Choosing the method by which hot water is supplied is often pre-determined by the choice of central heating system; which is ironic as heating systems in the UK are used on average for less than five months of the year. In addition the amount of heating required can be pre-determined, i.e. 18 degrees centigrade in the bedrooms, 21 degrees in the living room and so on.
It is the hot water requirement that tends to vary with usage, yet it is often treated as a lower requirement to, boiler location, ease of installation, cost etc. The issue is often compounded by the variety and choice of water heating systems that are now available, yet in general terms there are only two main types of system:
Many would argue that this is an over simplification, and of course there are many derivatives of each. Both hot water systems have different characteristics and some of the key issues for consideration include:
- Instantaneous water heating which heats water as required
- Hot water storage, which stores hot water ready for use
The key issue is to specify and install a system that is best matched to your individual needs and circumstances at a cost that you can afford. However care needs to be taken to ensure that the system installed does not adversely affect the value of your property. When purchasing a system the specifier needs to consider the type of property i.e. public building, rented accommodation, personal home dwelling and the long term plans for occupancy i.e. investment property or life long home.
A full central heating system is often perceived to add value to a property irrespective of age, yet in a small one bedroom or partially used property instantaneous heaters may be more appropriate. A balance therefore, needs to be obtained, between installation cost, intended usage and investment criteria.
- Type of fuel available
- Number and age of occupants in the dwelling
- How much hot water do you need
- Is the water heating system to be a part of the central heating system
- Number of hot water draw off points, bathrooms en-suit etc
- Speed of hot water delivery
- Flow rate requirement
- Space available for hot water appliances
- Suitability of location and technical feasibility, flues etc
- Preference for a dry loft space
- Cost verses benefits
Any hot water system must be able to meet the requirements of the whole house. That is all sanitary units and whatever appliances are connected e.g. dishwashers, washing machines etc. Bathing tends to create the largest demand for hot water; each bath will require approximately 65 litres of hot water. The size of the property and layout of the rooms that have sanitary fittings also needs consideration. Long pipe runs supplying hot water would probably be un-acceptable for centralized instantaneous heater systems, and a combination of systems may be more appropriate.
This section aims to examine the two main types of water heating and their derivatives, giving a simplistic overview of each system so that the reader can gain a holistic view of the choices that are available.