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Boots on the Ground Takes a Field Trip!

BOG

SUSTAINABLE.TO and GreenBilt Homes would like to invite you for a tour of their latest healthy, sustainable, and resilient home. Join us in the North York area (near Bayview and Finch Ave E.) on Thursday, June 9th 2016 at 5:30pm to hear Paul Dowsett, Principal Architect of SUSTAINABLE.TO, and Mike Manning, President of Greenbilt Homes, present their innovative approach to exterior insulation and continuous air-barriers. Blower door testing results will be presented by BlueGreen Group’s  favourite energy advisor, Graham Fisher. Sorry, Shervin and Greg will be in Halifax testing beers… er I mean windows!

Food and refreshments will be served. Space is very limited, so please RSVP early for the event address and details. We hope you can join us!

 

ABOUT THE PROJECT

To reduce reliance on energy, the Risebrough Residence is wrapped in a thick blanket of thermal insulation on the outside of the wood frame structure, which reduces heat loss and allows the home to stay comfortable with minimal energy input for heating or cooling. By providing an airtight building envelope, uncontrolled air leakage is minimized, reducing energy consumption and improving the durability and longevity of the building.

Conceptually, SUSTAINABLE.TO took inspiration from the Mid-Century Modern movement. The massing of the home as perceived from the street makes a subtle nod to mid-century design: low-pitched sloped roofs, clerestory windows, and a rich, natural material pallet allow the home to be lit naturally, breathe passively, and regulate temperature more efficiently.

These Mid-Century-inspired passive design features allow the architecture to do the heavy lifting. The staggered rooflines accommodate high clerestory windows that admit daylight naturally, reducing the need to switch on lights. During the shoulder seasons of spring and fall, convection currents passively vent warm stale indoor air through the upper windows, in turn naturally drawing in cooler, fresh air from the garden level. The remaining heating requirements are topped up with a hydronic in-floor radiant heating system fed with a super-efficient natural gas boiler. Since the home is designed to be airtight, air coming into the home is controlled by a fully ducted ventilation system. The system includes two energy recovery ventilators (ERV’s) that recover heat and humidity from the exhausted air to preheat and humidify incoming fresh air.

When
Where
Risebrough Residence – North York, ON
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Investment in Building Efficiency Coming to Ontario

The Globe and Mail reports today that the province of Ontario is to invest $7 billion over four years and plans to phase out cabon-based energies; this signals a radical departure from the past and couldn’t come any sooner as the CBC reports “NASA said over the weekend that last month was the warmest April in statistics dating back to the 19th century, the seventh month in a row to break temperature records.” The money to pay for these investments is to come from the province’s proposed Cap and Trade program set to start in 2017.

Specific to buildings, the two following bullets were taken from the Globe and Mail article cited above:

  • $3.8-billion for new grants, rebates and other subsidies to retrofit buildings, and move them off natural gas and onto geothermal, solar power or other forms of electric heat. Many of these programs will be administered by a new Green Bank, modelled on a similar agency in New York State, to provide financing for solar and geothermal projects.

 

  • New building code rules that will require all homes and small buildings built in 2030 or later to be heated without using fossil fuels, such as natural gas. This will be expanded to all buildings before 2050. Other building code changes will require major renovations to include energy-efficiency measures. All homes will also have to undergo an energy-efficiency audit before they are sold.

The last point will be interesting: making the Ontario Building Code retroactive fo those who chose to renovate their homes. Very few building codes compel existing building owners to upgrade their building efficiency and some new laws will have to be created that brings about these big changes. Interesting times around the corner! When the details get fleshed out, we’ll share our insights!

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Interior Air Barrier Systems for Solid Masonry Renovations

We’ve been on a number of very interesting Deep Energy Retrofits (DER) of solid masonry houses over the years and people often ask us what kind of air barrier strategy is the best for getting the air leakage rate down to Passive House levels (0.6ACH50) when choosing to insulate on the inside.

If you’re looking to get air tightness levels below 3ACH50, you have to do a Pre-Drywall Test to identify and rectify air leaks. Test your air barrier system before the drywall goes on or before the insulation is installed with some products below.

First, a look at what we mean by vintage “solid masonry.” Below are two cross sections of wall from different eras; a double red brick house (1900-1930) and a block and brick (1930-1960).

Toronto Red Double Brick

Typical wall cross section of a Toronto Double Brick house. The two wythes of brick make a structural wall and are tied with a brick across (seen above, in line with the bottom chord of the joist). Note the steel that connects the floor cavity to the front wall. Note that between the wythes there’s no drainage cavity and no room of insulation.

East York bungalow wall structure

This 1940′s block (grey cinder block) and brick (yellow) shows a new full width concrete block being laid on top of the old wall for a new second story. Note that between the wythes there’s no drainage cavity and no room of insulation.

J roller (Large)

Remember, almost all tapes and peel and stick membranes REQUIRE pressure and the right conditions on the substrate. Invest in a $15 J-roller from Atlas Tools on Queen Street. A narrow, small diameter roller gets everywhere and focuses pressure where it’s needed.

Below are examples of vapour open, or breathable air barrier systems we’ve seen used that are loosely organised from good to best. Remember, air seal everything to which ever sheet good you use below; openings for windows, doors, wires, plumbing, HVAC and framing!

1- Flexible Air Barrier:

Flexible Air barrier

Here we can see a snap shot of Tyvek and 6mil poly; either could be the air barrier, but the Tyvek stands the best chance at being the most continuous. Which ever you chose, you’ll have to seal, lap and clamp seams to be in compliance with OBC 9.25.3.3. (2) a & b. Note the top right corner of Tyvek in the photo above needs to be stretched… With flexible air barriers, some are vapour open in one direction only (writing facing outside) and Typar can’t be taped from the backside, only on the printed side.

 

2 – Fully Adhered Flexible Air Barrier

VP100 on primed double brick

This double brick house had the interior face of brick exposed, primed and Self Adhered Membrane (SAM) installed. See below for close up. Roll this stuff to ensure it sticks well.

VP100 Inside Air Barrier

The large space behind the new stud wall was to accommodate two layers of staggered seam Roxul and a 3rd in the stud cavity. For a more robust fabric, the VP160 offers a more robust barrier.

3 – Spray Foam

2 Pound spray foam

This block and brick house had 2 pound spray foam installed directly on the brick. See below for details.

2 Pound spray foam

In this photo, we can see that the new wall studs were spaced far off the wall so that a monolithic layer of spray foam could be applied to the inside face of the block wall. This layer helps ensure that wood elements don’t penetrate the air barrier (foam) and cause air leakage, and the layer also reduces thermal bridging at the framing members. Air tightness test spray foam every time, we find many air leaks in foam and because the air gap between the face of the foam and the back of the drywall, the air leaks are very noticeable.

 

4 – Liquid Applied Air Barrier

Liquid Applied Air Barrier

Here a 1945 block and brick house had  liquid applied air barrier installed with great success as far as low air leakage rates go. Sto Gold Coat was used in this case, but Henry also make a line of breathable, liquid applied air barriers called Air Bloc. Here we see the yellow air barrier that was painted on the wall with a standard paint roller. The latex-based air barrier sticks well and is easy to apply.

Liquid Applied Air Barrier

The yellow liquid air barrier is continuous and all penetrations are sealed to it like the transition to the roof cavity and the window buck. Note the 3M 8068 Flashing tape sticks incredibly well even in harsh conditions.

Liquid Applied Air Barrier

Here, where large gaps between the floor joists and masonry wall existed, a filler called Sto Gold Fill was used, followed by a fiberglass mesh called Sto Guard Mesh to give the top yellow coat some structure as the wood moves seasonally. Repairing air leaks in this membrane is exceptionally simple and tests have shown that liquid applied air barriers perform very well in solid masonry construction DER.

 

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Homeowners; Don’t let your Fresh Air Get Short Shift

I’ve often felt that most renovations are a compromise in efficiency, but when it comes to getting fresh air, everyone drops the ball. From the homeowner pleading ignorance, the builder, the mechanical designer, the municipal plans examiner and the building inspector, each having their own agenda; ventilation systems need more attention as homeowners pay the price in diminished health or loss of cognitive function. We love fresh, clear, clean water piped through our buildings, but for some reason, fresh air gets ignored by the designers, the renovators and municipal plans examiners. The air in your house deserves to be as fresh and clean as your drinking water; now pay attention!

The Washington Post’s Chris Mooney reported last year about “…a study published Monday reports that workers showed significantly lowered cognitive functioning after spending a day in a simulated office environment featuring high [typical] concentrations of carbon dioxide and volatile organic compounds. By contrast, in conditions set to simulate a… building with enhanced ventilation — cognitive performance was higher.” Lead researcher Joseph Allen at Harvard said the results in increased cognitive function were “Shockingly higher.”

Some histrionics for perspective on the ventilation issue are needed.  A new home’s design and construction processes are bound to follow the Ontario Building Code (OBC), but renovations of existing building don’t. The OBC is not retroactive and doesn’t compel the home owner to upgrade the existing building shell or mechanical systems to meet OBC requirements – they could if they wanted to. So at best the builder not wanting to charge for and build extra bulkheads (what’s with the hate-on for bulk heads anyhow?)  concealing  new duct runs keeps their mouth shut and the municipality’s all over the map depending on the mood of the plans examiner or the building inspector.

Judging from the evidence we’ve gathered in the field, municipalities have no clear, even-handed approach for resolving the need for ventilation when it comes to renovations. Sometimes building inspectors bully home owners into installing Heat Recovery Ventilators (HRV) even when the OBC ventilation requirements are met by more than one exhaust fan that constitutes a principal exhaust fan and even when the house is very prone to air leakage (well over 7ACH50).

Compared to Europe and the USA, few buildings are tested for air leakage. Consequently,  few professionals are fluent in air leakage metrics and the impact that air leakage has on a building’s “natural” infiltration rate. Some assume that leaks provide enough good ventilation, but ultimately they’re only guessing. So to help guide the renovation sector, this is what we have to say:

  1. Century-old, leaky buildings that are excessively air leaky only benefit by having ventilation systems if the home is air tight. Air seal your house then install a balance ventilation system with dedicated ducting so you can “dose” the fresh air per occupant designed per CAN/CSA-F326-M91.
  2. A good ventilation system is balanced (out with the bad, in with the good), is fully ducted and earns its keep when installed in an air tight home (less than 2.0ACH50).
  3. If municipalities compel home owners to add more mechanical ventilation, they should justify it with results of an air tightness test and also recommend the house be made more air tight.  Don’t rely on the HVAC technician to cobble something on the spot.
  4. Discourage fireplaces and seal up Rumfords, install sealed combustion appliances, promote the sexiness of induction cooktops and electric broilers and ovens.

In 2017, Part 12 of the OBC will change to require greater home energy efficiency and all prescriptive packages in SB-12 will require balanced ventilation systems. These changes will make new homes perform that much better, again, than vintage homes. However it would be unfortunate to see the municipalities push for balanced ventilation systems in partial renovations as a knee-jerk reaction without requiring that the building also be more air tight.

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Wake up Toronto, 2017 OBC requires Balanced Ventilation

Residential ventilation requirements and systems are poorly understood by many professionals, including municipal building inspectors. Yet, the next iteration of the Ontario Building Code comes out in 2017 requiring heat recovery in ventilation systems. It’s time we get it right for balanced ventilation systems like Enthalpic/Energy Recovery Ventilators (ERV) and Heat Recovery Ventilators (HRV). Will we be ready?

We test a number of high-end renovations and new residential construction projects and often, the balanced ventilation systems gets shockingly short shrift from builders and municipal inspectors. Some ventilation systems we’re asked to commission, but some systems we just happen to see glaring issues and feel morally compelled to say something to the builder or owner. Below are a series of photos taken of mechanical systems installed after 2014 in the Municipality of Toronto. The common issues we see in the field include:

- HRV with no condensate connection: Yes, it’s true that ERVs don’t require a condensate connection but HRVs do require a connection.

 

Condensate HRV

This HRV’s condensate nipple would have ensured 1.5″ of water under the core before it drained out… onto the floor.

No condensate hose

You can see if from a mile away, there’s no condensate drain hose under that HRV.

- E/HRV’s with the “fresh” air intake adjacent to 3 combustion appliances: cooking, hot water and forced air furnace.

Conglomerate

This composite image is of a wall section on a house. Yes, the flapperless brown grill (1st from the left) shows the ERV’s sucking air between the DHW, furnace and kitchen range exhaust. Stunning on a house built in 2015. See below for the close up.

HRV intake

HRV fresh air intake between a rock and a hard place. Trades and municipal inspectors need better training to avoid making these glaringly obvious mistakes.

- E/HRV’s with no insulation on the Fresh air Intake and a few other issues.

P1040099 Adjusted

While prepping for a duct leakage test, I noticed the fresh air intake was uninsulated…. OK that’s not all, in fact this unit didn’t have a stale air exhaust connected and all the punch-outs were still in place. A very incomplete install. I couldn’t believe my eyes. See accompanying image below.

Knock-outs

All metal knock-outs still in place, and the two back wall foam knock-outs are also still in place… With only one pipe, was this really inspected?

- E/HRV’s with excessively long or small diameter ducts to outside. For the record, most residential grade E/HRV don’t have much static pressure and therefore the duct runs that connect the unit to the outdoors are always large diameter (starting at 8″ID), run through short (ie less than 12′), hopefully smooth walled ducts. The cumulative duct length below is about 45′ each leg. About 60′ in total if you include the sections of corrugated flex duct. Adding insult to injury, the 4″ID lengths are sure to choke the flow down to a trickle. Note that the fresh air intake should be insulated all the way.

Flex Duct

Coming off the HRV, two flex duct lengths joined to two bare metal, straight galvanized ducts. Continued next frame along steel beam.

Ventilation Ducts

Fresh air intake of bare, smooth metal ducts as they pass along the steel beam transition to a smaller diameter duct and turn to go out the wall. Continued below.

Two elbows

Diameter reduction in metal pipe with two elbows as the metal transitions to a 10′ length of flex duct.

Stale air exhaust

The stale air exhaust pipes terminating outdoors with a diameter reduction in metal pipe with two elbows as the metal transitions to a 10′ length of flex duct.

- Insulated ducts: Why do we have to wait for this simple technology to make it to North America. Please let’s do get long, insulated and nearly seamless pipes!

German ducts in a row

This is what I call getting your ducts in a row: insulated, easy to air-seal and fewer seams. Available through Pinwheel Builds!

ERV ducts through thick wall

Pro Tip: Sleeve your walls early and use a seamless section of pipe to prevent in-wall condensation, especially if you have deep walls.

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How to Make it Air Tight: Move the AB Outside!

There’s no trick to making buildings air tight; pick the least penetrated sheet good either on the inside or preferably the outside of the building and seal everything to it. It’s that simple folks! Check out the image below:

 

Exterior Air Barrier

Portland Maine’s Jesse Thompson‘s got it figured out; put the air barrier on the OUTSIDE and seal everything to it! See the window bucks on the right; the pans are flashed! In the above, the insulation ideally will be placed tight against the air barrier. If you think this house won’t look groovy, you’re wrong, check out the rendering below. Canadian carpenters; take note.

I hope the house above will have overhangs added for protection of windows, doors and walls from the elements. Admittedly adding framing lookouts in situ is tougher than to build rake walls on the ground, but either way, this house has made air sealing very simple. The electricians and plumbers can drill away inside and it won’t affect the air barrier.

P1040481 (Medium)

The taping festival goes on in Ontario and it’s 2016. We know better, stop with the 6mil poly masquerading as an air barrier. Let the poly be what it’s supposed to be; a vapour barrier only! Then put your air sealing efforts outside where you won’t have to air-seal a million holes around framing, wires and plumbing penetrations. Besides, the OBC says if the above poly is the AB, the seams need to be clamped.

 

The other great advantage of sticking the air barrier, hopefully with shingle-style lapped seams, to the sheathing is that no air can travel under the fabric air barrier and its substrate. Tack on the vertical furring strips for the drainage layer and it makes for a durable air barrier. So if you’re considering making your indoor 6 mil the air tight layer, give us a call, we’ll show you why your building won’t perform optimally.

For the record, the blue house above will look like this when completed:

Thompson Kaplan Arch

If you were thinking the house wrapped in blue Henry VP100 was going to look square, think again; this rendering is what Kaplan Thompson Architects have in mind for their build. Fresh, contemporary and very appealing.

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What are the Feds doing for Building Efficiency?

“Budget 2016 proposes to provide $128.8 million over five years, starting in 2016–17, to Natural Resources Canada to deliver energy efficiency policies and programs, and maintain clean energy policy capacity. These resources will support improved energy efficiency standards and codes for products, buildings, industry and vehicles, and further the development of a legislative framework for offshore renewable energy projects.” reads the fed’s website, but if you’re wondering what the fed’s are proposing in their new budget for building energy efficiency, it’s a sea change from the last regime.

But as Elizabeth May says “… but when comparing Budget 2016 with the last Liberal budget – from former Finance Minister Ralph Goodale in 2005 – this one misses the mark on climate action,” said Elizabeth May, leader of the Green Party of Canada.”

Green Party Secretary Dan Palmer goes on to say “The 2005 budget offered a fully formed climate action plan, including eco-energy rebates for homeowners, substantial funding for provinces to act to address the climate challenge, rebates for the purchase of energy efficient vehicles, and a carbon pricing scheme through a complicated carbon credit approach. The 2016 budget contains none of these measures.”

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The Ground Source Heat Pump: SB-12′s Silver Bullet or Hail-Mary Pass?

Since 2012, for the well-to-do who want to build a new house anywhere that’s not serviced by a natural gas line in Ontario, the decision making process for custom homes with lots of glass eventually whittles down to installing a Ground Source Heat Pump (GSHP). But is the GSHP a Silver Bullet or a Hail Mary pass when it comes to SB-12′s distorted view of energy efficiency?

Heat pumps are brilliant machines and unlike the electric baseboard heater which converts electrical energy directly into heat, a heat pump uses electrical energy to “move” heat. A GSHP moves heat from the ground into the house in winter time but in summer time, it pumps the heat out of the house back into the ground. The same with an Air Source Heat Pump (ASHP), except that an ASHP moves heat from the air in the house to the air out outside. Because heat pumps move heat instead of generating heat, they are up to 3 times as efficient in their use of utility-based electricity.

It’s that last point that has many new home owners with GSHP in Ontario feeling the sting. As electricity prices keep going up, any GSHP that happens to run on auxiliary heat the during utility’s peak prices, will see a massive spike in heating cost. Remember, time of day use varies from 8.3¢ per kWh to 17.5¢ per kWh and at twice the price, it doesn’t take long. Imagine filling your car’s gas tank during rush hour for $2 a litre as opposed to filing up off-peak for only $1 a litre; when would you shop?

Putting aside Henry Gifford’s contention that “heat pumps actually use more fossil fuel than a furnace or boiler” one cannot deny that their exact energy performance isn’t always cut and dry. There are many factors that go into designing and installing a GSHP system and it should be known that identical systems installed in 2 different locations by different installers and used by a different occupants with different lifestyles will have an impact on the performance of the GSHP.

For example, did you know that some loop fields need to be “recharged” with summer-time heat and actually depend on the occupant using the AC to pump heat back into the ground or risk running out of stored heat the following winter? Did you know that a GSHP system’s loop length is something not to be be trifled with and that it needs to be purged with a very high powered pump when commissioned? Commissioned? Yes, your installer should provide you with a Commissioning Report. You’ll also need a very large electrical panel; 60A for the pump, 60A for the auxiliary heat (read: electric resistance heating).

Where the vagaries of GSHP systems seem to be given short shrift is in the Ontario Building Code. SB-12 relies on old energy modeling software used to calculate “compliance” to building codes and gives the GSHP with electrical resistance backup accolades that might not always be deserved given the potential for variance in their mechanical components, geological fields, occupant lifestyle and control parameters.

Remember, if you’re going to install a GSHP, get it commissioned per link above but first have an expert energy modeler help you reduce your loads. Not all software is equal and you may want to follow many of the Passive House principles to help you design with thermal comfort in mind. If installing lots of thermally weak components like windows, don’t cheap out; invest in high performance windows that are sized to benefit the occupant’s comfort and compliment your HVAC system. We’re also looking forward to the 2017 version of SB-12 that will see the adoption of new more powerful and specialised software – WUFI Passive -  that can help the design community avoid thermally weak envelope designs by calculating interior surface temperatures of window frames and exterior walls to avoid drafty feeling rooms and windows condensation.

Remember, don’t paint yourself in a glass corner; if you have large wall(s) of glass in a given room, the room should be thermostatically controlled and zoned independently to optimize comfort. Finally, if you’re betting on the Hail-Mary pass, heed Peter Yost of GBA words “Ground-source heat pump systems work great if you have an expert installer, for both the above- and the below-grade work, and you stick with the leading manufactured systems. Play with either or both of these and you are playing with fire.”

 

 

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Compliance VS Performance Energy Simulations

As change to the energy performance of proposed buildings goes through the meat grinder of the legislative process, we’re keeping our fingers crossed that the Ontario legislature brings meaningful change as they, rightly, slap consumers with higher electricity costs – albeit still substantially lower than EU rates. As a special to the Globe and Mail, John Lornic wrote two columns a few days ago focusing on the issues highlighted by Ted Kesik “a professor at the University of Toronto, [who] says the condo developers have exploited a loophole that allows them to erect towers clad in one of the least energy-efficient materials: glass.”

The sad truth is, it’s not just the high-rise sector that exploits energy simulation or modeling loopholes. The energy modeling loopholes also apply to the low-rise residential sector and BlueGreen Group is starting to see the fruit of the 2012 OBC changes in the volume of complaint calls from luxury homes, often with substantially more than 22% window to wall ratio. These well-to-do homeowners want to know what can be done to their new home to make the rooms more comfortable or figure out why their Ground Source Heat Pump is always running on auxiliary electric resistance as opposed to drawing from the bore field causing electrical bills in winter in excess of $2000. A $2000 monthly electrical bill isn’t chump-change, even for a rich guy.

Lornic touches on the Compliance concept in his second article saying “Despite all the political rhetoric about emissions reductions, if you want to build a really efficient home, you can’t rely on the code – you need to hire specialists to design it.” As we blogged a few days back about the myriad changes to SB-12 proposed for 2017, we wish more would have been done but hope at the very least that the proposed changes stick.

The proposed 15% increase in overall energy efficiency might just mean that serious changes to the building envelope and significantly better windows get installed – which by the way are still getting short shrift from building inspectors who rarely check that installed window performance is in compliance with what was promised in the Energy Efficiency Design Summary. For that matter, there are countless windows being installed TODAY that are NOT ENERGY RATED!

Compliance energy modeling differs from Performance energy modeling in that it only seeks to satisfy the bare minimum requirements building code. Compliance is the absolute minimum required by the code and it’s often calculated by a quirky piece of software – HOT2000written before the iPhone was available.

Whereas, performance energy modeling seeks to minimize utility bills and if the professional doing the energy modeling has a good grasp of building science, they bring comfort into the equation too by using more modern software like WUFI Passive. This is where the confluence of field experience and a deep understanding of how energy models or simulators work.

Just because an energy model says its OK, it still doesn’t trump common sense when designing a building and our diagnostic business is confirming that builds merely ‘complying’ with the code have some new home owners VERY frustrated. Some have been allowed to pain themselves into a glass corner, some were promised the Ground Source Heat Pump was a silver bullet.

Either way, if you’re an architect or design build firm, drop compliance energy modeling like a hot potato; it’s a liability to your reputation. Hire experts that do performance energy modeling and who can help you detail your building envelope to produce a home your client will be both comfortable paying the utility bills or lounging by a large window on a cold blustery day.

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Proposed Changes to SB-12 are Posted

Kyle Anders of Mindscape Innovation wrote a great blog piece highlighting the proposed changes to OBC’s SB-12. The following is an excerpted quote from their great monthly news letter:

The Ontario Ministry of Municipal Affairs and Housing (MMAH) is working to finalize the next version of the Supplementary Standard SB-12 (2017). SB-12 is the standard that Ontario home builders (i.e. for Part 9 buildings) must use to meet the minimum energy efficiency design requirements of Part 12 in the Ontario Building Code.  This SB-12 update will include more stringent energy efficiency requirements for new homes, in order to achieve the mandated target of 15% energy savings versus the current standard.  This is the first major SB-12 update since its inception in 2012, and it will come into effect for all permit applications after December 31st, 2016.  MMAH is requesting input from key stakeholders in the building, design, manufacturing and municipal government sectors to help finalize this standard, and has provided the following documents:

1) Draft MMAH SB-12 (2017) Version

2) Background Document and Comment Form

Anyone who cares about the future energy efficiency and cost effectiveness of new homes in Ontario should pay attention to this and have their voice heard on the issue.

 

Key Changes Proposed for 2017 Version

  • 15% Energy Efficiency Improvement: Each SB-12 package is designed to be 15% more energy efficient than current SB-12 packages, based on an ‘average’ home.
  • Fewer Packages: To reduce redundancy of unused packages in the current version, the proposed number of prescriptive packages will be less, e.g. 6 instead of 13 for the scenario of Zone 1 – Natural Gas.
  • Now in Metric! Metric thermal values are now included in addition to imperial.  Metric continues its slow and steady march to global domination
  • Effective Thermal Resistance: Minimum thermal performance values for various assemblies are now listed in both nominal and effective.  This will give a boost to buildings that use exterior continuous insulation, well the actual performance of the entire assembly, including thermal bridging through the studs, is recognized.
  • Mandatory Heat Recovery Ventilators: Heat Recovery Ventilators is proposed to be mandatory across all packages, in order to facilitate better indoor air quality in airtight homes.
  • Credit for Reduced Air Leakage: Recognition for demonstrating increased airtightess of the building envelope with a blower door test has been added.  Improved airtightness can be used as a substitution for various insulation upgrades.
  • Drain Water Heat Recovery (DWHR) Tradeoff has Been ‘Discreetly’ Removed: While MMAH doesn’t specifically indicate this in the list of proposed changes in their Backgrounder document, the proposed SB-12 (2017) update has been scrubbed of all traces of DWHR: where builders currently have the option of being credited for including DWHR by trading off another upgrade, they will no longer have this option under the drafted SB-12 (2017) update.
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