Older home on wooded lot
Energy Efficiency, Passive House facts, Passive House resources, Retrofitting Older Homes

Retrofitting an older home to Passive House standard

Next stop in our new series on retrofitting older homes: changes to attain Passive House standard. We have received many requests from readers on how to transform an existing home into a passive home.

Everyone who follows this blog is aware that our mission is to build passive whenever we can. Building to PassiveHouse standard makes the home environment healthy, therefore translating into healthy living. It also makes the world a much healthier place as our dependency on petroleum-based fuels as heating and cooling sources is removed. Finally, a passive house is much cheaper to run. You can think of a passive house as the domestic equivalent of an electric vehicle.

IPHA guidelines

EkoBuilt follows the guidelines from the International Passive House Association. There is a lot of building science behind passive, so it can get very complicated, but it can also be explained and understood very simply. From a build perspective, the world is slowly transforming to become completely passive. Certain areas of British Columbia already mandate the passive standard in order to qualify for a new building permit. It’s important for everyone to understand as it will be here in Ontario sooner than we think.

Passive House Explained in 90 Seconds from Hans-Jörn Eich on Vimeo.

The video was made by Hans-Jörn Eich, a certified Passive House Consultant (Passivhaus Institute in Darmstadt, Germany) and the founder of Pinwheel.

Why does passive house exist?

It’s simple: to replace heating and cooling dependency on gas with electricity. That said, this is only economical if the heating/cooling demand can be reduced to a point where it’s inexpensive to use electricity, and this is where design essentials come into play.

There are three essential design features in a passive home:

1. Air-tightness

It’s vitally important that heat loss is minimized through unwanted and unnecessary leakage of air. We conduct what’s called a blower door test to find the ACH (air changes per hour) a home experiences.

Most newly built homes experience ACH anywhere between 3 and 5, meaning 3 to 5 times the entire volume of air inside the home escapes each hour. This is basically a loss of heated and cooled air which can also result in condensation in the wall cavities, translating ultimately to unhealthy mold.

For newly built passive homes, the ACH rate is 0.6 and the retrofit standard is 1.0.

Old school thinking favoured this air loss, thinking it good for fresh air to enter the building and provide a natural fresh air environment. We now know this is laughable because of all the mold problems we’ve heard about with older homes. To be fair to the old schoolers, in the past, modern building techniques/methods did not exist, nor did heat recovery ventilators (HRVs), so the options didn’t exist to change this approach.

Modern building code recognizes this fundamental change. For example, since 2017 Ontario building code has made HRVs mandatory in all homes, which we were thrilled to see happen. The problem is the HRV is only required to be 50% efficient and most homes are still leaking more air than they should.

2. Thermal envelope

Currently new-build homes, according to the standard building code, are required to have R22 wall insulation, R32 roof insulation and R10 below slab insulation. By comparison, in our local area, newly built passive homes require R75 wall insulation, R110 roof insulation and R40 below slab insulation.

As a general rule of thumb, homes retrofitted to passive standard require R48 wall, roof and below slab (or floor) insulation.

3. Proper windows

For thermal comfort, it’s very important that a passive approved window is used. These are triple glazed units with insulated frames equivalent to an R12. This may not seem like much, but compared to a non-certified triple glazed window, it’s huge. With non-certified units, it’s hard to find a unit above an R4 rating.

Certified windows optimize comfort by having a high temperature interior pane (instead of being cold on the inside when it is cold on the outside). In the passive scenario, this means when it is 25°C outside, the interior pane must be at least 17°C. Non-certified triple glazed windows can be as low as 12°C on the inside under the same conditions.

For those who would like the complete building science, please have a look at the following 20-page document, Criteria for the Passive House, EnerPHit and PHI Low Energy Building Standard (pdf). You can also view four charts at the end of this article.

How can an older home become Passive?

With all of that out of the way, how does an existing home reach the Passive standard?

To be achieved in the most cost-effective manner, this approach will obviously vary depending on the home in question, but some general rules apply:

For the walls: Airtight/vapor tight permeable layers and extra insulation will need to be installed. This will mean that either the interior or exterior finish will need to be removed (the choice will usually depend on which is most cost-effective). Certified windows and doors will also be sourced.

For the roof: If the home has an attic space (most do), extra insulation will be added to that space with an airtight/vapor tight permeable membrane installed on the ceiling side. If there is no attic, then an extra thermal later will have to be installed on the interior. If the ceiling is cathedral in design, it should be simple to build the ceiling down to the required R value. If the ceiling is flat and losing height is an issue, than a vacuum panel will be used to provide a thermal barrier with minimal loss in ceiling height.

For the slab/floor:  If a basement is unavailable/unusable, then a thermal layer will be added to the existing floor cavity. If a basement is present and usable, a vacuum panel will be used to provide the thermal barrier with minimal loss in height.

Interested in making your existing/older home Passive? Give us a shout, we’d love to help you realize that goal.

You may also be interested in our blog post on taking a staged approach to retrofitting your older home.

What is a smart home anyway?
Energy Efficiency, Home Building trends, Passive House facts, Simply Sustainable

Measuring how smart a home really is

When we talk about ‘smart homes’, there is a general bias towards technology. Consider this definition:

Standard smart home definition: noun “a home equipped with lighting, heating, and electronic devices that can be controlled remotely by phone or computer.”

At EkoBuilt, we see the smartness in homes very differently, using a sustainability lens.

EkoBuilt smart home definition: noun “a home designed to be autonomous without the use of electronic devices for heating or ventilation control.”

We also think the smartest homes can be affordably net-zero, taking their energy from renewable energy sources. Truly there is much confusion over what a smart home really is. Conventional thinking holds that a ‘smart home’ is one that uses more technology for control. But is that really very smart?

Shouldn’t a truly smart home need less technology?

We feel that a smart home is one that uses the least technology possible. It’s possible to design homes that don’t require all kinds of devices for control.

For example, a home should not need to be heated when the occupants are not there, and blinds should not be required because unwanted heat needs to be kept out. In a true passive house excess technology is not required because the space requires little heating or air-conditioning to be comfortable.

Using energy from the sun as a heat source, the home can be heated naturally even in extremely cold conditions. To reduce the need for air conditioning in hot summers, windows are strategically located to naturally shade themselves so unwanted heat is not coming into the home. This is a smart home!

It is more sustainable, and much smarter to use less technology, both environmentally and physically. There is simply no need to have a wi-fi thermostat. Why spend money to operate a furnace in an occupied or unoccupied home when you don’t have to? It is smart to spend as little money and to acquire as few devices for your home as possible.

Why passive homes are the smartest homes

Our point is of course, to communicate the intelligence of building to the passive house standard. It is, after all, the only truly resilient home known to man.

It is a home that uses so little fuel to heat and cool the space that the electric bills are approximately the same amount every month of the year, whether the home is being heated or not.

Not to be coy, every house, even a passive house, requires a heating system – especially in this part of Canada – but the passive house leaks so little heat (even during extreme cold conditions) that it costs very little to keep the space heated. Less energy, in fact, than a refrigerator uses in a year. Now, that’s a smart home.

Ever compared your home to a thermos?

Thermos passive house analogyA passive house is as close as you can get to living in a thermos! The key difference is the passive space has constant access to fresh air, while a thermos does not.

Seriously though – a good thermos can keep keep tea extremely hot for 24 hours, which is really quite unbelievable when you think about it. Well, a passive house is basically the same thing in a home. And that really is a smart home.

From a health perspective, it’s much safer to live in an environment virtually free of interior toxins or exterior pollution (propane or gas emissions), full of ample fresh air, and designed to last generations. Again, that’s a smart home.

Another vital feature of a truly smart home is that it be electrically operated. We’ve come to the point where a home designed to operate by propane and/or gas, is a home designed for the past. Fossil fuels are not the way forward. Homes for today and tomorrow need to be 100% electrically operated — it’s simply the only fuel source for sustainability. It’s also the best for our health and for our pocketbooks.

A home that helps to create a healthier environment is a home that is healthier for us, and energy savings translate into lower operating costs, and that means more money in our pockets.

In conclusion, a truly smart home designed for today should be one that is built to passive house standards. Realistically, every home in the near future will be required to be built this way, but why wait when you can start now!

Contact us if you’d like to learn more about building your passive home.

EkoBuilt News & Happenings, Energy Efficiency, Passive House facts

International Passive House Days 2017

Passive House residents around the world open their doors Nov 10th – 12th, 2017. The EkoModel Home near Ottawa will open its doors after having been lived in for a year, so this is a great time to visit our project and check out others in the area.

Get first hand experience of the many advantages Passive Houses offer, and feel the supreme comfort of these super energy efficient homes.

Find Homes Near You

The EkoModel HomeTo search on participating homes in Ottawa, Eastern Ontario, or wherever you live, use the Passive House Database.

The listing for the EkoModel Home, including its passive house credentials, can be found at listing 5081 on the Passive House Database.

Please come out and visit our four-bedroom, 2,509 sq ft passive house on any of the following days:

Fri, 10 Nov: 9-3pm
Sat, 11 Nov: 9-3pm
Sun, 12 Nov: 9-3pm

See complete house plans for the EkoBuilt Trillium passive house right here.

See all 13 of our Passive House plans here – we can modify any of these plans to best suit your needs!

EkoBuilt's passive house solar engine
EkoModel News, Energy & Household Trends, Energy Efficiency, Passive House facts

Reflecting on a warm winter in the EkoModel Home

The sub-title for this post really should be “how comfortable is a passive house in winter?” And the answer is: very!

Okay, so the sun has been shining and we’re feeling the summer’s warmth, but cast your mind back to the long, grey winter we had here in the Ottawa Valley. Not for long, just long enough to picture the environment in which the EkoModel passive house spent its first winter.

Although the average temperature for the area was roughly -5.5C from December through March, December and January both saw some supremely cold days: -28C the low in December, -25C the low in January. Throughout the period we kept the house at steady 21C for daytime and evening; overnight, with no heating, the temperature would make a gentle fall to 18 or 19C by morning.

Having lived in homes in the past where keeping the temperature at 21C would have been too costly, this round the clock comfort was the revelation we hoped it would be. Both floors of the home, including the upstairs bedrooms, maintained these temperatures – no ‘cool spots’ as in many older homes.

The Eko Solar Engine - passive house infographic

Click to learn about the EkoBuilt solar engine that heats (and cools) this passive house

All of this was achieved using an average of just 31.75 kWh per day – which may not seem that low, until you remember that this passive house has NO FURNACE. That hydro-electricity usage simply represents the operation of the ‘solar engine’ components (including a fresh air exchanger, and an air-to-air heating and cooling pump) of the house, and daily living (lights, cooking, heating water*, PC and television usage) of a family of five.

So, our total energy bills for the four deep winter months was $801.48 (or $200/month).

*We heat our water to 120C.

An interesting note on Sunny Days

If it was a sunny day and we had approximately six hours of sun or more pouring through the south facing windows, we did not need to use the heating system at all.

The sun had no problem raising the temperature of the house from 19°C in the morning to about 24°C in the afternoon, in which case the temperature would drop to about 22°C in the evening and hover at about 20°C in the morning. Amazing!

 

What we’ll do differently next year

Overall, the house performed as expected, and the very low energy usage (seen here) and bills, even in a cold, grey winter, are great practical evidence. Less easy to share, but no less significant, is the supreme comfort that we enjoyed all winter long.

Hydry usage for the EkoBuilt passive house in winter 2017

Looking ahead to next year, we’re considering installing an ethanol (biofuel) fireplace. These units are a very simple and clean alternative to wood burning fireplaces and woodstoves, and their benefits are amplified in a passive house, where much less heat input is required to warm the home, and a fresh oxygen supply with good airflow is continually available.

There is a great overview of ethanol fireplaces on Houzz, and again we’d underscore the greater benefit to a passive house over a conventional build. In brief, this heating method has a very small environmental footprint, is low maintenance and attractive. We see this heat source as a great alternative when sunshine is severely limited, as it was this past winter in the Ottawa Valley. Any successful system has a built-in backup, and this looks like a great way to round out the solar engine that is driving our passive house.

Questions about the passive house performance?

If you have questions or thoughts about our passive home’s winter performance, please do feel free to comment here or contact us. We’re keen to share this information as clearly as possible in order to help homeowners to understand the huge benefits of building a passive house.

Southern elevation of Ottawa passive house by EkoBuilt
Home Building trends, Passive House facts

PassiveHouse and R2000: A comparison

The R2000 building standard has gained profile in recent years as an energy efficient approach to home building. The formalized program, which has seen thousands of building professionals trained and many R2000 homes constructed, resulted in a great deal of awareness across Canada.

At EkoBuilt, we believe that the PassiveHouse model is the superior choice for the 21st Century Home, and it matters to us that our customers understand how different the R2000 and PassiveHouse concepts are.

We’ve prepared a new page on our website comparing R2000 and PassiveHouse and invite you to read it if you’re considering a home building project or are wondering about the future for building codes and the energy efficiency of different home building methods. What better way to head into the future?

PassiveHouse Compared to R2000, by EkoBuilt

Passive House facts

How to solar power your house

House with roof panelsWe are frequently asked about solar panels and the passive house model.

Although solar panels are included in many passive house projects, the fact is that they are not part of the core design elements or criteria for a passive house.

Solar panels are certainly a good companion to a passive house, but not perhaps for the reason you might think.

Passive House vs Off-Grid

Unlike home building that is focused on being ‘off the grid’, passive house design has a different agenda. Passivehouse is concerned with creating extremely low energy buildings which are inexpensive to operate. The central concern of a passive house is really just to dramatically reduce the need for external energy inputs, thereby making it cheap to run. (In real terms, a passive house will use under 15 kWh per square metre, per year.)

Most off-grid homes tend to rely on fuel (oil, gas or propane) to operate a water heater, as well as the heating and cooling system(s). Geothermal is also common, but can be expensive to implement.

The superbly low energy requirements of a passive house design make it a great candidate for an off-grid project, as the need for additional energy input – from solar panels, for example – is so low. This makes the inclusion of a solar photo-voltaic system or array (an installation of solar panels) very cost effective, as it can be considerably smaller to meet the much reduced energy demands of the passive house.

The EkoBuilt Model Home will make use of a 6kW solar array to meet its total energy needs for roughly six months/year. Watch for future posts on our own installation.

Passive House & Solar Energy

Any home designed using the passive house standard begins with the ‘site’; the home will be optimized to face south if at all possible in order to maximize solar exposure.

Preferred siting of a passive house will be due south or within 15 to 20 degrees of south. Having said that, even in a wooded area the most efficient home to build is a passive house.

Building on the principle of southern exposure, in optimal circumstances between 25 to 35% of the home’s southern wall will comprise windows. With modern window technology, passive house is the only proven style of home where windows are actually used as part of the heating system. Solar gain in winter from well positioned windows is essential, and strategic shading helps with cooling in the warm months.

This focus on making the most efficient use of the sun results in a home that is not only extremely inexpensive to run, but also superbly comfortable.

Intrigued to find out more about our own solar project? Follow the blog or give us a call, we’d be glad to tell you more.

Passive House facts, Passive House resources

Insulation in a Passive House

Blown cellulose insulation around doorsOne of the keys to the super low energy footprint of a Passive House is abundant insulation. But not just any insulation will do.

For the EkoBuilt Model Home, we chose Thermocell’s ProCell Blue, a blown cellulose insulation that makes use of wood fibre.

ProCell Blue uses 100% post-consumer recycled content. It also contains naturally occurring, non-toxic borate (familiar to many in Borax, the natural detergent) which makes the insulation completely fire retardant, eliminates the risk of mold/mildew, and repels insects. A perfect choice for a healthy home.

The method of installation insures that the insulation is very densely packed, eliminating any possibility of the insulation settling and creating air pockets.

Interested to learn more? Find out more about what makes a PassiveHouse so efficient and comfortable on our Ottawa Passive House Design & Construction page.

Passive House facts, Passive House resources

HRV Units and the Passive House

Wondering how a PassiveHouse achieves such exceptional air quality and efficiency? It’s a good time to explain the HRV.

Heat recovery unit for the EkoBuilt Model Home

Zehnder Novus 300 – used in the EkoBuilt Model Home

A passive house is able to perform so effectively on very little energy in large part due to its exceptional air-tightness.  This very air-tightness, however, makes the need to introduce fresh air into the home all the more critical. This is achieved through an HRV Unit (heat and energy recovery ventilation unit) which draws fresh air into the home, filtering for pollen and other irritants and contaminants, and then exhausting used air while recovering the heat from that air.

With building standards generally improving year on year, HRV Units are now more common in conventional homes than ever. Most new homes in Ontario and elsewhere in Canada are now required to include an HRV. The difference between these units and the ones employed in a PassiveHouse build is the rated efficiency.

EkoBuilt’s Model Home is using a Zehnder Novus 300 HRV, which operates at 92% efficiency. This is extremely favourable in comparison to the 65% efficient units installed in most conventional homes. For a quick overview of how a home uses an HRV (in this case another model from Zehnder), this is a good video to check out:

 

A key indicator to be aware of is ACH or Air Changes per Hour. This is the number of times in an hour that a home refreshes its entire volume of air. Conventionally built homes tend to average a rate of 4-10, while Energy Star homes have an ACH of 2.5, R2000 homes average 1.5 ACH, and a PassiveHouse just 0.6 ACH.

Air Changes Per Hour by House Construction Standard

Conventional Homes: 4-10 ACH
Energy Star: 2.5 ACH
R2000: 1.5 ACH
PassiveHouse: 0.6 ACH

Keeping ACH at or under 0.6 is important, as it means that no condensation will form within wall or roof cavities. It’s very important for builders to be aware that insulation only performs to rating if ACH is kept to this low level.

Can a building be too air-tight?

All of this might leave you wondering whether the degree of air-tightness in a PassiveHome is healthy. The short answer is a resounding YES.

A home built to the PassiveHouse standard makes sure that both the home and its inhabitants are ‎healthy. As noted above, the reduced risk for condensation keeps air quality strong, while an ample amount of fresh air keeps the home’s residents healthy and feeling good. PassiveHouse is designed to provide each person with 30 cubic meters of fresh air per hour through a 92% efficient HRV.

How does the EkoBuilt Model Home Perform?

Blower door test results 0.53 ACH

Blower door results for the EkoBuilt Model Home

Just over a week ago we conducted the first tests on air pressure for the EkoBuilt Model Home that we’re building. Preliminary results were 0.53 ACH (air changes per hour), which is under the 0.6 benchmark for PassiveHouse construction.

After insulation and drywall, we hope that we’ll be able to improve further on this number. Stay tuned!

If you’d like to find out more about this or any other aspect of PassiveHouse construction and performance, please contact us.

EkoBuilt partners with CoolHeat Comfort Systems for the provision of the HRV units. CoolHeat Comfort Systems is a local family run HVAC Company in Ottawa providing HVAC services such as installations, maintenance, repairs and upgrades.

Passive House facts, Passive House resources

The Passive House concept in a nutshell

Still not entirely sure about the elements of a Passive House? If you have just 90 seconds to spare, the following is a brilliant and easily digested overview of the Passive House concept:

Passive House Explained in 90 Seconds from Hans-Jörn Eich on Vimeo.

The video was made by Hans-Jörn Eich, a certified Passive House Consultant (Passivhaus Institute in Darmstadt, Germany) and the founder of Pinwheel.

Pinwheel is a PassiveHouse building supply company located in St. Catherine’s, Ontario. EkoBuilt used Pinwheel to supply Agepan fiberboard sheathing and the Heat Recovery Ventilator (HRV) by Zehnder America.

You might be surprised to learn that Passive House materials are readily available in Ontario and across Canada, yet another factor in making Passive House easier to realize and more affordable to build than you might think. Find out more from EkoBuilt.