Choosing the right electric water heater isn’t as difficult as you may think. Picking an over or under sink model usually depends on how much free space you have available – i.e. a lack of wall space suits under sink units, whereas if there’s no room underneath (and no free cupboard space) then an over sink water heater is the way to go.
The other key consideration is how much water are you going to use – and how frequently will you be using it? If you know the latter, you should check a product’s reheat times to ensure it meets your usage requirements. For example, an Andris Lux 3kW 15L model can be ready again within 20 minutes after using all hot water in the tank, while a Velis Evo Wi-Fi 45L will have your next shower ready in less than 30 minutes! Our recommendations vary depending on these factors, but as a general guide, we offer the following advice:
For light water use
Starting with light use, for a single wash basin in a bathroom, a 5L wall-mounted point of use electric water heater (such as our Piccolo) will easily cope with demand, as 5L is the average amount of water required to wash your hands. As more basins require hot water, greater capacity is needed, so we recommend 6L models (such as Andris Lux) for two basins, increasing to 10L versions or instantaneous electric water heaters like our Aures Slim Multi for three basins (or a kitchen sink). Please note, although an instantaneous water heater can supply multiple outlets, it cannot do so at the same time; as water is drawn from the same source, opening a tap at a second outlet will cut the flow and temperature in half. So, if somebody runs another sink while you’re already washing your hands, you’ll find the water going cold very quickly.
Moving further up the scale, 30L electric water heaters can feed two kitchen sinks. 45-50L units, such as our Velis Evo Wi-Fi and Pro1 Eco, are enough for a shower, although for multiple showers and filling basins, the 80L versions of these electric water heaters are recommended. Please note, a 30L electric storage heater does not have sufficient capacity for a satisfactory shower.
For medium water use
The more frequent the use, the bigger the capacity of electric water heater required. So, in terms of medium usage, our 6L Andris Lux can be utilised for a single basin, moving up to 10L model or an instantaneous Aures Slim Multi fortwo basins. A frequently used kitchen sink would benefit from a 15L water heater (such as Andris Lux or Andris Lux Eco), with multiple kitchen sinks then requiring 45/50L models in the form of either the Pro1 Eco or Velis Evo range. We recommend these capacities as, on average, 15 to 25L is required to fill a standard kitchen sink; we also advise against connecting more than three basins to one electric water heating unit.
If the shower is going to be used consecutively, we recommend 80L units, with 100L Pro1 Eco water heaters best for medium use showers and basins. We have calculated the average shower uses 35L of water, so two showers in succession (as would occur in multiple occupancy properties) require 70L, hence the need for an 80L electric water heater.
For heavy water use
Finally, when a property’s hot water demand is high, the more capacity the better! In these circumstances, we recommend 10L Andris Lux units or Aures Slim Multi instantaneous water heaters for a single basin, moving up to 15L capacity Andris Lux or Andris Lux Eco models for two basins. Be aware that as an instantaneous unit heats water flowing directly through the unit, it requires slightly more power (9.5kW) compared to other models (although this does mean hot water is available immediately).
We then move into the realms of 30L Andris Lux models for multiple basins or a kitchen sink, with two of the latter in heavy use best suited to 80L Pro1 Eco or Velis Evo Wi-Fi electric water heaters. When a shower is under heavy use, only a 100L Pro1 Eco unit will do.
For fans of baths, an 80L Velis Evo Wi-Fi or a 100L Pro1 Eco will produce lashings of hot water to fill a tub. Bearing in mind the average bath holds 80L (with at least three quarters being hot water) you need ensure the correct capacity water heater accordingly – especially if it will be required to supply other outlets, such as a kitchen sink, at the same time as the bathtub.
If you have any questions about which electric water heater is the right one for your project, contact our technical and customer services teams to find out more – we’re happy to help!