We all experience the world differently, and no one solution will fit everyone – I’m sure you know someone that has no problem wearing just a t-shirt & shorts in Winter or someone who still wears a jacket during Summer. This becomes an issue when you’re an Architect or Engineer trying to create a building that will be used by a variety of different people, all with different needs and expectations. It’s a problem for many different aspects of building design, but here we’re just going to address thermal comfort and how we ascertain that a building’s thermal performance will be comfortable for as many people as possible. The method used to calculate human comfort is called the “Predicted Mean Vote”, or PMV, which is derived from ANSI/ASHRAE Standard 55. This refers to the Predicted Mean Vote of the thermal comfort as perceived by the building occupants.

Over many years in different experiments, thousands of people from varied sample groups have been tested at different environmental conditions to “vote” on how they feel. From these experiments, the analysis of trends and correlations have resulted in the PMV calculation formula.

PMV is an index that predicts the mean vote of a large group of people, represented as a 7-point thermal sensation scale.

A PMV between -1 and +1 means a maximum of 26% of people will be dissatisfied. In fact, a perfect PMV of 0.0 still means 5% of people will be dissatisfied, because some people are naturally more extremely “hot blooded” or “cold blooded”.

How does a building comply with the Predicted Mean Vote Requirement?

In NCC2019 Volume 1, in all three Verification Methods JV1, JV2 and JV3, the PMV must be calculated. In the building thermal simulation the PMV is determined for every occupied building zone/room for every single hour for a whole year. A building should have its results listed in a table that clearly says all the occupied zones, the zone floor areas, and the percentage hours of operation that zone has a PMV between -1 and +1.

Each zone is considered within its individual compliance range when the PMV is between -1 and 1 for more than 98% of the occupied hours. Finally, for a Building PMV Compliance “Pass”, the floor area of occupied zones that comply must be not be less than 95% of all occupied zones. If this is all a bit confusing for you, worry not – we’ll be showing you an example table further down below. But before we get there, let’s go through the actual parameters used in the PMV calculation itself.

Parameters affecting Predicted Mean Vote

Air Speed (unit: m/s, range: 0 to 2)
The speed of air circulating throughout the building space, in metres per second (m/s). If you want to know more on this, we have a handy article on how ceiling fans work with more information on the effects of air speed on comfort.

Air Temperature (unit: °C, range: 10 to 30)
The internal air temperature in a building space in degrees Celsius. It is measured as “Dry Bulb Temperature”, which is the measurement of true thermal air temperature, without influence from humidity or direct sunlight or reflected ambient radiant surfaces.

Mean Radiant Temperature (unit: °C, range: 10 to 40)
The average amount of heat that is radiated into the building from surfaces such as ceilings, windows and walls. This is most often heat that is absorbed and re-radiated by the building fabric into the living spaces.

Relative Humidity (unit: %, range: 0 to 100)
This refers to how much moisture vapour is in the air, expressed as a percentage of the maximum amount of moisture the air can hold at the current temperature, before it is released as condensation or precipitation. That is, the Absolute Humidity (grams per meter cubed (g/m³) of moisture) divided by the Saturation Humidity (e.g. 30g/m³ at 30 degrees Celsius), multiplied by 100 to give the Relative Humidity percentage (%).

Activity (unit: met, range: 0.8 to 4.0)
Activity rate combines two factors: metabolic rate and external work. Metabolic rate is the rate at which energy is produced by the body. External work is the amount of activity being performed by a person, therefore knowing the expected use of a building is important to find the correct activity rate. For instance, 1 metabolic unit (1 met) is about normal for an active seated person in an office. 1.5 met is typical for a standing person.

Clothing (unit: clo, range: 0 to 3)
The amount and type of clothing as well as the ratio of exposed/unexposed skin areas. This affects the rate of heat loss by the body. For example, 0.25 clo would be a T-shirt, shorts, shoes and socks, and 1.0 clo would be a light business suit with shoes and socks. For comparison, 1.0 clo is the value used in NatHERS Home Energy Efficiency assessments.

Using Predicted Mean Vote to determine human thermal comfort

It’s about time for a graph! What would be the air temperature needed to achieve equivalent human thermal comfort with varying air speed and clothing values? Lets use:

• PMV locked at 0.0, representing the mean of the population
• Air Speed on the x-axis of the graph
• Air Temperature on the y-axis of the graph
• Radiant Temperature equal to the Air Temperature (the building’s walls/ceilings are the same temperature as the ambient air)
• 50% Relative Humidity
• Activity Rate set to 1.5 met (a standing person)
• Over four levels of clothing: 1.0, 0.65, 0.4 and 0.25 clo

The result is a series of four nearly parallel curves, with each coloured curve for different levels of clothing. This quantifies the well-known effect of increasing airflow from breezes allowing satisfactory comfort at higher air temperatures. As expected, with more clothing the air temperature needs to be reduced for equivalent human thermal comfort. Interestingly, the curves also show the cooling effect airspeed has on comfort perception as the temperature increases.

The air temperature tolerance is increased by 3.5°C for 1.0 clo by increasing Airflow from still air to 2.0 m/s. This means there’s a certain degree of substitution possible between Clothing and Air Speed. So, when it’s not possible to vary Clothing greatly, Air Velocity can produce most of the desired cooling effect for the same level of thermal comfort… Or in other words, a ceiling fan can make up for situations where you have to wear warmer “smart” business clothing!

Less Clothing improves the tolerance to higher temperatures, but with diminishing effectiveness. For example in still air:

• reducing from 1.0 clo to 0.65 clo (35% less) allows 2.6°C increase
• a further reduction to 0.4 clo (~38% lower) allows a further 1.9°C increase
• and a final reduction to 0.25 clo (~38% lower) allows another increase of 1.1°C in air Temperature

The curves would be similar in shape at other Relative Humidity and Activity Rates with a shift in temperature. Higher Relative Humidity and Activity reduces the Air Temperature for equivalent human thermal comfort.

What my Assessment Report should include

Finally, the actual paperwork part. Your Building Energy Efficiency Assessor must use software that automatically calculates PMV over the simulation year. Therefore, depending on the software used, this should produce a Thermal Comfort Report similar to below (though the Compliance Report should show “PASS”). Knowing how to use the software correctly is of course a requirement, but that’s a complex topic far beyond a couple paragraphs at the end of a related article. Because of this, we recommend using only accredited, certified Assessors.

A table similar to the one shown is needed to confirm Building PMV Compliance. Otherwise, the Energy Efficiency Certification is incomplete as the calculation has not demonstrated compliance with the PMV requirement. In this case, we suggest you return your Energy Efficiency Report to the Assessor for amendment to include all the necessary data. It should go without saying, but all of our Energy Efficiency Reports that require Building PMV Compliance come with a table listing the specific results of your building.

Contact us for a Free Fee Proposal for your next Project!

The post How To Quantify Comfort with PMV appeared first on Anderson Energy Efficiency.

A client came to us with a difficult challenge, their house had the maximum glazing. Roughly 90% of the external façade of their house was composed of double glazed glass. Despite being double glazed, the Solar Hear Gain Co-efficient value of the glazing was high. This meant that large amounts of solar heat was being radiated into the building from each orientation. Hence, large amounts of cooling energy was required in order to maintain thermal comfort.

The client wanted us to achieve a 6 Star Rating for their house (without using credits such as solar panels, complying outdoor living area etc.). Additionally, they did not wish to change or reduce the proposed glazing at all.

Energy efficiency may appear to be a straight forward process. However, there are times when one comes across a project that presents a healthy challenge, for even the most experienced professionals. Though the design faced several compliance challenges, with the help of our expertise, our client successfully overcame them all.

How did we help our client? Read the full case study:
The Maximum Glazing House

Anderson Energy Efficiency provided energy efficiency assessment & consulting for this “high glazing” project. Including issuing a From 15 and Universal certificate (mandatory) required for Building Approval. The assessment was carried out using the NatHERS Star Rating method, which allowed us to observe how the proposed building elements impact the thermal performance of the house.

The post The Maximum Glazing House – A Case Study appeared first on Anderson Energy Efficiency.

1. Star Ratings Differ

When talking about NatHERS Star Ratings, the first thing to realise is that Star Ratings are mainly for comparing designs in the same climate. This means that if you are in a different climate, the amount of energy to achieve the same Star Rating will be different. The energy calculated is only for heating and cooling; nothing else. The units of energy used are MJ/m² which means larger houses use more energy to achieve the same Star Rating as a smaller house.

The table below is a summary from the NatHERS Software Accreditation Protocol, which determines the accuracy of the Star Rating software. The first column is the building’s location. The second column indicates that location’s climate zone. There is a total of 69 different climate zones that cover all of Australia in the current NatHERS software. The third column details the energy (MJ/m²) numbers required for a 6 Star building. These numbers relate only to the climates/locations listed, other nearby climates will have different MJ/m² numbers. There is roughly a 10:1 range between the highest – lowest energy number for “6 Stars” across all NatHERS climate zones.

2. Home Sizes and Uses Vary

The final column in the table above is an estimate of electricity used for heating and cooling only. Other uses of electricity (refrigeration, lighting, water heating, cooking etc.) are not included. Energy for these other uses greatly varies, depending on type and size equipment and how it is used. For example, one assumption made is that the thermostat settings for heating and cooling in the NatHERS calculation is similar to an actual home. In reality, there will always be differences (plus and minus).

If the home is constantly occupied throughout the day by temperature-sensitive people (such as small children or the elderly), the assumed thermostat settings may be similar. However, this assumption may be inexact for people who can tolerate cooler indoor temperatures in Winter and warmer temperatures in Summer (thus using the air-conditioning less often and having lower energy consumption).

We have also assumed the efficiency of the ducted, reverse-cycle air-conditioning unit (Coefficient of Performance and Energy Efficiency Ratio) is 3.0. (3.6MJ = 1kWh thermal = 1/3kWh electrical). The 200m² home may have several non-conditioned spaces, (such as a garage & outdoor living areas) that are not included in the calculations. A larger (or smaller) home, with a lower (or higher) efficiency air-conditioner will have proportionately different kWh numbers for indoor climate control.

Typically, the Coefficient of Performance for heating is higher than the Energy Efficiency Ratio for cooling. Both of these numbers refer to the ratio of heating or cooling delivered, divided by the amount of input electric energy. To split the result between heating and cooling requires more information about how the building is performing over a year. This information can be found from an Energy Rating Report or a NatHERS Universal Certificate.

3. Energy Costs Differ

There are a range of domestic tariffs available from different suppliers in each city. The rates vary depending on the type of account and metering arrangement. Have a look at your electricity account and find the energy charge in c/kWh (or $/kWh). On the electricity account there will be other fees or charges, per day or per bill, which are not energy-related.

Table below shows representative electric energy rates as of 1 December 2016. Electricity prices were for domestic (residential), marginal (last consumption band), all usage (not time of use) including GST. Time of Use tariffs could be more or less depending on whether the period was peak, shoulder or off-peak.

In summary, the Energy Rating of a home is a rough guide, giving only the likely electricity cost for space heating and cooling. The Energy Rating helps ensure buildings built in each climate achieve similar indoor comfort levels.

With the regulatory level for NatHERS set at 6 Stars, think of this as being “OK” (it meets the required minimum performance). Think of 7 Stars as “Good”, 8 Stars as “Great”, 9 Stars as “Exceptional”, and 10 Stars as “Amazing”!

As the regulatory stringency may increase over time, there will be a higher need for skilled, professional energy consultants to advise clients on how to improve their building’s performance. Anderson Energy Efficiency is here to do that with you.

The post Turning Star Ratings into Dollars appeared first on Anderson Energy Efficiency.

• Increase the insulation?
• Increase the efficiency of the compressor motor fans & lights?
• Or reduce the amount of infiltration (air leakage)?

Dr Clyde Anderson and Certified Energy Efficiency Assessor Michael Anderson have written an in-depth report comparing the energy consumption between existing and proposed-design walk-in Coldrooms with various options applied.

Read the full report on Walk-In Coldroom energy efficiency now

It’s a great read, but if you’re short on time here’s a quick summary:

1. There is a proposal from the Equipment Energy Efficiency Committee (E3) of the Australian and New Zealand Ministerial Council on Energy to regulate elemental parts of Walk-In Coldroom systems.
2. Rudimentary thermal modelling was included in the proposed 10 year strategic Draft proposal “In From the Cold… ”.
3. Manufacturers of insulation products — through the industry governing body “Expanded Polystyrene Panel Manufacturers Group” — are planning to make a submission to the Committee regarding the benefits of the proposed insulation increases.
4. Our Report addresses only the proposed changes in minimum R-value insulation of wall, ceiling and floor panels. It shows that increasing insulation R-value will only slightly reduce the energy consumed in Walk-In Coldrooms.
5. There are many transient heat loads that are part of operation of WICs that are difficult to include any energy efficiency regulation.
6. Compared to steady-state (closed box) heat transfer, one important factor in the calculation of total kWh energy is the loss of cold air due to door opening (infiltration).
7. Increasing only insulation will not achieve the expected overall benefits as the envelope heat transfer is only a small percentage of the total heat load.
8. Infiltration should be addressed before increasing the R-values of Walk-In Coldroom envelopes, as this would give a more cost-effective energy reduction.
9. A holistic, total system approach to efficiency certification of WICs is advocated since the incorrect application of efficient components can result in an inefficient design.
10. Performance-based assessment under a National regulatory body like the Australian Building Codes Board, is appropriate for WICs.

Disclaimer: whilst the data in this Report is provided with reference to calculations and computer simulations, it is only as good as the information provided plus the assumptions used in the simulations and is generic in its recommendations. Naturally, this may not reflect your specific building or simulation scenario. Alternative data & assumptions, different building designs & building fabric will produce different simulation results. If you’re interested in optimisation for your specific building, we offer full Commercial Energy Efficiency Assessments as well as thermal simulation consulting. Contact us for more information.

Read the full report on Walk-In Coldroom energy efficiency now

The post Refrigerated Walk-In Coldroom Comparisons Report appeared first on Anderson Energy Efficiency.

1. Incomplete Building Information

To get us started on the Energy Efficiency Assessment for your project, our assessors need to know certain details about the building. This information is best given to us by completing our Energy Efficiency Check List. Generally, we can’t proceed with a job until we have a completed Energy Efficiency Check List.

If the Check List or the provided drawings/specifications are incomplete, the project may be put on hold until we receive this information.

Whilst some special arrangements can be made for urgent jobs to commence without a Check List (or with a partially completed Check List), we would have to assume some temporary “default” settings on all building elements until we receive more information. As you’d expect, because every building is different these defaults are unlikely to be a perfect match for your project. This results a delay as we’ll have to enter some data twice, and we can only issue a Report once all the data is entered correctly.

2. Missing Drawings

In the early stages of a project we may use Development Approval (DA) drawings to calculate a fee proposal, however DA drawings are usually not detailed enough to be used for Assessments. For example; sections are needed to calculate ceiling heights – if no sections are available then a default worst-case of “no ceiling” may have to be selected.

If a major plan or drawing revision occurs, the Assessment result could also be affected. Frequent revision changes that can impact an Energy Efficiency Assessment include: roof form, building height, location & size of glazing, and the location of fire access-ways & plant rooms (non-conditioned spaces). In some cases an assessment calculation may need repeating, causing a delay. Redoing calculations for a major design revision may also incur additional costs not included in the original fee proposal.

Further delays can also be caused if the lighting plan or wattage schedules are not provided. While we can “skip” this section in our Report, Artificial Lighting is part of the Energy Efficiency assessment process. If lighting details are not included then the lighting will need to be assessed separately by an illumination consultant or electrical engineer.

3. Changing Building Specifications

As the project develops, the specifications of external colours, insulation or glazing can change for various reasons. Unless this is communicated to the assessor, the building being assessed may not have the correct specifications.

If the change involves lots of manual corrections, a re-calculation for changed specifications may take a few days. Having the latest information before the assessment is started is very important so that the building gets the correct assessment result the first time. It may be better to place a hold on your project, pending release of updated information, rather than have the assessor do unnecessary calculations.

4. Difficulty in Contacting Client for Feedback

In the course of the Energy Efficiency Assessment, we may have questions about your project and need to contact you. For example, the original building specifications may need to be changed to achieve a Building Solution.

These changes must be approved by you before the Energy Efficiency Report is printed. Delay in obtaining this approval could set back your assessment result. Naturally, we will do our best to contact you via phone and/or email ASAP. However if you are unavailable or out of the office for a few days, do not return our call, or your contact details have changed, then your Energy Efficiency Assessment could be paused until any questions we have are clarified.

So there you have it folks! Providing our assessors with a full set of the most up-to-date drawings, a completed Energy Efficiency Check List, keeping us informed of any design changes, and getting back to us promptly are the best ways to get your Energy Efficiency Assessment progressing sooner.

If you have any concerns or queries about the progress of your Energy Efficiency Assessment please don’t hesitate to call our office or send us an email!

The post What Can Delay My Energy Assessment? appeared first on Anderson Energy Efficiency.

Energy efficiency assessments can be performed in several different ways – each with their own strengths & weaknesses. Firstly, there is the Deemed-To-Satisfy (DTS) Energy Efficiency Building Solution. To achieve compliance through a DTS assessment, every individual element of the building must comply with the National Construction Code Section J (Energy Efficiency).

An alternative assessment method is the Verification Method (JV3) to find a Building Solution, which is more complex.

So what’s the difference?

While the DTS method requires all components to individually meet the Code, the JV3 method instead checks that the whole building complies with the NCC Objective JO1 “…to reduce greenhouse gas emissions”. This is done by first creating a computer simulated three-dimensional model of the building – everything from the interior wall cavities to the individual blades on a window shading device are replicated in the 3D model.
Once that’s done, we run a simulation that uses actual historical weather data from a nearby weather station to determine the building’s temperature for every hour of a whole year. In addition to calculating the transfer of heat through the building, the simulation includes the extra heat load created by the building’s occupants and electrical equipment according to JV3 modelling conditions.

The simulated building must also contain Section J-compliant HVAC and Artificial Lighting to calculate the building’s total Annual Energy Consumption (kWh). The “verification” of the building then occurs through the simulation of a Reference Building that complies with all the DTS elemental Requirements.
The calculated Annual Energy Consumption (kWh) of the Proposed Building must be less than the kWh of the Reference Building to achieve a Building Solution according to JV3. If this is all getting a bit confusing or you’d like to know more about the JV3 Assessment Method, check out our more in-depth article explaining Verification Method JV3.

Meanwhile, a DTS-compliant building doesn’t require the above complicated simulation. Every element of the building must comply independently, and there is no trade-offs between areas or any wiggle-room. Fantastically high-performing quadruple-glazed low-e tinted windows won’t do anything for your insulation requirements, and increasing the total insulation can’t be used to avoid installing roof raisers or spacers to prevent your insulation being squished by purlins.

DTS assessments are quick & easy to calculate but in almost every case, a DTS-compliant building will cost more and won’t be as efficient as a JV3-compliant building.

A DTS-compliant building must include all of the following:

• Insulation complying with Part J1.2 as a “continuous barrier” including under box gutters, walls above uninsulated ceilings, colour-backed glass or fascias, and internal walls to non-conditioned areas.
• Reflective foil insulation, if used in your design, must be installed with the manufacturer’s specified airspace gap.
• Roof or wall bulk insulation must be uncompressed, so roof raisers or spacers will be required if your insulation will be squished.
• Roof and Ceiling insulation (complying with Part J1.3) must have added internal ceiling insulation to an unconditioned space above.
• External and internal wall insulation must comply with Part J1.5 which gives you a limited ability to benefit from the passive cooling of thermal mass walls, and no ability to reduce or avoid adding insulation to envelope walls.
• Floor insulation must comply with Part J1.6 which means there is no ability to maximise the thermal mass benefit of concrete floors, nor the ability to reduce or avoid adding insulation to envelope floors including soffits to conditioned spaces.
• Glazing for each orientation façade must comply with the DTS glazing allowances, which depend on Climate Zone, façade area, glazing type (Uw and SHGCw) and shade.
• Roof Lights may need better thermal specifications, and the total amount must be no larger than 5% of floor area.

All of these DTS requirements will add significantly to the overall construction costs. Many of these restrictions become irrelevant in a JV3 assessment since the building’s elements can instead be modelled exactly, with their benefit or detriment calculated exactly for each specific project.

In short, because the Annual Energy Consumption is calculated to be less than the DTS-compliant Reference Building, a JV3-compliant building will always be more energy efficient than a DTS-compliant Reference Building. Yes, really – always!

What’s more, a JV3 Building Solution is able to take the increased information into account to optimise the building’s design by trading between elements, reducing the construction costs with less insulation than a DTS assessment requires. We won’t say “always” for this one because there can be the very rare outlier case, but almost always, a properly-optimised JV3-compliant building will be cheaper to build than a DTS-compliant building.

It might not seem possible, but you achieve both of these things at the same time. For more information about thermal trading between building elements, check out our presentation to the Australian Institute of Building Surveyors 2013 annual conference where we covered some Energy Efficiency Case Studies.

So why would anyone ever pick the Deemed To Satisfy assessment method?

A DTS-compliant building is much easier to spec out in the early design phase, since it’s an easy way to make sure a design will comply with the Code’s energy efficiency requirements. This makes it easier to estimate the total project cost too, since you already know what quantity of insulation you’ll be using before you’ve even locked down the floor plan. Some HVAC consultants also prefer a DTS building, because it’s straightforward to calculate the maximum heating & cooling loads based on the thermal conduction of different building elements.

They are skilled at calculating the required temperature/humidity conditions (summer and winter), which is similar but not quite identical to our calculations. Calculating the Annual Energy Consumption accounts for the thermal mass, the effects of solar radiation, as well as heat transfer on an hourly basis.
There’s a lot of debate over which method is more accurate & that’s a topic for another article. However, since the sizing of heating & cooling devices is part of our thermal simulations, we include our calculated kW in our Energy Efficiency Reports – you can use these to compare with the HVAC designer’s calculations if you like. Curious about what else we include in our reports? Have a look at our article showing how to understand your Energy Efficiency Report.

Are the NCC Section J DTS measures wrong?

Absolutely not – the Code is never wrong! We don’t mean that in a head-in-the-sand way either, since we’ll be the first to say something when we think the Code isn’t right and we regularly submit changes for review. We think the DTS assessment method is valuable & its requirements are at the levels where they should be.
However, like most other experts in the industry, we don’t think the DTS method should be relied upon as a design tool for a highly energy efficient building. Doing that requires optimisation of the total building using a thermal simulation. The reason for Section J in the first place was to overcome a “market failure” where the people who pay for energy consumption were not adequately encouraged to improve the building to achieve energy savings & reduce their greenhouse gas emissions. Hence the Code stepped in to address this imbalance.

A building that complies under JV3 is not “inferior” to a building that complies under DTS. True, a JV3 assessment can achieve a Building Solution without complying with all the strict DTS elemental Requirements – but that’s exactly the point of JV3 assessments.

Are all the DTS Requirements needed, and are they cost effective? If you ask the question “is a DTS-complying building a highly energy efficient building?” our answer for most projects is no, with the rare exception for a few number of projects in Climate Zones 6 & 7 (Canberra, Melbourne & Tasmania) which have a higher demand for heating energy. However, in these climates it is still possible to avoid some of the DTS-required insulation while achieving a Building Solution using JV3 that lowers the total construction cost.

Our clients have reported savings of tens of thousands of dollars in construction cost with our JV3 assessment reports, compared to a DTS-compliant building. In fact, it’s not uncommon for us to save a client over a hundred thousand dollars on a large project. Here’s an example similar to past jobs.

A JV3 assessment might cost more than a DTS assessment but it well and truly pays for itself. The savings are worth several times the investment in our Energy Efficiency consulting expertise, resulting in an incredibly quick return on investment.

If you are interested in reducing the cost of construction on your project compared to a DTS assessment while still maintaining a highly energy-efficient design, then the JV3 Method is right for you! Contact us for a competitive fee proposal.

The post JV3 vs DTS: Construction Cost Savings! appeared first on Anderson Energy Efficiency.

Confused about the meaning of some of the words & complicated jargon in our reports? We’ve also compiled a handy list of terms used in the Energy Efficiency Industry with definitions of the more common phrases — from α (greek alpha, the Solar Absorptance of a surface which is based on its colour) to U-value (the Thermal Conductance of a material). It’s a great reference to jog your memory.

We issue four main types of Energy Efficiency Reports:

• Star Rating for Houses & Residential Units
• DTS Compliance Report for Houses & Residential Units
• DTS Compliance Report for Commercial & Industrial Buildings
• Verification Method JV3 Report for Commercial & Industrial Buildings

Residential Star Rating Report Format (Class 1, 2 & 4)

Page 1:

• Project address & drawing details are listed at the top.
• A statement that the software used in the thermal calculation complies with the relevant Protocol.
• In the summary section, we list the assumptions made for the Proposed building based on the information provided in the Energy Efficiency Check List, Drawings & Specifications. Where an element of the proposed building has been changed (with client approval) in order to achieve compliance, the change is highlighted in Italic. For multi-residential projects, this information may be provided in a table.
• Finally, a Statement of the Requirement & the result of the assessment that shows it complies to the relevant Performance Requirement. This is signed by the assessor.

Page 2:

• The certificate generated by the software displaying the Star Rating is shown. There is also a table showing the individual Star Rating per Zone in the building, or per Unit in a multi-residential project.

Page 3:

• Form 15 Design Compliance Certificate, with our secure hologram sticker showing this is an original Report.

Residential DTS Report / Commercial DTS Report Format

Page 1:

• Project address & drawing details are listed at the top.
• There is a table listing each assessable element, the requirement, the proposed properties of the building & whether or not it complies. The proposed insulation is noted below the table.
• A Statement of the Requirement & the result of the assessment that shows it complies to the relevant Performance Requirement. This is signed by the assessor.

Page 2:

• Form 15 Design Compliance Certificate, with our secure hologram sticker showing this is an original Report.

Commercial JV3 Report Format (all Classes, excluding residential)

Page 1:

• Project address and drawing details are listed at the top.
• A statement that the software used in the thermal calculation complies with the relevant Protocol.
• We may include the type of activity schedule used in building modelling e.g. “The building was modelled as a Restaurant/Motel/Office”, etc.
• We state the number of zones in the building & which zones were included or excluded.
• In the summary section, we list the assumptions made for the proposed building based on the information provided in the Energy Efficiency Check List, Drawings & Specifications. In the square brackets are the Reference Building properties that follow the JV3 conditions. Where an element of the proposed building has been changed (with client approval) in order to achieve compliance, the change is highlighted in Italics. Where an element of the proposed building does not meet Deemed-to-Satisfy requirements, they are highlighted in bold.

Page 2:

• A table shows monthly & annual elemental heat transfer totals – positive figures are heat (energy) flow in or energy consumed, while negative figures are heat (energy) flow out. The Annual Energy Consumption is listed in the last column.
• Below the table is a statement of Annual Energy consumption comparison between the proposed & the Reference Building. The calculated lighting Allowances for the proposed building is given, or where a lighting plan is supplied the percentage of the Allowance is listed.

Page 3:

• Form 15 Design Compliance Certificate, with our secure hologram sticker showing this is an original Report.

A combination of using the approved software, with the correct procedures by competent persons means the building gets the assessment result it deserves (whether good or bad). It also means that any problem areas are genuine so trouble-shooting is accurate & effective. There is no substitute for experience & knowledge in providing quality consulting on building energy efficiency. This is included in our fee at no extra cost.

We guarantee to always find a Building Solution. If any changes are needed, the lowest-cost options are suggested for client approval & inclusion in the Report. If you have any questions about your report, feel free to contact us. We’ll be happy to answer any queries.

If you’re looking for an Energy Efficiency Assessment performed by someone reliable, with a report presented in a simple way to make your job easier, contact us for a competitive fee proposal.

The post How to Understand Your Energy Efficiency Report appeared first on Anderson Energy Efficiency.

To assist in calculating the R-value of compressed roof insulation, we’re releasing for free this handy tool to crunch the insulation compression value for you. This can be used to accurately work out the thickness of installed insulation required under a building’s roof to meet the requirements of the National Construction Code or your Energy Efficiency Assessment.

The post Roof Insulation Compression Calculator appeared first on Anderson Energy Efficiency.

A house’s Star Rating is calculated from the total annual energy required for the house to stay at a comfortable temperature all year long. This is done by a computer simulating the building in one of a few different software packages that calculates everything thermally relevant to a house. This computer simulation is not just for the building itself, but includes extra details like the geographic location for sun angles, the local climate, assumed average occupancy of individual rooms, the heat given off by appliances in different rooms, and importantly, the thermostat settings for the cooling & heating system.

The software’s Cooling thermostat (the hottest a room can reach before air-conditioning cooling is applied) varies across Australia & ranges from 22.5°C to 28°C. The software then increases this maximum value proportionally in each room depending on the amount of airflow in the room – whether from windows, ceiling fans or even a stack-based passive ventilation system – because people can tolerate a higher temperature if there’s some airflow cooling them down. The Heating thermostat (the coldest a room can reach before heating is applied) is much more rudimentary – it’s set according to the type of room & the time of day, but it’s normally around 20°C for living spaces during daytime.

The simulation software uses a full fluid dynamics engine to calculate how much energy is used to Heat & Cool the building for every square metre of floor area, for every individual room, for every hour of every day, for the entire year (phew!). The end figures are given in raw MegaJoules of heating & cooling energy required per square metre, or MJ/m². The total of these two numbers is used to calculate the building’s final Star Rating. A higher Star Rating will have a lower total Cooling + Heating value (it uses less energy).

Keep in mind that this is just an estimate of your predicted heating & cooling costs, assuming an “average” lifestyle. Everyone lives differently so it won’t be a 100% match but it’s a good ballpark figure. It also doesn’t include any other appliance running costs, just your air-conditioner/heater.

Now that that’s out of the way, here’s how to convert a Star Rating to Dollars:

1. Find the house’s separate Cooling MJ/m² and Heating MJ/m² values (not the combined total) from the Energy Efficiency Assessment Report, or if it’s not on the report ask the Energy Assessor for these numbers from their calculations.
2. Find or calculate the “conditioned” floor area (this should also be on the Energy Efficiency Assessment Report). The conditioned floor area is the floor area that is normally air-conditioned. This number is the floor area of all “habitable” rooms (excludes Garages, Verandas or Patios, Laundries & Bathrooms, but including Ensuites attached to Bedrooms). The conditioned floor area will be different to the total floor area on the plans since the total floor area includes these rooms that aren’t “conditioned”.
3. Multiply the Cooling MJ/m² by the conditioned floor area then divide by 3.6 to get the kilowatt-hours (kWh) of Cooling energy. Likewise, multiply the Heating MJ/m² by the conditioned floor area then divide by 3.6 to get the kWh of Heating energy. These are the raw “displaced” energy numbers – they represent just the amount of raw cooling/heating energy displaced, not the amount of energy used by an air-conditioner to actually cool or heat your home. We still need to apply an Energy Efficiency Ratio to get the actual values.
4. This next part depends on how you heat & cool your home.
   • If you have a reverse-cycle air-conditioning (a/c) unit, you need to find the Cooling Energy Efficiency Ratio (EER) and the Heating Coefficient of Performance (COP). These are different numbers because reverse-cycle heating is more efficient than cooling. You can find these numbers from a few different sources:
     • The identification sticker on the a/c unit itself or the “Appliance Star Rating” sticker. However the Appliance Star Rating stickers in particular are often removed on installation, damaged or too faded to read
     • The manufacturer’s brochure that came with the a/c unit, or on the manufacturer’s website
     • Go to www.energyrating.gov.au and search for your a/c system’s make & model. if you have a split system air-conditioner make sure that you match up both the indoor & the outdoor model numbers, as they can be different
     • If you can’t find your system’s details but you can remember its Star Rating, you can use some generic numbers. A 0 Star a/c unit has a cooling EER of 2.25, and it goes up by 0.5 for each extra Star. So for a 4 Star unit, the EER would be 2.25 + (4 × 0.5) = 4.25. The same values apply for heating COP too

     If you don’t have an a/c unit or you can’t find it’s Star Rating, then use an EER of 2.9 (1.3 Stars) for Cooling & a COP of 3.2 (1.9 Stars) for Heating.

     
   • If a heater is not reverse-cycle (e.g. a radiator, oil-filled convection heater or a portable electric fan heater) then the COP equals 1.0.
   • If you have another type of cooling or heating system (gas/wood/kerosene heater, evaporative cooling, stack-based ventilation, passive solar cooling/heating, geothermal, etc) then the Star Rating can’t be directly converted to dollars. You will still need to know your system’s EER/COP values and the fuel cost, but you’ll also need to know the estimated number of hours spent cooling or heating. This is not easily available as it isn’t provided as a standard number on Energy Efficiency Assessment Reports. However it can be calculated by a skilled thermal assessor – contact us if you would like us to simulate your house & provide you with these numbers.
   • Divide the displaced Cooling kWh (from step 3) by the Cooling EER, divide the displaced Heating kWh by the Heating COP, then add these two numbers together. This gives the annual electricity consumption in kWh.
   • Find a recent electricity bill & find your Tariff cost in c/kWh. If you can’t find a recent bill, the standard domestic electricity Tariff 11 in Queensland is around $0.30/kWh (June 2014 prices). Multiply this cost by the annual electricity consumption. This is your estimated annual heating & cooling bill. And there we have it, phew!

Here’s an example house: imagine a 5-Star house with a conditioned floor area of 230m². This house has an Annual Cooling Energy of 29MJ/m² and an annual Heating energy of 26MJ/m². The Air Conditioner is Cooling-only with a 4 Star Rating & they have some portable electric fan heaters for winter.

Now let’s imagine a 6-Star house with a conditioned floor area of 180m². This house has an Annual Cooling Energy of 18MJ/m² & an annual Heating energy of 24MJ/m². The Air Conditioner has a 5 Star Rating for Cooling & a 5½ Star Rating for Heating.

The first house costs nearly 5 times as much to keep comfortable – and at first glance, there doesn’t seem to be any huge differences between the two houses!

If you’re building a new house, here’s some things you can do to save money on the heating & cooling bills:

• Try to avoid building a larger house if you don’t need the extra space. It sounds simple, but every extra square metre of floor area is another square metre that has to be conditioned (this will also save you lots of money on construction costs!)
• Use smaller windows where possible (but make sure you still have enough natural ventilation; this will save money on construction costs too since walls are usually cheaper than windows)
• If you must use large glass areas, consider low-e glass or even double-glazing. In some cases it is difficult to achieve a high Star Rating without using high-performance glazing
• Build dividing doors into the house wherever practicable (especially stairwells) so unused areas can be closed off when people aren’t occupying them
• Apply weather seals to all external doors & windows. Remember that a weather seal only on the bottom of a door may stop the rain, but it won’t stop air leaking through the remaining 85% in the other three edges!
• Make sure the insulation is of a suitable thickness & is properly installed. Avoid downlights or use downlight covers so the ceiling can still be properly insulated. Small holes may look insignificant but they quickly add up – imagine how well a boat would float if it had many small holes in its sides
• Install thick drapes with a box pelmet – this not only helps block external sounds for a quiet night’s sleep, but it nearly triples the average window’s effective insulation value

If your house has been already built, here’s some things you can do to lower your home’s heating & cooling bills:

• If the temperature outside is cold enough or hot enough that you’re shutting the windows & turning on the heater or air-conditioner, shut all the doors in the house except for the rooms you’re living in to avoid heating or cooling unnecessary rooms
• Avoid using portable air-conditioners or heaters. These normally aren’t very efficient & consume a lot of electricity for a small amount of air-conditioning or heating, sometimes as much as six times as a similar capacity fixed reverse-cycle air-conditioner/heater
• Try to dress appropriately for the weather – this doesn’t mean you have to be freezing in your own home, but putting on a warmer jumper & lowering your heating thermostat by just two degrees can save you up to 30% on your heating bill
• Turn off your appliances at the wall when not in use, especially in summer. A lot of appliances still consume electricity when on standby, and every extra kilowatt-hour of heat being generated in the house is another extra kilowatt-hour of heat the air-conditioner will have to remove
• If you don’t have ceiling or roof insulation, consider installing some. R3.0 is a good price/performance value for retrofitting to an uninsulated home
• Consider swapping your existing curtains or blinds to thick drapes with a box pelmet – this not only helps block external sounds for a quiet night’s sleep, but it nearly triples the average window’s effective insulation value

If you’re interested in a full thermal simulation of your house to find some suggested renovation improvements, making your new building extra-efficient or even just some help making your dream design comply with the building code, contact us for a fee proposal.

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Your JV3 Report Should Include:

• Details of ABCB Protocol-compliant software used. Our JV3 reports are assessed using the most up-to-date version of DesignBuilder™ software.
• Notice that the calculations have followed the JV3 conditions (see below), including if they were performed on plans as supplied or modified, and for a Reference Building also in strict accordance with the JV3 requirements. All our assessments meet these requirements.
• The assessor’s details, stating that the assessment has been carried out by a trained, competent person. All our assessors have professional engineering qualifications & have been fully trained.
• A statement of the quality assurance & continual improvement system in place. We have a fully certified
  ISO9001 Quality Management System with documented assessment procedures which helps drive our quest for continual improvement in our professional consulting services.

Conditions for JV3 Thermal Simulations

A proper JV3 Assessment should have the following settings in the software:

• 3D model of the building in correct location, orientation and weather.
• Schedules for occupancy, internal heat loads, lighting and HVAC system.
• Simulation for 8760 hours (every single hour in a whole year), with an operating schedule of at least 2500 hours/year.
• Calculate aggregate heat transfer & cumulative energy consumption.
• Thermostats should be set at 18°C to 26°C. Note that these are wider than a typical building’s actual thermostats.
• Air conditioning plant and Artificial Lighting complies with NCC Parts J5 and J6.
• The air conditioning & heating Annual Energy Efficiency Ratio (AEER) must comply with NCC Performance Requirement JP3, while the cooling AEER must comply with MEPS (see energyrating.gov.au for more info).
• The HVAC Design Factors used were 1.0 for 98% coverage — actual systems will have a higher design factor to account for sizing, redundancy, maintenance & response.
• The fresh air rate is 10L/sec/person or as per AS1668.2. The Infiltration rate is 1.0 air changes/hour for the perimeter zone while the HVAC plant is operating.

The simulated Reference Building should be identical to the actual building except for the following conditions:

• Solar Absorptance (a) of Walls = 0.6 & Roof = 0.7
• DTS-compliant insulation in all envelope elements (roof + ceiling, walls, floor)
• DTS-compliant glazing to all orientations (including roof lights)
• All other conditions match the proposed building

The report should specify which elements do & don’t comply with DTS . In assessing the roof R-value, compression of the bulk insulation at the purlins needs to be either prevented by the use of spacers, or the reduction of the insulation’s R-value needs to be calculated. This can get very tricky and is very hard to get a correct answer, so as a service to the entire building industry, we provide a completely-free roof insulation compression calculator! The underlying algorithms have been adapted from the raw data plots from CSIRO research papers & the whole calculator is as accurate as we could make it (Regression Coefficient >0.9992). If you can’t get your insulation’s compression performance from the manufacturer (and many can’t supply it), our calculator is a great substitute.

In a Verification Method JV3 assessment, not all elements have to comply with DTS in order to achieve a Building Solution. So long as the Annual Energy Consumption for the proposed building is less than the Reference Building, that’s considered an acceptable Building Solution & it complies. Even if the proposed artificial lighting & air-conditioning don’t comply with DTS — it’s all about the Annual Energy Consumption of the whole building, not individual elements!

This can be used to create solutions that would never comply with DTS to obtain a certain architectural look, for example a building having a very large glazed area but offsetting this with increased wall & ceiling insulation. A JV3 Assessment can also be used to obtain significant construction cost savings. For example, if you have better-than-average glazing this means you can get away with reducing (or in some cases even eliminating) your wall insulation, so long as the Annual Energy consumption is still less than the Reference Building’s Annual Energy consumption. We’ll be providing another article soon about the construction cost savings between DTS & JV3 Building Solutions. Sign up for our free Newsletter to receive a copy before it hits our website, along with other regular hints, tips & guides.

Quality is Important

You can have confidence in our experience and expertise. We’ve been providing energy efficiency assessment services to the construction industry for over fifteen years. During this time we’ve carried out Energy Efficiency assessments for thousands of projects, from small detached houses to large multi-residential and commercial complexes. We aim to provide the highest level of professional technical service appropriate to the task at hand, including advice for our clients on understanding what an energy efficiency assessment means and how it should be implemented. If you are interested in a Deemed-To-Satisfy, Thermal Calculation, Verification Method or Reference Building assessment for your new building, contact us for a competitive fee proposal. We deal in both Residential and Commercial work throughout Australia, from tiny 1-room house extensions to entire shopping complexes.

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