SAP calculation and PEA certificate (Predicted Energy Assessment)

From 6 April 2008 it will be law to provide an Energy Performance Certificate for all new and newly built homes that are completed after that date.

An Energy Performance Certificate (SAP) gives information on the building’s energy efficiency.

Table of Contents

1. What does this mean in practice?
2. Energy efficiency and new homes
3. Why do we need Energy Performance Certificates?
4. Providing information about energy for homes
5. How much will an SAP-EPC certificate cost?

6. What does a SAP contain?

7. Elements effecting SAP rating?

8. Effects of heating system and hot water tank on SAP certificate?

What does SAP certification mean in practice?

Based on Building Regulations (2006) you will be providing an energy rating and report to building control for your new houses using SAP calculation (Standard Assessment Procedure) or new built EPC.

For all homes that are finished on or after 6 April 2008, there will be a requirement to provide an SAP-EPC certificate to the owner, with evidence shown to Building Control.

If you do any building work to your house which creates a separate dwelling that has heating, hot water or air conditioning, then you will need to provide an SAP calculation for your property.
When you finish your building work, Building Control ask you to submit a notice which includesan energy rating calculation to demonstrate your building complies with the Building Regulations 2006-2010 etc. By the same date on the notice, you must get a SAP certificate from an accredited SAP Energy Assessor, give the SAP calculation to the owner of the building and tell building control that this has been done based on standards.
This is what you have to do under the Building Regulations, Approved SAP Inspector Regulations and the Energy Performance of Buildings Regulations, and Building Control will not give you a final completion certificate until they are sure that everything has been done nicely and based on standards. If the completed home is being advertised for sale, the SAP certificate and SAP rating is available for potential buyers, for the next 12 months.

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Energy efficiency and new dwellings

In 2006, the Government in England introduced new Building Regulations which established the energy efficiency standards which new homes must achieve. New homes that are built to meet these regulations save more energy have lower carbon emissions (CO2) and cost less to run (fuel bills). In order to meet the Building Regulations, builders need to make sure that any new properties they build meet a minimum target for energy performance rating.

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Why do we need SAP Energy Performance Certificates?

SAP Energy Performance Certificates tell owners and potential buyers and tenants about the energy efficiency and energy loss of a home and how it can be improved and how much do they save by doing that.

The SAP rating shown on the SAP calculation certificate is the same number as is needed for Building Regulations but it is shown in a similar format to the energy labels that are now often used for many appliances like fridge and washing machines. The Environmental Impact rating is also shown in SAP calculation, which shows how much carbon emissions the home is expected to generate.
All SAP-EPC certificates come with a Recommendation Report which includes advice and suggestions on improvements you could make to save money and energy. The SAP certificate also shows the rating that could be achieved if all the recommendations are followed.

In the case of new dwellings, you will get a shorter Recommendation Report which contains more advanced energy improvements and energy saving suggestions such as wind turbines. This is because most cost effective  improvements will have already been included in the design of the home.

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Providing information about energy for homes that have not been built yet?

If you are selling a home before it has been built, you will need to provide information about energy efficiency in a Predicted Energy Assessment (PEA). This is simply the predicted SAP and Environmental Impact (CO2) rating from the SAP calculations and SAP Report you do at the design stage, to check whether you will meet energy saving targets and building regulations.

If the home is completed on or after 6 April 2008, you will need to give the owner a full SAP calculation and SAP certificate and Recommendation Report once the property is completed.

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How much will an SAP certificate cost?

The price of SAP-EPC certificates will be set by the market and market demand. It is likely in practice that the cost will vary according to a number of factors including size, location and age of the building.

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What does a SAP contain?

SAP certificate or energy performance certificate is an energy report which shows how energy efficient
the building is based on the heating and electricity consumption and energy loss.

In fact in SAP calculation we are not just showing how much energy we use, also we show how much
energy we save by good insulation and efficient heating systems.

Energy certificate is dedicated to each property and in the first page shows the property address, report
number, date of certificate, floor area and finally a graph which shows the rating and compare it to the
good practice.

The SAP certificate showing the performance based on terms of energy use per square meter of
floor area, energy efficiency based on fuel cost and environmental impact based on carbon dioxide
emissions.

The higher the rating is the more energy efficient the home is and lowers the fuel bills are likely to be,
and less impact on the environment and less CO2 emission.

Always remember that fuel cost and energy rating are based on estimates and actual figures might be
different.

SAP report is not based on meter readings and is not about household energy usage.

Estimated energy use, carbon dioxide emissions and fuel costs are also shown in the SAP calculation
to enable prospective buyers and tenants to compare these figures room this house with another house,
to enable this comparison the figures have been calculated using standard running conditions (heating
period, room temperature, etc) which are the same for all homes.

Consequently they are unlikely to match an occupier’s actual fuel bills and carbon emissions in practice.

The figures will be provided for heating, hot water and lighting. The price will be based on the date of
certificate and so it is unlikely to be accurate after couple of years.

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Element effecting SAP rating:

There are just some elements which we take into count when we calculate SAP rating and energy
performance certificates which are as follow:

Building fabric, glazing, insulation, hot water system and tank, boiler and heating system, lighting,
renewable energies (like solar heating, Photovoltaics, wind turbine, combined heat and power units),
property general dimensions and number of party walls.

Building fabric and its insulation has the biggest effect on the rating. Cavity wall insulation, roof
insulation and floor insulation are most effective elements. Based on the age of the building software
define the heat resistance of the building fabric and calculates the building heat loss, newer the building
better the heating resistance.

Windows are also having major effect as single glazing efficiency is almost half a double glazed
windows, also there is different in pre 2002 windows and post 2002 double glazed windows as post
2002 are more efficient and more draught proof.

Basically software assumes that single glazed windows are not draught proof.

Elements like cooker, computers and TV, fridge and other electrical devices have no effect on SAP
rating, fuel cost calculation and CO2 emission however in reality they have an effect.

Also swimming pool and air conditioning systems have no effect either.

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Effects of heating system and hot water tank on SAP certificate?

Heating system and hot water system have huge effect on energy performance rating.

Generally software assumes better rating for gas systems than electric, LPG and oil fried systems.

Boilers with more than 15 years old will come as 65% efficiency which will have a negative effect on
SAP certificate. Condensing boilers have better efficiency and come as 75% and more.

New boilers will have efficiency more than %85.In SAP calculation boilers effect the rating based on
how much energy they waste so boiler with less efficiency waste more energy than ones with higher
efficiency.

The best boilers for SAP report software are condensing combi boilers and worse one is old electric
heaters. Efficiency details come from SEDBUK website which get updated every month.

Boiler size is not important in the rating however it will effect the fuel cost and co2 emission.

Heating controls are effective too as they control the energy usage of heating system. In SAP
calculation control systems affect the rating based on how much energy they save.

The best control systems for SAP software are time and zone controls and after that combination of
TRV (thermostatic radiators valve), room thermostat and programmer.

Programmer and TRV is an effective combination as well.

Control systems are very cheap to install and easy to use and have a huge effects on energy
performance rating.

Hot water systems are the other element in the building which consumes energy.

In SAP calculation hot water systems affect the rating based on how much energy they waste.

Generally software assumes better rating for gas systems than electric, LPG and oil fried systems.

The best hot water system for SAP report software is condensing combi boilers as they don’t waste
energy by storing hot water and worse one are old electric tanks with no or bad insulation.

System control and insulation are all effective on the SAP rating as they manage the amount of energy
we waste.

Generally systems with no storage are the best systems as they don’t waste energy. Even good
insulated tank 50mm wastes about 2-3 kW every day, for not insulated tanks it can be up to 10 times
more. Also the size of the tank is important in how much energy it wastes, bigger tanks are normally
come as lower SAP rating. Smaller tanks with good insulation also reduces the co2 emission and fuel
cost.

Same as heating systems having a good control system is important in reducing the energy
consumption and get a better SAP rating. If it is electric heater the programmer with good timer can
set the system in order to get turned on during the night and heat up the tank will the electricity is half
price.(if they have dual rate meter).

Also tank thermostat controls the storage temperature and so reduces the lost.

In some SAP calculation hot water system has a bigger effect on SAP rating than heating systems.

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