Heating & Ventilation - Part 2

Now that the temperatures are starting to dip around these parts our minds are on staying warm indoors rather than cooling off in the lake. It's time to talk about how we will be heating Casa Tortuga.

Usually by this time of year, in any of our previous residences, I would have already been wearing a turtleneck for a few weeks and we'd have cranked the thermostat up to 24°C. The furnace would run almost constantly and there would be times, even though the thermostat said 24°C, there still seemed to be a chill that made me want to wear my turtleneck to bed. And I did sometimes...socks too. It was not fun...nor sexy for that matter. Anyway...

This is also the time of year when the clocks have been turned back and it's dark by about 4:30 pm that I wish I had a time machine that could fast forward through the dark cold months and transport us right into spring again.

This year sheds a whole new light on how I feel about the arrival of winter. With the sun getting lower in the sky every day we are benefiting from the solar heat gain. So now I look at the shorter days in a completely different way than I have in the past. I actually find myself looking forward to the next shorter day to see how much further into the house the beautiful sunshine will reach. To date, a sunny day will easily get the interior temperature to 24°+C, without the help of any other heat source.

The turtlenecks are still waiting for me. I say let them wait!

One thing Ras and I have both noticed is that 21°C feels warmer in this house than it ever did in the last house. 21°C was turtleneck temperature for sure (for me at least) in the last house and reason to bump the thermostat to 24°C. In this house, 21°C is perfectly comfortable. I continue to wonder if 21°C inside will still be comfortable when it's -21°C outside and the sun hasn't shone for 2 weeks.

It's the cloudy days for which we had to install the heat sources. So here's what heats the place.

Two Fujitsu air source heat pumps (16,000 BTU/h), one for each level.

One indoor heat pump head (white box on the wall, top right) on the main level.

One indoor heat pump head on the lower level.
Artwork still not hung making walls look too too naked.

Supplemental heat sources include...

Ditra-Heat in-floor heat in the master bath area.

There are 2 LED fireplaces in the house, one on each level. The electric
heat function was used toward our supplemental heat source calculations.
We only wanted the fireplaces for the (light) ambience. It's doubtful
we will ever use the heat function.



The building inspector was concerned we would have cold rooms in the house because the heat sources are centralized rather than ducted, therefore he insisted we wire for baseboard heaters in every room. Sacrilege! We wired to appease him but I refuse to let a baseboard heater anywhere near the place.

This past weekend we kept the door closed on the north-east-corner room on the lower level. There is no heat source in that room other than the east facing window. After 48 hours with the door closed the temperature was incredibly close to the rest of the house, almost imperceptible.

So far, the inspector has been proven quite wrong. I know it's still relatively mild compared to what we are in for but all the rooms in the house are comfortably warm. I haven't done my geek thing yet to measure temperatures room by room. That's a project I will get to. The ERV was just commissioned earlier this week so I didn't want to get too crazy measuring stuff until that was done.

Last, but not least. Our choice for water heating.

 80 gallon A.O. Smith air-source heat pump water heater.

We chose an air-source heat pump water heater for it's energy efficiency. Some would argue that the purchase price of the unit wipes out any savings gained by the lower energy usage. That may very well be true in this case too, but we needed the unit's efficiency and cooling capabilities to help with our passive house numbers. In for a penny in for a pound, as they say.

The water heater has worked like a charm...but it is noisy. The compressor runs at about the noise level of a canister-type vacuum. Until we get the insulated door on the utility room we have taken to switching the unit over to electric (silent) mode only when we have overnight visitors. I have checked the hydro website to compare electricity usage of both modes. The heat pump mode is definitely more efficient using about 4 kWh for one heating cycle vs about 10kWh during one heating cycle in electric mode.

Some advantages that this heat pump water heater has over a conventional water heater is that it cools the air in the room. That's how this water heater works...it takes the heat from the surrounding air to heat the water. Our utility/storage room is plenty big enough to accommodate the air volume needs of the water heater so we have not noticed that the air temperature in the surrounding rooms is noticeably cooler. This cooling feature will come in handy in the summer. As well, it dehumidifies the air. And...it keeps the air temperature of the utility room at the perfect temperature for storing wine. Bonus! Maybe the extra cost for the unit is not that bad after all.

That's enough for now...cheers,
Mimi

First Annual Cold Turkey Plunge

I hope all you Canadians out there survived your over-indulgence of turkey this long Thanksgiving weekend. We did!

Just for fun, and mostly for our friends who have heard enough about passive house and long for something more fun to read about here on the blog, this one is for you.

Ras has decided that the Thanksgiving tradition here at Turtle Falls should be as invigorating as it is crazy. So she initiated the Cold Turkey Plunge. And believe it or not she was able to recruit four other keeners to join her. Here they are...


The brave ones...2 nephews, a sister, a sister-in-law, and Ras

Now let me explain why I am not in the picture. Someone had to take pictures. And since I actually have a degree in photographic arts, who better to take the photos? It matters not that my sister takes way better photographs than I do even though she doesn't have the 4 years of training under her camera belt as I do. It matters not that the water temperature was a seriously shivering 15°C (59°F). Someone had to document the First Annual Cold Turkey Plunge. Right?

Ok, the truth is...I'm a big wimp! Cold is not my cup of tea. 'Nuf said.

So here it is, as best I could do with only an iPhone for a camera in a 14' boat on a blustery day in front of the Turtle Falls dock...

Note how the instigator of the event is the first one to hit the water.
Note the passel of paparazzi shooting from behind.

Oh...that has got to be cold.

I'd say by the look on Ras's face that...yup...it's cold.

I've never seen so much clambering to be the first to get to the ladder. Note the nephew with the casted arm up in the air. Everyone blew past the poor dude trying to get out as fast as humanly possible. From the boat I kept wondering when someone was going to assist the one-armed lad out of the water. His mother finally offered a somewhat numbed helping hand.

The yelping was pretty impressive too. Our apologies to the neighbors if the commotion interrupted your peaceful Thanksgiving dinners.

I do have a little something-something for the readers that visit my blog strictly for passive house stuff. A product endorsement. In the cropped photo below, look at the cast protector on the arm of tall nephew. I said "the cast protector" people...eyes right. Eyes right!

No you have not been redirected to www.hot_1-armed_guys(dot)com

First I wrapped his cast with pallet wrap then taped that with Tuck tape, a clear plastic trash bag next, taped at the top with Siga Rissan tape for a water tight seal. It worked great...until it was time to unwrap him. Oh dear! Lordy, that stuff is sticky. I have to admit I started to sweat just a little when I was trying to get the tape to release from his skin. He smiled through the whole ordeal. He didn't spill any blood. I think he'll come back again to visit us.

These passive house sealing tapes really are sticky, seal tightly in some pretty wet conditions (a frigid lake dip then a hot shower to warm up) and will hold like crazy. I think we can rest assured our miles and miles of tapes will do their job for decades to come. I'm just thankful I didn't go that one step further and use the Dockskin primer on his arm before taping him up. ;)

I'll end my foolishness here.

Cheers,
Mimi

Heating & Ventilation - Part 1

It's been too long since I last wrote about the adventures of building this passive house. March I believe. When we passed our first blower door test. Most homes could be built in the length of time since my last post, but not Casa Tortuga. I joke that maybe we should have named the place Puma Palace and things may have happened much faster around here. But where's the fun in that?

 

Much has happened here since March. We have actually moved into the house and Priscilla has
left Turtle Falls for her next adventure. Will we miss her? Yes. And NO! The camping memories with
family and friends will always be a highlight of the Priscilla years. The cramped quarters, the leaky
roof, the outhouse...in the middle of the
night, the ants, black flies, mosquitos and deer
flies, the lack of showering and laundry facilities,
the mice, the mice and...THE MICE! These are
just a few of the things we will not miss.

Moving on...

Recently someone asked us what has been the
most challenging or difficult part of the building of this house. Unequivocally, it has been the heating and ventilation system. Not because it is a difficult thing to do, but because we are building a house that no one in the building department in this township has ever seen. Mass confusion and misunderstanding ensued!

To back up a little, we originally were going to install an EcoLogix cold climate heat pump. After going through the whole process of having the heat/ventilation system designed for Casa Tortuga we were advised that maybe EcoLogix wasn't quite ready to offer the customer service we would want in the future. The product is apparently quite awesome, the support...not so much. Then we got jostled around from a ducted Daiken multi-split heat pump/Zehnder ERV (energy recovery ventilator) system to a ducted Mitsubishi multi-split heat pump/AirPohoda ERV system and finally to two individual ductless Fujitsu mini-split heat pumps/Zehnder ERV system.


Zehnder ComfoAir 550 Luxe ERV (L) with the
ComfoFond Brine Loop (R) option.

The move to a local HVAC company rather than the original company chosen by our architect makes for the first change for our system. The second, the heat pump we wanted was not available yet and the ERV was not on the approved list. And finally we settled on the best available cold climate heat pump and ERV options available to us for the least amount of grief. All the best laid plans of mice and men...

Too many mice may have been our problem, I think.

Or it could be said that the building inspector has been the main reason for so much of the jumping around from system to system. AirPohoda, virtually unheard of here, has not yet made it to the list of approved ERVs for Canada and as much as we fought to get this incredibly efficient system in our house, the inspector was making the hoop-jumping impossible for us. Our last option was to go with something that was on the approved list. The Zehnder products are recognizable and approved here in Canada. And even though the efficiency of the AirPohoda trumps the Zehnder by a few percentage points, this machine is also pretty impressive.

Having a tightly sealed house requires good ventilation. The ERV runs silently in the background 24/7 exhausting the stale air and replenishing with filtered fresh outdoor air. Within the confines of that darker gray box hanging on the wall, like magic, the majority of the heat from the warm exhaust air gets transferred (with no cross contamination) to the incoming fresh air. Efficiency at its best.

Sometimes more details are just not necessary. It's kind of like electricity for me...flip a switch and a light comes on. I don't need to know how it works, I just need to know it will work. Same goes for the ventilation. Plugged it in. It works. I'm happy. Finally! It sure was a long haul getting to this point.

The brine loop option (the light gray box) bumps up the efficiency of the ERV even more by pre-heating (pre-cooling in summer) the incoming fresh air. There is just under 500 feet (152m) of glycol-filled 3/4" Pex tubing buried in the ground on the north side of the house. While air temperatures can occasionally go below -30°C (-22°F) here in the winter, the ground temperature stays fairly constant at around +10°C (50°F) past 4' (1.22m) below the surface. The ground loop will temper that -30°C (-22°F) outdoor air so the ERV will work more efficiently. This will also work in reverse in the summer time when air temperatures are +30°C (86°F). The ground loop will help to lower the temperature of the incoming fresh air before it even reaches the ERV.

With limited space for the ground loop, the 500' (152m)
was installed in layers with a minimum of 2' (0.6m)
of fill separating each layer. The top layer of tubing
 is 4' (1.22m) below the surface.



The 2 smaller grey vents are the intake and exhaust for the ERV. At the 
time of this photo, the spray foam around each pipe and cutting pipes to
length is yet to be done. These need to be tightly sealed to maintain our
super tight air seal.

The two units sitting on the stands in the photo above are the mini-split heat pumps. I will talk about those in the next post since I've probably already bored you to tears with this post. Lucky for you...there will not be a 7 month wait for the next post.

And for those thinking of building a passive house, fear not! Our experience building a passive house is by no means typical. Far, far from it. Although we may not have approached this project with the simplest of ideals and plans, the resulting house is proving to be completely 100% worth the seemingly never-ending grief and gargantuan effort. As I write this, the morning sun is streaming in the gorgeously large east windows, gently warming the interior...for free. Life is good.

We remain grateful to the ever expanding league of extraordinary gentlemen helping us breathe life...and fresh air...into this labour of love known as Casa Tortuga.

Happy Thanksgiving to all the Canucks out there.

Thankfully,
Mimi

0.34 ACH @ 50Pa - We passed the first test!

Ross Elliott and Stephen Magneron from
Homesol Building Solutions collecting the numbers
from our initial blower door test.

It's was a pretty exciting day here at Turtle Falls yesterday. After months of building in record cold temperatures we finally reached the stage where we could put the house and its airtight barrier through its first blower door test. I have to admit I was a bit nervous. Tests have always jarred my nerves and probably always will.

But as the title of this post reveals, there was no need to be nervous. The guys from Crane Building Service have done an outstanding job so far building their first passive house, which was amazingly designed by Chris Straka at Vert Design Inc, modeled to achieve passive house standard by Homesol Building Solutions and the airtight installation of superior quality passive house certified windows and doors by Herrmann's Timber-Frame Homes. Ras and I extend our greatest gratitude to all the guys for their continuing support and careful attention to all the details required to get us on the right path to passive house certification.

One of the most important features of a passive house is it must be airtight to within 0.6 air changes per hour under a pressure of 50 pascal (0.60 ACH@50Pa), meaning that it will take one hour for 60% of the volume of air in the whole house to be exchanged or about an hour and 40 minutes for one complete air change. Little ol' Casa Tortuga and its band of brilliant builders achieved a mid-term test score of 0.34 ACH@50...pretty good indeed.

The meticulous men from Crane's Building Service
(l-r) Lee Ostrom, Mark Raison and Al Paige.
0.34 ACH@50Pa...well below the 0.6 required. 

To put that number in perspective, as tightly sealed as Casa Tortuga is it would take about three hours for one complete air change and this means that in the dead of winter with all the ventilation and heating systems switched off, a passive house would typically lose about 0.5°C per day, stabilizing somewhere between 10°C to 15°C (50°F to 59°F). And that's if the sun isn't shining.

Now I'll compare that to the house I grew up in...(sorry mom). Mom has been a real sweetheart to allow us to live with her during this crazy cold winter while construction continued. As much as we love Priscilla, winter is just too much for her thin-tinned walls to handle so mom graciously took us in. I must tell you that my childhood home is easily 100 years old and has had some updates over the years including a new kitchen addition, windows and furnace. I don't ever remember there being any insulation top-ups though. One cold night I noticed that the furnace was running almost constantly so my inner geek thought it might be fun to time this furnace cycling. It ran for 20 minutes, stopped for 3 minutes, ran for 20 minutes, stopped for 3...all night long and all day long for as long as those nasty -27°C days (and some -32°C) lasted. This house was losing about 1°C every 20 minutes with the heating/ventilation systems on. Compare that to the anticipated (systems off) passive house heat loss of 0.5°C per day. It makes the grief we have gone through with construction and weather delays worth every moment when I look at everything from this perspective.

So let me go back and show you some of the reasons we achieved such a good number.

The excellent triple-glazed Gaulhofer passive house windows installed by
perfectionists Adrian & Andreas of Herrmann's Timber-Frame Homes.
 These guys had smiles on their faces all week while installing in nasty
cold temperatures, even when they had to apply sealing tapes with
ungloved hands. I think they must be part polar bear! Fun guys.

Look at all the beautiful sunshine. But you know what sunshine in January
means in Eastern Ontario, eh? Minus 27°C (-17°F) or worse!  Ah, but days
like this make for some cozy temperatures inside a passive house.

The completed airtight envelope. This one inch of foil-faced insulation board
 is really all the wall/ceiling we have at the moment. The 6" (15cm) of Roxul
on the inside and 16" (40cm) of dense pack cellulose outside is still not
installed but we were reaching temperatures as high as 24°C (75°F) and
 maintaining at least 13°C (55°F) even in the -27°C (-17°F) weather,
using just one electric construction heater.
 

28" (71cm) of cellulose has been blown into the attic space
 by Green Giant Design Build. When settled, it should sit
 at a depth of about 25" (63cm). The R-value of the
insulation above the ceiling is closing in on 90.

The 2x6 space below the airtight foil barrier is the service chase for electrical
wires and ventilation ducts. All lights/ducts can be installed in the ceiling
 now without compromising the airtight envelope.

That's all for this post. Next up will be a smallish rambling about the heat and ventilation system for Casa Tortuga. I've lost count of how many times we've had to endure the comment that a house should not be so tightly sealed..."houses need to breathe, ya know!"

More later,
Mimi