A-RATING Energy Saving FAQ

 
 

What grants are available to you for your home energy efficiency?

The Greener Homes Scheme is now available and provides assistance to homeowners who intend to purchase a new renewable energy heating system for existing homes. The scheme is administered by Sustainable Energy Ireland and aims to increase the use of sustainable energy technologies within Irish homes.

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How efficient are open fires and fuel-effect fires?

Open fires are wasteful of energy . An open fire has an efficiency of only about 15 to 30%, meaning that 70 to 85% of the energy content of the fuel goes up the chimney. This is true both for solid fuel fires and for many fuel effect gas fires.
By comparison, efficient heating systems have efficiencies of 70 to 90%. These systems are better value for money than open fires or fuel-effect fires.

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How much can I save with attic insulation?

Insulating the 50 sq.m. (540 sq.ft) attic space of a typical house costs around €254 and could save approximately €76 a year (up to 20% of your fuel bill) so it would pay for itself in about 3 years.

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What are energy labels?

Energy labels are found on washers, dryers, fridges, freezers and dishwashers. They indicate the relative energy efficiency of the appliance on a rating scale from A-G, as well as indicating the actual energy consumption for typical operating conditions. They also give other performance indications, e.g. washing and drying performance and water consumption for laundry appliances.

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What are the primary ways to eliminate condensation?

The primary ways to address condensation in the home are to (where possible):
▪ Eliminate the source of the moisture
▪ Ensure that there is adequate ventilation throughout the house
▪ Properly insulate the home to bring up the internal temperature of the house
▪ Additional heating will also raise the internal temperature reducing the likelihood of condensation, but adequate ventilation would also be required

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What are Thermostatic Radiator Valves or TRVs?

A Thermostatic Radiator Valve (TRV) may be installed on a radiator instead of the hand wheel valve. The TRV contains a bellows which will close the valve on a rise in air temperature in the room, stopping the flow of heating water to the radiator.
The TRV has a number of settings, which the householder may use to set the desired air temperature for each room. In locations where a high level of heating is required, the TRV will be set at the top setting. Conversely, if only background heating is desired then the valve will be fixed at its lowest setting.
If installing a new heating system the incremental cost of TRVs is very small indeed.

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What choices are there for insulating walls?

Basically there are three choices for insulating walls: cavity, internal, and external wall insulation. Influencing factors include cost, the available space in rooms to be insulated (if dry-lining), suitability of the walls, whether the outside of the house needs to be, or can be, given a facelift and the typical occupancy patterns of the home.
▪ Cavity wall insulation
The insulation of external walls will provide considerable energy savings. If the house has suitable cavity walls, the application of insulation within the cavity is generally the most cost-effective solution.
This must be done by a contractor , and involves blowing or pumping the insulation into the cavity through holes drilled in the outer surface. However, filling the cavity is not recommended for highly exposed rainy regions of the country.
▪ Internal wall insulation or dry-lining
For solid walls, insulation must be applied either internally or externally. Internal insulation involves fixing a layer of insulation to the internal surfaces of external walls, usually with a plasterboard finish. This is also referred to as dry-lining. Care must be taken to install a vapour check (e.g. polythene sheeting) to seal the insulation against humid air penetration from within the house.
▪ External wall insulation
External insulation is more expensive than internal insulation, since it must be applied with a durable finish to withstand the weather and possible impacts. However, it is more effective at reducing heat loss since greater insulation thickness can usually be applied, and since it wraps around the whole wall. In older houses it can also give an attractive facelift.

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What is Pumped Cavity Insulation?

In relation to the pumping of your walls with a bonded bead system you would noticeably improve the overall thermal properties of your house and in turn reduce your energy bills for the winter months.
However, there are a number of issues you should be aware when filling your wall’s cavity:If there were any frost or structural damage to any of the house’s external walls pumping of beads into the cavity would not be advised.
The width of the cavity between your external wall leaf and the installed aeroboard should be at least 50mm. If there is any problem with dampness in the internal leaf it would not be recommended to add the beads to the cavity as they would only increase the path for water to travel into the wall.
Get a full assessment from a number of bead installers to compare prices, U–values promised, guarantees and their IAB certification (Irish Agreement Board).
The bonded bead system is the above mentioned and not the polyurethane foam, which expands in the wall, as the latter presently does not have certification from the IAB. The foam system will provide a lower overall U- value but could change the properties of your wall sometimes leading to moisture problems.

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What is 9” Cavity Block Insulation?

When you refer to foam filling of a 9" cavity block, you are describing the filling of the hollow cores of concrete blocks by injecting loose foam beads or liquid foam. If this is the case, we would advise looking at applying insulation to the interior or exterior surfaces of the wall, both of which are potentially better options for insulating a cavity block wall. There are a number of drawbacks to the insulation of hollow blocks:
▪ It's not uncommon for hollow block walls to have all kinds of rough bits of hardened mortar protruding inside. And depending on what you've got at your place, this could greatly impair the ability of insulation to fill all the spaces properly.
▪ Another problem is water infiltration from the outside. Concrete blocks are quite porous, and water can easily make its way inside, if insulation is not applied properly.
▪ With regard to thermal bridging. Those portions of the block wall that extend from the exterior surface all the way through to the inside will conduct huge amounts of heat, regardless of the insulation levels between them. Even if the cavities were completely insulated and dry, you'd probably gain little thermal benefit.
Note that even though filling the block cavities and special block designs improve a block wall's thermal characteristics, it doesn't reduce heat movement very much when compared to insulation installed over the surface of the blocks either on the exterior or interior of the foundation walls. Field studies and computer simulations have shown that core-filling of any type offers little fuel savings since the majority of heat is conducted through the solid parts of the walls such as block webs and mortar joints.

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What is Roof Insulation?

The options available to you for insulating your attic depend on whether you would like to insulate at ceiling level or at the rafters (at the slope of the roof). The attic should be insulated at the rafters only if you intend to use the area as a living space as it the heat will rise through the uninsulated ceiling into the attic and it is wasteful to keep the attic heated. Typically, Irish attics are not used as living spaces so detailed below are the measures available for insulating at ceiling level.
At ceiling level, you can lay fibre quilt between and over the joists. This is the cheapest and simplest installation option. The U - value requirement under the 2002 building regulations on insulation for a pitched roof with insulation at ceiling level is 0.16Watts per m2K. That requires 250 - 300 mm of insulation, if you are using rock wool, glass wool, or mineral wool insulation. Obviously there are higher performance insulations, but in any event, you should plan for at least 250mm.
In Canada, some people put 600 mm of insulation in the attic. The building code does not require this amount but if you would like to lose even less heat and increase indoor comfort, then increase the amount of insulation you install. You don’t need quite as much in Ireland’s climate but 400 mm of mineral wool is probably optimal. Make sure the load isn't too heavy for the ceiling (place planks or boards onto the beams and insulation on top of them) and that you still have access to any tanks, pipework etc.
The quilt should be placed in two layers to minimise thermal bridging or heat loss through the joists themselves. Any element that is a poorer insulator, and allows more heat to pass through it than the material in surrounding area, is called a thermal bridge. The first layer is placed between the joists. The second is laid at right angles across the joists.
This insulating fibre loses some of its insulating properties if it is compressed. Therefore, you can’t keep anything on top of this insulation. If storage area is required in the attic space, and a second roll across the joists is not possible, make certain that the storage is over a part of the house with less of a heating requirement, e.g. the bedrooms rather than the living room). The full thickness of insulation should be installed over the living room - the warmest room in the house.
Installing the insulation properly is very important. Ill-fitting or compressed insulation will not perform to its potential. When fitting insulation between rafters it is very important that it is cut tight, with no gaps. Gaps between the insulation lead to thermal looping, which causes the insulation to become ineffective. Good workmanship is key, otherwise you will not get the full benefits of the insulation. Also, when laying insulation in the attic, make sure to leave the openings at the eaves unblocked since it is important to allow for ventilation to prevent mould or damp occurring.
Another option is to have glass fibre, mineral fibre or cellulose fibre (i.e. recycled paper) blown into your attic by a professional between and above the ceiling joists. While this type is a better insulator than the other DIY quilting, it is also more expensive to install, as a professional must be hired. Storage in your attic is also reduced and it can look messy.
At the rafters, you could install a polyurethane foam insulation system or spray-on cellulose fibre between the rafters but if you choose to insulate between the rafters in this way, please ensure that you insulate the underside of the rafters also, to prevent the heat escaping along this path. Another option available here is to use semi-rigid boards with the insulation on the back.

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What is floor Insulation?

Installation under built suspended timber floors can prove difficult and usually would be viewed as an uneconomic energy saving measure. Timber floorboards can slightly warp and change shape over time and if taken up from the joists might not easily be refitted to their original position. Most floor improvements are expensive and disruptive so these measures are best incorporated in major refurbishment projects.
There are a number of less expensive improvements that can be made to a suspended timber floor that will reduce the heat loss from the room:
▪ Seal gaps and cracks: Simply sealing any cracks in the floor can improve internal comfort conditions and reduce costs.
▪ Seal gaps in skirting and between floorboards of suspended timber floors to save 1% of total heating fuel costs.
If you do decide to remove the floor boards and insulate under floorboards. Use good insulating materials such as cork or rockwool and a polymer sealant between floorboards to prevent draughts. Take care to ensure any electrical cables sharing the same space have enough room to prevent them from overheating.

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Who should I buy windows from?

A consumer should select a window manufacturer who manufactures and sells energy efficient products (i.e. meets the recommended U-factor and Solar Heat Gain Coefficient in your climate), has a reputation for service and stability, and provides a warranty on the unit.

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Where do I go to buy an efficient window?

Before you buy a window, we recommend that you do your research via the web and written material and then shop around.

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Why are my windows drafty and will new windows stop the draft?

Drafty windows and air infiltration could have several causes. Improper installation is often the culprit but not always. If windows are improperly installed, the defects can normally be corrected without removing or replacing the window. Proper caulking and flashing (types of sealing) should prevent perimeter air leakage.
However, if the installation twists or racks the window frame causing the sash weather-strip to be unable to seal the sash to the frame, removal of the window to correct the problem may be necessary. You can determine whether the air is coming in at the joint between the frame and the house or the joint between the sash and the frame by holding a lighted candle or lighter in front of each joint when the wind is blowing and slowly move it along the joint. If the flame flickers strongly or goes out, the joint is probably leaking.

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Will new windows eliminate condensation?

Condensation is a direct result of interior humidity and the difference between indoor and outside air temperature. If you keep the humidity in your house low, then the likelihood of experiencing condensation is also low. However, the efficiency of your window will also impact the temperature and humidity level at which condensation occurs. Energy efficient windows will help reduce condensation.

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Is it possible to insulate recessed lighting?

After carrying out some research into insulation of recessed lighting it would appear not to be practically and effectively achievable. Older recessed lights can be a significant source of air leakage, but sealing them can be difficult.
Insulation must be kept at least 3" away from the older style lights because of the heat they give off. Experts often make boxes to cover the recessed light fixtures in the attic out of fire resistant wallboard to reduce leakage.
However, unless the boxes are made large enough, the lights can overheat. The boxes should allow at least 3" space on all sides of the light fixture. If loose fill insulation is installed, a metal cylinder with an open top can be used as an insulation dam to keep the insulation away from the light. However, the dam will not prevent air leakage around the light. If you are planning a remodel job, leaky, old-style recessed lights can be replaced with "IC rated" lights. These lights can be in contact with insulation, and more recent brands are air-tight. Many of the new recessed light fixtures that are sealed use CFL bulbs, a great energy-saving combination .

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What is a U-value?

To put it simply, U-Value is the measure of the rate at which heat is lost through a material. As it is a measure of heat loss, the lower the U-Value the better. So for example, one square meter of a standard double glazed window will transmit about 2.5 watts of energy for each degree difference either side of the window (denoted by the unit W/m2K) whereas a low-emissivity window will do better at about 1.8 W/m2K.

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What is an ideal room temperature in a home?

20°C is a very comfortable temperature for living spaces while 16°C is sufficient for bedroom areas.

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What is low-e glass?

When purchasing double glazing it is possible to get a special coating on one of the panes of glass which further reduces heat loss below that of ordinary double glazing. This coating is called low-e for low-emmissivity and is often called Pilkington's K-Glass.

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What is the best fuel for home heating?

The choice of fuel for your heating system is influenced by the following factors:
▪ Availability of different fuel types (e.g. are you on the gas network?)
▪ Efficiency of heating systems available dependent on fuel choice (e.g. can you use a condensing boiler?)
▪ Costs of those fuels for your particular heating requirements (including standing charges, which is likely to be most cost effective - consult Sustainable Energy Ireland's Fuel Cost Comparison Sheets)
▪ Environmental impacts of using those fuels (some fuels are less polluting than others)
▪ Desirability of requiring bulk storage for certain fuels (e.g. coal bunker or oil tank)
The answers to these questions will assist you in the selection of the best fuel for your particular requirements.

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Where should radiators be located?

Windows and outside walls will be the coldest surfaces in the house. Cold windows cause down draughts and uncomfortable conditions for the occupants. To maintain air temperatures and achieve comfortable conditions, radiators should be located under windows to raise the glass temperature and to eliminate cold down draughts.

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