Openng the Window on Facts about Ventilation

As a metaphor, the open window conjures so much positive imagery; namely the connection with the outside world. Because most operable windows are human-sized, it’s usually a “one-on-one” intimate connection. So it’s not hard to imagine why we love the concept of open windows.  The open window, however, fails miserably as a dependable ventilation device and building professionals (read “architects”) need to understand why windows can’t ventilate reliably. They certainly won’t ventilate economically as Ontario moves to tax carbon.

Johannes_Vermeer_-_Girl_Reading_a_Letter_by_an_Open_Window_-_Google_Art_Project (2)

The draw of natural light and wind blowing through the house is powerful, but let’s not get carried away with this ancient technology. There’s a better way to ventilate; heat recovery with a dedicated distribution system. Girl Reading a [BlueGreen Group blog-post] at an Open Window, Johannes Vermeer.

Don’t get me wrong, I live in a tight neighborhood of semi-detached, century-old, Edwardian houses without Air Conditioning (I don’t recommend that either) and we rely on the centuries-old technology of “open windows.” At the very least, the open window ensures a connection with the neighbourhood and occasionally, the cooler night-time air brings in temporary relief along with a night-time sideshow. We hear intimate conversations of late-night lovers waltzing by, raccoons arguing over food scraps, and occasionally, the melodic, eerie voice of a neighbourhood chap who sings dreamy ballads as he walks. Top that all off with the morning chirps of cardinals and robins followed by a mess of starlings and your circadian rhythm stays in lock-step with the world around you.

The bad news is that often that cool air is laden with humidity and besides the animated street-life drifting in, we get dust and pollen. Lots of pollen. Pollen that could be easily filtered by a quality ERV’s pre-filter. The really bad news about open window ventilation is that it’s very inconsistent where a few rooms get over ventilated (3rd floor) and others get under ventilated (basement).

Ask any architect, and I do almost every time I give a technical talk, “How many glasses of water does a human need a day to stay healthy?” and almost universally, they respond with “8 cups of water per day!” Bravo, we have a baseline. The follow-up question however is always met with blank stares; “How many cubic feet per minute of fresh air does a human need to feel healthy?” The guesses are wild. The follow-up questions are “How long can you live without a glass of water?” followed by “How long can you live without fresh air?” So why the short-shrift on proper ventilation in architecture school?

Here’s a Pro Tip: The architect won’t be paying your monthly utility bills, so unless they’re Passive House enthusiasts, don’t rely on them for mechanical advice and stick to your guns. Repeat after me “I want a balanced ventilation system with heat recovery, that’s fully distributed.” Thankfully, in 2017, the heat recovery part will be law in Ontario under SB-12, but you still need to ask for good controls and a dedicated distribution system.


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Natural Gas vs Induction Cooking

Gas vs Induction Cooking Energy Comparison

This was originally posted by Paul Scheckel on June 14, 2016 at 6:10am in LBL’s Home Energy Pros. None of the content below was written by BGG, but we do find Paul’s write up a compelling argument for induction and thank him for posting it!

Comparison Between LP Gas Range and Induction Burner

Admittedly, this is a simple and very limited analysis, but it does offer some useful information. I wrote about induction cooking 2 years ago, the cost has since come down enough that I recently bought a single coil, counter-top unit, and after a week of use, the numbers are in.

As a long-time gas range cook, the switch to induction takes some getting used to, and it only works with pots that are magnetic. But I like that it heats fast and I can dial in the temperature fairly tightly. Of course, I didn’t trust any of the ad hype, so I got out the meters and the spreadsheet. Here are the results.

Gas range, 7,000 BTU burner: time to boil 1 quart of 60°F water was 8 minutes 30 seconds, consuming 992 BTUs of heating energy.

Induction cooker: same pot, same temperature and quantity of water, the burner draws 1,300 watts (4,436 BTUs) at the highest setting and took 5 minutes 50 seconds to boil. Total electrical consumption was 0.126 kilowatt-hour of electricity, equivalent to 430 BTUs of heating energy.

If there was a 100-percent efficient way to boil a quart of water, the energy required would be about 317 BTUs, the basis on which to calculate the efficiency of each unit.

The induction cooker is 74 percent efficient at transforming and transferring input energy to the water, and the gas range comes in at 32 percent. The induction method was 32 percent faster and consumed 57 percent less energy.

Efficiency and speed are compelling reasons to use induction cooking, but because I live off-grid, induction will be my go-to cooking method when sunshine is ample, offering an option for fossil-free cooking!

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We Can See the Signs

Change is coming and we can imagine the signs:

Pinch Me (Medium)

I can see the future and its bright!


In with the new and out with the old:

For Rent (Medium)

So ripe for mockery! This is the holy trinity of all that’s wrong with North American perception of luxury; zero consideration for comfort, health or utility bills…yet!

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BGG Delivers TSA Technical Series Talks on 2017′s SB-12

We’ve been invited by the Toronto Society of Architects to give a Technical Series Lecture June 22nd to be held at Daniels Faculty of Architecture (College and Huron Streets) at 6:30. Free for members, $10 for non-members, click on the links below to register:

The Ontario Ministry of Municipal Affairs and Housing is working to finalize the next version of the Supplementary Standard SB-12 (2017) and has published a draft version.  The central thrust of this SB-12 update is for a 15% greater building energy efficiency than currently required for new homes.  In this talk we’ll cover the key changes proposed which include; fewer packages, crediting envelope air leakage reduction, requires heat recovery in ventilation systems and will favour continuous insulation as effective assembly R-values are listed.

Taplin-Weir Inc.

TSA members can register using the promo code provided in the June e-Bulletin. If you are a member but are not subscribed to the e-Bulletin, please contact the Executive Administrator at If you are interested in becoming a member please visit our Membership Page.

These TSA Technical Series Lectures is approved by the OAA for 2 hours of Structured Learning Continuing Education credits.



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Infrared Scanning of Large Office Buildings

The Office Building ii

Composite image of large office building.

As part of a Building Envelope Commissioning (BECx) package, building owners often require infrared scanning of their building’s envelope, or enclosure, as part of a commissioning process. However, the methods for air barrier integrity testing are poorly understood and rely heavily on the building’s HVAC system and the vagaries of mother nature. If the standard selected is ASTM 1186 Standard Practices for Air Leakage Site Detection in Building Envelopes and Air Barrier Systems, then we have some recommendations; wait for a cold day, scan the indoors too and BYOF – Bring Your Own Fans!

The standard suggests a delta T of at least 5oC between indoor temperature and outdoor temperatures. The standard also assumes the building’s existing HVAC system will be able to pressurise the building to see if any hot spots can be identified from the outside. The standard requires a 20Pascal difference between inside and out, though its rarely achieved in tests as most thermographers don’t carry the equipment to measure pressure difference. The idea is that with the building pressurised, air leaks out of the envelope where breaches are and the thermographer can usually detect the leak(s) by means of surface temperature abnormality.

As soon as the initial scan is completed, then the indoor volume is depressurised to reversed air flowing through those breaches. Typically, the existing HVAC equipment is used to depressurise the building and the hot spots are scanned again to see if there’s a change from the pressurisation state. Typically a change in surface temperature between the depress/pressurisation states indicates a breach in the building’s air barrier system.

DSC_0510 (Small)

BYOF: When the existing HVAC can’t reach 20 Pascals, it’s time to pull in the big guns! We have ‘em; the dirty dozen Model 3 TEC fans will move a lot of air to really highlight the contrast in air barrier leakage diagnostics using infrared.

For success, it should be noted that ASTM 1185’s suggested minimum of 5oC is too low. The building owner would be well advised to re-schedule the scan for cooler exterior temperatures that are greater than 10oC. The mechanical operator will say, but “I can bring the temperature up!” and yes it might be possible, but it takes a great deal of time, especially if the building is using radiant heat or has large thermal mass that wicks up the heat.

Our experience on recently tested commercial office space suggests that the existing HVAC equipment can’t reliably create enough pressure change on the building envelope. ASTM 1185 suggests that a minimum pressure difference on the building envelope should be 20 Pascals. Getting the building up to 20Pascals of indoor pressure was possible, but getting the building to depressurise was not possible with the building’s existing HVAC equipment. Luckily we had brought and installed 8 Model 3 fans from The Energy Conservatory. This allowed us to precisely control the pressurisation and depresurisation stated so that we could do our scanning without the pressure dropping.

8 fans A 2

Using portable fans, we can control the pressurisation state of the building with consistency not achievable with the building’s HVAC systems.



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Remove that Renovator!

What’s wrong with the picture below?

Fire the Renovator Md

This 1890’s Victorian-era home in Toronto is being renovated and the early signs don’t look good. The dimensional lumber sheathing is exposed after 120 years and what an historic and great opportunity to install an air barrier and continuous insulation on the outside to go with those nifty black framed windows.

At the very least, this reno has two strikes against it: poor detailing for energy efficiency/comfort  and a complete disregard for durability due to eventual rain water intrusion around the windows.

First the Air Barrier, then the window…

Fire the Renovator - Window

The roughest opening I ever saw. A good renovator lines the rough opening with an water tight Self Adhered Membrane (SAM) on the sill with lapped edges, then lines the top and sides with a breathable air barrier. These RO membranes are tied into the exterior (weather resistant) air barrier and lapped to “drain the rain” as Dr. Joe says. Better yet, flash the RO with a liquid applied air barrier.

Once the windows are installed, it’s nearly impossible to achieve a good air seal if planning on using and exterior air barrier. It’s also game over for lining the window’s rough opening with a sill dam to prevent water from getting into the wall assembly below; remember what Joe Lstiburek says about water leaking though windows “There’s only 2 kinds of windows; windows that leak and windows that will leak.”

It’s a clear sign that many renovators in the GTA aren’t qualified or educated about proper building envelope detailing. Nothing a bit of hands-on training can take care. Although there’s no hands-on the OHBA’s Institute of Building Excellence offers renovator training for building science in order to get renovators thinking about these details.

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The Most Air Tight Home in Ontario?

Energy consultant Andrew Peel and home owner Alex Waters have teemed up to build a beautiful new house in Innisfil Ontario this past year with amazing success. Nestled in the trees, this lovely house was the most air tight house I’ve ever tested handily beating the European Passive House standard’s air tightness limit of 0.6 ACH50.


P1040778 Cropped (Small)

Having tested many houses in my day, I thought I was prepared with my ‘C’ ring, a ring that converges the little air flow leaking into this house through a smaller than typical hole. It wasn’t enough! Caught completely off-guard, I had to go back home to pick up my ‘D’ Ring. It was the first time I used a ‘D’ ring and doubted I’d ever need to use it!

P1040787 Cropped and Adjusted (Small)

The proud home owners, Mr. Waters holds the the TEC ‘D’ ring posing for a picture in front of the blower door. Good work on the air sealing!

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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 (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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