1. CASE STUDY:
200 HOUSE LOW ENERGY LOW CO2
DEVELOPMENT AT KILLEAGH, CO. CORK
The rapidly growing public interest in sustainable building is finally starting to impact
on property developers. Bill Quigley of Nutech Consultants describes an innovative
200 house development currently on site in Co. Cork where forward-thinking developers
J & W Leahy Brothers have decided that the market is ready for low energy, low CO2
building.
Probably one of the
most exciting large scale
low energy/low CO2
housing projects in
Europe is being con-
structed at present in
Killeagh, Co. Cork.
The housing at Killeagh
feature the following technologies:
A well insulated fabric with a
real U-value which will match
the calculated value.
The houses are designed to be
very airtight in terms of the
unwanted level of air infiltration.
A highly efficient heat recovery
ventilation system is fitted
which guarantees the level of
fresh air ventilation.
An air solar heating system is
being used which delivers
solar energy to the ventilation
and heating system together
with the domestic hot water
system.
Any required backup energy is
being delivered by way of a
wood pellet boiler that is sited
in the living room and is integrated
with the air solar heating and
ventilation system.
NuTech Consultants, in conjunction
with the Kingspan Century team
designed the low energy/low CO2 fea-
tures for this housing development.
The target was to design a house that
saved some 95% of the CO2 emissions
associated with space and water heat-

2. CI 37
ing demands of a standard 3 to 4 bed-
room house as typically built by a
developer.
In this article we will explain the design
brief for the energy systems as set out
by the developer/builder, the back-
ground to the thinking behind the
design, the systems and hardware
being used and the results in terms of
the actual construction of the houses.
THE HOUSING DEVELOPMENT AT
KILLEAGH, CO CORK
This development consists of 200 hous-
es. There will be 2, 3 and 4 bedroomed
houses on the site. Some of these will
be bungalows on fairly large sites. The
site size is 22 acres and the resulting
density is roughly 22 houses per acre.
The developer / builder is J & W Leahy
Brothers of Middleton, Co. Cork. The
architect is Richard McGrath and
mechanical services were designed by
EDC Consultants Ltd. All of the energy
calculations and systems were designed
and carried out by the Kingspan
Century team with NuTech Consultants.
THE BUILDER/DEVELOPERS REQUIREMENTS
& BACKGROUND TO THE DESIGN
Initial discussions took place between
Kingspan Century including NuTech
Consultants and J & W Leahy Brothers
to consider possible designs and sys-
tems that could be used to satisfy the
space and water heating demands of
the houses. Bill Leahy, Director of J &
W Leahy's, stated categorically that he
did not want to use oil or gas fired sys-
tems as the primary or secondary ener-
gy supply units for these houses. His
main idea was that he wanted to 'future
proof' these houses and his clients
against oil price rises and availability
of supply. This did put some pressure
on the design team to come up with a
design and energy supply package that
was practical, economical and deliver-
able within a reasonably short space of
time.
It was explained to Bill Leahy that
Kingspan Century with NuTech
Consultants recently completed the
Kingspan Century Formula 1 House
Project. This project had received sup-
port from Sustainable Energy Ireland
under its House of Tomorrow research
and development fund. The team had
arrived at a number of conclusions
principally as follows:
Firstly,
Typically, 1/3 of the energy
required for space and water
heating in a developer type
house is accounted for by way
of heat loss through the fabric.
The second 1/3 is by way of
energy required to counteract
the heat loss due to unwanted
air infiltration and the necessary
air for ventilation.
The third 1/3 is by way of the
Solar panels (opposite & p41) which assist the heat recovery ventilation (HRV) system to pro-
vide adequate quantities of fresh air, and also supply the energy for the domestic hot water
demand. This means that the domestic hot water demand can be reduced by some 60%.
Furthermore, it is possible to use the solar air HRV system as the heating system of the
house, thereby saving in costs. Although general attention to airtightness was based on
factory fitting, proprietary tape and seals are installed on site where necessary (above and
below left) to ensure airtightness.

3. CI 39
energy required for domestic
hot water.
Secondly,
This meant that the energy demand for
space and water heating could be
reduced to as low a figure as economi-
cally possible by doing the following:
Insulate the houses to as high
a level as possible. Ideally this
insulation should be factory
fitted. This deals with the
first third of the energy
demand.
Make the houses as airtight as
is practicable - a level of 0.1
air changes per hour at normal
pressure was decided upon.
This means that a mechanical
ventilation system is required.
It was decided to use a solar
assisted heat recovery ventilation
(HRV) system to provide adequate
quantities of fresh air. This
ensures that the second third
of the energy demand is greatly
reduced.
Utilise the same solar heating
system to supply the energy
for the domestic hot water
demand. This means that the
domestic hot water demand
can be reduced by some 60%.
Furthermore, it is possible to
use the solar air HRV system
as the heating system of the
house, thereby saving in costs.
Building in highly insulated
and airtight construction that
is achieved with Kingspan
Century's special timber frame
design is a huge advantage.
Great use of the 'balanced
thermal capacity' of timber
frame construction can be
made as this allows excellent
use of the low level solar gains
that are available in Ireland in
winter.
Having reduced the energy demand to
as low a figure as practicable, the ener-
gy supply side was addressed. A small
wood pellet stove with a back boiler
was used as the backup energy supply
unit. This stove could be conveniently
placed in the living room. By way of all
of these techniques the Kingspan
Century team with NuTech Consultants
had reduced the CO2 emissions of a
typical house by some 95%.
Bill Leahy decided, following discus-
sions with his fellow directors, to use
these techniques to build the houses at
Killeagh such that they would be low
energy/low CO2 houses that did not
rely on oil or gas as the fuel to supply
the space and water heating demand.
Furthermore, because the energy
demand of these houses is low it would
not require a large tonnage of wood
pellets per year. This meant that the
supply of wood pellets could be by way
of the standard 18kg bags rather than
by way of requiring a delivery of 3
tonne lots to a storage room.
Bill Leahy had considered the use of
ground source heat pumps but rejected
for a number of reasons. Firstly, if the
instantaneous design heat load was
reduced from as much as 10 kW to as
little as 3 kW it did not make sense to
go to the expense of a heat pump and
heating system for such a small load.
Secondly, Bill Leahy was not happy with
the potential CO2 savings with such a
heat pump. For example, if the heat
pump achieved a seasonal coefficient
of performance of as much as 4 and
with electricity delivered by the ESB at
a primary efficiency of 30% then this
meant that the CO2 emissions were
only reduced by approximately 20% -
this was not what he had envisaged as
being the best result. NuTech
Consultants pointed out to Bill Leahy
that heat pumps do have a role to play
in certain circumstances but not partic-
ularly in this case.
In short, Bill Leahy saw that with this
package he would be supplying houses
to his clients that would offer the fol-
lowing major benefits:
Very low running costs for
space and water heating by
way of the house construction
and the fully integrated air
solar heating, ventilation and
hot water system.
Houses that are 'future
proofed' against fluctuating oil
prices and indeed the supply
of fossil fuels.
High levels of comfort in
terms of the average house
temperature and humidity in
autumn, winter and spring.
An increase in the level of
comfort by way of fresh
filtered air and a consequent
reduction in the risks from
dust, pollen, and so on.
A degree of cooling in summer
during both the day and night
by way of the fresh air intake.
Finally, the project was put forward to
Sustainable Energy Ireland for funding
under House of Tomorrow.
SUPPORT UNDER HOUSE OF TOMORROW
The House of Tomorrow Programme
administered by Sustainable Energy
Ireland (SEI) grant aids projects whose
main aim is to save energy. Basically,
energy savings of at least 40% are
required over the base case house to
qualify and the houses must be built to
incorporate certain minimum standards
of insulation. The base case house is
defined as the house being built that
would just satisfy the requirements of
Part L of the 2002 Building Regulations
when considered under the Overall
Heat Loss Method or the Heat Energy
Rating Method. This means it could
have U-values as poor as the following:
Ground Floor < or = 0.37 W/m².K
External Walls < or = 0.37 W/m².K
Roofs < or = 0.25 W/m².K
Windows < or = 2.20 W/m².K
To comply with the rules of House of
Tomorrow the U-values for the various
elements must be as good as or better
than the following:
Ground Floor < or = 0.20 W/m².K
External Walls < or = 0.27 W/m².K
Roofs < or = 0.16 W/m².K
Windows < or = 1.90 W/m².K
The elements of the fabric of the hous-
es at Killeagh have been built to satisfy
and in some cases are better than the
U-values demanded by SEI. NuTech
Consultants examined the houses using
their hour-by-hour energy analysis
computer model. This model takes
account of the following:
The U-values of the elements
of the house
The level of airtightness of the
house
The use of heat recovery ventilation
The use of various areas of air
solar collectors to reduce the
energy demand for heating
ventilation and hot water
The amount of hot water used
per day
The level of occupancy in the
house
The utilisation of passive solar
gains and energy attributable
by way of gains from occupants
Energy supplied by the boiler
with an applied efficiency
Using this model NuTech Consultants
demonstrated that houses being con-
structed by Leahy Bothers would have a
gross saving in energy for space and
water heating amounting to 75% when
compared to the base case house.
This meant that the maximum grant
aid of 8,000 per house was awarded
for the first 50 houses in this scheme.
Results from this project will be fed
through to SEI over the next few years.
The main items of interest are the actu-
al running costs in terms of the number
of kilograms of wood pellets used per
year and the level of airtightness
achieved by way of the construction
methods used.
The House of Tomorrow programme is
a most welcome development in
encouraging builders to build low ener-
gy/low CO2 houses. It allows builders
to become familiar with the principles

4. CI 41
involved in designing low energy hous-
es and helps them to see the benefits
not just for themselves but also for
their customers. Under the require-
ments of the Energy Performance of
Buildings Directive all houses will soon
be energy rated and certified. This will
allow the prospective homeowner to
assess how energy efficient their new
home is. Most builders will want to
deliver an A-rated house to their clients
in the same way as a company such as
Siemens deliver an A-rated fridge to
their customers - Siemens do not manu-
facture any C-rated fridges.
THE TECHNOLOGIES BEING USED
The basic concept is as described previ-
ously. The technologies used are as
follows:
The Kingspan Century special
package of pre-fitted insulation
that has been shown be effective
in terms of its calculated U-value
is the same as its U-value in
practice.
This special package has factory
fitted air tightening seals
which ensures that the house
can achieve an air infiltration
rate of less than 0.1 Air
Changes per Hour.
The NuTech Consultants
designed air solar heating and
hot water system with an
integrated Heat Recovery
Ventilation module. A 3-panel
Sunwarm air solar heating
system is used here linked to
the unique 140 Air Handling
Unit designed by NuTech
Consultants. A Mitsubishi
Lossnay Heat Recovery
Ventilation unit is integrated
into the system and is
controlled by the Sunwarm
controller.
A Wodtke wood pellet boiler is
used as the backup energy
supply system.
This overall system is the heating sys-
tem of the house-the ventilation system
is oversized in order to be the heating
system of the house also. However, in
the first fifty houses a radiator heating
system is being installed on the ground
floor. The bedrooms are heated by way
of the Sunwarm system.
The controls for the system are simple
in that the Sunwarm system is thermo-
statically controlled and will control
whether warm air is delivered to the
house or not. On a warm sunny day in
summer, cool ventilation air will be
delivered to the house while the solar
panels will deliver energy to the
domestic hot water cylinder. On a
sunny day in winter, energy from the
solar panels will be used to provide
both heat to the domestic hot water
cylinder and heat to the house by way
of the ducted air system. The system
is completely automatic and all the
householder has to do is set the ther-
mostat to the house temperature
required. The boiler is also automatic
and will be enabled to fire by way of
the boiler timer and the required tem-
peratures in the house and hot water
cylinder.
CONSTRUCTION OF THE HOUSES
The construction of the houses has
gone very smoothly. The onsite man-
agement team of Oliver Leahy and Alan
Harty has resulted in some impressive
targets being met.
It was found that the Kingspan
Century/Leahy Brothers team could
deliver and erect six houses per week
quite easily. It should be remembered
that these timber frame houses come
pre-insulated and with the airtightening
seals pre-fitted - this speeds up the
building process enormously. With lev-
els of airtightness of 0.1 Air Changes
per Hour being achieved in practice,
this is indeed a remarkable level of
progress in low energy house building
in Ireland. It has to said that the level
of site supervision by the Leahy
Brothers' team and the attention to
detail by their sub-contractors has paid
handsome dividends.
The roofing sub-contractors employed
by Leahy Brothers have installed the
Sunwarm air solar collectors. Similarly,
the Sunwarm air handling unit, together
with the Mitsubishi Lossnay HRV unit
and all of the ducting and controls have
been installed by both the plumbing
and electrical sub-contractors to Leahy
Brothers. This utilisation of the normal
on-site trades has been a huge benefit
to the efficient building of the houses.
NuTech Consultants trained these per-
sonnel in the fitting of the various sys-
tems which on completion will be com-
missioned by NuTech.
IN CONCLUSION
This project has gone extremely well
because of the 'build speed' of this spe-
cial timber frame construction from
Kingspan Century with factory fitted
insulation and airtightening seals.
The utilisation of the existing site
trades also added to the efficiency.
The determination of the builder, the
suppliers, designers and the site team
to build the house as designed such
that it will perform in practice has been
a key element of this project.
In order to ensure this teamwork Leahy
Brothers with Kingspan Century and
NuTech Consultants organised a confer-
ence in the Midleton Park Hotel to
explain to all concerned what technolo-
gies were involved and how each sector
was interdependent with the other.
This conference was attended by all
concerned with the project - the design
team, the build team, all of the sub-
contractor trades involved, the mechan-
ical services team and very importantly
the auctioneers involved in selling the
houses. It was also attended by per-
sonnel from the Department of the
Environment and from HomeBond.
It was felt that, with the attractive
design of the houses and the careful
integration of the technologies
involved, these houses offer the buying
public a wonderful opportunity to own
a house that is 'Future Proof' branded
by Kingspan Century against the energy
supply and price fluctuation situation.
Proof positive of the success of the
approach taken by Leahy Brothers is
the fact that all of the houses in this
House of Tomorrow Project have been
sold. Bill Leahy offered houses with
the option that they could choose
either the 'low energy/low CO2' package
as described above or a standard oil-
fired heating system. All of the clients
opted for the low energy house with
the wood pellet boiler as backup. As
Bill Leahy says …..'I did have to explain
to all of our clients how all of the sys-
tems worked and the technologies
being used in the houses. It took a lot
of talking but, with the high oil prices
and concerns over supplies, all of them
were most pleased to find we were
offering such a well-developed solution
being supplied by large reliable compa-
nies such as Kingspan Century, NuAire
Ltd and Mitsubishi Ireland. Once they
saw the benefits they all went for the
low energy package on offer'.