Energy Revolution in a Brooklyn Townhome
Category Archives: Passive House BKLYN I
The windows were completely installed at the end of April and allowed us to move on to the long list of things that were contingent on the windows being in place, such as all of the interior finishes!
The custom casement and crown moldings were delivered and installed along with the newly designed marble mantel.
The work on the backyard and deck began (a blue stone paved yard, a metal deck topped with FSC-certified Ipe wood and StepStones and a green roof projecting from the parlor floor).
The skylights were installed. (The skylights took a very long time to obtain. First, the difficulty was finding a company who made skylights that achieved the standard we required. After much searching, we selected Fakro, a Polish skylight manufacturer. Thus the second difficulty was the lead time.)
Next up: A summation of the systems used in this Passive House, Things we’ll know for next time, and Where do we go from here?
Sorry for the lack of updates on our progress. We have been and are continuing to work feverishly to complete this project before the clients move in August. We have much to share and will do so as soon as we can squeeze in the time. Thanks for continuing to follow our efforts!
As many of you know, the Passive House Alliance, a national trade organization, is being formed in parallel with other regional Passive House groups around the country. The PHA board of directors is looking for people interested in helping to found and lead the national organization. This is an opportunity to help build a strong and vital Passive House community across North America. If you are interested in participating, please see the official announcement below…
Passive House Alliance – Request for Volunteers
Passive House Alliance is looking for interested individuals with specific knowledge of the Passive House Standard to assist in committee level appointments as well as future board member appointments. If you are interested in such a volunteer position to help grow the newly formed PHA, please send a brief bio and a statement outlining your current interest and involvement with Passive House to Jeremy Shannon, VP/Secretary PHA, email: email@example.com.
PHA Mission Statement:
“The Passive House Alliance is a national trade organization that promotes the Passive House building energy standard through public outreach, education, support of industry professionals and advocacy.
We provide marketing opportunities for our membership, and support the success and vitality of the Passive House community. Public outreach efforts include publicity, information, and education. We offer a platform for knowledge transfer within the Passive House community.”
The windows are finally on their way and will finish crossing the seas on April 14th. We will be having an open house on Saturday April 24th for members of the Passive House Meetup group. The Optiwin reps will be on site to demonstrate the proper air tight installation of the windows. To join the Meetup group (free) visit this link … http://www.meetup.com/Passive-House-NYC/
Hope to see you there!
We are installing a rain barrel for to capture some of the roof runoff for use in the future garden. The rain barrel that the client has selected is the “Abe” model by AquaBarrel. http://www.aquabarrel.com/product_rain_barrel_complete_80gal.php. While this isn’t part of the Passive House Standards, Passive House ideologically encourages additional sustainable measures in building practice.
We recently conducted a preliminary test of the air leakage in the house by using a blower door and an infrared camera. While we are not close to the Passive House standard of 0.6 ACH50 which for this house is 300 cfm50, the test was a success because we were able to come up with a system to address the leakage points that still exist. When we tested the house with the blower door prior to the start of construction the house was at 8500 cfm50. A blower door test that we did prior to the new year and before all of the window area, cellar, and addition spray foam was installed was a disappointing reading of 7100 cfm50. The next blower door test yielded 4100 cfm50 which is still higher than the code requirements for new construction at 5.5 ACH50 or 2750 cfm50. This was after getting the final main areas of spray foam installed.
Because we still had a long way to go we needed a method that would pinpoint our leaks more exactly. We started by using temporary heaters to bring the house temperature up to around 50-60 degrees (still significant stratification due to air leakage), and then turned the blower door on for brief periods to draw in the outside air which was around 30 degrees. With our Flir i7 infrared camera, we went around and looked for the cold points along all of the walls. The air leaks were surprisingly easy to see and it was the first time that I could prove that the spray foam insulation was not performing as well as expected in terms of a continuous air barrier. We had holes in the middle of the spray foam in some places even with 3″ of depth and many of our corners did not perform well. We used a low VOC spraypaint to quickly mark all the areas that we found and over the next week filled them all in. Once we ran the test again we got down to 2,500 cfm50.
Still a ways off, we repeated the testing method with the blower door and the IR camera and found more leak spots. Our last test as of the begining of March is at 2,100 cfm50. I would like to get the numbers down to 1,000 cfm50 prior to drywalling all of the walls. Because of the long lead time of the German windows, we can’t wait for their installation before we have to close up all of the other walls. This is nerve-wracking because it would be much better to leave everything open, install the windows in an air tight way, and then test everything again. This way we could be assured of reaching the 300 cfm50 required prior to sealing off any areas.
We are in the process this week of detailing more leak points in the envelope and will be putting a lot more man power into tackling this issue. We still have as a backup our drywall layer as a secondary air barrier which we are planning on air sealing anyway, but I don’t want to rely too heavily on that because of the large increase in surface area of the drywall layer as opposed to the exterior wall sealing.
This is an image around the chimney header just under the roof decking taken while the blower door was running. The blue area is the cold air leakage streaking across the underside of the roof deck.
The cellar floor and insulation system was a complex layering of elements designed to keep the water from infiltrating the cellar side walls or slab and to maintain a continuous air and thermal boundary. The client plans to use the cellar as recreation and work space so even small amounts of moisture are of greater concern than it might otherwise have been.
The steps involved in the cellar are:
1) Remove old cracked slab.
2) Excavation about 12″ below existing slab height. Attention was given to verify that the foundation wall footing was below 12″ at all points so as not to disturb the earth around it.
3) Dig three narrow trenches running parallel to the party walls about 10″ deeper than the existing excavation and gently slope the rest of the ground to be pitched toward the trenches. Tamp the earth to reduce future settling.
4) Install recycled content HDPE percolating 6″ pipes into the trenches. These pipes need to be gravity pitched to the sump pump in the front of the house. (See cellar 3D diagrams in the Building Envelope tab)
5) Cover the trenches with gravel and the pitched earth with 2-3″ of gravel. This releases the hydrostatic pressure from the ground below the slab.
6) Tamp the gravel down to reduce settling.
7) Remove and reinstall gas lines, meters, and electrical panels off of the cellar front stone wall so that the insulation layer can be continuous behind.
8 ) Frame out the cellar walls with 2×3″ wood studs spaced 1 1/2″ off of the cellar walls and 6″ from the level line of the gravel below. No bottom plate will be installed; instead we are temporarily bracing the wall with diagonal supports to keep the wall supported and level prior and during the insulation installation.
9) Install 2″ of spray foam insulation on top of the gravel floor and then 3″ of closed cell bio-based spray foam up the walls. Because there is no bottom plate, this spray foam can be a continuous from the floor to walls.
Our plumbing inspection passed and we’re working on the final leg of our electrical and hvac roughing before the walls can be closed up. First we”ll perform another blower door test to see where we fair with our air leakage tests. We’ll likely have to do another run through with cans of foam and tubes of caulk. An air test will also be done on the ductwork to check for air leaks along the joints. these joints were covered heavily with mastic which is a sealing agent that paints on and dries to an air tight surface (if applied thoroughly). Old installation practices and tests have shown that as much of 30% of heating and cooling energy is lost behind walls and ceilings from unsealed duct joints. The air tests we do will point to any leakage and assure minimal loss of our conditioned air into interstitial spaces for maximum efficiency.
In the cellar the percolating lines will be set any day, a 3″ layer of gravel will follow before a 2″ layer of foam is sprayed. Details in the basement where the floor and walls meet are very important so a close eye on the how the different contractors perform their work is necessary. We have a mason, a carpenter and a spray foam installer working on this so the need for oversight is high. The extreme cold weather has also proven to be a challenge and will push back the sprayfoam installer if we don’t get a few milder day’s soon.
Our client has decided to go ahead and replace the roof on the addition. After demolition of the interior room there was some rot and water damage on the underside of the roof deck. There was no clear water leak but there was too much uncertainty in the roofs integrity to install interior finishes. This work will give client the peace of mind in knowing they have strong new roof joists, roof deck and membrane which will last for 20 plus years. The interior side of this roof deck will be sprayed with 8+ inches of foam with an R-60 protection from heat loss.
Passive House BKLYN is featured in Spray Foam Magazine. Check it out at… http://www.sprayfoam-mag.com/articles/passive-house-requires-an-active-endeavor.aspx
We have been going back and forth for a couple months now, debating which backup gas heating system we should use for the solar hot water. What is set is using the Heliodyne flat plate collectors with the Heliopak heat exchanger. The collectors will be (3) 4’x6′ units that we have to line up on the roof laying at a roughly 20 degree angle but unconventionally with the long side against the roof. We have Landmark visual clearance issues from the street behind the building. The tank size we have assumed is 120 gallons and the system is roughly sized for 75-80% of the hot water annual demand for the 2 families. Therefore, it will cover close to 100% of the summer demand and probably 60% of the winter demand. For this reason, a backup heat source is necessary. We have been looking at the Phoenix Solar tank with a gas burner attached. It is a condensing direct vent burner which means that we can side vent rather than go up the chimney to the roof. This is good because we do not have confidence in the fire-proofing of the old brick and mortar chimney after seeing some of the areas exposed on upper floors.
However, the cost of the Phoenix is quite steep at around $6,500 after tax and shipping, so we checked into many other tank-less and condensing burners to supplement a water storage tank. While these will be cheaper in materials, the plumbing costs will increase and we will have more external parts to maintain. Something that I learned while researching the Navien and Bosch condensing tank-less burners (I think it applies to all of the tankless) is that they start their operation based on flow rate and not temperature. Why does this matter? If you are not using a solar thermal system to pre-heat your water, it doesn’t, because you always have 55-60% water coming from the city supply and for one faucet of hot water demand will need at least the lowest level of modulation on the burner for heat. If you have the water preheated to 100 degrees or even 120 degrees at your set point and the flow rate turns on the tankless burner, then you will get the base modulation for heat output (Navien is 15,000 BTU) that will bring your water higher than your set point. You will then have to have your mixing valve introduce more cold water to lower the temperature and you will have effectively reduced the efficiency of the system. We figured out a plumbing bypass to this problem which would be a separate temperature regulated zone valve, and while that would work it would add complexity to the system.
This week we are making the final decision, but it looks like we are going to push ahead with the Phoenix, do to the compact design and simplicity of operation. I will let you know if it changes and why.