A domestic hot water heating system is one of the most important factors in the energy efficiency of the home.
The law has set forth minimum efficiency standards for gas hot water units. The system will also affect the cost of operation and the level of carbon dioxide that is emitted.
The efficiency of the gas hot water systems will depend on:
- The fuel
- The type of gas hot water heater and the design
- Whether it is an automatic or permanent pilot
- The burner control including gas, modulating, or air/gas modulating
- The location of the gas hot water heate
- The radiator size and the design heat load
- The controls of the system
- The flow and the return temperature
- The commissioning and installation
- If the system if free of sludge and scale
- The schedule of regular maintenance
New gas water heater technologies are more efficient and are improved.
They are designed to use less energy and be durable. New regulations require that gas fired hot water unit need to be condensed. This excludes range cooker gas hot water heaters. Gas hot water heaters use more energy than most household appliances. The central heating system uses around 23,000 kilowatt per hour each year. Eighty-five percent of this energy usage is for heating up water.
To reduce the cost of it is important to get an energy efficient system.
Condensed gas hot water heaters and Energy Efficiency
These systems have a larger heating exchange unit or a second unit that is able to get more heat from the gas. If the gas hot water heater is non condensing the gases are set at a temperature from 120 to 200 degrees Celsius. In a condensing gas hot water heater the temperate ranges from 50 to 100 degrees to reduce the operating temperature. The water vapor is able to make a liquid that does require draining. If the flue gas side gets wet it may be likely to corrode.
The unit should be made from a corrosion resistant material such as aluminum or stainless steel.
Exceptions for a Condensing gas hot water heater
To determine if a non condensing gas hot water heater can be used a property assessment must be performed.
There are some key factors to look during the assessment including:
- The type of fuel that is used, the type of building it is used in, the position of the gas hot water heater, the options that the flue has, the terminal position of the flue, and the condensate drain points
- The lowest cost for installation
- The standard costs versus the benefits of the unit
- The installation position which will be determined by the ignoring furniture, fittings, if the building is occupied, and the preferred location of the unit
- A competent person must perform this assessment. A copy must be provided to the owner of the building. The owner needs to hold onto this copy to prove the assessment was performed.
- If approved during the assessment a non condensing gas hot water heater may be installed. The assessment form must be provided to the new owner if the building is sold.
- A condensed gas hot water heater is often preferred and may need to be installed for an additional cost.
- Any gas hot water heater installed needs to be evaluated and an assessment must be conducted.