water heaters basics
Water heating involves 20% or more of the energy used by average households, making it an important element of our energy bills.
Different Products, technologies and Prices
Water heater technology has evolved a lot during the last decade. In UK the term boiler is basically equivalent to the term water heater in USA and Canada. In USA or Canada, the term boiler refers to high-capacity appliances used in space-air heating (which are different from water heaters).
There is now available very different units and models, incorporating different technologies (tankless and storage, condensing and standard, solar, electric heat pump water heaters...), with different prices and involving different fuels or energy sources, making the choice rather confusing.
Left: A gas boiler, a gas tankless water heater and a gas storage water heater
See also: Boilers Basics
The main options
The main technological options in water heaters are:
1- Tank-storage vs. tankless water heaters
2- New efficient condensing water heaters vs. standard water heaters
3- Solar water heaters
4- Gas vs. Electric heaters (including the Point of Use Heaters and the new Electric Heat Pumps Water Heaters).
5 - Integrated Space and Water Heaters
The solar water heater option
Solar water heating is now a tested and proven technology, highly competitive. The right system varies with climate, and may demand some backup systems (often a gas or electric water heater) in cold climates…
See: Solar Water Heaters
new gas condensing water heaters
If you want a gas water heater, consider the gas condensing technology. It’s a novelty in USA, but in UK and other European countries it’s already the standard technology in the gas hot water heating.
Gas and electric water heaters
Gas water heaters are usually more energy-efficient and economically more advantageous than electric water heaters, but there are situations where electricity should be considered, namely if your outlet is electric or for small uses.
Electric Heat Pumps Water Heaters are also a new option to consider.
See also, for small uses: Point of Use Electric Water Heaters
Tankless (on-demand) and Storage water heaters
Tankless water heating has some advantages over the tank-storage technology, but difference in prices and in installation costs should be taken into account (in existing homes with storage units).
See:
Tankless (On-Demand) Water Heaters
Choosing a Tankless Water Heater
Condensing Water Heaters
Storage Water heaters
Water heaters fuel
The fuel and the energy source is an important issue. Solar, natural gas and electricity have different costs and efficiencies.
Sizing and installation
Details like the design associated to the water heater, the installation and its costs, or the capacity and power of the different models and technologies should also be considered.
See:
Installation & Water Heaters
Design & Water Heaters
Sizing Water Heaters
See also: