Choosing a Water Heater: Instant, Storage or Central

The right water heater depends on how many taps run at once, the available energy source and the distance to the taps. A wrong choice means cold showers or needless expense.

In the morning, two family members shower at the same time, dishes are being washed in the kitchen, and suddenly the water turns cold. Or the opposite: a large tank is kept hot all day, but hot water is only used in the evening. People tend to pick a water heater last, yet its pipes, power supply and mounting space have to be decided at the very beginning of the renovation.

Assess demand first

The right choice starts with three questions:

• How many hot water outlets could run at the same time? Two showers and a kitchen tap in use together is a very different demand from a flat with one bathroom.
• Which energy sources are available? Natural gas, sufficient electrical capacity, a heating boiler, potential for solar energy.
• How far are the taps from the heater? On a long pipe run, a lot of cold water flows before hot water arrives, wasting both water and energy.

The number of bathrooms, whether there is a bathtub, household size and usage times are the main indicators of demand.

The heater's location is chosen at this stage too. Placing it as close as possible to bathrooms and kitchen, yet accessible for servicing, shortens pipe runs. For bathrooms at opposite ends of a house, two smaller heaters instead of one large one sometimes make more sense: each sits near its own zone and hot water arrives faster.

Instantaneous water heaters

An instantaneous heater warms water only while a tap is open and water is flowing. With no tank, it takes little space and uses no energy keeping water hot.

Electric instantaneous heaters need high power. For a model serving several outlets at once, the apartment's wiring, cable size and circuit breakers must be up to it; in some buildings the allocated supply does not allow it. A small single-outlet unit, however, can be a practical solution for a distant kitchen or guest toilet.

Gas-fired instantaneous heaters offer higher output but require a flue or balanced flue outlet, ventilation and compliance with gas safety rules. Installing them is work that needs the appropriate permission and a qualified specialist.

Storage water heaters

An electric storage heater warms water in advance and keeps it in an insulated tank. It needs far less electrical power than an instantaneous unit, but tank volume limits how much hot water can be used in a short period: once the tank is empty, reheating takes time.

The tank size is chosen according to the household's peak-hour use. An oversized tank constantly keeps surplus water hot, while a small one cannot keep up with evening showers. Weight matters too: a full tank puts a serious load on a wall, and fixings must suit the wall material.

Central and alternative systems

A combination gas boiler both heats the house and produces hot water. It is compact for small apartments, but temperature and pressure can drop when two taps are opened at once. An indirect cylinder connected to a system boiler handles several bathrooms in use simultaneously much more comfortably in larger houses.

Heat pump water heaters use heat from the air and consume electricity economically, but need space and a ventilated room. Solar collectors can supply much of the hot water in summer and work together with a backup source for cloudy days and winter.

In large houses, a secondary circulation loop is planned so hot water reaches distant bathrooms quickly: hot water keeps circulating in the pipes and arrives as soon as a tap is opened.

Safety and maintenance

• A storage heater must have a safety valve, and its discharge should be connected to the drain.
• In sealed systems, an expansion vessel absorbs the increase in water volume as it heats.
• To reduce bacterial risk in stored water, periodically keeping the temperature high is recommended; where there are children, a thermostatic mixing valve reduces scalding risk at the taps.
• Hard water forms scale, so the magnesium anode and heating element should be checked periodically.
• Leave clear access to the heater for maintenance rather than hiding it in a fully enclosed recess.

Zaferoğlu İnşaat sets plumbing routes and the positions of plant rooms and water heaters together with the layout in apartment and house renovations. Give us the household size and the number of showers likely to run together, and the heater type and position can be chosen from those two figures.