There are principally three methods it seems. One is the Supply method (used by manufactures) and this usually gives a higher efficiency value than the real world values. The Extract efficiency method is used to give a closer to real world value and then the passive house efficiency method which adds the following formulae to the Extract efficiency method.
Pel = real electrical power, W
M = mass flow, kg/h
Cp = specific heat of the air, kJ/kgK
The good news is that it appears if the HRV is certified to the Passive House standard then the difference between the supply method and the extract method is very small.
In the near future I plan to connect to the HRV unit I purchased and view the efficiency values.
The Passive House certificate shows the following
The most cost efficient unit I came across was the Airflow DV145 passive house certified unit for our 200 m2 house with an airflow capacity of 542 m3/h. I paid around €2200 for it. If one has a smaller floor area then more savings can be made by using a smaller unit. As a self builder technical support was important and their main offices are in the UK.
If one opts for a non-certified HRV unit a 12% reduction must be applied to the manufacturers specification . Some manufacturers might not renew the certificate each year so it is a good idea to ask if a certificate exists. The data must be entered in the planning software for the passive house. For those interested in the passive house planning software (PHPP) there are courses run in Ireland frequently so I would suggest that one does this 3 day course (typical) and usually one finds the software discounted on the course.
It is an enjoyable course where one can select your own pace (the first time I did the course I wanted to listen and learn rather than calculate the performance of our own home). One such place is http://www.passivehouseacademy.com/
There are two types of HRV units that I came across -Heat (HRV) or Energy (ERV). The ERV is used principally for recovering humidity and heat. I selected a HRV unit,
When selecting a HRV unit it appears that one of the biggest mistakes is to select a unit that is too small but still satisfies the current regulations. What appears to happen in the competitive world of quotations is that a unit that just ticks the box comes in as the best price.
In selecting a unit for our home I selected a unit that has a manufacturers capacity of 542m3/h where the floor area of our house is 205 m2. Currently the unit is running at 31% of its capacity and it is maintaining a CO2 (Carbon Dioxide) level of around 700 ppm when the four of us occupy it . I use a stand alone CO2 sensor to measure the CO2 in different rooms. (I have not commissioned the unit yet as the internal doors/glazing are not installed).
Another advantage of selecting a larger unit is that it can run more efficiently at lower speeds and generates less noise through the ducts or from the unit itself.
Some of the options from the manufacturer Airflow (my unit is the third from the right).
September 2018 performance (with no heating switched on yet).
The graph below gives an idea of how the HRV works when managing heat from the house and supplying fresh air. For the coldest days of the year so far (2 degrees at night-in September) I put the unit into summer bypass mode the next morning (take in outside air directly and pump it around the house) because the sun was shining that day. The winter sun is lower in the sky so solar gain increases in the winter (when the sun shines). The house is made of timber/glulam construction. The main thermal mass is the concrete floor at the moment soon to be covered by a 32 mm thick wooden floor so the response times of house I suspect will change. The floor and wall temperatures are approximately 22 degrees Celsius.
Example above of HRV in use in our home.
Sample Data in our home using Google Fusion to visualise the HRV data for a week in October. (see link below)
One can select the chart tab and visualise the graph.
Use the bottom graph to zoom in.
The data is from the 21 October to the 28 October 2018.
One storage heater rated at 1.7kwh was used for 5.5 hours a day off peak.
The storage heater was switched off for one day on the 23rd October.
The graph starts at midnight on the 21 October.
Each ref reading is every 10 minutes.
The CO2 reading vary between 480ppm and 700ppm when fully occupied.
All HRV units contain a maintainable part called filters. They have a number of functions.
Clean the air being pumped into the house, and
Keep the internal components such as fans, ducts and HRV housing clean.
One typically finds one coarse filter and one fine filter on the air supply into the house and a coarse filter on the extract air from the house before the extract fan. The coarse filter is typically a G4 and the fine filter is a F7 (Pollen filter). I installed a 400mm x 400mm G4 coarse filter at the duct inlet so that I could keep the main supply duct clean. It is a bit more effort to maintain this but it will hopefully minimise the maintenance of the duct.
Self Build air tightness test -0.22ach with a volume of 603 m3 @ 50 pascals.
When one is building to a performance standard the day of reckoning is the airtight test. The reason for this is that when one is pumping fresh air into the house using a Heat Recovery System, rather than relying on simple multiple holes in the wall, it becomes important to control where the fresh air is coming from and where the heat is going.
If air is leaking in or out around windows /doors/walls or other gaps in the building fabric then heat is lost and moisture problems in the form of mould can arise or else give rise to damage to the building fabric.
The pressure 50 pascals equates to a 20 mile per hour wind which is not too untypical in Ireland. So if one opts for the Irish building standard (a minimum standard) this equates to the air in the house changing/leaking 7 times a hour when a wind blows at 20 miles per hour. No wonder people block up the hole in the wall vents .
The current Irish building standard require 7 air changes per hour (ach) also called leakage at 50 pascals typically with no heat recovery system. As a guidance heat recovery manufactures recommend 3 Air leakages per hour to ensure that the heat recovery system can push fresh air into the house and recover heat leaving the house through its own system rather than through gaps in the building fabric.
The passive house standard for a new house requires 0.6 Air changes per hour (ach) at 50 pascals to ensure the heat recovery system works efficiently, ensure that occupants receive the correct amount of fresh air and minimise building fabric damage.
The passive house test differs from the Irish test because it must include pressurisation and depressurisation and use the volume as set out per Vn50 (EN13829).
Gavin O Shea from Greenbuild was hired for the job. He is certified/audited by the National Standards Authority of Ireland (NSAI).
The preparation for this entailed sealing all cable ducts and the inlet and outlet pipes for the Heat Recovery System. One also ensures that the shower and sink outlet traps are full of water. The overflow outlet for two water tanks were not sealed off. I did consider a duck valve but it was not in place at the time of the test.
The test using the Irish method gave a result of 0.181 m3
Gavin O Shea calculated that the equivalent size hole that equates to a result of 0.22 ach is approximately 65.25 cm2 (@50Pa) or a hole 81mm x 81mm if all of the leaks present in the dwelling were concentrated into one hole. That is about a tenth of an A4 sheet of paper.
The results of the air tight test can also help determine the selection of the Heat Recovery System. If the airtight test is lower then more options are available when selecting a unit.
From my research a passive house standard Heat Recovery Unit will cost more because it needs to be independently tested by the Passive House Institute using their test method. Heat Recovery manufactures have also the burden of putting the unit through national tests or international tests with the end result being the customer pays more. One has also the option to select a non passive house certified unit for a passive house but when calculating the performance value one needs to account for this in the PHPP software with a 12% reduction below the manufacturers performance claim.
If one wants to view certified Heat Recovery Units one can find and sort them at the following link. One can see for example at this link the capacity (Column- Air Flow Range) that these units have as it is important to select a unit that is oversized for your particular self build. I would compare it to selecting a mini car to tow a caravan up a hill compared to using a larger car. The small car will struggle from an efficiency and noise point of view while the larger car will be quieter and more efficient at the require flow rates. I will do a separate post on how I selected our Heat Recovery Unit.
Having carried out some DIY painting in the past I decided this time I would invest in good tools as this was going to be the biggest job to date. This first entailed selecting a brand whose painting equipment is rated highly. I selected tools from the Wooster product range.
There are a few essential tools.
The Pole (I selected a 4 to 8 foot adjustable pole called the Wooster Sherlock GT extension pole ). This tool has a few good features such as snap on paint roller head, an extension that snaps in set positions, a tool to fit screw type paint rollers. A substantial rubber hand grip that made the job easier . The highest point of our ceilings are 3.6 metres and this version allowed me to reach the ceilings directly from the floor. Narrow hallways that are less than the length of the pole plus the roller would make it difficult to use this pole length.
Rollers– I selected a 3/8 inch nap (pile depth) for the plasterboard because of its smooth surface and I tried a 9 and 14 inch roller called the pro-doo-z. The Nap determines the amount of paint applied and the paint texture of the wall surface . The 3/8 inch gives a fine finish. If one used a 1/2 inch nap the roller can hold more paint but the texture is different. After trying the 9 inch and 14 inch roller my preference was to use the 14 inch roller as I found it easier, faster and more stable because it is supported at both ends (see below). I would be tempted to try the contract rollers that are supposed to be faster the next time but the finish may not be the same. One can select the right roller from the web site link Wooster Rollers.
Cutting In– A very useful and time saving tool was the Wooster hand-held Pelican kettle .
It is available with liners to make it easy to change colours. It has a section to hold a cutting in brush and a mechanism to hold a small roller. Both of these are necessary in order to end up with the same wall surface texture as the main roller for example around switches and sockets. I used non diluted paint for the cutting in process. One needs a mini roller also for the Pelican holder.
Brush– The cutting in brush I used was the Silver tip wooster 2 inch model. I never owned a high quality brush before and it is working out great.
Tray/Kettle-I tried the Tray and the Kettle. My preference is the 25 litre Kettle with replaceable liners. I initially bought a Kettle with no liners and the washing out of the tray or kettle at the end of a days painting is time consuming and non environmental as one must wash the inside completely . Comparing this to using a liner that one can dispose of in the bin. I know at the end of the day it all is non environmental but using plastic liners keeps everything clean and saves time.
Safety Glasses and peaked cap -While painting the ceiling it is a vital item.
Fresh Air– While the paint is wet the smell is stronger so ensure that your rooms are very well vented. As I am painting in the winter the house temperature has dropped to approximately 9 degrees.
Paint-I used Dulux paint as it has a good reputation for quality.
Cling Film-In order to keep the brushes and rollers clean I wrapped them in clingfilm overnight. The roller lasted a week and I did not notice any problems even with this amount of time . One just took of the clingfilm and started again with no cleaning required. It also reduces waste.
Technique I used for painting
First Coat– For the first coat on the plasterboard I mixed the paint to a 3 to 1 ratio (one litre of water to 3 litres of paint) as advised. By diluting the paint for the first coat it is supposed to allow the paint to get a good bond with the paper finish on the plasterboard. I did not use the traditional wet plaster method on the walls. The paint also needs to be mixed in a separate container. One requires a 1 litre container to carry out the measuring. I experimented with a lower ratio of water and I could not see much of a difference with the Dulux matt white paint on the bare plasterboard only that with two paint coats undiluted the finish looked better . If the walls were wet plastered in the traditional way then the water mix appears to be vital.
I started out using the paint brush and mini roller for the first cutting in but later on I just used the paint brush for the first cut and then used the paint brush and mini roller for the second cut in order to finish with the same texture as the 14 inch roller.
After watching numerous methods and comparing the comments I think the following is the best I have come across to date and having used the ideas it it all makes sense. With Youtube I found one has to watch about ten videos and then decide who is doing it right. Below may help.
When the first coat of paint is applied it often identifies small imperfections in the plastering. When this happens let the paint dry and fill the imperfection with USG or Gyproc ready made joint filler. When this has fully dried sand it by hand and repaint it with a few coats. This method worked for me.
The golden rule is-avoid sanding as much as possible by ensuring that the knife finish is smooth at the edges and as close to a final finish as possible. If one had to do this manually with a sanding block and pole it would be a tough job.
Thankfully over the years people have been improving the tools. I was lucky enough that the builder loaned me his sanding machine. I just needed a hoover to manage the dust which was picked up free on the free cycle web site. The sanding machine looks like the following:
Even though the above Flex machine makes the job easier and faster it still is a physical job especially when working overhead. The hoover was not designed for the above but it worked out OK once the bag and filters were cleaned regularly.
I would suggest safety glasses when working overhead and a face mask at all times.
Technique for Sanding Used
The joints had a second coat of plaster and then a touch up coat was used to remove any edges and at the same time look for and fix any imperfections on the butt finishes (where two boards are joined with no taper edge) or tapered edges. USG 3 Sheetrock (see previous blog) was usedfor the second and third touch up coat. I would not recommend the Gyproc joint filler for the second and third coat as it is primarily used for the first coat and it does a great job. When dry the finish is very hard and it would be difficult to sand. There is a Gyproc pro finisher but I found the Sheetrock product very economical and easy to work with for the second and third coat compared to other options.
I used a 150 grit sand paper on the Flex machine and left it at speed 4. I was expecting that the sand paper would get blocked up but this did not happen. I was advised and found it very important to sand the edges of the joints and ensure that one does not stay too long on the edges as the paper on the plaster board could be damaged. A light sand in the centre of the joint is how I finished each joint.
I also found it necessary to manually inspect the wall after the electric sander as one is too far away from the wall with the sander to spot imperfections. I made up a hand sanding block for this with a wood fibre board angled to get into corners.
The angled wood fibre board worked out better for me than dedicated sanding blocks and I used a pre-used sanding disc from the electric sander.
I experimented with the wall corner finishes on whether a sharp edge or rounded corners worked out better. The sharp edges looked like that shown in the top image below and the rounded corner is the image below that. If I was doing it all again I would use the rounded corners as I feel it looks better.
Typically with internal wooden stud walls there may be gaps between rooms at floor level or vertically. For this reason one may want to ensure that fire compartmentalisation is addressed (a previous blog covered this in detail). In order to do this I have chosen a B1 rated fire foam for the floor gaps. It also has a secondary benefit of reducing sound travel between rooms at these gaps. The foam I used was Olive PU-476. The price varies and the best value I found in Ireland was at National Seal Systems in Dublin. I also bought intumescent water based fire sealer for small gaps around the edges of the distribution board and vertical uprights where one partition meets another.
Plastering – Taping and Jointing. Tools and Lessons Learnt.
I finally completed installation of the plasterboard with the help of the mechanical plasterboard lifter and I have now just started taping and jointing. I decided on the international method of finishing the plasterboard rather than the Irish method ( see previous blog https://selfbuild.blog/2016/07/10/plaster-board-plan/) . If one is determined to use the traditional Irish method of wet plastering the whole wall I would still tape the joints with paper tape rather than the nylon/plastic mesh. The paper tape ensures the fire proof rating and from my research it is a stronger joint.
Below is an image of what it looks like when one applies the first joint filler tape coat. There are two to three more coats of plaster filler/compound required to hide the joints completely and some sanding.
I tried different methods and tools such as using a hawk instead of a mudpan to hold the plaster. For me the 12 inch mud pan worked out the best .
The tape dispenser is more important than I thought. The unit I purchased was a good design on paper but not very practical. If I was purchasing a unit again I would go for the steel design . The current model I am using is as shown below.
For ones own safety one must be able to roll the paper up after taping the joint as the hanging paper can become a trip hazard when moving around. I would try this steel one instead if I was starting again (see below).
Another item is a glove for the knife hand. If one is working with the filler for a few days I have found it to be very rough on the hands. Over time the skin will toughen up I suppose.
There are two main types for corner beads used for edge finishing . The steel micro edging (first image below) or the paper tape reinforced with steel (second image). I found it easier to use the steel micro edging rather than the reinforced tape edging. I tried a few methods of attaching the mesh and I settled for first applying the compound and using a few stainless steel staples(the standard ones are not stainless steel) to fix it securely while applying a finishing coat to fully bed it in. Note-ensure that one fully cleans the stapler after doing this.
The steel micro edging I feel is a better method to finish an edge and it is easier to sand and clean when applying wet filler.
Another idea that I did not get to try but it looks interesting is the use of pre-formed corner / edges using plasterboard. This avoids the use of beads and it is called the ZaapSystem from Prodar.
The reinforced tape comes into its own when one needs to tape two walls that meet with slight angles. The price of this varies from €15 to €30 for the same length.
I tried different fillers/joint compounds . Gyproc dry wall filler (it comes in a bag and is quick setting ). One mixes it with water and it requires the use an electric mixer to prepare it. This bag works out fairly economical but the time spent mixing, the dust, washing out the bucket every hour or so is very time consuming. Another disadvantage is that it sets very fast and is very hard to sand afterwards. The colour is also a disadvantage as it does not blend well with the plasterboard. An advantage is that it works out well when fixing the steel micro mesh.
The next product I tried is the Gyproc bucket version (pre-mixed) 15 litre. This is easy to work with but again it is a white finish which will make it harder to blend into the wall and will require more painting. It is also very expensive.
The best product I found and the most economical for the joint is supplied by Greenspan called USG plus 3 (it is an American product) and it comes in a 17 litre tub. It has the best colour blend for the board, it gives a finer finish, and is easy to sand. It does require a small amount of water to be added to make it extra easy to work with (this makes it go a bit further).
When applying filler near floor level increase the width of the filler to ensure that any skirting board lies flush against the plasterboard.
Use paper rather than plastic mesh for a stronger and fire safe joint.
Practise filing joints in a non critical area such as behind future wardrobes, en-suite or storage room etc.
Have a rag /clothe clipped to your belt to wipe away any dried plaster pieces before they get caught in the fresh new compound and leave streaks.
Use the 4 inch knife to remove any dried plaster compound or for checking screw heights. The other knives need to be protected from any edge damage or you will get streaking.
If the corner is less than 90 degrees I found it difficult to get a clean edge as there was limited space. In this case I made a finishing tool cut to the angle of the wall and ceiling with a rigid plastic cover to give a smooth surface.
I found it helpful to have the 4 inch knife stuck to the pan with a magnet. It saves some time bending down or climbing down the ladder to get it when using two other knifes. I typically would have the 6 inch knife for finishing edges and either the 10 inch or 12 inch for finishing butt or tapered joints. The 10 inch stayed in the back pocket .
Fully clean the knifes and dry them at the end of the day.
You will notice the difference between good quality knives and low cost knives.
If a knife should get damaged by a screw head I used a sharpening stone to repair it.
In order to minimise sanding sometimes it is better to re-apply another filler coat to get a perfect finish.
For corners I found it easier to use a corner knife (90 degree angle) and feather the edges with the 10 inch knife.
Use the 4 inch knife to clean away any small hardened plaster bumps before starting the second coat.
As part of the passive house requirement one needs to eliminate or minimise heat loss through linear lengths or points around the house. Some of the thermal bridges in my build are typical of other builds. I hope to provide more details in the future.
One of the main linear heat losses is with window/door installations (its connection with the wall frame ). It has been said numerous times that selecting a high quality window/door and installing it poorly can equate to buying a low energy window .
As mentioned before I will use the free software called Therm to calculate the losses. The first detail to tackle is the glazing which was directly mounted in the frame of the house without a window frame. These windows are 2.4 metres x .9 metre and there are 11 of these mounted on the south face.
The calculation of these linear losses can be expensive to get done so I will be doing the task myself and have it checked by others. I am surprised that good details are hard to come by on the web for free to help the self builder. One of the most time consuming exercises with thermal bridge calculations is drawing the detail. If one undertakes drawing this oneself using CAD (Computer Aided Design) software it can help to reduce the cost of the calculation.
When one needs to come up with a detail to minimise the losses there are a lot of products that help to keep the losses under control. These are semi-rigid insulation products like compacfoam, foamglass blocks, standard insulation, TECTEM, PU or rockwool and fibreglass products and aerogels (which is one of the highest performing insulators being made).
To date there appears to be very few online resources to guide the self builder or provide details that one can use before one starts a build.
Some background and details I found to date on thermal bridges can be found at the following links.
Below is an example of the thermal bridge calculations one needs to carry out to establish the thermal bridge performance values in W/(mk).
One draws the detail as a DXF file using a drawing package (or draw the detail manually in Therm)
Import the detail into Therm Software
Add the technical details such as thermal conductivity of each item
Tell Therm where on the drawing to stop the calculation (Adiabatic)-top and bottom of the drawing shown below.
Tell Therm what the internal and external temperatures are
Go to a spreadsheet and calculate the psi values of the thermal bridge detail for the passive house performance value.
When this is done one ends up with the calculation and an image like that shown below. In this image the glass is shown near the top right.
In the next image the colours show the temperature gradients. The purple colour is the outside temperature at -10 degrees.
There is thermal bridge software that one can buy where the software calculates the psi value without using a spreadsheet but Therm is free and there are courses available in Ireland.
If one wants to show the real design and installation details of the thermal bridge values for the Irish regulations rather than the accredited details (without a performance value) one needs to use a certified thermal bridge accessors but this is not the case for the Passive House Institute.
We can all look forward to the day when standard construction details that are typically used in Ireland are already calculated for the self builder and there will be no need to pay to find out the thermal bridge losses . The Scottish accredited details (see above link) come close to taking the guess work out of construction.
Having lived in an house that had single glazing and was draughty, I only realised how inefficient the ventilation was when I purchased a Carbon Dioxide meter (CO2) for the old house. This meter measures the amount of carbon dioxide in a room (as we all exhale CO2). The bottom line is that a level below 1000ppm (part per million) is taken as a healthy starting point. Another factor that is not healthy is Volatile Organic Compounds (VOCs) these are the chemicals, gases given off by furniture, paints, floor coverings, household cleaning agents etc. When one reads the possible health effects from VOCs it becomes clear that one needs to reduce these. See for example http://www.epa.gov/iaq/voc.html
In our last home what was amazing was how little oxygen we were getting especially when asleep (and in turn high VOCs). Within an half an hour the meter would alarm that the levels of oxygen (fresh air) were low.
What I used to do in the old house is determine if there was a wind blowing or a storm due. This then entailed adjusting the window opening to a minimum in order to ensure that we would get some level of oxygen. If there was no wind blowing outside then I would open the window to approximately 75 mm (The horizontal window was over a meter and a half long) and leave the bedroom door open for some cross ventilation through the house.
I think it is now widely accepted that holes in the wall or opening windows does not work for fresh air and a healthy environment. The only way that appears to work is to blow fresh air in / suck stale air out.
CO2 meters for some reason are expensive. The unit I purchased was over €300 a few years ago. I came across a more affordable unit recently on ebay for approximately €100 (allow for customs and excise) that also has a data logger (records the information over time). I feel it is well worth investing in one of these as the true quality of air in a house can only be believed when the CO2 levels are measured.
One seller on ebay was perfectprimetechnology . If one types in the word co2 at their store it should be easy to find or in any other store.
While there is no direct link between VOCs and CO2 I have read that if one is breathing air in a room with high CO2 levels it gives a good indication that the VOC levels are also high.
In the new house we plan to use controlled ventilation which will supply fresh air and in turn recover some of the heat blown out of the house . It is a mechanical system called a Heat Recovery Ventilation Unit (HRV). I do not know why they don’t call it a fresh air unit as this factor has to be more important than recovering heat. In order for this fresh air supply system to work one has to control all drafts in the house as one does not want to be drawing air in around windows and doors and hope that the fresh air ends up in the correct room. This can only be achieved by eliminating drafts by sealing the building in an air tight membrane/system and blowing fresh air in and extracting stale air out using two ducts.
In order to carry out airtightness in a home one appears to have a few options -On a block house this is achieved by internal plastering (and some preparatory work) or for a wooden frame house one can use a membrane or take a chance on using OSB (Oriented Strand Board). Even a block house will still need air tight membranes on some structural details.
Another reason for using this special air tight system is to control moisture generated in the house from showers, cooking, drying clothes etc. This moisture can have a detrimental effect on the building fabric and reduce the insulation levels and in a worse case scenario lead to mould growth. I feel the mould issue is going to be a health issue for generations to come where insulation is added ad hoc to dwellings without a proper design using building physics. I am not aware of any building physicists in Ireland guiding the construction industry. A worrying trend I am hearing of is cases where the consumer believed that adding insulation was a good thing not expecting the creation of mould and health issues for themselves.
The Airtight Target for a Passive house
In order to control the ventilation and heat loss the passive house standard requires less than 0.6 air changes per hour at their test pressure. The best analogy I could find for this figure was at the passivhaus.org.uk web site. One must achieve no holes or less than one 18 mm hole for every 5 m2 of the building envelope.
Practical Experience of the first steps in airtightness
As I was installing counter battens on the ceiling in front of the airtight membrane I know from experience I missed the rafters in 3 locations in the roof. I am using serrated nails with a nail air gun. Once these nails are fired they are almost impossible to remove.
The strategy is not to try and remove them as this would leave a hole other than a nail in a hole behind the batten.
Installing battens on the ceiling
Another factor is to ensure that the insulation does not sag below the rafters before the airtight membrane is installed.
When one is laying out the membrane one needs to work in a triangle when stapling. For example staple 3 metres or more forward on one side and then find the centre of the other side and staple from this point to either side. Ensure that stainless steel staples are used as there is very little in the price difference.
There are a few tools that I found very useful as a self builder (which are free).
One such tool is Evernote. As self building involves plenty of research and the need to access information. This tool has proved invaluable for me to store information, share information, find information and make it accessible on a smart phone, any computer and automatically back up the information (nothing worse than loosing or not being able to find information). It also allows one to take pictures and have these stored in the same place.
All one needs to do is tag the information (a tag example could be the word insulation)-when you store the price/information you found on the internet about insulation it is stored with this tag and any other insulation data found over time. All pdf documents (these are usually research papers) can be stored also. There is an option to buy the premium version at €40 a year then the individual pdf content of the documents can be searched.
Another tool is Autodesk Design Review 2013. This tool allows you to open autocad files that your architect or engineer may have used for your build. It also allows you to edit these with your comments , take measurements of the drawing and draw simple shapes to highlight issues.
Another tool worth mentioning is Autodesk DWG Trueview. This is more similar to Autocad as it is mainly a viewer (allows one to open files).
A tool that allows one to calculate the heat loss of thermal bridges is Therm. It was developed by Lawrence Berkeley National Laboratory (LBNL) and again it is free. This tool will show you how cold (and the heat loss) your floor/window reveal etc is going to be near outside walls and the actual performance value so that the real heat loss can be calculated. (One can easily get a feel of the importance of this detail and the energy lost if you see mold/condensation around windows/doors etc ). This software will show graphically how much heat is lost (once calculated) and the temperature/heat loss you can expect on details such as window frames, door thresholds, the steel ties in your block work, the steel beam sitting on your inner wall or foundation etc.
There are two parts to calculating the actual heat loss – the first is drawing the detail (fairly simple and involves time) and the other is the actual calculation (tricky I feel for a self builder). If one draws the detail this can save costs if a third party does the calculation for you).
This tool allows one to model in 3D your house design and carry out a walk through to get a feeling of the internal or external design. It also is used by the passive house institute on their energy balancing software PHPP so it is a worthwhile tool to learn.
Other than a smart phone which is a real help when one wants to send/receive files, images or emails and keep things moving on site a device called the Samsung Note 10.1 (2014 Edition) makes documenting ideas and drawings a great resource while on the move. It is only one of a few devices that has a real pen and sketch pad that allows one I feel to replace a piece of paper because one can rest your palm on the screen like a piece of paper and write or draw.
Sun and Climate
Sun Surveyor Lite predicts and visualizes Sun, Sunrise and Sunset positions and times with a 3D Compass on your smart phone. It is useful in identifying the site layout and potential shading issues from trees etc. One can simulate the sun at different times of the year. If one want to do the exercise on paper then this web may be of help- http://www.gaisma.com/en/
The passive house software allows one to set your own performance standard by selecting how much energy (oil/gas/electricity) one wants to use to heat the building.
For example current Irish house builds that comply with today’s standard 2014 are estimated to use 100watts per m2 (subjective). The passive house standard if one goes for certification uses 10w per m2 (objective).
The real benefit for using the PHPP software is that the performance approach can be set by the home user. For example if I want to reduce my energy consumption to 1.5 litres of oil per m2 of the house size then I can set the software to a maximum of 15kwh per m2 for the year while maintaining a temperature of 20 degrees Celsius.
In a typical 3 bedroom house with an area of 100m2 the oil usage would be 150 litres a year. With the PHPP performance software one can set the number of litres of oil (or gas etc) per year that your residential or commercial property will use to within a small margin of error. In other words you select the performance value of your build.
In summary the PHPP software takes into account your comfort and health (temperature and oxygen levels) by removing high CO2 levels and VOCs and providing an even temperature throughout the house.