Commercial Plumbing & Heating Engineer 

Every premise will require a form of hot-water heating system to enable the provision of adequate welfare facilities throughout the building.

Water heaters use a burner or element to heat cold water when demand is placed, to produce hot water on demand, or they may use a tank to store the heated water for when it is needed. They differ from a boiler which is a closed loop system and circulates hot water around a series of pipework, radiators, and other radiant heat systems before returning to the boiler to be reheated. A boiler will use much hotter water temperatures than a water heater for ease of transportation throughout the pipework and for better heat retention.

Types of water heaters:

Storage

Uses a separate tank to store water which has already been heated meaning there is always a constant supply ready to be used but there is potentially greater heat loss through the walls of the storage tank.

Standard – have a fast recovery rate making them a good choice for premises with a high volume of hot water demand.

Balanced flue – all the benefits of a standard storage heater with the added benefit of being able to deliver hot water to the point of use immediately.

Fan-assisted flue – ideal for premises requiring a long flue run as they do not require installing at the point of use.

Tankless

Are able to supply hot water on demand rather than heating up water in a storage tank meaning they are smaller and more efficient than storage water heaters and you will only ever heat as much hot water as needed rather than having a full-tank waiting to be used. However, heating hot water on demand requires the use of larger heating elements and so energy demand whilst actually heating the water can be high meaning more energy will be used to heat the same amount of water as in a storage water heater.

Comparison:

Demand

A tankless water heater should be able to provide hot water without running out whereas a pre-heated storage tank may not be able to keep up with demand but there may be a slight delay in being able to access hot water whilst waiting for the heater to fire up on demand.

Space

Tankless water heaters are more compact making them a good choice where space is limited and they can also be wall-hung to free up floor space.

Cost

The initial purchase, installation, and maintenance of a tankless system are usually higher than for a storage system but the efficiency savings of the unit made over time should make up for the initial outlay if not deemed unaffordable.

Lifespan

The average lifespan of a storage water heater is 10 years whereas a tankless unit should last up to 20 years.

Fuel options:

Electricity

Elements are used similar to those inside a kettle to heat the water but electric water heaters are not always as efficient as other fuels and electricity is also more expensive, although the initial cost of installation is usually lower due to the non-requirement for outside venting. However, electric water heaters can be ideal if hot-water demand is not particularly high.

Gas

Use a burner at the bottom of the tank and therefore require a venting chimney to release CO2 and water vapour. They are more expensive to install than electric water heaters but they are more efficient and the cost of gas is cheaper than the cost of electricity.

Propane

Similar to gas water heaters but often used where there is no access to the mains gas supply so propane will be supplied to the water heater from a storage tank installed nearby on the premises.

Oil

Similar to gas water heaters but often used where there is no access to the mains gas supply so the oil will be supplied to the water heater from a storage tank installed nearby on the premises.

Solar

Use the sun’s energy which is absorbed by solar panels installed on the roof which heat transfer fluid as it flows through the panel which in turn warms a heat exchanger which heats the water in a storage tank. Initial installation costs can be high but this option is environmentally friendly as provides a free source of energy. However, it may be best utilised alongside another fuel to maintain a reliable source of hot water as it is difficult to ensure consistency of supply all year round.