderstanding is to confuse power output (kW) with energy consumption (kWh). But there is a very big difference. Many people see that COAX has a high power output and therefore assume that the electricity consumption must be high too. In practice it is the opposite. COAX does indeed use a high power output for brief moments in order to deliver hot water immediately, but the total energy use is lower because, The water is heated only for the short time you are actually drawing hot water. The average draw-off times for water heating in Norway are only: Kitchen: 30 sec. Shower 4 min. Hand washing 10 sec.

- There is no standby loss, and you avoid keeping a large hot water tank warm around the clock. - The COAX water heater is compact and can therefore be placed more conveniently close to the tapping points. - No long hot water pipes, so you avoid running the tap wastefully and using a lot of hot water unnecessarily. - Shorter hot water pipes mean less heat loss - It also makes it possible to use modern water-saving nozzles and still have hot water quickly at the taps.

- It raises the temperature only up to the preset temperature you want.

The result is lower energy use, especially in homes, flats and cabins where hot water consumption varies through the day or from period to period.

COAX is effectively maintenance-free in normal use. There is no tank to drain or clean, and no moving parts to wear out. The only thing we recommend is cleaning the inlet filter and the tap aerator now and then, particularly in hard water areas.

Even with a so-called " smart hot water tank" that can optimise energy use by heating water when the electricity price is somewhat lower, comparisons show that COAX tankless water heaters are considerably more energy-saving and cost-effective. A hot water tank still uses an old tank-based solution without the important points below that apply to COAX hot water - completely without a tank!

This is because it

COAX water heater - completely without a tank eliminates, among other things, the standby heat loss entirely and uses electricity only for the seconds and minutes that hot water is drawn.

COAX Water Heater is COMPLETELY OFF around the clock, and is only switched on for the seconds and minutes that hot water is drawn.

- only WHEN hot water is actually drawn. - Heats the water WHERE it is drawn - Raises the temperature only up to the desired usage temperature. For example from 10 to 40, raising it by only 30 degrees. - Heats only the amount of water that is to be used, no long pipes or controlled draw-off at full flow. - The heating element is always clean, which gives good contact with the water - good heat conduction! - Heats the water at the point of use and can therefore use modern water-saving tap nozzles and still get hot water quickly at the point of use. Water-saving nozzles will not work with long hot water pipes.

A new smart tank usually costs 15.000–25.000 kroner including installation, while converting an existing conventional water heater to a smart solution costs 10.000–25.000 kroner. Annual savings are typically between 2.000 and 5.000 kroner, very much depending on consumption and electricity prices.

By comparison, the EPA (Environmental Protection Agency) shows that direct water heaters can cut hot water costs by 24–50 %, which often corresponds to an annual saving of 4.000–10.000 kroner for an average household. In addition, COAX has a lower total cost, usually 10.000–15.000 kroner including installation.

Conclusion: COAX water heater - completely without a tank is in any case the most cost- and energy-efficient option, particularly for households that want minimal energy loss and a solution with no maintenance or tank-related problems.

Many people think that COAX tankless water heaters may not manage to heat water quickly enough, or supply enough hot water over time, in a cold climate like Norway's. Modern water heaters are of course built for northern as well as southern regions. In the Nordic countries you simply allow for a water temperature about 10 degrees lower in winter, and then choose the power output of the heater accordingly. Every type of heater that heats water or air in a cold climate has to make the same allowances for power output in winter, including a conventional water heater. When the flow rate, the model and the wattage have been chosen correctly for the desired jet size in litres per minute and the desired temperature, the result is exactly the same. In the Nordic countries everyone allows for the winter months anyway.

But then we have good access to "power" in Norway. And remember that power output is not the same as electricity consumption! Rather the opposite: if you have the power output, you can be efficient and therefore use less! As COAX proves!

COAX hot water is hygienic, oxygen-rich, fresh hot water – every time you draw it, which matters especially in the shower. With COAX, the cold, fresh drinking water is heated directly from the cold water inlet without any storage in a tank! The temperature is raised gently in a clean stainless steel channel to the temperature you want, with nothing else affecting it.

This eliminates the risk of bacterial growth of the kind found in a hot water tank, where a lot of dirt collects at the bottom and deposits burn onto the heating elements, with a risk of bacterial growth such as legionella and similar.

It turns out that storing hot water in a hot water tank can make the hot water aggressive and dissolve heavy metals, which can and does happen there. There are good reasons why most people know you should not drink hot water from the taps. NB. Is it not then at least as risky to shower in it, since we then get the water into our lungs, which are more exposed and sensitive than the stomach?

No. Legionella bacteria need standing water between 20 and 50 °C and, not least, time in order to multiply. COAX has no storage tank, and fresh cold water is heated instantly to the desired temperature right there and then as it passes the heating elements, leaving no time for bacterial growth. Without a tank there is no lukewarm, standing volume where legionella multiplies, and you avoid having to keep a conventional water heater at 70 degrees as the Norwegian Institute of Public Health recommends.