Glow-worm talks heating and ventilation for 2010

Darren Finley of Glow-worm considers the significance of the rest of 2010 for the heating and ventilation industry and looks at the regulations that the industry needs to take note of...

As the Government continues to drive for zero carbon new buildings from 2016-19, the amendments to the building regulations Part L and Part F this October, mark a significant date in the heating and ventilation calendar.

The introduction of the updated regulations will mean all new build properties will be required to meet a 25 per cent improvement in energy efficiency compared to the 2006 building regulations.

The publication of new guidance for building regulations Part L and Part F, in the form of a new release of the Domestic Buildings Services Compliance Guide, highlights the need to evaluate how we move forward both in terms of products and heating systems for a carbon free world.

One aspect is crystal clear: It is definitely out with the old, in with the new across the board.

Boilers From October, boilers will be restricted to SEDBUK A rated units only.

The decision to restrict boiler efficiency to SEDBUK A rated boilers will apply to both new build and existing stock.

Modifications to appliance efficiency requirements include: Increase the minimum Gas Boiler Efficiency to 90 per cent SEDBUK A Increase the minimum COP for heat pumps from 2.0 to 2.2 Upgrade Domestic Hot Water storage heat loss performance for new build Q=1.15x(0.2+0.051V2/3) kWh/day From October, SAP 2009 will be used as the assessment procedure for compliance with the building regulations, with monthly calculations for energy gains and losses making the calculations more accurate.

It offers a more satisfactory modelling of modern low energy dwellings with a shorter heating season and also offers better accuracy for modelling solar gains and solar thermal contribution.

Monthly modelling also allows for variation in domestic hot water efficiency input.

The key changes to SAP 2009 methodology include: Monthly calculations for energy gains and losses Cooling included Thermal mass Party walls Thermal bridging Weather data Internal heat gains.

Heat pump performance Community heating Domestic hot water CO2 emission factors Gas boiler efficiency SAP 2009 assessment procedures will also cover cooling systems modelled for the first time, and applies to fixed mechanical cooling systems.

Calculations will be made on a seasonal basis for the three summer months.

System energy usage in the SAP model depends on area of usage and appliance characteristics.

Thermal mass input in SAP 2005 is implicit input into the calculation.

SAP 2009 uses explicit information input into the calculation for external walls, roof and floor, internal walls, party walls, ceilings and intermediate floors, and has a pronounced effect when applied to low energy house design.

Performance of heat pumps will be based on test data similar to that used for current gas boilers.

Approved Appliance performance will be listed in Appendix Q, and the measured figures used in the SAP calculation.

Unapproved or unlisted appliances will still be calculated using default efficiency levels listed in the Appendix of SAP 2009, which will be announced once the Appendix Q methodology is completed.

The listing of heat pump efficiency will certainly encourage the development of heat pump performance.

For community heating, there is more flexibility in SAP 2009 to allow modelling of a combination of primary heat sources and fuel types.

Allowance is made for the electricity used for circulation pumping while boiler efficiency can be used from test data.

In the domestic setting, test data for combi boilers can be used for hot water performance (EN13203-2).

Annual demand is reduced in the calculation by 5 per cent if the 125L per person per day target is achieved for all water usage (both hot and cold), achieving the Code of Sustainable Homes level 3 target.

CO2 emission factors have also been updated: now kg CO2 "eq"/kWh.

SAP 2009 takes into account the other greenhouse gases CH4 and N2O as CO2 equivalents and a wider consideration of upstream emissions is given.

New fuels have also been added including biodiesel, biodiesel blends and rape seed oil.

When it comes to measuring boiler efficiency, single SEDBUK efficiency will no longer be used in SAP calculations, and will be replaced by separate heating and hot water efficiencies that can be varied by month, enabling more precise modelling for low energy housing.

SEDBUK is still the basis for the minimum standard in building regulations (Minimum SEDBUK A requirement in 2010) but capping is applied in SAP 2009 to reduce laboratory test efficiencies.

Confirmation of the method and allowed efficiency band is still pending; there is a need to understand risk and sensitivity for gas appliance ranges.

Renewables Obviously, renewables are going to come more to the fore as the search for greater sustainability continues.

Solar heating is increasingly being installed into new build social housing and private sector projects, and is becoming ever more sophisticated.

Air to water heat pumps have also recently been added to the mix, which has made solar even more attractive as a cost effective option.

Consisting of a single external unit requiring just an electricity supply and heating flow/return connections, an air to water heat pump is simple to install and there is no need for the expensive ground loops or drilling of bore holes that are required with ground source heat pumps.

They are also highly efficient - for every 1kW of electrical power consumed to run the compressor, up to 4kW of heat energy is produced.

Ventilation The main changes to the building regulations for October 2010 also affect Part F which should not be undermined.

The key aim of Part F is to ensure sufficient ventilation to maintain a healthy environment.

The provision of natural ventilation and local intermittent fans will become more challenging, meaning there will be an increased trend towards mechanical ventilation systems.

Part F now includes revised ventilation tables to accommodate houses with low permeability.

CLG propose to make all ventilation systems a controlled service.

Only the replacement of continuous mechanical systems should be notifiable to Building Control.

Mechanical ventilation with heat recovery, maintains fresh air conditions for the occupants, removes moisture, odour and bacteria build up, without reducing the internal room temperatures: A fundamental necessity in new air tight homes.

Previous methods included providing individual fans to bathrooms, a cooker hood in the kitchen to extract air, odours, humidity and heat, and trickle vents in windows replaced extracted air.

This air was, however, introduced at ambient outdoor temperatures and often lowered the overall room temperature.

This change in room temperature required additional energy to be added to the property in order to maintain comfort levels.

With new homes becoming increasingly more air tight, a requirement further strengthened with the implementation of the Government's Code for Sustainable Homes expects heating and ventilation suppliers to be providing a complete one-stop shop to satisfy all needs.

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