Hot Water Efficiency

Building and insulation standards have improved considerably over the past number of years which has meant that it's possible to reduce boiler and heat pump sizes.  However, simultaneously, our demand for hot water has increased (more bathrooms, shower rooms, ensuites, wet rooms, swimming pools) and this has resulted in driving the size of boiler and heat pumps back up again.  It is vital that you consider your hot water requirements and that your domestic water system is designed properly.  You need to install the appropriate size tank and pipe to ensure efficiently delivering enough hot water.

IMPORTANT

Correct pipe sizing and selection of shower heads for domestic hot water is just as important as all the other energy efficient measures that IHS recommends  There is no point in investing in a renewable heating system if all the benefits it delivers are wasted by using inefficient water sysems.

To assess your requirements
Add up all the hot and cold outlets you require on each floor, zone or area.
This should include all sinks, toilets, showers, baths, outside taps, dishwashers, washing machines etc.
This will tell you the size and quantity of manifolds you require for each area.

When choosing your shower:  Some shower heads demand so much hot water that your heat pump or boiler will use more energy heating the hot water than delivering heat.  Also, you may have a number of showers running at the same time.

When you purchase your shower, you should be aware of the following:
A fully operational power shower should use no more than a maximum of 11 litres per minute
An Eco Shower uses 7 litres per minute
A Norweigan Eco Shower uses 4.5 litres per minute

If you have a 500 litre tank (of which 320 litres is hot water), you can have:
3 (fully pressurised) showers of ten minutes' duration
or;
5 Eco showers of nine minutes' duration
or;
7 Norweigan Eco Showers of ten minutes' duration
If you have a mock Victorian shower rose (approx half meter diameter) you can have
1 shower of eight minutes' duration (You'd need a 135kW boiler to keep up with this shower!)
The quality of your shower should not be judged by the volume of water you're using; it's affected by how this water is nozzled.  Therefore, if you invest in an expensive heat pump installation in order to use less energy, look seriously at the volume of water used by the showers, bath valves and tapes you acquire!

Pipe Sizing

If you have a 3-bar supply of water coming into the house, the following (preferably plastic) pipe sizes should be used:
10mm pipe to all toilets, wash hand basins, dishwashers, washing machines, bidets, kitchen sinks
Showers should be supplied by 10 or 12 mm pipe depending on the length of pipe
Baths should be supplied by 15mm pipe and not more (NOT 22mm)

Pipe in Pipe

We strongly recommend that you use a modern plastic pipe in pipe system with manifolds and stop taps.  The use of plastic pipe will eliminate the sound of cavitating, rushing water which is associated with copper pipework so it's much quieter.  Plastic pipe in pipe materials and installation is considerably cheaper than a copper pipe system - it's also less intrusive.  Typically, Aquaflex water pipe in pipe is sold in 50m lengths.

System Design

The basic principle is that for every 28mm supply coming into a house, you can "T" off 3x22mm supplies from which you can take 3x15mm supplies from which you can take 3x10mm or 2x12mm supplies.  This will allow equal pressure throughout the house if different taps and water points are used - so there will be no pressure loss.  Think of it as the branches coming from a tree; first you have a large trunk from which large branches come off, followed by a network of smaler branches.
Speedfix fittings are used to make all connections and are available from any plumbing merchant.

IHS can design your system and supply you with the right pipework, shower fittings and valves if you require.