Thursday, January 11, 2018

2017 Utility Data

2017 Energy Data

To meet International Passive House (PHI) Standards the house must be built to the following performance criteria:

  • 4.75 kBTU/sf/yr - Heating Demand (or 3.17 BTU/hr/sf Heat Load)
  • 5.39 kBTU/sf/yr - Cooling Demand
  • 38.0 kBTU/sf/yr - Primary Energy (2.6 Source Energy Factor)
  • Thermal Bridge Free
  • Airtightness below 0.6 ACH50

To meet Passive House US (PHIUS) Standards the house must be built to the following performance criteria - this is based on Climate Zone 5 (Rochester International Airport)

  • 6.0 kBTU/sf/yr - Heating Demand
  • 2.2 kBTU/sf/yr - Cooling Demand
  • 6200 kWh/per person/yr - Primary Energy (3.16 Source Energy Factor)
  • Thermal Bridge Free
  • Airtightness below 0.05 CFM50/sf envelope area
* Keep in mind the way both standards measure sqft is different
** Watch our for UNITS! kBTU and kWh

To keep this post relatively short, we will only focus on the 1st 3. I suppose you'll just have to trust me that we are still below the airtightness and we are thermal bridge free.

I have compiled all of the energy data from 2017. Here is a quick break down of the different components I have been metering over the past 12 months:

Over the past year, my total electric usage - according to my bill was 8129 kWh - $1050.63
Here is the Breakdown, based on my meter readings:

*** I estimated the electric use for the water heater or ventilation system for January 2017 because I didn't install my meters on those components until Feb 1, 2017

Here are some comments on the utility data breakdown:

  • My largest single expense was the $17/month Service Charge
  • My Average monthly bill is $87.55
  • The 10 year average HDD for Rochester, NY is 6265
  • 2017 had 5766 Heating Degree Days - so it was a "warm" winter.

Okay this is all great, but low utility bills are objective. After all, this barn used 100% less energy than me last year:
(This is also a case when a single pane window is more efficient than a wall)

This is where comfort comes into play. Now here is Western NY I have done plenty of Energy Audits and people will go to some pretty extreme lengths to keep their heating bills as low as possible. I have heard the following quotes more than once:

"We turn the thermostat back to 55 F at night"
"We only set the thermostat to 64 F during the day"
"We don't heat the upstairs"
"We don't heat the basement"
"We don't heat the extra bedrooms"
"We burned 9 cords of wood last winter"

I've heard them all.

Well, obviously we have done none of that, and we have kept the whole house warm (or cool) all year.

I downloaded the weather data from my NETATMO weather station (Its a really cool device that can give you more data than you'll ever care to analyze).

I took a look at every day last year and took the high and the low temperatures - both indoor and outdoor. Then I averaged the high temperatures over the course of each month and I averaged the low temperatures for each month and made this graph:
The Blue Line is the Outdoor Average Maximum temperature for each month
The Red Line is the Outdoor Average Minimum temperature for each month
The Green Line is the Indoor Average Maximum temperature for each month
The Purple Line is the Indoor Average Minimum temperature for each month.

Basically the Outdoor Temperature was between the Blue and Red Line most of if not all of the year.
On the same note, the Indoor Temperature was between the Green and Purple line most of the year.

Here is some interesting notes:
  • We maintained the indoor temperature between 70-72 degrees for most of the year (Close to 80% of the time)
  • The highest recorded indoor temperature was 79 F - this is because we had a 72 F day on Feb 24th. I was NOT going to turn on the A/C is February. 
  • The lowest recorded indoor temperature was 64 F - this was because I left too many windows open overnight to achieve some passive cooling in September.
  • There have been a few times it has been colder than 30 F outside and we have had to open windows to cool off. This does mess with the Relative Humidity a little bit. On Christmas Day 2017 we had to open windows to cool down the house with company over. We were at 75 F inside.
  • In the summer the heat pumps only ran in the "dehumidify" mode (where they try to maintain 60% RH), and we only turned them to A/C with a set temperature when we were gone for a week for vacation.
  • I will be doing a ERV vs. HRV post in the future so I don't want to go into too much detail, but we have swapped to the ERV core for the winter to help maintain RH. From January-March we struggled to keep the RH around 30-35%. So far this winter we are in the 40-45% range - even with the bomb cyclone dropping temps here to around 0 F for a few days. 
  • For 80 % of the year we are in the 40-60% RH. The other 20% is due to opening windows for passive cooling in the shoulder months - when it gets down to 55 F at night and 90% RH. Then heats up to 80 F during the day at 60% RH. I am not good enough with Excel to show you a graph of that. 
Okay, Back to the Utility Data:
Now to take a closer look at how we used our Energy compared to the PHI and PHIUS Standard: The number on top of the Bar Graph is the Passive House Limit. The number in the blue is the 2017 energy use for RPH.

One quick note on the primary energy from PHIUS. It is calculated as 6200 kWh per person per year divided by 3.16 (losses in the grid). The number of "persons" is based on number of bedrooms +1 (just like RESNET). We have 3 bedrooms and an office without a closet. For purposes of this calculation included the office as a bedroom. Amazingly, that closet matters! We currently have 5 people living in the house, so I figured it was okay. I know neither standard is perfect but seems silly that the difference between certification and not is whether or not you build a closet in a room.

Thanks for taking the time to read, and if I messed up any of my calculation I'm sure someone will tell me. 

I'll be working on a post for HRV's VS ERV's and my experience with both shortly.

Tuesday, January 2, 2018

Glazing Surface Temperature

Glazing Surface Temperature

DISCLAIMER: This is for informational purposes only, I only own an IR Camera and I am NOT a certified thermographer. I know enough to be dangerous, and that is about it!

Here is my attempt at figuring out the glazing surface temperature at Rochester Passive House. I did 2 different scenario's.
                 1) Full Solar Gain - South facing window
                 2) No Solar Gain - Breezeway (north) door glass

Here were my test parameters:
                                         Full Solar Gain:                                 No Solar Gain:

The difficulty with finding an actual glazing surface temperature is glass tends to reflect quite a bit, so you are not reading the glass temperature, but the temperature of what is reflecting on the glass.

You can see my reflection in this IR Photo. 

To get closer to an actual glass surface temperature I took a scrap piece of paper, and covered half with black electrical tape, and covered the other half with 2 layers of painters tape. I taped this square to near the center of glass and let it sit there for a while. I am going to assume the paper will become the same temperature as the glass.

This is the paper I taped to the glass. I needed to make sure the paper was completely opaque. I used black electric tape for half, and 2 layers of painters tape for the other half. According to FLIR electrical tape has an emissivity of about 0.95. The painters tape is not as shiny (lower emissivity) but I wasn't sure if how the black tape would show a hotter temperature with the solar gain. 

Here is the Solar Gain Photo:
You can see, the black tape is hotter than the painters tape. But both of them are in the 103-106F range. The hottest temperature is not centered in on the black tape because of the angle the sun is hitting the exterior glass.
I have 2 images for the shaded glass
This one was taken roughly 1.5 ft away at a slight angle. It is roughly 65F
This one was taken about 6" away, but you can see how varied it is, there is quite a bit of reflection going on - but the average temperature is about 62 F

Because I was going in and out of the breezeway multiple times, the breezeway door and interior walls may be a few degrees cooler than normal. I took an IR photo of the interior wall, next to the breezeway door and it was 65F. I didn't post it because it is just an orange square - nothing really to see. 

Glazing Surface Temperature of South Windows in full sun = 100-105F
Glazing Surface Temperature of Windows in full shade = 60-65F - within 7F of indoor air temperature.

 Someday I am going to do this with an Energy Star Window and compare. 

Thermal Imaging Scans or Rochester Passive House

Rochester Passive House Thermal Image Scan

To close out 2017 I thought it would be a good idea to do on IR scan of the house while it was really cold outside to mimic my Summer IR Scan. Here they are:

Rochester Passive House Summer IR Scan

Rochester Passive House Winter IR Scan

Wednesday, August 2, 2017

Passive House Standards Met

Passive House Standards Met
It has been just over 1 year since we moved into the house. I finally have about 1 years worth of data (minus cooling for this year). Here is where we stand:

One really nice thing about PH International is the simplicity of the standard. I don't mean it is simple to achieve, but it is simple to explain.
1) Airtightness under 0.6 ACH50
2) Heating Demand - 4.75 kBTU/sf/yr
3) Cooling Demand - 5.39 kBTU/sy/yr
4) Primary Energy - 38.0 kBTU/sf/yr
5) Thermal Comfort / Thermal Bridge Free design - Blog post to come!

So lets do some unit conversions, since my house is totally electric - so my calculations are in kWh:

  • Heating Demand - 1.39 kWh/sf/yr
  • Cooling Demand -  1.58 kWh/sf/yr - I'm told this is to account for dehumidification being energy intensive. 
  • Primary Energy - 11.1 kWh/sf/yr
Lets see how we did - Our PHPP model shows 2930 sqft

1) Airtightness: My previous blog posts shows how we met this standard comfortably

2) Heating Demand: I installed 2 electric meters measuring my 2 air source heat pumps that I read monthly, so I can accurately measure my electrical consumption for Heating and Air Conditioning.

  • The top meter measures the Water Heater electrical consumption (installed on 2/1/2017)
  • The bottom left measures the 2nd floor minisplit heat pump (installed on 10/25/2016)
  • The bottom right measures the 1st floor minisplit heat pump (installed on 10/25/2016)
I should note, we had not used the minisplits for heating until after the meters were installed.

My electrical use dedicated to heating over the 2016-2017 winter was: 1730 kWh

1730/2930 =
0.59 kWh/sf/yr or 2.02 kBTU/sf/yr

The 2016/2017 winter had 5593 Heating Degree Days - our 30 year average is about 6380. So our winter was about 12% warmer than normal, but we are less than 1/2 of the PH limit of 4.75 kBTU/sf/yr

3) Cooling Demand: We are not done with cooling for this summer yet (it is early august). But we can interpolate a little bit. So far for the summer of 2017 we have used 187 kWh

0.06 kWh/sf/yr or 0.22 kBTU/sf/yr

As long as I don't use 4,400kWh the rest of the summer I will be under the limit (remember I've only used 187 so far this summer)

4) Primary Energy: Now that I have a full year's worth of electric bill I can do this calculation. The primary energy portion of the Passive House accounts for grid losses (The assumption is the grid is 38% efficient). We moved into the house in July 2016, so August 2016 was our 1st full month of utility bills. This number includes all of the heating, cooling, water heating, ventilation, cooking, plug loads, etc. 
 Here is our Monthly breakout of usage:
August 2016             685 kWh -  $85.53
September 2016       573 kWh -  $75.15
October 2016           452 kWh -  $63.80
November 2016       622 kWh -  $73.63
December 2016       968 kWh - $103.94
January 2017         1232 kWh - $142.60
February 2017         957 kWh - $121.58
March 2017             848 kWh - $93.68
April 2017               633 kWh - $79.51
May 2017                418 kWh - $65.79
June 2017                474 kWh - $66.36
July 2017                 537 kWh - $75.48
Total                      8399 kWh - $1,047.05

2.6 x (8399/2930)= 
7.45 kWh/sf/yr or 19.37 kBTU/sf/yr

Again, we are FAR under the limit of 38.0 kBTU/sf/yr.

I do have a meter on the water heater and ventilation system but I installed it in late January, so I don't really have meaningful data yet. But this is what I have so far:

The Water Heater Electrical usage so far has been:
February 2017    136 kWh - $14.86
March 2017        166 kWh - $15.01
April 2017          113 kWh - $11.16
May 2017           104 kWh - $12.14
June 2017             86 kWh -   $8.96
July 2017             69 kWh -    $7.51
Total                   674 kWh - $69.64

The Ventilation System Electrical usage so far has been:
February 2017    38 kWh - $4.15
March 2017        42 kWh - $3.80
April 2017          34 kWh - $3.36
May 2017           32 kWh - $3.74
June 2017           42 kWh - $4.37
July 2017            46 kWh - $5.01
Total                  234 kWh - $24.43

Lets take a look at how my electrical bill breaks out for 2017:

(This is only from January on, so the heating number may seem misleading since it is only for half of the winter)
The 2 things that stand out to me are:
1) The $17 per month service charge certainly adds up fast!
2) I am surprised at how little the ventilation system costs to run considering it is the only piece of equipment in the house that runs 24/7 (roughly $4 per month to operate - and that includes the Comfofond ground loop!)

I hopefully will have some news on the Certification front soon! Passive House Academy is working on it! 

Tuesday, July 4, 2017

Offical Blower Door Test

Official Blower Door Test

Well we've been in the house for almost a year now, and we are just now getting all of the necessary documents sent to Passive House Academy (PHA) for final certification.

The big remaining items are:
  • Installation PSI values for our windows - results for this will be in a separate blog post. 
  • Zehnder Commissioning to verify airflow in each room and ensure proper balancing from the supply and exhaust from the unit
  • Official Blower Door Test
So this post will go into some depth on what is required for the Passive House Institute Airtight Test

Calculate the House Air Volume
This is maybe the biggest difference between the ASTM and European Standard. We calculate the air volume of the house from slab to interior drywall and exclude ALL interior wall and floor air volumes. Essentially the "visible air volume" inside the house.

Sketchup makes this much easier!

I broke up the volume into 4 components
Volume of the Basement = 8,888 cuft

 Volume of the 1st Floor = 9,896 cuft
 Volume of the 2nd Floor is = 8,727 cuft
Volume of the Staircase Shaft is = 1,846 cuft

This give me a total volume of 29,357
(and just over 2900 sqft for those keeping score at home).

For you PHUIS people - my surface area is 6371 sqft

Here are my results from the official PHI Test:

Multi-point Depressurization

Final Depressurization : 51 CFM50

Multi-point Pressurization

Final Depressurization : 49 CFM50

Average per PHI Standard = 50 CFM50 => 0.10 ACH50

Now for the actual test. Enjoy the videos!

Blower Door Setup

Airtightness test with Duct Blaster Ring 3

Airtightness test with Blower Door Ring D

So here are our results:

Rochester Passive House is one of the tightest in the world!

Monday, April 17, 2017

Questions for my wife

Questions for my wife

Many times during tours questions come up that are best answered my by wife. The questions are generally asking for a different perspective from mine. It makes sense. I am, after all, selling Passive House Design and Tradesman services through Airtight Services. So how much can you believe from a salesman?

 My wife Brianna has offered to answer some questions from our most recent open house. Here you go! These questions are in no particular order.

Hi Everyone! Brianna here. Before I go into answering these questions just know that I am not a designer, architect or engineer. Many of the finishes in our house I found on pintrest. Some of these questions are hard to answer, but I will do my best.

What was the biggest challenge with the layout / floor plan in order to keep it "Passive"?
  • Definitely working within the "simple shape" I am really not good at visualizing how large a space will be from the prints, so we ended up with bedrooms on the 2nd floor that are too big in my mind. I would love to move some of that square footage back to the 1st floor. No fireplace was a challenge too when it came to decorating the family room / dining room area. I've always had a fireplace but we never really every burned anything. But losing the focal point in a room is a challenge. 

What is it like to cook on an induction cooktop?
  • I have cooked on standard electric and gas, but I really like the induction. You have to really watch it. The days of turning the pot on to boil 30 min early are over. If you boil a lot of things, you will boil something over. It is really easy to clean up though - since the water doesn't burn into the cook top like on a standard glass top. A damp cloth will clean it right up every time. There also is no gas smell in the house when the burner is on.

What was it like dealing with the Amish for your kitchen? Why didn't you have them do your bathroom cabinets also?
  • Working with the Amish was certainly an experience. It really gives you an appreciation for ALL of the modern day conveniences. There was no show room, there was no photos of previous work, there was no "options". When we sat down with them in their shop the piece of paper was blank. We had our "design" and photos of the style we wanted, a color sample we liked and that was it. We could have anything. I suppose this was the start of the endless decisions you get with a custom home. 
    • Choice of wood - Oak, Maple, Poplar, Cherry, Hemlock, Rustic Hickory, Walnut, Pecan... you name it. 
    • Color - stain color, paint color
    • Style - inset drawers, full overlay, etc. style for sides of cabinets not tight to a wall, etc.
    • Design - We were working around 2 load bearing posts, and had to tie them into the island. We also could choose from any of the kitchen cabinet gadgets like spice drawers, garbage drawers, hidden areas, adjustable shelves. They really wanted us to utilize every inch of possible space.  
    • We put in our order, wrote a check and just had to trust that they would deliver
  • If I could do it all over again, I would have them stain the lower cabinets and have our painter paint the cabinets. The Amish don't have a "clean room" so the finish on the paint is kind of rough - but they have been great working with us, and are always happy to "rebuild" cabinets if necessary. I also would have used a less expensive wood for the painted cabinets. We used maple on the lower cabinets
  • We put in our kitchen order with them very early in the process, and totally missed our window to have them build our bathroom cabinets. We may have saved a little bit of money on the bathroom vanities since we bought ALL of them on the clearance rack at like 50% off, we certainly got an cheaper product.  
  • I have told Matthew to write a blog post on our dealings with the Amish, since he is the one who took 3 or 4 trips down there to meet with them while they were building them. He has some good stories.

Are all of the rooms really the same temperature?
  • No. This winter the kids bedroom was about 2-3 degrees cooler than the master bedroom. We have a thermometer in there to make sure they didn't get too cold. We also opened up their door when we go to bed. The basement was also 3-4 degrees cooler than the 1st floor. 

How are you dealing with all of these open houses?
  • Thinking positively, it forces us to keep the house clean and any "projects" we are working on have to be done before the next open house. 
  • It can be difficult, particularly for the Veterans Day Weekend when we do a multi-day open house. But if we can bring in some donations for the area veterans, it it worth it! 

What is the biggest difference in this house from other houses you have lived in?
  • This is a hard one. It is definitely quieter, not only from outdoor noise, but there wasn't a loud furnace that kicked on every so often. Everything is quieter. I also grew up with a bedroom over a garage - and it was ALWAYS cold. There is no room in this house that is ever cold.

What is the biggest drawback from building such an efficient house?
  • Reduced options for appliances (no gas) - I am not complaining at all about the dryer, but we did need to buy a ventless one and there was only 1 choice. We also needed to have an electric stove, again not a big deal, and I LOVE the induction cook top. And designing a focal point in our family room that is not a fireplace is hard. We will end up building a fake one where we can burn candles or something. 

Where did you get your kitchen floor from?
  • Phew, an easy one! Matthew showed me an ad in one of his builder magazines for Armstrong Architectural Remnant Line. There was a local company in Rochester that is a dealer for that line of floor (Rochester Linoleum and Carpet One). Once I saw it at the store I knew I wanted it! Much of the color scheme in the house is based on the floor. I was going to be VERY UPSET if that color, or line was discontinued. I am not sure what would have happened if the floor had to be changed. Our kitchen cabinet color was based on that floor color, our paint scheme was based on that floor color, the stair tread stain color was based on the the floor color. The day we placed the order I was much happier! 
  • Here is the exact flooring: Armstrong Architectural Remnant Natural L3103
This was fun! Send me more questions!