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.
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?
A 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.
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
To 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!
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.
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.
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.
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?
How to solar power your house
We 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.
Insulation in a Passive House
One 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.
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.
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 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.
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.