House Energy Rating

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The House Energy Rating (HER) or House Energy Rating Scheme (HERS) are worldwide standard measures of comparison by which one can evaluate the energy efficiency of a new or an existing building. The comparison is generally done for energy requirements for heating and cooling of indoor space. The energy is the main criterion considered by any international building energy rating scheme but there are some other important factors such as production of greenhouse gases emission, indoor environment quality, cost efficiency and thermal comfort, which are considered by some schemes. Basically, the energy rating of a residential building provides detailed information on the energy consumption and the relative energy efficiency of the building. Hence, HERs inform consumers about the relative energy efficiency of homes and encourage them to use this information in making their house purchase decision. [1]

Contents

There are many energy rating tools by which one can calculate the energy performance of a building. Basically all these tools involve a numerical description or prepare a computer-based model for the rating of a building against standard occupancy and activity templates. [2] HERS uses computer-simulation based methods for assessing the energy efficiency of buildings under standard conditions and its potential for improvement.

House energy rating schemes

HERS is a standardized scheme for evaluation of a home's energy efficiency and expected energy costs. A HERS represents the guideline of a House energy rating. In all countries, HERS show variations in objectives, assessment methodologies and measurement criteria but after all this variation, the goal of all HERS is approximately same and these generate the output in same way.

HERS outputs

Basically HERS generates three types of outputs [3]

Rating Scores
The energy performance rating is a type of energy assessment how efficiently the buildings use energy, relative to similar buildings. The performance scores use generally a scale ranging from 0 to 100 or 1 to 5 stars. The value of score is based on the comparison made between the rated house and a reference house that meets a desired energy code or standards.A rating of 50 indicates average energy performance, while a rating of 75 or more indicates best performance. More the score obtained by a house more will be the energy efficiency of the house and the high rating scores have many direct applications, such as it permits a buyer to quality for more mortgage comparatively.
Energy use/Cost prediction
HERS generate energy use and cost predictions for specific end uses like space heating/cooling, hot water and for whole house. These outputs are obtained in absolute measures and unlike to score rating these outputs can be used to compare houses like that of miles-per-gallon ratings are used to compare the cars.
Recommendations
HERS can produce a list of recommended improvements based on some life cycle's effective cost analysis. These recommendations may be pertaining to any of the inefficient components of a building i.e. insulation layer in the composite wall of building, air conditioning equipment, water heating unit, double-glazed windows, etc.

HERS types

As per national energy policies, HERS are known by different names in different countries. The implementation and promotion of HERS in a country depends upon the national energy policy. Beside all this, the aim of all HERS is almost same and it can be classified into three types:

Need for HERS

Worlds past, present and future energy consumption scenario World market past, present and future energy consumption scenario.png
Worlds past, present and future energy consumption scenario

Increase in population, economic issues are the some factors which have escalated the energy demand across the world. In developed countries, the growth rate of energy consumption rate is 1.1% per year while in developing countries the energy consumption growth rate approximately 3 time to that of developed countries. Beside this high growth in energy consumption it also causes to increase the production of green house gases to the atmosphere. The increase in demand of energy, limited resource of convention energy sources, hike in conventional fuel prices, global warming are some important factors which Impetus us to adopt energy saving techniques and alternative sources of energy. [4] Building sector consumes one third of world's resources. Building currently shares approximately 40% of energy in most of the countries and are considered among the largest end-use sector. As per International energy agency (IEA) world energy consumption and green house gases level is going to increase rapidly every year. IEA recognize the building sector as one of the most cost effective sector where energy consumption can be reduced. It is estimated that the energy consumption can be reduced to 1509 million tonnes of equivalent (Mtoe) and at the same time it will cause to reduce the green house gases production up to 12.6 gigatonnes (Gt) by 2050. [5] The international energy outlook report reveals that the energy consumption is increasing in each year and the energy increment trends are shown in the right-hand figure.

So, we conclude that the building sector is one of the largest sector where energy consumption and green house gases emission can be reduced effectively by improving the energy efficiency of buildings and hence HERS can play a vital role in achieving all this.

In different countries

Australia

In Australia, Five star is the first house-rating scheme, which was developed in 1980 by the GMI council of Australia. This scheme was basically based on the three basic elements, glass, mass and insulation of dwelling. Due to many limitations this system failed to attain popularity and in 1990s they develop Victorian scheme. This scheme attains some popularity but it was also not suitable for all climate of Australia. In 1993 a more flexible HERE, known by Graded five star rating system was developed. This rating scheme was much flexible and was suitable to all climatic conditions of Australia. Presently there are different HERS available in Australia which are used in different Australian states. Some of HERS used in this country are:

Brazil

In Brazil, the first national program for energy efficiency in buildings (HERS), PROCEL EDIFICA was developed in 2003. The use of this rating scheme was extended to public and commercial sector in 2007 and from 2012 the operational rating is mandatory for both residential and commercial buildings. The rating system consist of a scale ranging from A to E basis, where A represent the most efficient and E represent the least efficient rating. The rating scheme consider three aspects of buildings;

  1. Building envelope thermal performance
  2. Lighting system efficiency
  3. Installed power and air conditioning system efficiency

The three groups are evaluate individually and the combined results of these indicates the level of efficiency of a building.

Canada

In Canada, home energy ratings have been in existence since 1997. The two government energy rating programs are:

Both of these programs use HOT2XP and HOT 2000 as their rating tools. Beside the aforesaid government rating programs in Canada, there are two standard bases are available for evaluating the building are;

  1. R-2000: as per this rating, 80-85 points are needed to meet Canadian specification code.
  2. Model national energy code of Canada (MNECB): as per this rating, 70-75 points are needed to meet Canadian specification code.
  3. Other HERS in Canada

LEED is used in Canada as one of home rating scheme. This rating scheme is an adaption of the US green building council's LEED and has been modified as per the Canadian climate, construction and regulation policies.

China

In China, the Ministry of Housing and Urban-Rural Development (MOHURD) developed a national building energy rating and labeling HERS in 2008. This HERS is mandatory for government buildings, big commercial complexes and those buildings applying for public retrofit funding or green label. this HERS consist a star rating scheme, ranging from 1 to 5 star. As per this HERS, more the star, more will be the energy efficiency of the building. The rating level of buildings is determined in three parameters;

  1. Basic Items: refers to the regulated energy use per square meter, obtained by computer modeling or measurements.
  2. Required Items: refers to minimum performance requirements for building envelope and Heating Ventilation and Air-Conditioning (HVAC).
  3. Optional Items: refers to the additional energy management system which are not mandatory in the rating scheme. it covers, the application of renewable energy, innovative energy efficient technologies.

Denmark

In Denmark, the energy rating scheme are in existence since 1981. Denmark is the first country in Europe (EU) to begin issuing Energy Performance certificates (EPCs). The EPCs are mandatory in all types of buildings in Denmark. The rating system in Denmark includes three parts.

  1. The first part of rating consists reports on water consumption, energy consumption and GHGs emission per year, which are compared against a standard building of same type on a scale ranging from A1-C5.
  2. Second part of the system, proposes the different possible ways for saving of energy and water consumption with respect to the cost involved
  3. This part of report provides the present state of buildings in term of size, heating system, energy usage and the cost of energy and heating.

France

In France, "Diagnostic de performance energetique" (DPE [7] ) is used as HERS. This scheme was developed in November 2006 and in July 2007 its use becomes mandatory for all those buildings whose registration had been filed after 1 July 2007. This rating scheme consist of two types of measurements.

Both of the measurements comprises 7-label ratings, ranging from A (best) to G (worst) which are presented by the color coding. In ratings, the green color represents A and red color represents G label. In both cases of measurements, the buildings are evaluated in terms of necessary resource for heating, hot water production and air conditioning. The PDE of a building remains valid for 10 years. [8]

Ireland

In Ireland, the building energy ratings are in existence since 2007. In this country Building Energy Rating (BER) is used as EPC. The scheme was mandatory for new dwelling and in 2008, its use was extended to non-residential and public buildings, in 2009 the HERS cover the all types of buildings. BER is a calculation based HERS. Due to transparency in this HERS, there is a more awareness among the people and is accepted widely.

Portugal

In Portugal, the EPCs scheme was launched in July 2007 and was implemented for new buildings. The use of this scheme was extended to existing buildings in January 2009. This rating scheme covers mainly the indoor air quality and energy performance of the buildings. This rating scheme is also a calculation based HERS. The compliance in the country is high and the EPC is issued only when 90% of building completion and transaction observed. There is a national database who covers all EPCs registration record and this is available for all countrymen.

United Kingdom

The United Kingdom (UK) is one of the countries where HERS has been developed and implemented strongly from a very long time ago. In UK, National Home Energy Rating (NHER) scheme is used widely. NHER scheme measure the thermal efficiency of the dwellings on a scale of 0-10 in terms of energy running cost. The dwelling rating is done through computer modeling which uses a computer program based on Building Research Establishment Domestic Energy Model (BREDEM). Basically NHER measure the energy efficiency of dwellings as a function of energy cost per square meter. The energy usage is calculated by considering the all aspects of buildings (location, design, construction, water heating, cooking, ventilation and appliances, lighting etc.) and for dwelling energy rating it use some standard assumptions, such as occupancy scenario, thermostat setting, occupant stay timings.

United States

In the United States, HERS are since 1980s. Among the various HERS energy rated homes of America is used widely. It is used in more than 18 states of US. This scheme uses a 100 points scale of efficiency and it is further divided into 10 categories of star rating which ranges from one star to five star plus. In this rating scheme a higher star rated house represents higher energy efficiency of the house.

ENERGY STAR Energy Star logo.svg
ENERGY STAR

The energy efficiency rating in this HERS represents the predicted energy consumption, represents the form of normalized annual energy consumption. This rating scheme consist a detailed measure of CFLs, water heater tanks, ceiling, floors and pipe insulation, efficient refrigerator and freezer, high efficient space and water heating equipments, air leakage and controls. The other important rating schemes used in US are: [9]

Issues regarding building energy rating schemes

See also

Related Research Articles

<span class="mw-page-title-main">Energy Star</span> US energy

Energy Star is an energy-efficiency program administered by the U.S. Environmental Protection Agency (EPA) in partnership with the U.S. Department of Energy (DOE). The EPA establishes energy efficiency specifications, and those that meet these specifications are eligible to display the ENERGY STAR logo.

<span class="mw-page-title-main">Energy conservation</span> Reducing energy consumption

Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively or changing one's behavior to use less and better source of service. Energy conservation can be achieved through efficient energy use, which has some advantages, including a reduction in greenhouse gas emissions and a smaller carbon footprint, as well as cost, water, and energy savings.

<span class="mw-page-title-main">Green building</span> Structures and processes of building structures that are more environmentally responsible

Green building refers to both a structure and the application of processes that are environmentally responsible and resource-efficient throughout a building's life-cycle: from planning to design, construction, operation, maintenance, renovation, and demolition. This requires close cooperation of the contractor, the architects, the engineers, and the client at all project stages. The Green Building practice expands and complements the classical building design concerns of economy, utility, durability, and comfort. Green building also refers to saving resources to the maximum extent, including energy saving, land saving, water saving, material saving, etc., during the whole life cycle of the building, protecting the environment and reducing pollution, providing people with healthy, comfortable and efficient use of space, and being in harmony with nature. Buildings that live in harmony; green building technology focuses on low consumption, high efficiency, economy, environmental protection, integration and optimization.’

<span class="mw-page-title-main">Low-energy house</span> House designed for reduced energy use

A low-energy house is characterized by an energy-efficient design and technical features which enable it to provide high living standards and comfort with low energy consumption and carbon emissions. Traditional heating and active cooling systems are absent, or their use is secondary. Low-energy buildings may be viewed as examples of sustainable architecture. Low-energy houses often have active and passive solar building design and components, which reduce the house's energy consumption and minimally impact the resident's lifestyle. Throughout the world, companies and non-profit organizations provide guidelines and issue certifications to guarantee the energy performance of buildings and their processes and materials. Certifications include passive house, BBC—Bâtiment Basse Consommation—Effinergie (France), zero-carbon house (UK), and Minergie (Switzerland).

<span class="mw-page-title-main">LEED</span> Standard for green building design

Leadership in Energy and Environmental Design (LEED) is a green building certification program used worldwide. Developed by the non-profit U.S. Green Building Council (USGBC), it includes a set of rating systems for the design, construction, operation, and maintenance of green buildings, homes, and neighborhoods, which aims to help building owners and operators be environmentally responsible and use resources efficiently.

The Nationwide House Energy Rating Scheme (NatHERS) is an Australian scheme to measure the energy efficiency of a residential dwelling. An accredited software tool assesses the home based on a variety of criteria and produces an energy star rating.

<span class="mw-page-title-main">Zero-energy building</span> Energy efficiency standard for buildings

A Zero-Energy Building (ZEB), also known as a Net Zero-Energy (NZE) building, is a building with net zero energy consumption, meaning the total amount of energy used by the building on an annual basis is equal to the amount of renewable energy created on the site or in other definitions by renewable energy sources offsite, using technology such as heat pumps, high efficiency windows and insulation, and solar panels.

Domestic housing in the United Kingdom presents a possible opportunity for achieving the 20% overall cut in UK greenhouse gas emissions targeted by the Government for 2010. However, the process of achieving that drop is proving problematic given the very wide range of age and condition of the UK housing stock.

<span class="mw-page-title-main">Energy World</span> Exhibition of low-energy housing

Energy World was a demonstration project of 51 low-energy houses constructed in the Shenley Lodge area of Milton Keynes, United Kingdom. The project was promoted by the Milton Keynes Development Corporation and culminated in a public exhibition in August and October 1986 that attracted international interest. It was a significant landmark in the design and construction of low-energy housing, and in the development of energy efficiency evaluation tools. It has had a long-term impact on Government policy and within the national house-building industry, insofar as the progressive 'tightening up' of the energy section of the Building Regulations has largely been founded on this pioneering work.

The National Home Energy Rating Scheme (NHER) is both a UK accreditation scheme for energy assessors and a rating scale for the energy efficiency of housing.

The Code for Sustainable Homes was an environmental assessment method for rating and certifying the performance of new homes in United Kingdom. First introduced in 2006, it is a national standard for use in the design and construction of new homes with a view to encouraging continuous improvement in sustainable home building. In 2015 the Government in England withdrew it, consolidating some standards into Building Regulations.

<span class="mw-page-title-main">Energy Performance Certificate (United Kingdom)</span> Scheme for rating the energy efficiency of buildings

Energy performance certificates (EPCs) are a rating scheme to summarise the energy efficiency of buildings. The building is given a rating between A - G (Inefficient). The EPC will also include tips about the most cost-effective ways to improve the home energy rating. Energy performance certificates are used in many countries.

<span class="mw-page-title-main">Energy performance certificate</span> Rating scheme to summarise the energy efficiency of buildings or devices

An energy performance certificate (EPC) is a rating scheme to summarise the energy efficiency of buildings or devices.

<span class="mw-page-title-main">Efficient energy use</span> Methods for higher energy efficiency

Efficient energy use, or energy efficiency, is the process of reducing the amount of energy required to provide products and services. There are many technologies and methods available that are more energy efficient than conventional systems. For example, insulating a building allows it to use less heating and cooling energy while still maintaining a comfortable temperature. Another method is to remove energy subsidies that promote high energy consumption and inefficient energy use. Improved energy efficiency in buildings, industrial processes and transportation could reduce the world's energy needs in 2050 by one third.

The Home Energy Rating is an American estimated measurement of a home's energy efficiency based on normalized modified end-use loads (nMEULs). In the United States, the Residential Energy Services Network (RESNET) is responsible for creation and maintenance of the RESNET Mortgage Industry National Home Energy Rating Standards (MINHERS), a proprietary system of standards, which includes standards language for the certification and quality assurance for RESNET Provider organizations. RESNET is an EPA recognized Home Certification Organization (HCO) that also help's create standards in compliance with the American National Standards Institute, namely ANSI 301, ANSI 310, ANSI 380, and ANSI 850. The Building Science Institute, Ltd. Co. (BSI) is another EPA recognized HCO that maintains the ANSI Standards to produce Energy Ratings and compliance with above-code programs such as the ENERGY STAR New Homes Program.

A Domestic Energy Assessor (DEA) for efficient energy use is an accredited position in the UK that is approved by the Ministry for Housing, Communities and Local Government (MHCLG). Under the UK's Energy Performance of Buildings Regulations, an Energy Performance Certificate is required for the sale or rent of a domestic dwelling. DEAs are qualified and accredited for the production of RdSAP EPCs - these are specifically for use on existing buildings, which would include a dwelling built after 2008 which had already received an on-construction SAP EPC. As of November 2018, DEAs had produced 16,849,375 RdSAP EPCs since the inception of the industry.

<span class="mw-page-title-main">Bureau of Energy Efficiency</span>

The Bureau of Energy Efficiency is an agency of the Government of India, under the Ministry of Power, created in March 2002 under the provisions of the nation's 2001 Energy Conservation Act. The agency's function is to encourage the efficient use of energy in India by developing programs to support it. For example, the government proposed to make it mandatory for certain appliances in India to have ratings by the BEE from January 2010 onwards. The mission of the Bureau of Energy Efficiency is to institutionalise energy efficiency services, enable delivery mechanisms in the country and provide leadership to energy efficiency in all sectors of the country. Its primary objective is to reduce energy intensity in the economy.

A Deep Energy Retrofit is an energy conservation project in an existing building that leads to an overall improvement in building performance. While there is no exact definition for a deep energy retrofit, it can be characterized as a whole-building analysis and construction process that aims to reduce on-site energy use by 50% or more using existing technologies, materials and construction practices. Reductions are calculated against baseline energy use using data from utility bills. Such a retrofit reaps multifold benefits beyond energy cost savings, unlike conventional energy retrofit. It may also involve remodeling the building to achieve a harmony in energy, indoor air quality, durability, and thermal comfort. An integrated project delivery method is recommended for a deep energy retrofit project. An over-time approach in a deep energy retrofitting project provides a solution to the large upfront costs problem in all-at-once execution of the project.

<span class="mw-page-title-main">Green home</span> Type of house designed to be environmentally sustainable

A green home is a type of house designed to be environmentally sustainable. Green homes focus on the efficient use of "energy, water, and building materials". A green home may use sustainably sourced, environmentally friendly, and/or recycled building materials. This includes materials like reclaimed wood, recycled metal, and low VOC paints. Additionally, green homes often prioritize energy efficiency by incorporating features, such as high-performance insulation, energy-efficient appliances, and smart home technologies that monitor and optimize energy usage. Water conservation is another important aspect, with green homes often featuring water-saving fixtures, rainwater harvesting systems, and grey water recycling systems to reduce water waste. It may include sustainable energy sources such as solar or geothermal, and be sited to take maximum advantage of natural features such as sunlight and tree cover to improve energy efficiency.

Public plans for energy efficient refurbishment are put in place by states to encourage building owners to renovate their properties in a way that increases their energy performance. As financing represents the most important obstacle to this type of renovation, the plans favour financial incentives in the form of loans or grants. Various institutions can be involved in the process, such as ministries, banks, firms, or energy services companies (ESCOs).

References

  1. ↑ kordjamshidi, Maria (2011), House rating schemes, Springer, ISBN   978-3-642-15790-5
  2. ↑ Hernandez, Patxi; Burke, Kevin; Lewis, J. Owen (2008), "Development of energy performance benchmarks and building energy ratings for non-domestic buildings: An example for Irish primary schools", Energy and Buildings, 40 (3): 249–254, Bibcode:2008EneBu..40..249H, doi:10.1016/j.enbuild.2007.02.020
  3. ↑ Stein, Jeff Ross; Meier, Alan (2000), "Accuracy of home energy rating systems", Energy, 25 (4): 339–354, Bibcode:2000Ene....25..339S, CiteSeerX   10.1.1.110.1666 , doi:10.1016/S0360-5442(99)00072-9
  4. ↑ Newsham, Guy R.; Mancini, Sandra; Birt, Benjamin J. (2009), "Do LEED-certified buildings save energy? Yes, but.", Energy and Buildings, 41 (8): 897, doi:10.1016/j.enbuild.2009.03.014
  5. ↑ http://www.iea.org/publications/freepublications/publication/buildings_certification.pdf Energy performance certification of buildings
  6. ↑ https://natural-resources.canada.ca/energy-efficiency/energuide/12523 [ bare URL ]
  7. ↑ https://www.critt-tti.net/le-dpe-ou-comment-diagnostiquer-la-consommation-de-sa-maison/ Le DPE – ou comment diagnostiquer la consommation de sa maison
  8. ↑ http://uniondesconsommateurs.ca/docu/energie/EEratingHouses.pdf Archived 30 June 2013 at the Wayback Machine FOR ENERGY EFFICIENCY(EE):A HomeEnergy Rating System
  9. ↑ kordjamshidi, Maria (2011), House rating schemes:from energy to comfort base, Springer, ISBN   978-3-642-15790-5

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