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BER FAQ
Are there any grants for home energy
efficiency?
Quite simply - no, but we can provide advice and
information free of charge on making your home energy efficient.
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.
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.
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.
The primary ways to address condensation in the home are
to (where possible):
- Eliminate the source of the moisture at source
- 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.
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.
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.
On a standard cavity wall the cavity is normally 100mm
this allows for 60mm of partial fill cavity insulation while still providing a
gap of 40mm. When the cavity width exceeds 110mm. the wall and the foundations
must be designed by and engineer in accordance with IS325 Part 1: 1986. This is
because the construction of walls with cavities in excess of 110mm wide requires
adjustments to lintels, wall ties, cavity barriers, etc. It is therefore
necessary that cavity walls are adequately designed in respect of structural
stability and fire safety in accordance with Parts A and B of the Building
Regulations.
The engineer appointed must be qualified by examination,
be in private practice and possess professional indemnity insurance. If a wider
cavity is specified, it will also have the added cost of an increase in
foundation width to accommodate the greater thickness. Internal insulation is a
good way of increasing the overall level of insulation when cavity width is
limited, it has the disadvantage of placing the thermal mass of the wall outside
your heating envelope. Your Architect may wish to look at full fill cavity
insulation, this method of construction would mean that the cavity need not be
increased, while increasing the amount of insulation. This method is dependant
on the location of the dwelling and the external finishes specified.
External insulation is another option, which would have
the added advantage of keeping the thermal mass of the concrete walls within
your envelope. It is very popular method in Europe, and becoming more common in
Ireland Your Architect should be able to talk you through all the different
construction methods available, and recommend the solution, which is best suited
to your situation.
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 thicknesses can usually be applied, and since it wraps
around the whole wall. In older houses it can also give an attractive facelift.
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 aero
board 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.
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.
• If you decide to use polyurethane foam it is worth
noting that presently this product does not have Irish Agreement Board
Certification. If you check out
www.irishagrementboard.com it will give you a list of all certified
suppliers and products.
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.
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 150 - 200 mm.
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, pipe work 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.
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 rock wool 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.
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.
Before you buy a window, we recommend that you do your
research via the web and written material and then shop around.
Draughty 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 not to be able 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.
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
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
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.
20°C is a very comfortable temperature for living spaces
while 16°C is sufficient for bedroom areas.
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-emissivity and is often called
Pilkington's K-Glass.
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.
Windows and outside walls will be the coldest surfaces in
the house. Cold windows cause downdraughts 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 downdraughts.
"Quoted from
Sustainable Energy Ireland Website"
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