Open for International Passive House Open Day on Friday 8 November 2013 - booking in required

We are opening the house again this year for International Passive House open day on Friday November 8. Morning

Located just 10 minutes from the M50 in Greystones, Co. Wicklow, experience for yourself what a Passiv Haus really feels like for the homeowner. Ask those questions you always wanted to & get a first hand account of the challenges of building to this exacting standard. See the building systems & better living environment for yourself.

We have no links to suppliers, or builders & are independent. There is no charge.

Date & Time : Friday 8, November 2013 , 0930 and 1100 am appointments available

Pre Booking required, there is no charge for these visits

Further Information, Project 2309, www.passivhausprojekte.de
About the house : passivebuild.blogspot.com
Also , on the NZEB website:

http://www.nzeb-opendoors.ie/node/557

How do I go about building a passive house? Where do I start?

How do I go about building a passive house?

Just like getting anything started, considering designing, organising & building a house from scratch....to be honest its a massive undertaking.

• There are simply so many variables from
• Knowing the budget including site works, fees, development levies?
• How big a house do you want, how many bedrooms etc...?
• Is there a particular layout that will suit you best?
• Are there particular planning concern/?
• Any neighbours , site, views, prevailing wind or boundary questions?
• Do I need to install percolation areas for waste water treatment?
• Can I afford the 10% premium for a Passive House over a house that meets building regulations ( budget for €1250 to €1400 per square metre for the house finished)

Understandably, the first port of call for many clients is a local architect, planing consultant, draughtsman or engineer to go about putting together some sketches, drawings & then a planning application. These professionals are very experienced in knowing local issues & will hopefully guide you through this process. This is very important as it sets the scene for the big decisions....don’t worry, there will be hundreds of smaller decisions to be made. They as very experienced in understanding client requirements & potentially bring real design & flair to your new home. However, just before you agree to pair up with the local professional for the complete build ….I would advise you to stop & ask a few questions to make sure their experience matches your end goal.

As you will see through the build process & I have mentioned before, there are so many companies tradesmen & people who claim to experience in  building passive houses & their components : be that window installers, timber frame companies, heat recovery installers, plumbers etc..........but the reality is that the vast majority do not have such experience however well intentioned. Indeed, there is no uniform definition of what a Passive House is, so one man's B3 rated building with fancy add ons or eco-bling is another man's super low energy passive house. In my opinion you need to recruit people & companies with the right experience to the job & who can get someone to answer the really detailed technical issues as they arise if they cannot themselves.

Even if you are planning on building a 'low energy house' the question is even more acute as there really is no actual agreement on, It all sounds a bit like there is no uniform agreement on what a fuel efficient car is – is it a 0.7 litre Toyota Yaris car or a 2.5 litre Lexus Hybrid

Speaking with an architect you visited our home recently , he was quite surprised at how technical & detailed the design and construction process for a Certified Passive House. He was very impressed at the outcome that achieved. What this means is that each component of the build needs to be really considered & details resolved well before the contract starts building it. This may sound obvious , but in construction most tradesmen just want to crack on & do what they always do, be that right or be that wrong for your case. In the case of a passive house you need to ensure that that the building, and all its installed components, that you submit for planning is capable of being built cost effectively as a passive house & there are no surprises. You have to make sure that the house you get planning permission for can actually be built as a passive house - the most common issue I have seen in Ireland is the inclusion of dormer windows in houses which are extremely difficult to airtight & remove thermal bridging

The example I always think of is a car. if you have a house design & want to make it a passive house, this is a bit like taking an existing car design & trying to make it a fuel efficient car. However, if you can rewind & make sure that the car design was efficient in the first place, then ensuring that car the leaves the production line is fuel efficient is a whole lot easier & potentially cheaper.

If you want to build a passive house then there are a host of specific considerations, which include:
Location of the heat recovery & associated ducting
Location of the airtightness membrane & insulation layers
Location of solar panels, tanks etc..
Reduction in summer overheating & introduction of shading
Reducing windows on the north side & optimising the quantum of glass on the south side
Optimal room locations, so that rooms that don’t need much solar heating e.g. bedrooms are not on the south end

So , to answer the question I posed at the start, I would advise the following:

Step 1 : Answer the big questions yourself if you can, go & visit houses that are open to the public, keep an eye out for International Passive House open day in chilly November. Scandanavian Homes in Galway have a great setup, are very welcoming, & whilst the design might not been to your own taste, they are extremely experiences & knowledgeable.

Step 2 : Either get the local architect / engineer / draughtsman to do up your drawings but make sure that they are reviewed in detail by someone which make sure that the house will work as a PH

Step 3 : Once you have planning permission, get specifications, drawings completed for the house, but again the specification should be written to ensure that the house will actually perform as a Passive House

Step 4 : Recruit a contractor who has actually built a passive house before & tie them into meeting the specification

Step 5 : Get people / tradesmen / companies / professionals involved who understand the specific detail required in a passive house e.g. detailing where the floor meets the walls, MHRV ducting layouts, airtightness membranes overlapping, to regularly inspect the build.

Step 6 : Upon completion of the final airtightness test & confirmation that the house meets the construction specification, submit the design package for approval as a certified Passive House.


In our experience there are few professionals who can supply that level of design support & site monitoring to your house build, be that a self build or a contractor build. One of the few practices I've found in the field who have that level of experience required to support the client, architect or contractor is Archie O'Donnell at Integrated Energy (www.integrated.ie). Archie & his team have many years experience in passive house specification, design & construction monitoring and much of their work these days is in assisting architects in delivering the level for required for a passive house

If I were to summarise succinctly what you need to do to start & finish a passive house build successfully, it is best done in the words of Ronald Regan ' Trust, but verify'.

Windows in a Passive House : choices , techy stuff & how to save money

The single biggest line item / expense in building a passive house is the choice of window supplier and system. As we all know window supplier have an historically poor reputation , when in Ireland at least, window sales men went door to door selling PVC windows in the 80s. Nonetheless, whenever you go to a trade show or building expo you are likely to be bombarded by science / facts / figures from the various companies who sell in your local market.

If there is one area where people are going to cut their cloth to measure when they choose to 'near passive' rather then passive , then windows is likely to be top of that chopping list. But, chop carefully. as to get PH certified or ever ‘ near passive’ means choosing very high performing windows - far beyond the capability of most window supplier....no matter what claims they make. I’ve included a few photos of what triple glazed windows look like to demonstate how very different they are.

Passive House window - looking from the inside out

 

 

Width of central mullion is approx 160mm

Quick summary of windows

• There are 3 components to the windows : the glazing, the frame & the spacer which separates the glass sheets inside the glazed panel.
• U values / numbers quoted by salesmen usually refer only to the thermal performance of a piece of glass not the overall window. Good quality spacers ( e.g. Swiss, thermix) and frames ( insulated , thermally broken, quality seals etc..) cost more than poorly engineered products or metal
• You obviously want both a manufacturer & installer who are likely to be in business in 5 or 10 years time lest window elements get damaged or need replacing
• Glass is the cheapest part of the window & the part that performs best thermally; frames are generally expensive & have worse U values.
• The PHI has a standards for window frame testing, those that pass this standardised test are said to be ' Passive House Certified'. There are also standard tests conducted by trade bodies, such as the British Fenestration Council (BFC) which are again a standardised approach rather than just a number. The two standards are not comparable & neither deals with the actual quality of the window or how well it will be installed; rather they deal with the thermal performance of the product.
• The importance & efficacy of triple glazing in a passive house cannot be underestimated; good quality windows eliminate draughts & temperature differences in a room.
• Some people will argue that in certain climates , in certain orientations that you can get away with high quality double glazing. This may be true in a minority of cases....but they are forgetting that one has to use the same frame as the triple glazing with double glazed glass panels; this negates most of the cost really.

The thickness of the window ca. 110mm...they are huge!

Central Mullion again

Sample key questions to ask:

1. Do the windows & doors open in or out?
2. How bulkly are the frames? Get specific dimensions & drawings!
3. What are the materials available : aluclad( timber / aluminium skin on the outside), timber, PVC...How long have they been making each for?
4. What is the spacer material?
5. What are the various restrictions on open sections, e.g. Height vs width?
6. What is the ironmongery range & what is their warranty?
7. What quality of locks are supplied as standard?
8. Are window locks & restrictors included?
9. What are the treshold details around doors?
10. Who so going to be responsible for airtighting up the the windows
11. Who supplies window cills? Are they metal, plastic, concrete?
12. Is a thermal calculation / therm on the proposed installation required?
13. Is the warranty supllied from the manufacturer for the windows ex-factory or as installed?
14. For non typical items such as patio doors, sliders, front doors, get specifics as the installation details
15. What is tilt & turn, provide a demo of the mechanism?
16. Multiple customer references, please?

Looking at a bottom hinged window from the inside

To be honest, the above list just begins to scratch the surface of dozens of questions I'd have for any window supplier, but should get you started.

How to save money on windows?

1. Consider installing yourself & possibly buying directly from the supplier ( most likely in Germany). This may have VAT implication as, in Ireland at least, supplied products incur 23% VAT whereas installed products incur 13.5% VAT
2. Perhaps choose an older product from their product range which is not as bang up to date or has as modern a profile. Considering that you would like windows to last 20 years minimum then fashion today should really not be a driver.
3. Cut out fancy extras like designer ironmongery or alarm contacts, the multiplier on each window is prohibitive – try to choose from the standard range
4. Limit the number of open panes. On average an opening pane is a few hunderd Euros more than a fixed pane
5. Cut down on central mullions & other decorative frame components.
6. Whilst all such windows are made to order & you can technically choose any RAL colour, perhaps there are colours or finishes ( either internal or external ) which might be less expensive
7. Bargain hard. & get at least 3 quotes & don't commit to anyone– you will be amazed at the variation in price

A passive house slider door - the mechanism is quite complicated to say the least!

Air Quality & Humidity levels in a Passive House

Air Quality & Humidity levels in a Passive House

One of our main reasons to build a passive house was to live in a building that is really comfortable & healthy. Based on our experiences of living in 1920s, 1940s and 2000s built homes in Ireland, I can say with certainty that the its not something we've found in many buildings

One of the key measure of indoor air quality is humidity which is a measure of how much water is in the air. If humidity is too high or two low then there are definite health implications:

• Too high & mould growth is likely
• Too low, its starts to feel very dry, skin drys out quicker, musical instruments like pianos are damaged!

The consensus is that the optimal range for humidity is between 35 -55%, the figure above is from the PH training package.

Other pollutants in any building include:

• Bad odours – usually in bathrooms
• Formaldehyde & other volatile organics– often off new furniture, ;paints, flooring, varnishes, treated wood, plastics
• Ozone
• Radon – naturally occuring from the underlying rock / soil

Usually in homes, ventilation is supplied via trickles vents on windows , wall vents, bathroom fans, kitchen extractors...or a combination of the above combined with uncontrolled air leakages from the attic hatches, doors, windows, drains, downlighters. In our previous houses this gave a humidity usually in the range of 60-70%, but often as high as 90-100% depending on conditions outside.

 

Photos of the MHRV (during installation) & the filter cartridges

With an airtight building , the air passing though the building is controlled by a heat recovery unit, also called an MHRV , which strips heat out of the stale building air. There is no air cross over / recycling & the air coming in is filtered. These systems need to be commissioned correctly to deliver the correct amount of air to each specific room type. If the overall system over-ventilates then excess air is being drawn though the building resulting in low humidity and higher heating bills.

So...bottom line is what is our experience with the air quality in the house over the last year?

• Humidity levels are consistently between 47-53%, with very little variability; have verified this with a mobile humidity meter ( about €5 on ebay) & and the humidity sensory on the MHRV system, both of which tally
• The air filters on the MHRV need to vacuumed about once per month
• Reckon that is took about 4 months after moving in for the dust to settle from the build process, this was despite the house being well aired before moving in
• The dust in the house is all from internal sources : clothes, furniture. I've heard it said that there is no dust in a passive house & thats unfortunately not true.
• You can & do open windows in a passive house, during the summer I noticed this meant that the dust was a slightly darker colour than the dust during the winter when all the air was filtered
• The air is very consistent, crisp, there are no drafts. If there is a big group, like during the international passive house open day, then I tend to turn the system up a knotch
• With the constant movement of air through bathroom, utility & kitchen setting up a constant flow of air, there is no need to extract fans – the MHRV does an excellent job
  
  
  All in all, we've found the air quality really high, ventilation levels high enough to shift smells, the MHRV does an excellent job. The air quality in a passive house is really unlike any building I've been in

Feedback from International Passive House Open Day

We had 45 guests for the open day in November ,ranging from architects to home owners looking to retrofit their own houses to tradesmen. The visit consisted of a presentation on the overall PH design principles and photos of the build process for this specific house. There was specific interest in the heat recovery system ( which somebody described as looking like something from Star Trek), the windows which are a triple glazed aluclad & the differences between block versus timbre frame construction. 

We presented a 'hands on' number of items such as a sample of the wall buildup, airtightness tapes & membranes, heat recovery filters & live thermal imaging camera images of the building fabric. The was followed by a detailed tour of each type of room in the house, the plant room & the heat recovery installation.  Observations from the visitors included the quality of the air, good natural lighting levels & a very high degree of comfort

If there was a theme to my presentation / talk through the build process, it was that great products , from whatever source, need to be correctly designed, installed & commissioned in order that they work correctly for the home owner over the lifespan of a building. Furthermore , the Passive house building standard is a challenging design & construction standard for all involved but results in a very special living environment for the homeowner.

Questions raised which I'm in the process of answering:

•  Explain the certification process, what 7 who does it involve
• Climate files for PHPP
• Is heat recovery noisey? Can i save money by turning it off? How much does is cost to run?
• What is this supply air heating
• How much to MHRV filters cost & how often replaced?
• What are typcial construction details & why are they important?
• What is the ideal humidity level in a building?
• When is solar shading needed & not?
• Payback period for passive
•  Does it work in practice -predicted v actual data
• How do you airtight around windows
• Heat recovery as bathroom extract, can it reduce humidity.
• Do sliding doors work with passivhaus
• Opening windows in a passivhaus
• Costs.  How much more is a Passivhaus than conventional.
• What are the costs for the certification process alone
• selecting heating, reneables and ventilation systems and choosing between wall build types is confusing and the salesmen even contradict themselves how did you make decisions.
• How does timberframe breath or diffuse moisture is it to a cavity/rainscreen or inside through an intelligent membrane?
• Can you have an open fire or extractor fans in a passivhaus
• Is a passivhaus and a zero energy house the same.
• When contractors see passivhaus in for pricing do they think Ka-ching,
• Why did you decide to pursue such a low energy building?
• Is there such a thing as near passiv.
• Can you use cavity wall for passivhaus.