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UPGRADE YOUR HOUSE Part 2: The Solution To Your Sick Home

Updated: Feb 21, 2023



This is a follow-up to my article "Is Your Home Slowly Killing You?", and here I present the solutions.

Houses and apartments in Canada are heated by several methods, some of which are a little more efficient but over the course of a year not cheap to operate. Some parts of Canada have mild winters and others have brutal winters, but we all have a prolonged subzero season. Dad says turn down the thermostat and grab a sweater.


Many people spend tens of thousands of dollars on renovations to update their homes often not for worn-out items or even to improve the functionality but to keep up with fashion trends in home design. After twenty years, maybe the oak panel kitchen cupboards are passé, the plastic laminate bathroom counter is so 1990s, or hardwood flooring would be so much more contemporary than that nasty, old carpet. While someone understandably wants to update the 'look and feel' of the home, it looks like there's a bit of mildew around the windows, and it feels cold next to the exterior wall during the winter. New drapes don't fix that.

By adding insulation to the roof, to the walls, and - if it's a new house - to the floors keeps the house warmer during the heating season. If you recall the explanation from my previous article though, the studs in the walls are thermal bridges and detract from the overall insulating effect. You know now that thermal bridges are where there is much higher risk of condensation on the interior surfaces and consequently an opportunity for mould growth. Adding a continuous layer of insulation around the outside the structure nearly eliminates the thermal bridges and condensation. Continuous insulation can also be added on the interior of the structure, but it does have a few comparative disadvantages.


In my earlier article, I pointed out how leaky most residential construction has been and continues to be. Since a large amount of heat is lost by warm air escaping through the gaps, cracks, joints, and penetrations, the energy required to heat that air is wasted. The entire volume of air inside your home is lost through unintended leakage at least twice an hour and as much as ten times an hour depending on the age of the house and the quality of its construction. Apartment buildings are a little better, but still can be expected to lose their air several times an hour. That is literally money flying out the walls. By sealing all joints, cracks, gaps, and penetrations through the walls, roof, and floors; this air loss can be brought down to around 2% of what it was. Not a typo, not 20% -- but 2%.

Some of you familiar with analyses of the Leaky Condo Crisis may rush to point out that sealing the building enclosure was the main cause of the leaks. The first part of my response is: attempting to seal both the interior and the exterior faces of exterior walls while not providing appropriate cladding drainage detailing is one of the factors contributing to the problem. The second part of my response is: procedural issues and errors were the other main factor contributing to the problem.


In the middle of winter even in our mild climate, a typical Vancouver Special will run a heating bill of $200 for January fairly easily regardless of whether heating is by gas or electricity. Electricity rates are currently 9.3 cents up to about 1350kWh, and 14 cents above that - an increase of 5% over the previous year. If you cut the heating required by 90%, your monthly heating bill is only $20 - that's the price of three or four cups of StarWaveBlenz coffee.

How do we magically drop the electrical demand by 90%? Enter the star of the show: the heat recovery ventilator (HRV) - or sometimes energy recovery ventilator (ERV). An HRV/ERV for an average-sized home is about the size of an undercounter refrigerator and has a heater attached; the system runs about 1500W - about the same amount of power as a hairdryer or a toaster.

Replacing the heating system with an HRV or ERV will save you an appreciable amount of money in the long run, but the key to huge savings is when you combine it with the other measures. Since we've added much more insulation around the building to keep the warmth in; and we've sealed the walls, roof, and floor to prevent the heated air from escaping; a small heater is all you need to keep the space warm.

When I say keep the space warm, I mean keep all spaces in the house actually warm and feeling warm -- right next to the window, in the corner of the bedroom, in the bathroom, anywhere. I also mean keep those spaces warm all the time. Because you're not "turning down the heat" at night to save money, the bathroom floor tile and the kitchen counter are both just as comfortably warm as they were yesterday afternoon -- between 20°C and 25°C year-round. Unlike a home that uses radiators (electric, chimney, hydronic, or steam), there are no cold, damp corners. The temperature at any location will be within 2°C of that in any other location. There's also little stratification - the tendency of air temperature to be lower at the floor and higher near the ceiling. The difference in air temperature in this new system is only 3°C between your head and your toes. You're walking around in shorts and a t-shirt 365 days a year.



But wait, there's more! As noted above, the HRV/ERV isn't something that you would generally install in isolation. Likewise, the benefits of an HRV/ERV system go far beyond just saving appreciable money on heating costs.


The HRV/ERV is installed as a system that blows fresh air throughout your home. The key difference between it and a furnace is that it runs all the time yet still costs far less over the course of a year. By running full-time, every room into which air is supplied is guaranteed fresh air all times of the day every day of the year - not just when the thermostat hits a threshold and not just during the heating season like a furnace. That constant supply of fresh air to the living room and bedrooms migrates to the bathroom and kitchen where it is extracted by return ducts that go back to the HRV/ERV to be exhausted from the building.


A typical residential HRV/ERV is outfitted with a MERV-13-rated filter. A filter of this type will trap allergens, fine dust, tobacco smoke, and bacteria that most furnace filters do not. In addition, a HRV/ERV may be outfitted with a HEPA-rated filter which filters out even more particulates and ones smaller in size. Over the past year, Australia and Western North America both experienced massive wildfires that lowered the outdoor air quality even in major cities that typically have relatively high air quality.

These photos are from Oregon and Australia but also New York and Vancouver - far from the sources of the fires. Regardless of where you live, you may be faced with days or weeks of smoky conditions. Homeowners from several affected cities around the world recently shared in an online conference their experiences during the wildfires; all of them had already been using one or more home air quality monitoring devices on an ongoing basis. The homes had HRV systems and were significantly more airtight than typical residences. Each of the owners improvised a HEPA pre-filter or post-filter, and the single filter was enough to bring the level of airborne particles down to a safe limit because the homes were fairly airtight and the ventilation systems operate around the clock.

smog in Beijing

When a city isn't blanketed in wildfire smoke, a resident's HRV/ERV is still filtering out to differing degrees a diverse mix of airborne contaminants. For example, a MERV-13 filter removes a majority (60% according to one study) of the diesel exhaust and nearly all (>99.97%) of tire dust and brake dust. Allergens and pollen are nearly all filtered out - all day, every day, year-round.

false colour scanning electron microscopic photo of SARS-COV2 virus

Though there are still some people who dispute the impact of face masks on transmission of viruses, one must understand that a filter does not work like a net or even like a sieve. A particle that is smaller than the typical opening size is more likely to pass through, but it is not guaranteed to pass through. Re-read that last sentence, because it's not an obvious truth. In addition, particles smaller than 0.1 microns have such little mass and therefore inertia that some of them are stopped or deflected by electrostatic forces, molecular forces, and collisions with air molecules. In other words, some particles that are smaller than the size of the openings will be trapped. These reasons are why a two-layer tight-weave cotton mask worn properly does decrease substantially the passage of a virus despite the virus size being miniscule compared to the openings in the mask. A HEPA-rated filter by definition must trap at least 99.97% of particles 0.3microns in size. Coronaviruses (MERS, SARS, COVID-19) are 0.1 microns in size (+/- 40%). One Minnesota study found that HEPA filters trapped 99.9% of silver particles 0.02 microns in size (a third the size of a coronavirus). One could reasonably infer that the effectiveness of HEPA filtration of coronaviruses would be similar.


photo of water drops on a window glass against an overcast sky in the background

A well-designed forced-air ventilation system that operates around the clock is able to control humidity. A healthy and comfortable level is between 40% and 60% relative humidity, with 45% being the optimum. Supply airflow adequate in both volume and speed will cause air circulation in even most corners of a room. As well, the constant replacement of just the bulk of air in a room encourages localized high-humidity air pockets to give up their moisture by simple diffusion. The ongoing replacement of indoor air helps keep the indoor relative humidity level comfortably low.

There are situations - usually very cold climates - in which the rate of airflow through an HRV to satisfy fresh air requirements lowers the indoor relative humidity too low. These situations are the reason for the ERV; the ERV differs from an HRV in that it recovers moisture from the outgoing, stale air and injects it into the fresh air stream. The recycling of the moisture keeps the indoor relatively humidity comfortably high.



So far, I've presented the cost-savings, fresh air, pollution filtering, and healthy & comfortable relative humidity. It gets even better though.


We know that natural daylight is psychologically beneficial. Provided the level is high enough without creating glare, sunlight and daylight are the most comfortable forms of lighting in a space. Proper daylight design also is the most diffuse and brightest type of light and therefore the best suited to nearly any task. The improved design system I present uses sunlight as a means of providing heat to the building's interior but curtails the solar gain to prevent overheating. The result is having throughout the home maximized daylight and sunlight tempered by the use of overhangs or exterior shading devices.


An environment in which the air does not move at all feels stifling because perspiration does not evaporate well and because of the air quality issues I discussed in my last article. If the air moves too quickly, we feel this as a draft. The designed air velocity in this improved ventilation system is kept below 0.08 m/s - the average speed at which most people begin to feel a draft.


The superinsulation of the building envelope and its airtightness virtually block outdoor noises from entering the home. This is an obvious benefit to urban inhabitants - no more sirens, garbage truck squealing brakes, or motorcycle exhausts - but even suburban residents will enjoy not having to listen to the neighbour's lawnmower, the road noise of occasional passing vehicles, or even the blustering of heavy rain and windstorms. In fact, a home designed well enough can be so well-protected from outdoor sounds that the operation of the refrigerator for most people is the most noticeable sound.


You may recall a section in my previous article, under the heading 'YOUR BRAND NEW HOME IS ALREADY FALLING APART'. When a high level of airtightness is actually achieved and appropriate moisture-control measures are designed into the building envelope, the building will last far longer. By also using durable products whose properties do not noticeably change over time, a building designed and constructed well enough may perform well for a hundred years.



I know that everyone who's read the description above would love to live in a home - either a house or a condo - designed in this way. What I've described isn't imaginary, it isn't hypothetical or theoretical, and it doesn't require great wealth or overly-sophisticated construction to achieve.


As if complying with any of the current energy efficiency standards isn't confusing enough, telling them apart and making sense of which one you need is that much worse.

  • The R-2000 program was developed by the National Research Council of Canada as a standardized means of achieving energy efficiency and indoor air quality in new building construction, beyond what was required by the Building Code.

  • HOT2000 isn't an energy standard but instead an energy loss and design tool. Energy Star for new homes was developed by the U.S. EPA, is now managed also by the U.S. Department of Energy, and requires a building constructed to consume only 85% of the power of a baseline building code compliant building.

  • ASHRAE 90.1 is a U.S. standard currently listed in the Canadian National and British Columbia Building Codes as one acceptable design standard for the energy efficiency of a building.

  • Net Zero Energy Ready is an undefined concept promoted by the Canadian government, that suggests consuming only as much energy as is produced.

  • Energy Step Code is a set of requirements developed by the government of British Columbia that involves maximum energy use limits and maximum air leakage rates determined by airtightness testing.


One of the big weaknesses with almost all of the systems and standards listed above is that they are theoretical calculations that do not hold the actual constructed building accountable to the designed energy efficiency performance. A second, big weakness with all of the systems and standards above is that they do not require drastically lower energy consumption. Significantly in some cases - yes, but not enough usually to yield worthwhile operating cost savings.

The third, giant limitation of the above systems is their sole requirement being energy use. They do not address or require adequate ventilation quality, air filtration, protection from outdoor pollution infiltration, uniformity of air temperature, elimination of noticeable drafts, elimination of damp spots, appropriate relative humidity, plentiful daylighting, indoor quietness, and a long lifecycle.

The Passive House standard does all that.

Passive House International established, maintains, and updates the standard and certification to the standard. This Passive House standard is applicable to nearly any building type and applies to all countries (though an American group calling itself PHIUS created a deviant version of the otherwise international standard).

The international Passive House standard was originally designed to improve energy efficiency, but it results in more thoughtfully-designed and more carefully-constructed buildings that are ultimately more healthy, more comfortable, and energy-efficient. In an this article 'Introduction to Passive House', I will show some more concrete examples of how a Passive House building is achieved.

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