The Technical Team at Heatstar take a closer look at the recent changes to the building regulations. Big changes have arrived. What you need to know!

1. Technical
Advice
Paper
ADVANCED SWIMMING POOL CLIMATE CONTROL SYSTEMS
The Technical Team at Heatstar take a closer look
at the recent changes to the building regulations.
Big changes have arrived. What you need to know!
NEW 2022
BUILDING
REGULATIONS

2. 2
Another step is expected in 2025 to reduce carbon emissions
yet further, currently being referred to as the ‘Future Homes &
Building Standards’. The proposed 2025 standard is intended
to enable a ‘zero-carbon’ dwelling, but that would depend
upon electricity supplied from the national grid being
decarbonised in the future.
Approved document parts
The elements of the new Building regulations that we will
review here are:
There are separate regulation documents for ‘Dwellings’ and for
‘Buildings other than dwellings’. Domestic and commercial
swimming pools will therefore fall under the different categories
with different stipulations. Generally, domestic regulations are
more stringent than commercial. Whereas previously there were
separate documents for newly constructed projects and
refurbishment of existing projects, now there are just single
documents that describe the differing requirements for both.
Part L ‘Conservation of fuel and power’
The elements of the new Building regulations that we will
review here are:
Pool shell thermal insulation requirements
The requirement of meeting a minimum thermal insulation
value of 0.25 W/m².K for the pool shell, perhaps surprisingly,
remains unchanged. Relying solely upon a typical proprietary
rigid polystyrene insulation (0.034 W/mK), 140mm thickness
of insulation would be required.
Pool surface area excluded from energy calculations
For both domestic and non-domestic applications Part L
contains direct instruction upon how an indoor pool room
should be considered as part of the energy efficiency
calculation for the whole project; basically that the pool room
must comply with the same energy requirements as the rest
of the project, with the exception that the area taken up by
the pool water surface should be treated as a normal floor,
theoretically offering the same thermal insulation value as the
rest of the pool surround.
The updated regulation wording is as follows:
When calculating the dwelling primary energy rate, dwelling
emission rate and dwelling fabric energy efficiency rate for a
dwelling with a swimming pool, the thermal performance of the
pool basin should not be included in the calculation. Instead,
the dwelling primary energy rate, dwelling emission rate and
dwelling fabric energy efficiency rate should be calculated as if
the area covered by the pool were replaced with the equivalent
area of floor with the same U-value as the pool surround.
This emphasises that a pool room needs to be designed to
the same building control standards as any other room in the
house – there are no special dispensations.
Part L
Conservation
of fuel and power
Part F
Ventilation
Part O
Overheating
Recently introduced, and applicable to all new projects now presented for Local Authority
planning approval, the latest Building Regulations seek to achieve a whopping 30% reduction
in carbon emissions over the outgoing regulations – and they will affect indoor pools!
NEW 2022
BUILDING REGULATIONS

3. 3
Thermal insulation changes for buildings
Understandably, the thermal insulation values of buildings are
required to improve, as has the air-tightness of the building.
The ‘target’ U-values are now:
Roofs: 0.11, Walls: 0.18, Windows: 1.2, Floors: 0.13
The lower the U-Value, the more effective the insulation.
To achieve these standards solely using proprietary PIR
insulation (0.022 W/m K), a typical thickness of 125mm in
walls and 200mm in roofs/ceilings and 170mm in floors
would now typically be required.
The target for glazing is now near the maximum achievable for
double glazing & increased application of triple glazing can be
expected.
Maximum boiler water flow temperature
Note: Major implication for swimming pools!
This is about the boiler water heating circuit, which may
typically have previously been designed for a flow (outlet pipe
from the boiler) of 70°C, with a return temperature of 50°C.
Both domestic and commercial building regulations now
stipulate a new regulation that:
All parts of the system including pipework and emitters should
be sized to allow the space heating system to operate
effectively and in a manner that meets the heating needs of
the building, at a maximum flow temperature of 55°C or lower.
So, the maximum flow temperature from a gas / oil boiler or
heat pump boiler cannot now be greater than 55°C.
Those who have been involved in applying heat pump boilers
for indoor pools will appreciate that low heating circuit flow
temperatures can have significant implications for required
size of heat exchangers, heating coils and air ducts within the
design.
Broadly speaking, all projects are now required to be designed
so that they can operate successfully on the low flow
temperatures previously associated with heat pump boilers!.
Caution: Going forward, it is clearly vital to ensure that the
heating system, pool ventilation unit and air ducting are
being designed at the correct heating circuit temperature.
The implications of attempting to rectify a fundamental
aspect such as this after the project is finished is potentially
huge.
Whilst improved thermal performance of a new building will
help, this new requirement will have notable implications,
typically increasing the size of air heating coils, air ducting
and air flow rates by as much as a 30%.
TECHNOLOGY HIGHLIGHT
‘Cross-flow’ multi-plate
heat recuperator
A recuperator is a ‘passive’ device that has no moving
mechanical parts and consumes no power in order to
function. It relies upon air being passed through it by
operation of the fan systems.
The recuperator is a series of many channels. Expelled
warm pool room air is passed through a channel and cold
fresh air is drawn in through an adjoining channel.
Energy is transferred from the warm side into the cold
side through thermal conduction via the partitioning
‘plate’ that separates the two air channels.
The opposing air paths are not mixed within the device.
Cold outside
fresh air
Pre-warmed fresh
air into pool room
Warm air from
pool room
De-energised cold room
air exhausted to outside

4. 4
Specific Fan Power (SFP)
Specific fan power is the term used to assess the energy
efficiency of a ventilation system in moving air.
These requirements have now been moved (logically) from
Part F (Ventilation) into Part L (Fuel & Power)
SFP describes the maximum amount of power necessary to
move a pre-determined quantity (volume) of air:
Normally the power is expressed in watts and the air volume in
Litres per second.
For example:
1.5 Watts of power, per 1 Litre per seconds of air volume
moved = 1.5 W/(l/s.)
This would relate to the maximum power consumption
permissible to move the stated quantity of air.
Different SFP ventilation efficiencies are stipulated
depending upon the complexity of a particular ventilation
system. For example, the SFP for a simple extract fan
operated intermittently would be 0.5 W per L/sec, whereas an
extract & supply system including heat recovery is permitted
1.5 W per L/sec..
The overall required efficiency has not been improved for the
new regulations, but there is now an expectation that a heat
recovery device will always be included. Variable speed
controller is now required for all domestic systems which
provide supply & extraction from the same unit and all
commercial systems which have motors rated more than
1100 Watts power.
Typical example equipment formats
Conclusion: Equipment formats that have commonly been used in the past no longer comply with the new building regulation standards.
Example 1 Example 2 Example 3 Example 4
Primary
dehumidification
method

Heat pump
dehumidifier

Heat pump
dehumidifier

Heat pump
dehumidifier

Ventilation with
fresh air

Mechanical
fresh air
provision

Through-wall
heat recovery
ventilator

Exhaust / fresh
air ports
into unit

Exhaust / fresh
air ports
into unit

Exhaust / fresh
air ports
into unit

Heat recovery
on exhaust /
fresh air

Via plastic
heat recovery
ventilator

None

Via integrated
recuperator
box

Via integrated
recuperator
box

Compliance
Must capture at least
73% of heat
Must capture at least
73% of heat
If 73% permanent heat
capture is achieved
If 73% permanent heat
capture is achieved
DID YOU
KNOW ?
Heatstar have been producing modern format packaged
environmental control systems longer than any other
company and were amongst the first to become
involved in this specialist field. This experience is evident
throughout the product range.
For over 40 years Heatstar have been guiding their clients
towards responsible energy solutions, setting the
benchmark in an environmentally conscious industry.

5. 5
Heat recovery provision
Note: Major implication for swimming pools!
The new building regulations introduce a fundamental change
in the requirement to capture heat from any warm room air
ventilated to outside.
‘Heat recovery’ is the process of capturing heat from any
warm pool room air being blown outside the building, and
transferring this heat into the cold incoming outside fresh air.
For example, a heat recovery efficiency of 73% means that
73% of the heat that would otherwise have been thrown away
is captured (and 27% is still lost).
The heat capture achieved must now permanently be at least
73% (up from the previous 70%) and comply with the test
procedures of BS EN 308 ‘Heat exchangers’.
Pool ventilation units that merely rely upon the periodic /
occasional function of a refrigeration dehumidifier to recycle
heat from the exhausted air do not comply with the new
regulations.
The ability to incorporate a summer by-pass facility, to
neutralise the effect of the heat recovery system when room
cooling is required, is also stipulated.
Caution: It is important to ensure that any pool
ventilation unit that has exhaust and fresh air duct
connections can provide a minimum 73% heat capture
between the two at all times, using a recuperator box.
Thermal insulation to services
Building regulations now ‘spell-out’ the typical thickness of
insulation required on heating circuit pipes and on air ducts.
For example, 28mm diameter pipework is required to have
10mm of insulation, 35mm diameter pipework 15mm of
insulation.
For air ducts, a typical minimum insulation thickness of 21mm
(0.025 W/mK) is stipulated, 36mm for air ducts intended for
heating and cooling*.
There are no specific insulation stipulations for swimming pool
pipe work within the building regulation documents.
* For swimming pool warm air ducts, because of the higher air
temperatures involved, an insulation thickness greater than this
is normally recommended.
Regulation 25A: ‘Consideration of
high-efficiency alternative systems’
Building regulations now require a formal analysis to be
undertaken at the design stage into the feasibility of using
high-efficiency alternative systems, such as heat pump boilers
and renewables.
Ultimately, a heat pump boiler will potentially reduce the
project’s carbon emissions by as much as 60% compared to
mains gas, which is clearly very significant. However, that is
not to say that the heat pump boiler will result in lower running
costs and lower carbon emissions invariably come at the price
of increased equipment purchase costs.
A dehumidification heat pump is another approach that can
offer notably lower carbon emissions if applied.
Feasible or not, a particular client may, of course, simply prefer
lower priced equipment, even though it may result in increased
carbon emissions.
DID YOU
KNOW ?
Heatstar have been utilising ‘cross-flow’ multi-plate heat
recuperators in their product range to exceed stringent
UK building regulations since 2008, and were the first
company in the UK to do so.
The combination of the recuperator and dehumidification
heat pump in a system such as the Heatstar Phoenix EC
offers true dynamic heat recovery for indoor pools with
active energy recycling efficiencies of up to 380%.
In a tightening of the regulation, it is now a requirement
that, if both air exhaust and outside fresh air are provided
at the same ventilation unit, then heat capture between the
two air passages is now mandatory.
If a pool ventilation unit exhausts air to outside and also
takes in outside fresh air, it no longer complies with current
building regulations unless it incorporates a dedicated heat
recuperator box or, alternatively, a recuperator box is fitted
externally within the air ducting in the plant room.

6. 6
Part F ‘Ventilation’
Part F is the document which relates to the provision and
control of adequate ventilation and air distribution for a
building, for the benefit of the people occupying it.
There are no specific stipulations included for swimming
pools. However, as with all rooms, there is a requirement to
demonstrate how adequate outside air provision is achieved.
‘Dilution rate’ of room air with fresh air
Beyond the fresh air appropriate for occupants, a pool room
benefits from a constant requirement for the dilution of
chemical related gases / odours and a coexisting requirement
to maintain a negative air pressure balance within the pool
room, to help discourage migration of pool room air into other
rooms or into the structure of the building.
Within the ventilation design this is referred to as the ‘Dilution
rate’, being a comparatively small quantity of mechanical
ventilation with fresh air, that is typically provided on a
continuous basis to the pool room.
A key consideration is that, with a lightly used domestic pool
equipped with a surface cover, the dilution rate is sufficiently
adequate to achieve much of the dehumidification necessary
for the room, leaving the dedicated method of
dehumidification often on stand-by.
Therefore, if the dilution rate fresh air ventilation can be
provided via a recuperator box, able to capture heat that
would otherwise be lost on a continuous basis, then the
benefit to overall operating costs is very substantial.
Conclusion: Any ventilation unit equipped with a
recuperator box will be able to offer significantly better
operating costs, irrespective of the method of primary
dehumidification chosen.
Commissioning requirements
The new building regulations maintain the requirement for the
formal commissioning of fixed building services, to ensure
adequate ventilation and optimum energy efficiency in
operation, and contain detailed guidance on the
commissioning requirements of the various types of systems.
Part O ‘Over heating’
Part O is a newly introduced document that seeks to limit
unwanted heat gain from too much glazing etc.
It is detailed and considers the geographical location of a
project and supports the use of shutters & overhangs etc to
mitigate the effect of solar heat gain.
It makes reference to G-values, which is the ability of glass
to reflect solar radiation.
TECHNOLOGY HIGHLIGHT
‘Blue-EC’ ultra-efficient
digital air fans
Against the consideration that the permanent operation
of an air fan motor may represent the largest consumer
of energy within an indoor pool, Heatstar systems
employs a very special type of digital fan to offer the
best possible energy efficiency and, so, the lowest
operating cost of any such system.
The digital fan uses a directly driven, backward curved,
centrifugal impellor, which features a DC motor coupled
to an AC inverter.
These special fan feature ‘auto-fan’ technology, whereby
the speed and power of the air recirculation fan is
managed automatically to enable significant energy
savings whenever there is low demand for
dehumidification or air heating.
For a domestic pool equipped with a surface cover, there
will typically be long durations of low demand and the
energy saved by ‘auto-fan’ would be very considerable.
Additionally, when the fan is operating on low power,
ventilation air noise in the pool room can also be
reduced.

7. 7
At 0.136 kg per kWh, electricity is now rated significantly
better than mains gas 0.210 kg per kWh, which will
advantage the theoretical comparable carbon
performance of heating systems utilising electricity, such
as heat pumps.
The effect of improved thermal insulation to the building
increases the potential benefit of a dehumidifying heat
pump dynamically recycling spare heat back into the pool
water. This can significantly improve carbon emission and
operating cost, particularly if the pool does not use a
surface cover.
Government ‘Standard Assessment Procedure’
(SAPs)
The designers of a building are expected to carry out SAPs
calculations to demonstrate compliance with building
regulations by achieving the Target Emission Rate (TER) for
carbon. The current SAPs version 10.2 is now the required
standard for building regulation compliance. The detail
involved in these calculations is very exact and dedicated
software is utilised. The TER is expressed in kg of CO²
produced, per m² of floor area, per year.
SAPs give the government carbon rating for each fuel (gas /
electric / oil) etc. The latest carbon intensity for electricity used
in calculations is actually lower than that currently achievable
and assumes continued decarbonisation of the national grid
over years to come.
Implications: Operating costs
Everyone will appreciate the significant increases in
electricity and gas prices witnessed this year. However, for a
modern indoor pool utilising energy efficient equipment, the
budgets involved remain comparatively realistic.
Taking energy prices at the current government capped level,
for a typical 10m x 5m domestic swimming pool constructed
to the new building regulation targets, the following
approximate operating costs are possible:
Surface cover used 22 hrs per day: £4000 per annum.
No surface cover used: £8000 per annum.
These figures include air heating, pool water heating,
ventilation & dehumidification.
They are based upon a ventilation system equipped with
recuperator box on exhaust / fresh air and the inclusion of a
dehumidification heat pump, to offer an optimum ‘hybrid’
approach.
To download full copies of all current building control
regulations visit www.planningportal.gov.uk or contact
Heatstar who can supply copies.
How we can help
At Heatstar we will obviously take all necessary measures
to ensure that these new building control regulations do not
cause you undue hassle, including:
Fully compliant product options
Heatstar can immediately offer a range of fully compliant
equipment options, offering heat capture rates that exceeds
the required standard.
Building Regs Compliance Statement
At the quotation stage, we will provide you with a clear
statement / assessment of the applicable building control
regulation requirements and a compliance report for the
proposed Heatstar system.
Commissioning plan
At the quotation stage, we will provide you with a
commissioning requirement statement for the proposed
pool room system, which can be included within the
‘commissioning plan’ for the whole project.
Specific Fan Performance
We will clearly highlight and confirm the Specific Fan
Performance of the proposed Heatstar system.
Pool room structural insulation values
On new projects, we have updated our thermal insulation
values to match the requirements of the new building
control regulations.
Fuel boiler efficiencies
We have updated our boiler efficiency ratings to match
those used within the new regulations.
Boiler flow temperatures
We have updated our LPHW flow temperatures and heat
output ratings to match those required by the new
regulations.
Thermally insulated swimming pool shell
Our heat load calculations make allowance for the benefit
of stipulated thermal insulation requirement.
Unit commissioning
We will continue to provide free unit commissioning and
generate a commissioning report in line with the format
required under the new regulations.
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8. Manners View
Dodnor Technology Park
Newport
Isle of Wight
PO30 5FA
+44 (0)1983 521465
info@heatstar.com
www.heatstar.com
ADVANCED SWIMMING POOL CLIMATE CONTROL SYSTEMS