Hot water for the impatient nation

25th Oct 2016


You’re in a hurry and need to know what this article is all about, right? OK, OK. It's about impatience (and hot water).

In the past few decades we have become the Impatient Nation. The demand to ‘have it now’ is seeping into every corner of our lives. We want quick answers to complex problems, we speed date, eat fast food, use self-checkout lines, try the "30 day Abs” challenge, pay extra for overnight shipping, beep when the traffic lights turns green, speak in half sentences. Start things but don't fin...

We twitter stories in 140 characters or less. We cut corners, take shortcuts. We txt.

We’ve even become impatient with ... wait for it ... impatience.

So how do we meet the impatient hot water demands of today’s household? How do we ensure both bath and en suite shower can run simultaneously, and the impatient nation can go about their day without having to …………………………………wait?

Fortunately advancements in technology mean we can.


Hot water storage tank solutions allow for someone to take a hot shower, whilst someone else runs a fast filling bath; no-one has to wait, a perfect solution for the hurried household.

Unvented units work directly from the mains supply of water, meaning that providing the incoming mains pressure is sufficient (which in the vast majority it is), hot water can be delivered quickly, via more than one outlet.

Many people remain under the impression that hot water storage tanks mean that they will run out of hot water, and therefore have to wait for the tank to heat up. If the tank is sized correctly according to the needs of the household, this should not happen. Here’s a quick guide to sizing;

Obviously larger houses will have larger tanks. When selecting the size of the hot water tank, a simple rule of thumb is that for a typical domestic household, you should allow between 35 and 45 litres for every occupant. That said a mains pressure system can use about 18 litres of water per minute at 40 degrees Celsius if a decent quality shower head is used. Certain brands of shower can use up to 25 litres of water per minute.


However, it must be noted that personal habits also play a big part in total hot water use. Two households of the same size can use completely different amounts of hot water, with one of them using twice as much as the other!

In determining how much hot water you require you should always consult with the occupants, and consider the following:

  • A bath uses 100 litres of hot water at 40 degrees Celsius (equating to 60 litres at 60 degrees Celsius)
  • Showers can use about 18 litres of hot water per minute at 40 degrees Celsius (equating to 11 litres at 60 degrees Celsius)

The following average consumption values can be used as a general rule (hot water requirements per person per day): 

  • Low Consumption                            =             20 – 30 litres
  • Average Consumption                     =             30 – 50 litres
  • High Consumption                           =             50 – 70 litres

On this basis a typical four person household would often use around 200 litres of hot water a day and this is the figure that will generally be used under the new EU energy labelling scheme.

This does not necessarily mean that a 200 litre tank is required as dependent on the heating system the tank may be partially reheated during the day. It is up to the installer to match the correct size of tank relative to boiler (or electrical) input to avoid running out of hot water.

Future proofing

So we have established that the hot water industry can meet the needs of today’s household, now let’s look at how they also meet the needs of tomorrow’s.

With renewable energy heating sources receiving consumer buy in and Government encouragement via schemes like the Renewable Heat Incentive (RHI). It is clear that Renewable technology is here to stay.

The latest figures for RHI show that as at February 2016, 49,340 homes have applied for payments under the domestic RHI. Many new build housing developments feature hot water storage as standard also, enabling the homes to be ‘renewable ready’, should the homeowner wish to install a renewable heating system at a later date.

Renewables partnered with hot water storage is the only practical solution to turning the energy produced into something useful, and banking it for when it needs to be used. 

Hot water storage tanks are the perfect companion for renewable energy sources, which can be inflexible in terms of their energy supply. You are often at the hands of the weather (e.g. solar thermal and air source heat pumps); hot water tanks can heat the water when your renewable source is generating energy; store it, and then use it when needed.

The features of hot water storage tanks, which are purposely designed for use with renewables, allow maximum heat transfer of renewable energy into the stored water. Acting as the heart of an alternative energy system, there are tanks designed for use with one energy source available; as well as products which can take input from multiple heat sources; including solar panels, biomass, heat pumps and other heat sources.

In addition there are now also products available which come pre-wired and pre-plumbed to save on installation time; taking on the technology industries phrase of ‘Plug and Play’. Products with single coils for use with one heat source, and twin coils for dual heat source, or plate to plate heat exchangers are also available.

Hot water storage tanks are an efficient and environmentally friendly way of providing domestic hot water and cutting energy bills. They are also perfect for meeting the impatient demands of today’s households; of multiple instant results, leaving them free to identify other ways in which to hurry.

It seems impatience has been a driving force behind progress. Impatience can be key to moving things along.

As ever, HWA members will be pleased to offer advice on best practice. You can find member details ‘quickly’ on the HWA website