Energy Efficient Boilers

Energy Efficient Boilers (fitted with heating controls)

	DESCRIPTION Boilers account for around 60% of all domestic carbon dioxide emissions. A condensing boiler is a hot water heating device designed to recover energy normally discharged to the atmosphere through the flue. When a condensing boiler is working at peak efficiency the water vapour produced by the burning of gas or oil in the boiler condenses back into liquid water - hence the name "condensing boiler". The boiler uses a heat exchanger so that incoming air or water cools the exhaust, forcing the condensation of the water vapour it contains; this heats the incoming air (if an air-to-air heat exchanger is used) or pre-heats the water (if an air-to-water heat exchanger is used). A small proportion of the extra efficiency of the condensing boiler is due to the cooling of the exhaust gases, but the majority of the energy recovered is from the condensation of the water vapour in the exhaust gases. This releases the latent heat of vaporization of the water - 2260kJ/kg (970btuh/pound) of condensate (the water vapour released whenever one burns fossil fuels). The actual operating efficiency of a condensing boiler depends on the ambient air temperature and the relative humidity. If the incoming air is at 100% relative humidity, the condensing boiler will operate at its maximum efficiency (since it can - in theory - condense all the extra water vapour introduced by combustion). As the relative humidity falls, so will the actual efficiency of the condensing boiler (because less of the water vapour produced can be recovered from the exhaust). Condensing boilers are now largely replacing earlier, "conventional" designs in powering domestic central heating systems in Europe and to a lesser degree in North America. The Netherlands was probably the first country to take them up in a large way. In Europe, their installation is strongly advocated by pressure groups and government bodies concerned with reducing energy use. In the UK, for example, since 2005 all new gas central-heating boilers fitted in England and Wales must be high-efficiency condensing boilers unless there are exceptional circumstances, and the same applies to oil-fired boilers from 1st April 2007 (warm air central heating systems are exempt from these regulations). Condensing boiler manufacturers claim that up to 98% thermal efficiency of fuel conversion can be achieved in normal domestic use, compared to 70%-80% with a conventional design. Typical condensing boiler efficiencies are around 90%, which brings most brands of condensing gas boiler in to the highest categories for energy efficiency; in the UK they receive a "SEDBUK" Band A or B energy efficiency rating. Gas condensing boilers have only one extra element to be installed - the drain pipe for the condensate collected during operation. This comprises a short length of inexpensive plastic waste pipe. Since the final exhaust from a condensing boiler has a lower temperature than the exhaust from a conventional boiler a fan is always required to expel it, with the additional benefit of allowing the use of low-temperature exhaust piping (typically PVC in domestic applications) without insulation or chimney requirements. This allows for the added benefit of flexibility of installation location. Condensing boilers are up to 50% more expensive to buy and install than conventional types. However, at UK prices the extra cost of installing a condensing boiler should be recovered in around 2-3 years through lower fuel use. Obviously the exact figure will depend on the efficiency of the original boiler installation, boiler utilisation patterns, and costs associated with the new boiler installation. HEATING CONTROLS UK law now also requires new boilers to be fitted with a timer, room thermostat, and thermostatic radiator valves (TRVs). Heating controls do exactly as their name suggests - they allow you to choose when the heating is on, how warm it is, and where the warmth is concentrated. This further reduces the amount of CO2 produced and your monthly energy bill because the boiler doesn‘t have to work as hard. PROGRAMMERS Programmers allow you to set when the heating and hot water come 'On' and go 'Off' again. By installing a programmer, and heating your home and hot water only as and when necessary, you will save energy and money. THERMOSTATS A room thermostat constantly measures the air temperature of a space and can be set to whatever temperature suits you best. They are usually in halls, stairs or landing areas to sense the average temperature of a home's main living spaces. When the temperature falls below the setting, the thermostat switches on the central heating; once the room reaches the set temperature, the thermostat switches the heating off. Please note that the heating needs to be switched on for the thermostat to work. PROGRAMMABLE ROOM THERMOSTATS A programmable room thermostat lets you choose the times you want your home to be heated and the temperature you want it to reach while it is on. In other words, it allows you to heat rooms or the whole house to different temperatures in your home at appropriate times of the day and week. And again, by heating your home and hot water only as and when necessary, it can save energy and money too. CYLINDER THERMOSTATS A cylinder thermostat keeps a constant check on the temperature of the water in a hot-water cylinder. It switches the heat supply from the boiler on and off as necessary to keep the water at a set temperature. Installing a cylinder thermostat could save you up to £15 and 80kg of CO2 a year. THERMOSTATIC RADIATOR VALVES (TRVs) TRVs sense the air temperature around them and regulate the flow of hot water entering the radiators to keep a set temperature in a room. Again, they can help you save money and energy - by allowing temperatures in some rooms than in others, and to turn off the heating in rooms that aren't used. In the majority of cases TRVs can not turn off the boiler when the whole house has reached the right temperature. To do that, you will need a room thermostat as well. Radiators in the space containing the room thermostat should not normally have TRVs. But if they do, you should keep the TRVs on their highest possible settings, and set the room thermostat to the required temperature instead. By installing TRVs, you could save up to £10 a year and around 60kg of CO2 a year. [sources: Wikipedia and Energy Saving Trust] Back to full range

DESCRIPTION
Boilers account for around 60% of all domestic carbon dioxide emissions. A condensing boiler is a hot water heating device designed to recover energy normally discharged to the atmosphere through the flue. When a condensing boiler is working at peak efficiency the water vapour produced by the burning of gas or oil in the boiler condenses back into liquid water - hence the name "condensing boiler". The boiler uses a heat exchanger so that incoming air or water cools the exhaust, forcing the condensation of the water vapour it contains; this heats the incoming air (if an air-to-air heat exchanger is used) or pre-heats the water (if an air-to-water heat exchanger is used).

A small proportion of the extra efficiency of the condensing boiler is due to the cooling of the exhaust gases, but the majority of the energy recovered is from the condensation of the water vapour in the exhaust gases. This releases the latent heat of vaporization of the water - 2260kJ/kg (970btuh/pound) of condensate (the water vapour released whenever one burns fossil fuels).

The actual operating efficiency of a condensing boiler depends on the ambient air temperature and the relative humidity. If the incoming air is at 100% relative humidity, the condensing boiler will operate at its maximum efficiency (since it can - in theory - condense all the extra water vapour introduced by combustion). As the relative humidity falls, so will the actual efficiency of the condensing boiler (because less of the water vapour produced can be recovered from the exhaust).
Condensing boilers are now largely replacing earlier, "conventional" designs in powering domestic central heating systems in Europe and to a lesser degree in North America. The Netherlands was probably the first country to take them up in a large way. In Europe, their installation is strongly advocated by pressure groups and government bodies concerned with reducing energy use. In the UK, for example, since 2005 all new gas central-heating boilers fitted in England and Wales must be high-efficiency condensing boilers unless there are exceptional circumstances, and the same applies to oil-fired boilers from 1st April 2007 (warm air central heating systems are exempt from these regulations).

Condensing boiler manufacturers claim that up to 98% thermal efficiency of fuel conversion can be achieved in normal domestic use, compared to 70%-80% with a conventional design. Typical condensing boiler efficiencies are around 90%, which brings most brands of condensing gas boiler in to the highest categories for energy efficiency; in the UK they receive a "SEDBUK" Band A or B energy efficiency rating. Gas condensing boilers have only one extra element to be installed - the drain pipe for the condensate collected during operation. This comprises a short length of inexpensive plastic waste pipe. Since the final exhaust from a condensing boiler has a lower temperature than the exhaust from a conventional boiler a fan is always required to expel it, with the additional benefit of allowing the use of low-temperature exhaust piping (typically PVC in domestic applications) without insulation or chimney requirements. This allows for the added benefit of flexibility of installation location.

Condensing boilers are up to 50% more expensive to buy and install than conventional types. However, at UK prices the extra cost of installing a condensing boiler should be recovered in around 2-3 years through lower fuel use. Obviously the exact figure will depend on the efficiency of the original boiler installation, boiler utilisation patterns, and costs associated with the new boiler installation.

HEATING CONTROLS
UK law now also requires new boilers to be fitted with a timer, room thermostat, and thermostatic radiator valves (TRVs). Heating controls do exactly as their name suggests - they allow you to choose when the heating is on, how warm it is, and where the warmth is concentrated. This further reduces the amount of CO2 produced and your monthly energy bill because the boiler doesn‘t have to work as hard.

PROGRAMMERS
Programmers allow you to set when the heating and hot water come 'On' and go 'Off' again. By installing a programmer, and heating your home and hot water only as and when necessary, you will save energy and money.

THERMOSTATS
A room thermostat constantly measures the air temperature of a space and can be set to whatever temperature suits you best. They are usually in halls, stairs or landing areas to sense the average temperature of a home's main living spaces. When the temperature falls below the setting, the thermostat switches on the central heating; once the room reaches the set temperature, the thermostat switches the heating off. Please note that the heating needs to be switched on for the thermostat to work.

PROGRAMMABLE ROOM THERMOSTATS
A programmable room thermostat lets you choose the times you want your home to be heated and the temperature you want it to reach while it is on. In other words, it allows you to heat rooms or the whole house to different temperatures in your home at appropriate times of the day and week. And again, by heating your home and hot water only as and when necessary, it can save energy and money too.
CYLINDER THERMOSTATS

A cylinder thermostat keeps a constant check on the temperature of the water in a hot-water cylinder. It switches the heat supply from the boiler on and off as necessary to keep the water at a set temperature. Installing a cylinder thermostat could save you up to £15 and 80kg of CO2 a year.

THERMOSTATIC RADIATOR VALVES (TRVs)
TRVs sense the air temperature around them and regulate the flow of hot water entering the radiators to keep a set temperature in a room. Again, they can help you save money and energy - by allowing temperatures in some rooms than in others, and to turn off the heating in rooms that aren't used.
In the majority of cases TRVs can not turn off the boiler when the whole house has reached the right temperature. To do that, you will need a room thermostat as well. Radiators in the space containing the room thermostat should not normally have TRVs. But if they do, you should keep the TRVs on their highest possible settings, and set the room thermostat to the required temperature instead. By installing TRVs, you could save up to £10 a year and around 60kg of CO2 a year.

[sources: Wikipedia and Energy Saving Trust]

Back to full range