Boiler Considerations

The Better Energy Homes scheme provides grants to homeowners who invest in energy efficiency improvements in one or more of the following areas: Roof Insulation, Wall Insulation, Installation of a High Efficiency (> 90%) Gas or Oil fired Boiler, Heating Control Upgrades and Solar panels.

For houses equipped with gas or oil-fired central heating, one of the key issues associated with an extension is whether the existing boiler has adequate capacity to heat the enlarged house. In many cases, the additional heat loss associated with the extension makes it necessary to install a new boiler with appropriate additional capacity, at significant cost. However, in some cases a better insulated extension may reduce the overall heat loss of the house by covering up some of the original, less well insulated areas. Sometimes the boiler in the original house has been over-sized, and it may be able to cope perfectly adequately with an increase in heat loss of the order of 10 per cent. It is therefore worth calculating the effect of the proposed conversion on the heat loss of the house, at an early stage of the design.

Normally the recommended factory or “fresh out of a box” efficiency of an oil or gas boiler over 15 years old would have been less than 80%. Its current efficiency today due to age, and general wear and tear will probably only achieve from 50% to 70%.
All boilers on the market today will achieve efficiencies greater than 90%. This is a huge improvement on boilers that are 15 years and older and represents in operational improvement of up to 20 percentage points.
So by replacing your old boiler with a new 90% efficient one can affectively offer actual fuel savings of up to 25%.

By replacing an old boiler you will benefit in the following ways:
– Significant fuel cost savings and more efficient (min 90%)
– Improved reliability and safety.
– All works are fully grant aided with the Better Energy Homes scheme, which will help cover the cost of boiler and heating control upgrades.


Replacement Boilers/Condensing Boilers

If a new boiler is required a condensing boilers is worth considering as it is the most efficient type of boiler. They use less fuel and have lower running costs than other high efficient boilers. Higher efficiency levels are made possible by extracting heat contained in the combustion gases, which would otherwise have been lost to the atmosphere, hence the term condensing boilers. Now the science bit, all carbons contain hydrogen locked in their chemical structure. When gasses or oils are burned the hydrogen links with the oxygen in the air to form H2O or water. This vapour contains about 8% of the fuels energy and capturing this makes the burning process more efficient. burnerSo it condenses the waste vapours and captures the energy with in that vapour.Condensing boilers have larger heat exchangers than regular boilers,and achieve seasonal efficiencies between 86 and 91 per cent. The efficiency of a condensing boiler remains high even when it is working at a low level of output (e.g. providing hot water only, in Summer.

Where a new boiler is required to cope with the additional heat load of an extension, the improved efficiency obtained from a condensing boiler (compared with an original, conventional boiler) will often offset the additional demand, resulting in little or no increase in fuel cost. It is recommended that you replace your old boiler with a new one that uses the same fuel. However your house may be on a natural gas supply which may offer a reduced cost for install and for running costs. If you are not on Natural Gas Grid you may choose between oil, LPG, or pellet boilers. The average price of a wall moutnted condensing burner installed are €1,800 plus for a 25 or 30 watt burner. Brands include Potterton, Vokera, Grant, Zanex and Viessmann. The removal of an old burner and installation of a new boiler takes about a day. It is also possible to heat the immersion and radiations from the same condensing burner.


Room Heaters / Stoves

Where the house that is being extended does not already have central heating, it is a good idea to consider the system, with a condensing boiler, as part of the extension project. However, if this is not appropriate or affordable the extension may be equipped instead with one or more fixed individual room heaters. There are several types of room heaters, which run on gas, electricity or solid fuel. Better types of room heaters are equipped with time and temperature controls. Unless it is electric or has a balanced flue, a room heater must have a supply of combustion air brought into the room from outside.

Natural gas heaters include wall-mounted models as well as traditional open hearth and fireplace installations. Wall-mounted heaters provide more flexibility of siting within the room, depending on the type of flue; some models must be fitted on an external wall, but others can be fitted on an internal wall with the flue routed to an external wall. The efficiencies of natural gas heaters vary. Some decorative ‘open-basket’ focal-point heaters have efficiencies as low as 20 per cent, but the efficiencies of closed radiant convector heaters (including some with the popular coal effect) can be 75 per cent or more.

Electric room heaters such as radiators panel heaters, convector heaters and radiant heaters are 100 per cent efficient (all the energy in the electricity is turned into heat in the room) but they can be are very expensive to run because they use on-peak electricity, and the associated carbon dioxide emissions are high. Wherever possible, these heaters should be equipped with programmers or time-clocks, and thermostatic controls.

Solid fuel room heaters include open and closed solid fuel fires with and without back boilers (to provide hot water), and free-standing solid fuel stoves. Closed room heaters (with glass doors) and stoves are much more efficient than open fires and work well in open plan extensions. stoveThey can insert into existing fireplaces or stand alone for greater heat efficiency. A minimum output of 7 kw is recommended for any stove specification. Stoves bring a cosy feel to an extension and avoid draughts normally associated with open chimneys.

Underfloor heating is becoming more popular in the last few years as the technology has improved and specialist fitters are more widely available. While it is expensive it is suitable for large areas it is ideal for large tiled areas and in houses that are occupied a lot during the day.Underfloor heating is a way of transferring heat into your home. Using radiators is another way.The floors of the house act like a giant radiator and they provide a steady, even temperature to the entire house. The type of heat from an underfloor heating system is far superior when compared to traditional radiators. A radiator system will have hot and cold zones in the house and as you walk around the house, you will be drifting from hot to cool areas.With underfloor heating, the room temperature is identical in all areas, at all times.You can connect a heat pump, condensing boiler, stove or solar to your underfloor heating system.

Solar Heating

Solar energy is renewable and new uses of solar thermal energy are being developed such as solar thermal panels. Solar Thermal Energy is the use of solar energy to produce heat. This is the most common use of active solar heat technology. In domestic situations, solar thermal can provide 50-60% of the annual hot water requirement of the dwelling.solarpanelslook Solar thermal energy works in the same way except that the heat generated is put to practical use to heat water or other mediums. During this energy conversion and exchange the water is pumped into the water storage tank where it is heated. This is a continuous process; therefore you will always be supplied with hot water for your use anytime.

A solar panel is installed on the roof surface by a specialist firm and are unsually guaranteed for 10 years.

Photovoltaics is the conversion of light into electricity. Photo meaning light and voltaic meaning volt, or electricity.There are some materials that will generate electricity when light is shone on them. The amount of electricity generated by one cell is only small; so many cells are arranged together to form a module or a solar panel. One solar panel might have 60 small solar cells in it. Then you might have any number of solar panels wired together, to form an array or a bank or solar panels. A typical domestic system would have 10 to 20 solar panels on the roof. For commercial solar PV installations, there could be hundreds of solar panels in the array.

The electricity usually travels by a cable from the array down to an inverter in the attic. The inverter changes or converts the electricity from DC to AC electricity. AC power can be used in almost all homes in the world.

Once the power is converted to usable AC power, it’s sent to the fuse board in your home. From there it will go to all the power outlets in your home as it always would. If there is more power being generated by the panels than your home requires, the excess is sent to the national grid. It will roll your electricity meter backwards when doing this. The cuts down on your electricity bills dramatically.

If the panels are only generating 60% of the power that your home requires, the 40% balance will come in from the grid as it normally would. Practically every home already has a connection to the grid, which is where electricity comes in to your home from the ESB.So, if you install a solar PV solar panel system, you will benefit from reduced electricity bills forever, your BER will be increased and your green credentials will be greatly increased. A solar PV system can save you up to €200 to €800 per year on your domestic electricity bill.Having a high quality Solar Cylinder is such an important part of your solar panel system.30% of the payback from solar, comes directly from the cylinder itself. Therefore, if you just install a solar cylinder in your house, in place of your existing standard cylinder, you will see 30% of the financial benefits that a person with a complete solar system will see!

The reason for this is a combination of a few things;

  • Pre insulated with high density insulation
  • High efficiency, large surface area coils
  • Special configuration of the coils
  • Cylinders are tall and slim, not short and wide