Water heaters

When the water heater breaks, you have two choices, repair it or replace it. If the problem is a burned element, or a faulty thermostat the water heater can be repaired, although some knowledge and tools are required. But if the unit is leaking or is more than ten years old, resign yourself, as its time to consider a replacement. Face it, it’s just not worth effort- or the risk.
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Types
Characteristics
To install or not install oneself
Energy consumption and safety
Maintenance
Accessories
Guarantees

Types

There are five types of residential water heaters: on-demand water heaters (tankless), integrated water heaters (with residential heating system), storage-type water heaters, heat pump water heaters and solar water heaters.

Demand water heaters (tankless)

As its name would indicate, the on-demand water heater heats water based on demand and as required. As a result, it does not use a storage tank. This type of system, whether electrically powered or fired with liquid propane or gas, can help reduce energy consumption by up to 30%. The drawback associated with this type of heater is that it does not have the capacity to respond to demands exceeding 3 to 4 gallons per minute. In practical terms, this means that you would have to wait for the dishwasher to finish its cycle before taking your shower. For this reason, this type of water heater is typically used as a support (or auxiliary) system for a specific application (i.e. to supply hot water to the kitchen faucet, etc.).

If you still intend to use a tankless water heater to provide for all your domestic hot water needs, it is recommended that you install a low-mass system. This type of system is designed to provide larger volumes of hot water in order to better respond to household requirements (people living alone and childless couples) and also provides improved energy efficiency.

Integrated Systems

This type of appliance, which uses a single heater fed by an external storage tank, combines two functions: it can be used to heat up the home, as well as the water. Although they are efficient and fairly inexpensive to install (a single unit handles two household functions), integrated systems are not that popular as they tend to deliver poor seasonal energy efficiency: system design requires that the heater work during the warmer months, even though the house may not require heating during this period.

Storage tank heaters

There are four types of storage tank automatic water heaters, i.e., electric, oil, natural gas and propane gas and their basic operation is quite simple, i.e., when hot water flows out, it’s replaced by cold water. A thermostat, adjusted to a preset temperature, commands one or two heating elements to bring the newly introduced cold water up to a desired temperature. Insulation around the tank keeps the water hot and cuts down on energy costs. The beauty of this system is the absence of moving parts. Water enters, either by gravity or is pumped from the outside, and these same forces assure its outflow. This means that water heaters can last for years with very little or no maintenance as long as the water quality, read mineral content, is favourable.

Heat Pump Water Heaters

Heat pumps do not produce heat on their own. Instead, they are designed to capture heat from external air sources and transfer it. In the case of water heater systems, the heat is transferred to the storage tank. This transfer process generates cold air, which may in turn be used to contribute to the home’s air conditioning; thereby providing even greater energy savings. The high cost of heat pumps is largely offset by the savings they provide (up to 50%), especially when installed in temperate zones. The efficiency of this type of system is reduced in areas where the mercury frequently falls below the -8º C mark.

Another type of heat pump, called “forced air”, captures the heat within the home and transfers it to the water. While delivering lower hot water costs during the colder months, these systems can result in increased household heating costs. During the warmer months (or in more temperate areas), this type of system can provide energy savings.

Finally, geothermal pumps (typically installed during the construction of new homes only) use underground heat sources, which provide improved stability over forced air or ambient sources, to heat the home during the winter. During the summer, the warm air is evacuated into the ground. With the addition of a desuperheater, geothermal pumps preheat the water to provide an average 25% savings on energy costs but will add approximately $1000 to the cost of installation of the geothermal system. System performance will ultimately depend upon your choice: would you like the geothermal system to primarily address your residential heating requirements while using the remaining energy to heat your water, or would you prefer the opposite? Regardless of the scenario you opt for, another energy source will be required to fulfill your heating requirements.

Solar Water Heater

We all know that the sun represents a free source of energy. Unfortunately, the specialised equipment needed to convert this energy is far from free. In the end, the savings provided will more than compensate for the purchase and installation costs of the system, which can typically deliver up to 50% of household hot water requirements.

There are two types of solar water heaters: passive and active. The first sends water (preheated by the sun) towards a standard storage-tank water heater. This transfer is done in passive fashion, using line pressure. The second type, or active system, uses pumps to transfer the water. In colder climates, water cannot be used for this process. Instead, an antifreeze solution is used to capture the heat, which is then transferred to the water via a heat exchanger.

Characteristics

Fossil fuel heaters
Fossil fuel heaters (oil, natural gas and liquid propane gas) need to be vented, either through a chimney or a wall-mounted vent to the outside. All things being equal, gas and/or oil powered units are generally less expensive to operate than their electric counterparts, although this can change at any given time according to prevailing energy prices.
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