We have blown in the large majority of the insulation. This is really exciting because insulation is the foundation of an energy efficient home. The cellulose insulation that we are using is made locally in Belchertown by National Fiber. They use shredded and fluffed unread New York Times and Boston Globe newspapers. The cellulose is mixed with 17% borate which is a non-toxic fire-retardant and insect repellant. It also inhibits the growth of mold and mildew. Competitor’s use ammonia sulfate which is more toxic and less effective.

When all is said and done we will have 12.5″ of cellulose in the walls (R-45)

Cellulose spray box truck.

This pile of 125 bales of cellulose is only a fifth of what I estimate the house will need.

Uptight Insulators at work blowing dense pack cellulose

Cellulose in the bays of the parallel chord trusses

Thank you John for helping to load the cellulose!

I forgot to add one other interesting detail about our solar hot water system. We were not terribly excited about the off-the-shelf insulation for the exterior piping for the solar hot water system. It seemed that it would leave exposed gaps. Like the perfectionists we are, we thought we could do it better.

Adam suggested cutting 4″ PVC in half, reassembling it around the pipe, and then blow in spray foam insulation. The process certainly took more time than using off the shelf materials, and we experienced some problems with the spray foam. It turned out there wasn’t enough moisture in the PVC after we sprayed in the foam and it never cured. Rather than take the whole thing apart, we drilled in new holes and sprayed in water and foam. This seemed to solidify it all, but I am sure that the resulting foam is not as insulative as it could be.

In the end, I am not sure we would use this method again–even if we did spray in some extra water to start. Probably the way to go is to try to double up Armaflex pipe insulation.

Experiment with alternative method for insulating exterior solar hot water piping

Another milestone that I never thought would happen is all but done–the preparations for insulation. This involves netting and strapping all of our exterior walls and ceilings as well as any interior walls we want to sound/fire proof. This process has taken about a week and a half and we will begin blowing insulation tomorrow.

One of the more complicated aspects of this job is the exterior ceiling. Before we were able to begin we needed to work with our local building inspectors who didn’t think that using Typar in the roof was allowed by code. Eventually, we got an engineer to provide us with a stamped diagram of the assembly. The assembly itself is fairly complicated to execute because we wanted to create a solid air-vapor barrier below the cellulose and we are using two different ceiling materials. In the master bedroom and hallway we are using tongue and groove knotty pine, while the third floor, the bathroom, and the closet will be sheet-rocked. The vapor-air barrier behind the pine will be a cross-laced polyethylene plastic called Tu-Tuf (a superior plastic available through EFI.org); the sheet rock will be the air barrier elsewhere and it will be treated with a vapor barrier primer. Making sure that the air-vapor barrier is continuous across the top plates of the partition walls is the challenging part. This involves using acoustical sealant behind the Tu-Tuf, sheet-rock, and strapping so they all seal to the top plates. The acoustical sealant is desirable because it never hardens. So when one installs the sheetrock it can just compress the sealant that may have been applied the day before.

Netting and strapping first floor west wall. We are really starting to get a feel for the actual space in the house--much smaller and cozier.

Netting and strapping first floor living room. The ceiling, which is below the master bedroom will also be insulated for sound proofing.

Uptight Insulators installing Typar in the roof

Using Typar to create a ventilation plane below the sheathing of the roof. In the bottom left hand corner you can also see that we used white styrofoam packaging for insulation.

Adam installing bedroom ceiling tongue and groove boards.

Tongue and groove knotty pine boards used for the ceiling in the upstairs hall. We really like the look. After finding out that a white wash stain was $54 a gallon we figured out how to make our own at a fraction of the cost. We combined our white exterior solid stain with water at a ratio of 1:1. Voila, semi-solid white-wash stain at $20 a gallon. You can see the Tu-Tuf vapor-air barrier hanging down on the right. When doing this type of installation you want to leave a generous flap so it is easy to use the acoustical sealant behind it.

Over the last couple of weeks I have installed the solar hot water piping runs from the third floor drain-back tank room to the mechanical room on the first floor. The drain back tank is on the third floor in its own little mechanical room to improve the electrical efficiency of the system. The pump has to work harder to restart the system after it has drained back and the shorter the distance between the drain back tank and the panels the less the pump has to work.
Installing the pipes was quite easy with the help of my plumber’s ProPress. Rather than soldering all of the fittings this tool–along with its associated specialized fittings uses rubber O-rings and compression to make a seal.

Third floor drain back tank room

Here is our drain back tank.

Solar hot water pipe run under third floor stairs. The aren't parallel because I ran out of soft copper. I was creating 60 degree bends whereas you can only purchase 45 and 90 fittings. We had the soft copper for use in the area where the pipe ran through the roof insulation--this way we avoided any fittings in an area that we don't want to ever have to disassemble.

Solar hot water pipe runs along the first floor ceiling heading to the mechanical room.

Before we take down the staging to the solar hot water panels or cover any of the pipes with insulation, we wanted to make sure there were no leaks. We capped off one end and put this gauge/schrader valve combination on the other. The panel loop held 80 psi for several days (an hour would have sufficed). It was neat to see it oscillate between 70 psi at night and 80 during the day.

About a month ago we got our application approved for our solar hot water rebate through the Massachusetts CEC (a “quasi-public” organization). We were awarded $2425 for our solar hot water and monitoring systems. I was also hoping to apply for a Massachusetts zero interest HEAT loan, but those are, unfortunately, for existing construction.

Our system:

Here is the diagram I created for the drain back solar hot water system.

Our equipment list:

• (2) Sun Earth EC-32 panels (now EC-40)
• Heat transfer products SuperStor Contender Solar 80 Gallon hot water tank with electric back up and internal heat exchanger
• AET 10 gallon drain-back tank
• Resol Deltasol BS Plus differential controller with variable pump speed control
• Sun Reports Apollo 1 monitoring system with Internet reporting
• Grundfos UPS 15-58 pump (with check valve removed)
• Grundfos VFS 2-40 flow-meter

On 7/29 our solar hot water panels, which we purchased through Northeast Solar of Hatfield MA, arrived. Good news bad news time.
Bad news: The wrong ones were delivered.
Good news: We were allowed to keep them.
What happened is Northeast Solar’s distributor delivered 4×10 panels instead of 4×8. Since they operate out of Cape Cod they weren’t about to drive back and forth to correct the matter. So we got an extra 16 square feet of panel for free! We weren’t sure at first if the panels would even work for us and we spent about 20 minutes of head scratching to make sure they would fit on our roof, which, subtracting the over-hang, is only 10.5 feet. In the end, as you can see in the photo below, the panels stick up several inches past the peak of the roof.

On 8/3, with the generous help of Dan and Ashley we mounted the panels on the roof without incident. The larger panels were certainly a challenge to lift though. Adam swears they weigh more than the 141 pounds that the SRCC data sheet claims.

Photos by Hannah

Solar hot water panels mounted. Although it is not obvious in this picture, you can tell from the image below that the panels are not straight on the roof. This is no accident. This is a drain back system, where, if the sensor detects that it is too cold out, or there is no need for heat in the main tank, it automatically tells the pump to stop pumping. The water then drains back into the drain back tank. In my opinion, this type of "stagnation protection" technique is better than the more common use of pressurized antifreeze combined with a heat dump if there is too much heat in the system.

Solar hot water panels peeking over the roof

This past week Adam’s friends Dave and Nancy, who have built their own custom home and blogged about it at http://nancydavebuildhouse.blogspot.com stopped by for a visit. In one of our conversation’s we discussed orienting our homes due South. It struck me that the method I used would be worth sharing since it was fairly creative. I retrieved that neighborhood satellite image from Google maps and imported into Archicad, where I already had created an accurate plot plan based on the original survey. I then measured the angle between Vernon St. and due South. From that, I laid out the four corners of the house in Archicad and measured and triangulated the theoretical distance from the corners of the property to the corners of the house. Although we didn’t have any pins available to us, my neighbor had done an unofficial survey for us so it was easy to transfer the triangulated distances to reality.

This method is only available to those who have straight lines from streets or other structures that show up on a satellite image and are close to the construction site.

You can see that our foundation is perfectly square with the image frame indicating our house is indeed pointing exactly due South.

On August 2nd, Mike Hubbard, of Hubbard Heating and Cooling, installed our ductless minisplit AKA air source heat pump. This unit will serve as our primary heat source for the house. It works much like an air conditioner or refrigerator. All three use what is called the refrigeration cycle to remove heat from one location and put it in another. In short, there is a copper loop that carries a refrigerant fluid (formerly freon, now R410A) that has a really low boiling point in it. Along this loop is a pump (compressor) that circulates the refrigerant. Also in the loop is a choke point or expansion valve that causes the fluid to expand once it passes through. When a gas/fluid expands it becomes cold (think using a spray paint or aerosol can). Put a radiator on the pipe after the expansion valve, blow a fan over it, and you can effectively extract the cold off of the pipe. This part of the refrigeration cycle is called the evaporator. The fluid continues on back to the compressor, which re-pressurizes the fluid causing it to boil and heat up. Have a radiator and a fan at this point in the cycle and you have effectively extracted heat from the condenser side of the refrigeration cycle. One of the nice things about ductless minisplits is that they can both provide heat and air conditioning.

A good good diagram showing the refrigeration cycle can be found at Wikipedia: http://en.wikipedia.org/wiki/File:Heatpump.svg

The most common question is: “But it is, like, 10 degrees outside, how can you extract heat from that?!”

This is fine. It only feels cold. A penguin might think 10 is balmy. Also, keep in mind your freezer is tasked with removing heat out of 20 degree air. That heat is then transferred into your kitchen. As long as molecules are moving there is what we call “heat”. Negative 457 degrees F or zero degrees Kelvin is when there is technically no heat–a far cry from 10 degrees F.

The heat pump we purchased, a Mitsubishi MSZ-FE12NA, operates fine at temperatures down around -5 degrees Fahrenheit.

This is the indoor unit for the heat pump. We were originally going to mount in under the window, but I had no idea that it was going to stick on nearly a foot into the room. You can see the refrigerant lines to the right of the sheet rock.

The compressor part of the Mitsubishi minisplit. This is lower to the ground than I would have liked. We will need to make sure snow doesn't build up around it. Eventually I will build a little roof over it. It is stood off from the house by about a foot and half so the fan can properly blow the cold or heat off of the radiator.

If you are from New England, or other cooler locations of the world, you might be asking “Why haven’t I heard about this technology?” The reason for this is, generally, these units only put out around a quarter of the heat a typical New England house would need. Of course, with our double stud walls, and plenty of foundation and roof insulation we only need about a quarter of the heat of a typical house.

Another frequent question is “How will the upstairs be heated if the heat is only coming from one spot on the first floor?”
I agree this is a concern, but my understanding is that the heat will distribute itself through the house faster than it can escape through our super-insulated shell. To assist in the distribution we have an open floor plan on the first floor, as well as an over-sized stairwell opening. All this being said, I still have some concern around the upstairs and third floor room being cool, which is why I had Hubbard Heating and Cooling install a second refrigerant line-set that goes to the master bedroom. This way, if it ends up being to cool upstairs, all we have to do us plug in an additional air source heat pump.

Mike Hubbard can be reached at 413-498-2970, he operates out of Northfield Massachusetts

A couple of weeks ago, after talking with my insulator, I discovered we had a serious mis-communication forcing us to radically switch the design of the roof system. The original plan was to have an un-vented roof system with 32″ of dense pack cellulose (4 pounds per cubic foot) filling the parallel chord trusses. My understanding is that there was nothing intrinsically wrong with this approach. The cellulose would stop any air movement that might carry moisture to the colder exterior part of the roof system. However, I have since learned that it is virtually impossible to dense pack such a huge thickness. Furthermore, the added weight on the trusses was not factored into their design.

The new plan is to vent the roof by:

• Creating an airspace underneath the sheathing by installing Typar on the underside of the top chord of the truss.
• Installing one 4″ circular soffit vent per bay
• Cutting holes in the wall sheathing where it meets the roof sheathing, install screen to prevent pest entry
• Cutting holes in the lookouts where they pass through the interior bay so those bays can vent all the way up
• Removing the ridge cap, cutting a slot for the air to escape through the ridge, replace the ridge cap with Coravent (a thick bug-screen material)
• Switch from having the sheathing be the air barrier to having the interior ceiling plane be the air barrier. This will mean using a combination of sealing the drywall to the framing, and using Tu-Tuf cross laced polyethylene behind the wood ceilings.

Although we will lose some 30 R-value points, the R scale is not a linear one and the decrease has less impact than one might think. As one goes up on the scale each successive R-value insulates less than the previous one. After R-80 there is very little payback. So, from an insulation point of view, we were going to pay for about $800 worth of cellulose that wouldn’t benefit us except to make dense pack system work.

The new roof system will have 24″ of cellulose blown in at 3 pounds per cubic foot for what will be around R-85. Since this lighter pack of cellulose can’t be relied upon to block air flow through it we will need to install a an air and vapor barrier underneath the cellulose.

Adam and I have been dreading doing the ridge cap work for obvious reasons. Over the past two days we got it done–in large part prompted by the arrival of our solar hot water panels. Adam, as he put it, doesn’t remark about the difficulty of work; not so this time. Thank you Adam!

Here we are just starting the removal process: unscrewing the ridge cap. The red boards near the ridge are a shelf that the cap rested on while we worked on cutting open the ridge and laying the Coravent. Although slow, we found that a sawzall was the best tool for the job.

Throughout the last week I have been plugging away at the duct work for the HRV (Heat recovery ventilator). For those who don’t know, a HRV is a ventilation device that passes stale exhaust air from the house by fresh exterior air thus exchanging the heat from the exhaust to the fresh air. Best practices call for exhaust registers to be in the bathrooms and kitchen, while supply registers to be in the living spaces and bedrooms. When installing the exterior vent shrouds, one should place them at least 6′ apart so the two air flows don’t mix. Also, the shrouds should be on the same side of the house to avoid differential between air pressures.

For the ducts I have been running 6″ round main lines with 4″ round branches. For an HRV we are using a Venmar EKO 1.5 which runs on a very efficient 24 watt ECM motor while transferring 80% of the outgoing heat to the incoming air. In order to boost its efficiency I located the unit on the south side of the house where the exterior air will be warmer. The downside of this is that the HRV is in the master bedroom closet taking up most of the space.

The installation for the Venmar EKO 1.5 calls for it to be hung from joists by chains that have springs on them to mitigate the amount of noise it transmits. On the left side of the picture you can see insulated flex duct. The ducts that go to and from the HRV and the exterior need to be insulated to prevent condensation on them. One thing I didn’t like about the EKO 1.5 is that all four ports are on the top. Most HRV’s have two ports on opposite sides. Having all the ports on the top means they get in each others way. Also, if you are like me, and decide to install the unit on a second floor, you are guaranteed to have to make U-turns in the duct work. Whenever one is trying to move air (or any fluid) through a pipe one tries to avoid sharp bends that restrict flow and can increase noise.

Our Venmar EKO 1.5 HRV heat recovery ventilator installed.

The HRV produces condensation, which ordinarily is run into a bucket, to the outdoors, or into a drain line. A bucket is work, outdoors meant another penetration in our envelope, and my plumber didn’t think the inspector would allow it to go into the drain. Creativity won out–we ran it into the toilet! A 5/8″ diamond hole saw cut right through the ceramic.

Photos by Hannah