Solving a (self-created) Problem with Heat Distribution

First, some background…

Using a ductless mini-split to heat and cool a home (even a passive house) takes some thought.  One needs to think about where, exactly, the mini-split head, or cassette, will be placed, and how the warm (and cool, in the summer) air that it creates is likely to flow.  Take my home, for example.  We opted to place the “winter” mini-split head in the “living” area on the first floor (we also placed a second, separate, mini-split head at the top of the stairway to the second floor, which is essentially the second floor “hallway,” to cool the entire house in the summer).

That single mini-split head (on the first floor) heats the entire 2,000 square feet of living space (1,000 sqft on each floor) on all but the coldest days, and does the job amazingly well.  When the outdoor temperature is above 20 degrees, the 2nd floor stays within two degrees of the first floor (which, again, is at 70 degrees).  Frankly, that’s warmer than I prefer, since all we do is sleep on the 2nd floor).  But it makes my wife happy.  When it gets below 20 (and the sky is overcast during the day), the 2nd floor can drop to 66 degrees, and if the temperature drops to the single digits for prolonged periods it can eventually go a bit lower. In those instances, I’ll turn on the 2nd floor min-split, and it will periodically kick on, when necessary.

And now, the problem…

When the house plans were drawn, the architect anticipated that the entry to the first-floor office would be directly off of the living area.  He also anticipated that the first-floor mini-split would be mounted on the narrow wall between the living area and the kitchen area.  Both are shown in the drawing below:

(Ther drawing also shows an exterior door on the south wall that I decided against because it just wasn’t necessary.)

When I framed the interior of the house, I decided to move the office entry to the hallway because it unnecessarily ate up wall space in the living area, leaving no room for a T.V., for example.

I also had to find another place for the mini-split because the wall that the architect had intended to place it on was too narrow for the mini-split head; it wouldn’t fit.

Given those issues, I changed the first floor as follows:

Moving the office door to the hallway (and eliminating the unnecessary hall closet) freed up valuable wall space in the living area and widened the hall.

And as the drawing also shows, I moved the the mini-split to a wall that had suffficient room.

Here’s how it looks:

In this photo, you can see the location of the mini-split relative to the back hall:

And here is a similar view in which you can see the door to the office: 

So what’s the problem?  Somewhat ironically (at least in my view) the only problem that we’ve had is that, during the winter, the office, which is the room closest to the mini-split,  can be two to six degrees colder than the rest of the house, depending on the outdoor temperature. The only exception is during sunny days, when the office warms up perfectly.  But that leaves many winter mornings, days, and evenings when my wife isn’t happy (because the office is her place of work).  And it should be noted that she almost always works with the door fully open.

I pondered over this problem for two years.  Initially, I thought that the problem was the ERV.  More specifically, there is only one first-floor ERV supply, and it is in the office.  Why?  Because that’s where Zehnder said it should go.  And it’s consistent with the general rule; pull stale air from the kitchen/baths/laundry room and push fresh air into the bedrooms (the office could also be considered a bedroom).

But I eventually found out that the ERV wasn’t causing the problem, and had no detectable (at least by me) effect on the room temperature.  So while the ERV is constantly pushing cooler air into the room, the temperature (above 60 degrees) and flow ( about 24 cfm) of that air just isn’t enough to make a difference in the room temperature.  This should have been no surprise, as it is consistent with what the experts suggest.

So my current theory is a bit different.  First, after framing the office walls, I insulated them Roxul so my wife could work in relative peace if I chose to watch TV; admittedly a bad idea with regard to heating the room. But I also suspect that any warm air that makes it into the rear hall is probably more likely to rise up the stairs (which are to the right) than into the office (which is to the left).

The easy thing to do would have been to install some baseboard electric resistance heat in the office, which my wife (or a thermostat) could turn on as necessary.  But that clearly seemed like a wasteful overkill to me.  So what I decided to do instead was install a Tjernlund ASI AireShare Room-to-Room Ventilator fan. The idea came to me as I was painting the wall in the family area that separates the family area from the office.  Unsurprisingly, the air near the ceiling (which is almost 9′ high) was several degrees warmer than the general temperature of the house down among the living.  It therefore seemed reasonable to believe that, if I could push some of that air into the office, the problem might be solved and, since the fan only draws 25 watts at full speed and pushes the air at 75 cfm, I figured that its use would prove to be much more user-friendly and cost effective than baseboard heat.

If the intent is to move warm air, ideally, these ventilator fans would be installed with the intake high on one side of a wall and the diffuser low on the opposite side. In doing that, the bay in which the fan and diffuser are installed acts as the vent; air enters from the top and is pushed out through the bottom. However, I decided not to do that because, as I stated earlier, I had insulated the office walls with Roxul, and I didn’t want to completely remove the insulation from the bay in which the fan was to be installed.  Of course, this meant that the warm air would be brought into the room closer to the ceiling than the floor, which is less than ideal.  But the room isn’t that big (it’s about 120 square feet), so I was hoping that it wouldn’t matter.

With minimal effort, I was able to cut the hole on the intake side of the wall about a foot from the ceiling, clear out the insulation in a space of about 18 inches, and seal off the bottom of that space with a piece of 1/2″ foam board and caulk.  Prior to sealing off the bottom of the space, I fished Romex up from the basement and installed a variable speed wall switch. The intake vent and fan are located at the top of the space, and the diffuser is located at the bottom.

You can see the intake for the fan in the upper left-hand corner of this photo…


…and the exhaust above the chalk/cork boards in this photo (it’s a bit difficult to see because it is a narrow diffuser rather than a traditional vent)…

Here’s a better photo of the diffuser (my apologies for the temporary “flow-detector”) and the variable speed switch…

The fan has now been in service for about a month, and I am happy to say that it has performed better than I had anticipated.  So far, it has resolved the issue completely.  For example, last night the low was 23 degrees, and the entire house, including the office, maintained 70 degrees +/- one degree. While not annoying, the fan is detectable at full speed.  However, we run it at what I would estimate to be one-third to one-half speed, and it is essentially silent.

Certified Passive House Consultant Training

Last September, after receiving Passive House certification of our house, I decided to take the Certified Passive House Consultant (CPHC) course.  I knew that I may never put the training to actual use.  But I wanted to better understand the science behind what we built, and fortunately I had the time and resources necessary to take the class.  So I thought I’d pass on my experience for anyone who might also be considering the training.


There are prerequisites that must be met for entry into the CPHC program. Generally, this means some affiliation with the building industry. But it appears that there is some flexibility, as one other student in my class appeared to have no connection to the building industry, but was taking the class because he was planning to build his own home, and, like me, was interested in the Passive House standard. In my case, the fact that I was the General Contractor on the construction of our house was evidently enough to qualify.


At $1,800, the class is not inexpensive.  On top of that, if you want to be certified, it will cost an additional $300 to take the two exams; an “in-class” three-hour multiple choice exam that is accessed through your personal computer, and a “take-home” practical exam that you’re given about three weeks to complete.

The Class

The class objectives are fairly aggressive.  As PHIUS puts it:

  • Learn the principles of passive building design: heat transfer, air-tightness, thermal bridge free detailing, super-insulation, highly efficient ventilation, moisture control.
  • Learn WUFI Passive, the next-generation passive and hygrothermal modeling tool developed in partnership with Fraunhofer IBP and Owens Corning. It’s a remarkable all-in-one performance and risk management tool for building professionals. Students receive a free 8-week license to use the full version WUFI Passive! (NOTE: Other programs require students to take energy modeling as a separate module.)
  • Gain proficiency in energy modeling skills by completing an entire project including energy balancing (static and dynamic), and hygrothermal assessments of all building components and comfort assessments according to ASHRAE 55.
  • Learn to implement high performance building science principles and passive house techniques in residential, commercial, and retrofit scenarios across all North American climate scenarios.
  • Learn from North America’s most experienced and accomplished passive house practitioners. PHIUS instructors have designed and certified projects across the United States and Canada.
  • Study built examples—including mechanical systems—for each North American climate zone.
  • Learn about suitable materials and components available in local U.S. and Canadian markets, and details for passive house applications according to climate.
  • Learn the best air tightness strategies, thermal bridge free detailing and how to evaluate your design in THERM.
  • Learn how to assure quality and performance for your client from the design process through construction using PHIUS+ Certification & Q/A.

Although there are occasions where the entire training (with the exception of the take-home exam) is a traditional classroom event, for the most part, the training is divided into two phases.  Phase 1 is a series of eight three-hour virtual classes that you “attend” via your personal computer.  The sessions are live, and the attendees have the ability to ask questions via a chat function.  During the class, the instructor will read each question and provide his/her answer.  The sessions were titled as follows:

  1. Metric and Fundamentals
  2. The Thermal Enclosure
  3. Thermal Bridges and High-Performance Windows and Doors
  4. Ventilation Systems
  5. Space Conditioning
  6. Multi-Family and Commercial Buildings
  7. Retrofits
  8. Quality Control (I may be mistaken on this last one, as I forgot to put it in my notes)

A variety of instructors teach the Phase 1 virtual sessions.  In addition to Katrin Klingenberg, there were a number of other experienced trainers who I am confident are well-known within the high- performance building industry.  Each instructor taught, at least, one three-hour block.  All seemed well-versed in their subject matter and engaged in their work.

Make no mistake, the students must absorb a significant amount of information during the class, and at least during Phase 1, it is challenging (maybe even impossible) to separate the wheat from the chaff.  Of course, that’s probably because there isn’t much “chaff” to begin with.  Even the background information on the history of the Passive House movement has its relevance and serves as a foundation for understanding how we “got to now.”  If I have a criticism, it is that there is a lot packed into each session; so much so that the instructor moves at a fairly rapid pace.  So there’s not a lot of room for detail, or detailed discussions, on any particular point, which may leave the student scratching his/her head when each class is over.  The students are provided with “homework” questions after each session (together with the necessary answers), and students are free to ask questions (via the electronic class forum) even weeks after a particular three-hour session has ended. But my guess is that the Phase 1 sessions will leave any serious student wishing that the classes had been in-person. Of course, the downside to that would be limited availability and greater cost (life is about compromise!).

Because of the limitations noted above, the real meat of the training occurs during the five-day in-class sessions; so much so that I almost think the serious student could miss the on-line sessions and still learn everything that is necessary to pass the exams.  The beauty of the in-class sessions is (obviously) that questions can be discussed in depth and answers explained in detail.  And if all of the in-class instructions are as good as the one we had (John Semmelhack) there’s really no excuse for failing to understand the required concepts.  Semmelhack had a high degree of comfort with the material, an easy-going manner and the ability to simplify relatively complex concepts enough to be absorbed by (even) me.

The Phase 2 sessions ran for a fairly solid eight hours per day and basically reviewed all of the key concepts that were covered in the Phase 1 sessions (and there are quite a few). There are a lot of formulas to understand.  Ever wonder about how to determine the annual heating/cooling demand for a building?  Well, wonder no more.  How about calculating the remaining peak load?  Annual total losses?  Peak losses? Converting heating degree days to heating degree hours? Transmission losses, thermal bridge losses, ventilation losses, air permeability, energetically effective air exchange rate, infiltration air change rate, the R and U value of homogeneous and non-homogeneous sections, installed U-values of windows, etc.  Yes, it’s all here.  Everything even the geekiest among us could ask for and more.

But not to worry.  The test is open book, and a study guide is provided.  So as long as the student acquires an understanding of the formulas (both how they work and when they are applied) and takes good organized notes, the tests are passable, even for those who never went beyond high-school algebra (and did that many, many, years ago).

All kidding aside, it is really an excellent class. Ours had about a dozen students. A number were architects, some were employed in various other capacities that dealt with energy efficiency, and, as previously indicated, a couple of us were just guys interested in what it takes to build a comfortable, energy efficient house.  There was a lot of discussion during the class (and it was always interesting) and, assuming the general topic interests you, there’s no time for boredom.

In addition to all of the above, the class provided an introduction to WUFI Passive, and the instructor worked through some practical examples of using it, with each student following along on their own computer.  Unfortunately, my computer has some personal issues that prevented me from doing the same.  But it worked out just as well following along with the instructor’s computer-projected images.  WUFI is an involved program that requires a fair amount of practice to attain proficiency.  I’m sure it’s a powerful tool in the hands of an expert, and most likely a danger in the hands of a fool.  I strongly suspect that almost without exception, each student will have to learn the program if, and when, they go through their first Passive House certification.

The three-hour multiple choice exam was given on the last day of class, and results were available immediately upon completion.  Again, if you pay attention, ask questions when you don’t understand, take good notes, and organize your material, passing it is well within anyone’s reach.

The final hurdle is the take-home exam.  It’s a workout.  But again, if your notes are good and you don’t wait until the last minute, it’s totally achievable.

So, you might ask, what’s the point?  I’ve been asking myself that question for decades, but I’ll restrict my commentary to the issue at hand.  As they say in Spain, “me gusta mucho esa clase.”  The class was work, but I liked it.  I now have a much better understanding of the “why” that led to the “what.”  When we built our house, I knew that I wanted 2×6 walls filled with cellulose and about four inches of polyiso on the outside.  But I wasn’t all that sure why that was any better than any other alternative.  I knew that the house had to be extremely airtight and that we had to have a ventilation system.  But I didn’t know what the appropriate ventilation rate was or how it was calculated.  And I had a good idea that a 9,000 btu mini-split would probably heat this place, but I had no idea how that conclusion was specifically reached (nor did the HVAC contractor, for that matter).  And maybe most importantly, I had no idea of the may pitfalls that await he (or she) who assumes that they know enough to charge ahead without a solid foundation in the fundamentals (and  in my view, gaining a truly “solid” foundation in the fundamentals is beyond the scope of this class).

And that last sentence leads me to what is probably the key lesson.  The most important thing I learned in this class is how much I still DON’T know about building science.  That isn’t meant as a failing of the class or the instructions.  Rather, it’s an acceptance that like any other complex subject, it requires an ongoing commitment to learn.  But as long as each student keeps the proper perspective, there will always be others willing to help along the way.  After all, real knowledge isn’t so much about possessing the necessary facts as it is about knowing where to find them when they’re needed.


Update on Power Usage – One-Year of Detailed Data

As of December 7th, the eGuage energy monitor has been installed for a full year, giving me the ability to know how much energy it took to heat our house for a full one-year period.  The data was actually a bit better than I anticipated:

Total kWh used to heat the house for the period December 7, 2014 through December 6, 2015:  2,549.6534

At 15 cents per kWh (winter rate) that resulted in a total cost of $382.45 (This includes all charges on our electric bill).

Knowing that natural gas is generally much less expensive than electricity, I thought it might be interesting to compare the two.  In other words, if we heated the house with natural gas, what would the cost have been?  Here are my calculations.  Feel free to let me know if you think my numbers are incorrect:

One kWh of electricity will generate approximately 3.14 kBtus of heat energy.  Therefore, our house used 8,007 kBtus of energy to heat the house during the one-year period.

8,007 kBtus equals 8,007,000 btus.

A “therm” of natural gas produces approximately 100,000 btus and costs approximately 79 cents (of course, this varies by location).

Therefore, if our house had a 100% efficient natural gas furnace, it would have used slightly more than 80 therms of natural gas for heat (8,007,000/100,000) and that would have resulted in a cost of $63.25 for the year.

Now, of course, we can’t use natural gas for several reasons; natural gas is not available where we live, they don’t make a natural gas furnace small enough, and a Passive House is so tight that burning any fuel in it is not advisable.  But I thought the comparison would help put the energy efficiency of a Passive House in perspective for those who use something other than electricity to heat their home.

Some other highlights from the one-year data:

The water heater used 715.516 kWh; about 31 cents per day.

The clothes dryer used 634.7463 kWh; about 28 cents per day on average.

The ERV used 369.02674 kBtus; about 17 cents per day.  However, it should be noted that the ERV was off for an estimated 50% of the three summer months because we had the windows open.

Transom Window Over Powder Room Door

As previously discussed, our house is heated with two ductless mini-split heat pumps; one at the top of the stairwell to the second floor and the other in the main living area on the first floor.  To ensure that pressure is equalized between the rooms and conditioned air can freely moved into those rooms when the doors are closed, I installed transoms above the doors to the bedrooms and bathrooms.

At least for now, I don’t plan to install windows in the transoms over the bedrooms and 2nd floor bathrooms.  As I see it, this type of detail would be largely decorative, and would have almost no functional purpose.  Yes, there’s the issue of privacy (sound).  But in a 2000 square foot house with only two or three occupants, that just hasn’t proven to be an issue.

I did, however, recently finished installing the transom window over the powder room door on the first floor.  This is a necessity due to the proximity of the room to the main living area.  The room is actually off the front foyer.  But it’s still close enough to provide some potentially embarrassing or uncomfortable moments for guests.

It didn’t occur to me (until it came time to install it) that a properly installed transom window is in the same plane as the door below it.  Initially, I thought that I’d have the window open to the inside of the powder room.  But that wouldn’t have looked quite right because the door opens to the foyer, and therefore the window should do the same. At first I thought it might look odd with the window mechanism on the outside of the bathroom.  But looking at the final installation, I think the window and the mechanism add something interesting and unique to the foyer.

Also, as I understand it, ideally the window stiles should be the same width as the stiles on the door.  I cheated on this a bit because it seemed a bit “heavy” to me.

I laminated up two pieces of 3/4″ clear pine to make the frame.  That allowed me to end up with a thickness that matched the door (one and three-eights inch).

Both the construction and installation of the window are pretty straight-forward.  But the mechanism isn’t cheap, at just over $100.

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An Alternative to Purchasing Blinds for Tilt-Turn Windows

The tilt-turn Intus windows that we installed in our house are excellent products.  They’re robust, airtight, and extremely efficient.  Nearly everyone who visits offers positive comments on them. However, from our perspective here in the U.S., they do have two drawbacks.

The first is that they open to the inside of the house, rather than to the outside, which could cause unanticipated problems.  For instance, a tilt-turn window over the kitchen sink our counter could be problematic.  It could be blocked (from opening) by the faucet, or it could interfere with a person who is standing at the sink and trying to access to the upper cabinets that are to the left or right of the sink.  Tilt-turn windows in other rooms could also be troubling if the homeowner doesn’t consider furniture placement and natural walkways.

Fortunately, this issue hasn’t been a problem for us.  Over the kitchen sink, we almost always use the “tilt” or venting option rather than opening the windows.  But I did take great care when installing the kitchen cabinet to ensure that the faucet does not interfere with the windows if we choose to open them.

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But the other issue…one that I didn’t give as much thought to…is providing privacy shades, particularly at night.  Tilt-turn windows require unique blinds. The blinds must be attached at both the top and bottom to keep them from swaying away from the window at the bottom when the window is tilted.  In addition, the blinds must be attached to the window, rather than the wall or trim surrounding the window.  Otherwise, it would be impossible to use the “turn” function to open the window or the tilt function to vent the window, when the blinds are “down.”

To my knowledge, only one U.S. company currently makes blinds for tilt-turn windows; RS-Sylco.  So the blinds can be purchased.  But there are two problems.  First, the blinds are far from cheap; typically in the area of $300-$500 per window.  That problem can be easily solved by those with enough money.  But then there’s still the second problem.

The tilt-turn blinds attach to the windows in two ways.  Either they can be attached directly to the glass with a special double-backed tape, or they can be attached to the frame that surrounds the glass by drilling holes and using screws.

I don’t like the idea of drilling holes into the window frame, so that option was out.  But I thought that the second option would do, particularly given that I only needed blinds on two windows (the second floor bathrooms).  But the problem is that our windows have a (simulated) divided light option, with the “mullions” adhered to the face of the glass. These mullions stick out about a quarter-inch, making it impossible to adhere the blinds to the glass.

Fortunately, after giving it a bit of thought, I was able to come up with an economical solution.  What I did was make a narrow frame out of poplar.  The frame is large enough to cover two-thirds of the window and is 1″ wide by 5/8″ thick (so as not to interfere with the window lever).  I gave the frame a beveled profile with a router to lighten it up a bit, mitered the corners, and assembled it with glue and small biscuits.  I then purchased a roll of shoji paper to use as the shading material, which I cut to size and stapled to the back of the frame.  There’s a lot of different shoji material out there.  I purchased mine from esojhi.   It has a durable laminated coating and can be wiped clean with a damp cloth without damage.

The shoji frames are incredibly light.  So I was able to attach them to the window frames using four one-inch squares of velcro fasteners, one in each corner.  The frames fill the need perfectly.  They move with the window, don’t permanently affect the glass or frame, and can be removed or replaced in seconds.

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Finishing the Interior Trim

For the past few months, I’ve been working on finishing the interior of the house.  I’m almost finished with the first floor trim.  So I thought I’d offer up my approach, which can hopefully be used as a point of reference for other non-professionals who are considering doing the same.

I’ve installed 14 of the 16 interior pre-hung doors, many of them with a great product called “The Quick Door Hanger,” which you can purchase at Home Depot for about $5 per door.  It makes the job much, much easier than dealing with shims.

I decided to trim out the doors and windows with a craftsman-style trim, primarily because I wanted to give the interior some character.  I could have had the drywallers run the drywall around the window jambs to finish the window openings.  That would have saved a fair amount of money (actually a bundle) and a lot of time.  But things are turning out well, so I’m happy with the choice I made.

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Trimming out a one of these windows isn’t cheap.  It takes six to eight eight-foot boards finish a window, depending on the size of the window.  That translates to about $60 to $80 per window.  That could have been about 25% less if I used MDF instead of finger-joint pre-primed pine.

One thing I found amazing, is how much wood it actually takes to trim out the interior. Given the 16 interior doors, 15 windows, and the necessary baseboard, I figure I will use about 200 eight-footers (mostly one-by-sixes) to finish everything out. At about $12 per board, that’s about $2,400 in materials.  I could have saved some money by making the verticals for each door and window 3.5″ wide.  But the proportions seem to look better with 4.5″ “legs,” a 7″ headpiece (which consists of a 1×5, a 5/4 top piece and a 7/16″ lower trim piece), and an inch-and-an-eigth sill (which is the actual size of a 5/4 finger-joint pre-primed board found at the local Home Depot.  I used the same basic dimensions for both doors and windows.  For the baseboard, I used one-by-sixes with a base cap on top.



Back when we started construction of the foundation, someone asked me if we were going to include a radon mitigation system.  My response was something along the line of, “No.  We don’t need one.  It’s a Passive House and will be so well sealed no radon will be able to creep into the structure through the basement foundation.”  So much for uninformed confidence.

Flash forward to last month, when I came across a blog post by Paul Honig, who lives in a similar Passive House in Connecticut.  Surprisingly (at least to me) he wrote about his own discovery that his house had tested high in radon, and required the installation of a mitigation system.

In case you are unfamiliar with them, these mitigation systems are incredibly simple. Generally, a four to six inch hole is drilled through the basement slab.  Some stone and/or dirt is removed.  A PVC pipe is inserted.  The pipe is either run up and out through the rim joist (below the first floor) and then up to the roof, or all the way up through the attic to the roof.  A special fan is installed on the pipe, either outside the house or inside the attic.  The fan then runs 24/7, sucking air from under the slab, and thereby depressuring the sub-slab area and moving the radon outside. From what I’ve read, these systems generally cost around $1,000, give or take.

A homeowner can test for radon several different ways.  He or she can purchase a short term test on the web or at stores like Home Depot or Lowes.  They generally come with two vials.  The homeowner is then instructed on where to place them and how long to leave the caps off.  When the necessary amount of time has passed, the caps are replaced and they’re sent to the testing facility.  A week or so later, the results are viewable online.

Paul used a continuous electronic monitor called the Safety Siren Pro Series3 Radon Gas Detector, which sells for $130 through  It’s very simple to use.  Just plug it in, wait 48 hours, and it starts providing a short and long term radon level reading, updated each hour.  The long term reading is an average of the hourly short term readings.

My curiosity was piqued enough to make the purchase.  Living is such a tight house, I had no desire to take a chance with radon just to save $130.  It proved to be a wise investment, as it reported a radon level of 6 pCi/L.  This is 150% above the remediation limit of 4 pCi/L.

I decided to check the accuracy of the Safety Siren by using a short term test that I purchased from Home Depot (that test cost me $15 plus a $30 lab fee).  The lab results showed one vial reporting a level of 4.7 pCi/L and the other reporting a level of 7.2 pCi/L.  The lab interpreted this to be an average reading of 6 pCi/L, the same as the Safety Siren.

I had almost zero enthusiasm for installing a traditional radon mitigation system.  Given the amount of insulation in the attic and the fact that the house has two stories, it would have been both difficult and messy to run a 4″ PVC pipe up through the roof.  Additionally, the first floor pent roof and the porch roof almost complete surround the house.  Therefore, there is very limited space to run an exterior pipe up the wall, and that space is near the front of the house, which would be less than appealing.  And finally, I have no desire to drill a 4″ hole through the basement slab and vapor seal.  Fortunately, after thinking about the issue for a while I came up with a possible alternative.

Instead of using wood to form the footers for our house, we used a product manufactured by Certainteed, called Form-a-Drain. Form-a-Drain footer forms are hollow, plastic, and have hundreds (or thousands) of small slots on both sides to allow water to drain away from the foundation.  Before the concrete is poured, a short section of PVC pipe is installed to connect the inner and outer forms.  Then another 4″ pipe is run to daylight to complete the drainage path.  Although I didn’t know it at the time, Certainteed bills the system as a “three-in-one concrete footing form system, foundation drainage system and sub-slab perimeter radon reduction system.”   Here are a couple of photos of the installation:



The drain pipe on our house exits the ground on a slope about 30 feet from the southwest corner of the building. The idea I came up with was to install a Fernco rubber 4″ elbow on the end of the pipe, run a two-foot section of PVC up from that, install a radon fan on the top of that pipe, and cap the horizontal outlet.  My initial thinking was that no measurable water actually exited the drain, so I suspected that a cap wouldn’t cause a problem.  I was wrong.

During rain and melting snow, a fair amount of water did build up at the end of the drain pipe; somewhere between a half-gallon and a gallon per day.  In one sense, that complicated the installation of my radon mitigation system.  But on the other hand, I took it as a positive sign that the system was working as designed.  So I had to come up with a way to allow water to drain from the pipe while maintaining the system pressure being developed by the fan.

After doing some research, I concluded that there were two possible solutions to this problem.  The simplest would be to drill a few weep holes in the end cap; enough to let the water trickle out, but not so much that it would cause a critical drop in air pressure.  The other solution, which I chose, was to install a waterless “J-Trap” on the tee instead of a cap.  The product I found was the Hepvo Waterless Value, which sells for about $23.  It’s an incredibly simple device that works like a J-Trap in that it allows water to drain, while preventing sewer gas from entering the house.  But it does this without actually holding any water in a trap.  That’s important at our house because any sitting water would freeze in the winter.

For the fan, I chose to use the Energy Star-rated RadonAway RP-140, which can be found for less than $130 on the Web.  At 15-21 watts, it has, by far, the lowest draw of any fan I found.  It also has lowest airflow, maxing out at 135 CFM.  But everything I read indicated that it was more than sufficient to handle the problem.  Installation was incredibly simple; a Fernco union attached it to the lower pipe, another Fernco on top connected it to two PVC elbows (to keep rain water from entering the system.  For testing purposes, I ran an extension cord to one of our outdoor outlets, figuring that if the system works, I’ll run a buried line to it this summer.

And work it did.  It took a couple of days, but the radon level is now at 1.0 pCi/L, well below the 4 pCi/L limit.  The only things left to do are install the underground electric supply and disguise the fan and pipe, which should be much simpler than the alternative. Here are a couple of photos taken before I replaced the end cap with the Hepvo waterless J-Trap:

IMG_0946 IMG_0948

Energy Usage Update

As I said in the last post, I installed an eGauge energy monitor on December 7th.  That gives me the ability to isolate the energy used by the heat pumps. The two heat pumps have used a total of 899 kWh during the 53 days that have since passed.

Broken down further, the first floor unit used 682 kWh during the period, and the 2nd floor unit used 217 kWh.   I anticipate that this ratio will change significantly in the future because the 2nd floor unit idles most of the time, rather than cycling on and off every three to five minute as it did before the remote thermostats were installed.

So overall, that’s an average of just under 17 kWh/day.  At 17 cents/kWh, that amounts to $2.88/day.

During the period, the thermostat for the first floor has been set at 70 degrees, and the second floor thermostat has been set at 68 degrees for the most part.   According to the electric company, the average daily temperature was 35 degrees for the 35 days ending January 22nd.  The average temperature for the month prior to that was 41 degrees.

One side note…I spoke with the electric company after receiving the January bill, and asked if they had a special rate for homes with electric heat.  They do, and will be reducing my rate to 15 cents/kWh on my next bill.

Septic Tank Leak

Earlier this summer, as I was working on the interior framing of the house, I noticed the sound of dripping water.  The weather was clear, but it had rained the prior day.  At first, I ignored it.  But after a couple of hours of listening to it, I decided that I needed to track it down.  In a few minutes, I was able to zero in on the source; the first floor toilet drain.  The plumber had finished installing his system a few days earlier, and, in doing that, connected the drains to the septic line in the basement.  Since the noise was coming from the drain, I went outside and lifted the two concrete access covers on the septic tank.

Although no toilets or faucets were installed, the tank had at least a couple feet of dirty water in it.  The problem was the two risers that connected the tank access holes to the surface of the ground.


As it turned out, the installer hadn’t sealed the joint between the risers and the cement tank with a butyl cord gasket, and the water in the soil was leaking into the tank through the seams.  When I pointed out the mistake, he was quick to dig up the risers and re-install them with the gasket.  Problem solved.  But it made me wonder what would have happened if I hadn’t heard that leak, and muddy water leaked into the tank for months or years.  And it made me wonder how many people ever think to check such things…

Problems With the Siding

Early in the project, my wife and I decided that the exterior of the house would be covered with fiber cement siding.  Lap siding would be used below the gables, and board and batton would be used in the gables.  I had considered vinyl and fiberglass siding, but ruled them out because neither was approved for installation over 1×4’s placed 24″ on center.  All things being equal, I would have preferred to use wood, but decided against it for several reasons.

The first reason was cost, particularly with regard to cedar.

The second reason was durability.  We currently live in a house clad in cedar lap siding.  We also have a garage clad in wood (board and baton), though I’m not sure if it’s cedar.  The problem has been woodpeckers and carpenter bees.  I didn’t want to have to deal with either in the new house.

The final reason centered on paint.  The thought of painting another house was not enticing.  And I didn’t want to deal with the added expense of having to back-prime every board during installation and then paint them after they’re installed.  I purchased the fiber cement siding pre-painted, and my hope was that the paint would last longer on fiber cement than it would last on wood.

So fiber cement it was.  Once that decision was made, it came down to a choice between Hardi and Certainteed.  We settled on Certainteed because my wife liked the color they offered (Cyprus).

The siding was purchased in December 2013, and installed the next month.  Seams between siding boards were butted without gaps.  Gaps were left around window trim (generally about 1/8″) and caulked.  The installation looked great.

But problems started surfacing a couple of months later.  In March, cracks started developing around some of the windows; usually at a lower corner, but in a couple of instances at an upper corner.

Here’s a piece that feel off of the upper left corner of a second floor window on the west side of the house (I placed a piece of coil stock over the hole to keep the rain and bugs out):


Here’s a crack that developed at the corner of a window that is under the porch roof on the north side of the house:


This crack developed at the corner of a first floor window on the west side:


Eight instances of these issues have since developed.  They’re on all four sides of the house.  There was some initial speculation that the cracks may have been caused by expansion of the Azek window trim.  But I’ve discounted that for several reasons.

First, per Azek, the expansion rate of their product is 1/8″ per 18 feet.  This is consistent with the 38 feet of skirt board on the south side of the house.  It consists of three pieces, and two one-eighth gaps were left between them.  No issues have developed:


Also, gaps of 1/8″ were left (and caulked) between the siding and the window trim, and none of the trim pieces are anywhere near 18′ long. Even on the widest window,the Azek expansion shouldn’t have been more than 1/16″.

In addition, as the temperatures have risen, we’ve noticed some obvious cupping of the siding on the east and west sides of the building when the sun hits the surface:


As seen in the photo, the cupping has occurred on all the boards, even those below the window.  The same issue hasn’t developed on the south side of the building.  But my guess is that this is due to the roof and pent overhangs, which keep almost all of the surface in the shade.  Here’s a photo of the same (east wall) area when the sun is not hitting it:


The most obvious explanation for the above photos (in my opinion) would be that an insufficient gap was left between the boards at the time of installation, particularly since the installation occurred during the January, when the temperatures were generally below freezing.  However, leaving gaps would have run contrary to Certainteed’s installation instructions, which contain the following note on page 36:

“Note: It is never acceptable to leave a gap of any size at a butt end/joint.”

My conclusion is that the cracks are developing at the windows simply because they are the weak points in the siding.  And one thing that surprised me about the siding was it’s brittleness.  There appears to be absolutely no give in the product.  I’m surprised that it can even be nailed.

This prompted me to do a bit of research, during which I discovered the following:

– In November 2013 (one month before we purchased the siding), Certainteed entered into a $100 million settlement pertaining to this lap siding.  The settlement covered any siding installed prior to October 1, 2013.

– The siding on our house was manufactured in December 2012.

– On February 1, 2014, Certainteed stopped selling fiber cement lap siding.

Needless to say, all of this is concerning.  Certainteed has no comment on the cause of the issue.  I’ve got the siding sub coming out next week to replace the boards that have cracked, and I’m hoping that more do not develop.  I don’t yet know what I’ll do about the bowing issue which, at this point, is only cosmetic.