Category Archives: about the house

Insulation! 3000 => 1400 CFM50

Insulation by definition does not necessarily tighten up a house (think fiberglass batts) but many types of insulation do:
– spray foam
– cellulose
– foam board (as long as it is sealed at seams with the proper tape, and at edges with “good stuff” type spray foam.

So that’s been the story with the insulation we just added to this house:
– walls (there was none) => DENSE PACK CELLULOSE
– garage wall and ceiling separating garage from the house
– attic (loose fill cellulose, lots of spray foam filling up leaks everywhere, and some poly iso foam board on a few knee-wall areas touching living space)

Original blower door was 3000+ CFM50. The one today after the work was 1400 CFM50.

I am not sure I quite believe it, but we’ll see… I believe an inspector will also do a blower-door test.

– windows and doors
– cathedral ceiling (someday…. maybe 4″-6″ of polyiso right on the existing drywall, with new drywall over it?)


Interesting, Washington state has a new-building requirement for SLA — Specific Leakage Area

Click to access air_leakage_testing.pdf

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Well, the almost passive-house/almost net-zero Stow house sold in a week to a smart buyer who got a great deal. And we’ve already moved (to the 1958 split level mentioned earlier).

I’m missing…
– the warm basement (my office)
– the quiet HVAC (the new house has a typical forced-hot-air system)
– the even temps (both room to room, and time of day)
– those huge window sills!
– the attic playroom
– the very quiet location (far from highways and other major roads)

There are some nice things about our new place too though (the main one being that we are 3 or 4 minutes to the kids school) so we save lots of time/money/CO2 each day on that.

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It’s payback time…. insulating a 1958 split-level house

We’re moving soon to a “normal house” built in 1958, and that means beginning to ponder what heating-system, insulation and air-sealing projects to embark on.

My go-to blogger will be Marc Rosenbaum:

Here’s what we will be working with. The house is a split-level with 4 different living levels all separated by half-flights.

My first thought is that the way to go is to get a pellet-stove installed in the main living area. There’s a good central spot for one. The house is currently heated with a forced-hot-air (FHA) furnace with smallish “high-velocity” ductwork. But my guess is that in the winter it probably heats up the basement level like crazy, which is a waste since we won’t use that much. So like with our pellet stove in our previous Shutesbury, MA house** (and with Marc in his post above), getting point-source heat (a pellet stove) directly on the living floor will make a lot of sense. It will effectively limit the amount of space we are heating.

(**Our basement in Shutesbury definitely got down to at least 45 if not 40 sometimes. And we still ran the FHA occasionally. Nice.)

Other obvious things will be to improve the insulation on the 3 attic hatches. (as in… add insulation and air sealing. There is none now!)

And generally go nuts with cellulose in the attic.

And ponder what to do about the rooms above the 1 car garage since there is probably no insulation in those floors. Or basically none.

Payback will be an important consideration.

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Our House for Sale: 147 N Shore Dr, Stow, MA 01775

It pains me to say it, but our house is for sale.

We love love love this place, but the daily carpool/commute to our kid’s school in N Framingham is killing us. It’s 17*4 = 68 minutes in a car. When it could obviously be 5 or 10 if we lived closer.

So inquire quickly if you are interested! It’s been on MLS for only a day and we’ve already had several pings. google: 147 N Shore Dr, Stow MA 01775

The basic ideas of the house is:
– IAQ (indoor air quality)
– Comfort (living with no drafts and even air temps is an amazing experience)
– Daylighting. All of our rooms (including our bathrooms and basement) have nice daylighting.
– *Insanely* energy efficient (we EARN over net $1100 on our utility bills due to solar SRECs)
– Durable (little or no maintenance needed… hardiplank siding, hardwood floors, etc)
– “Passive Survivability” (I like that we can lose power and not worry about the house getting too cold very quickly or pipes bursting)
– Someday… homestead. There is a LOT of space in the front (S) of the house for a suburban vegetable “victory garden”. If we were more ambitious, I assume we could easily grow all our veggies.

I’ll follow up soon with some photos…

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Experimenting and sharing the results

“I built a [solar thermal heating] system that I subsequently figured out didn’t make the most sense – why can’t others discuss the shortcomings of their experiments? People must like story-telling more than science.”
— Mark Sevier, PE (our “neighbor”)

From article:
Using Sand to Store Solar Energy
Assessing the controversial claim that solar thermal heat gathered in summer can be stored in sand for winter use

Go Mark! I think also, people are busy, and so after they have built a house, and perhaps it doesn’t work as well as hoped for — in terms of being 100% solar, or zero-energy, or meeting the passivhaus standard (or pick your criteria) — then people are loath to brag/blog about that. But I think it’s certainly useful and will help others learn from our experiments and/or mistakes.

Our house is *pretty much* working as expected I think, but I don’t think quite as well as the PHPP perhaps estimates, and certainly there are lots of things I would advise people to do differently, but that’s ok! (*”Pretty much” as in… our heating bills are VERY VERY low — like maybe 1/5th or a 1/10th of typical house of this size?) We are on target to use approximately 10,000Kwh total for all purposes for the year (june2010 thru may2011) I think. That’s heating, hot water, electricity, lawn mowing, etc). But that’s minus car use, buying stuff, food, etc. We could be living much greener! We’re working on it!

See also:
Mark’s House — a 14 HERS house in Sudbury, MA
Other comments from Mark at GBA — favorite Solar Homes section
Solar heated buildings of North America: 120 outstanding examples by William A. Shurcliff
Edision: The experimenter’s journal

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Monitoring your house (or solar heating system) temps

What fun is having a superinsulated, almost passivhaus, almost(?) net-zero energy house without monitoring temperatures and relative humidity I say! So here is a summary of what I’ve figured out on that topic here in 2011:

I have no doubt that the accuracy and the resolution of the Onset HOBO units are far better, but here is a price comparison between a home-monitoring solution using the “weatherdirect” LaCrosse TX-60U-IT vs Onset HOBO U12 data loggers vs the even more expensive wireless Onset solution of ZW Series “Wireless Data Nodes”. The latter is what I would want (if I went with Hobos) because I am not satisfied with stringing wires all over the house and I don’t just want to “log” temps, I also want to be able to monitor/view them in at least somewhat real-time fashion. So one either needs a way to string wires outside windows and up the side of the house, or run the sensors thru cat-5 wire (telephone/ethernet lines already in the house) or… something.

OK, so here is the rundown:

Both offer:
– some substantial data storage on device if wireless connection (router to device) or internet connection (router to internet) go down
– no computer needs to be on (BUT… hobo needs to be connected somewhat I think since the ZW-RCVR connects via USB to a computer instead of via ethernet direct to a router.)
– no ongoing subscriptions needed for monitoring of temps/RH

Lacrosse Advantage:
– low price
– wireless sensors
– automatic FTP storage of data
– uses normal AAA batteries
– total no-brainer. no software install. No computer needed.
– each sensor has internal temp and rh sensors plus a external connection (and 6 foot waterproof wire and sensor) for measuring another temp
TOTAL PRICE FOR MONITORING 3 indoor locations, 1 outdoor: Approximately $120 total (1 router, 3 sensors) all available from Amazon website


Hobo wireless advantage:
– resolution
– accuracy
– looks like you might get nice graphs with the “HOBOware Pro/HOBOnode Manager” software . though using the FTP option with lacrosse one could pull that off easily enough I think.

TOTAL PRICE FOR MONITORING 3 indoor locations, 1 outdoor:
$200 receiver — HOBO Data Receiver – ZW-RCVR
$239 x 4 — HOBO ZW-003 Temperature/Relative Humidity (RH) Data Node
(or maybe there is a way to do 3 but use one model that has plugs for external sensors and buy 2 $35 6 foot temp sensors. That might bring the total price down slightly??? Call Onset to get the exact number of course.)
~$1156 plus shipping


Summary: I went for the Lacrosse solution since it is ~10x cheaper and so far so good. It might be interesting to compare temp readings between a Lacrosse and Onset unit. I’d love to do a review of the Onset stuff but can’t afford it.

Contact me if you have a better idea! I’d love to hear it! “One-wire” sounded intriguing, but I need plug and play and most look like kits.

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Things I would do differently…

Not to be a downer, as the house is really AMAZING, appears to be performing right in line with estimates we made for heat load and UA and the more detailed PHPP workup. But I can’t help it, there are definitely things I would do a little differently if I were to build a house again.

  1. Our property has a 2-bedroom deed restriction, which we knew going in, and it’s totally fine, but if I were to do it again, I would have been in communication with the town’s building inspector (who is also the zoning enforcement person) early on in deciding — show him our rough plans, what we were going to build — instead of waiting until submitting formal plans. Novice mistake. Luckily things turned out fine.
  2. Don’t be afraid of stock plans. I don’t think one necessarily needs custom home plans to build a superinsulated house. Certainly if you are trying to do passivhaus then you probably do since it will mean really messing with window sizes and placement, but otherwise, I would advise that, if you already have a plan that you really like, just go with it, and ask your builder to build 12″ or so double walls, rather than the 2×6 walls shown in the plans. Spend that money you save on something else!
  3. If I were to do it again, I might not be quite so enamored of strict strategies for reaching/approaching passivhaus in New England. A passivhaus would use 2.5x less energy than our house, approximately (assuming the same TFA) but we’re talking maybe $200 in heating PER YEAR vs $600 PER YEAR. I am not at the moment convinced it is worth the substantial extra effort/expense due to slightly unusual methods needed and products. It’s still tricky to do this stuff and so it means having a team — a builder and architect — who are obsessed I would say. Correct me if I’m wrong! So, do all of the items on the passivhaus checklist that are low-hanging fruit, but pass on items that are stretches. Might as well do 6″ of foam under the slab and edge, for instance. But have nice views on the North, East or West of your house? I would say not to feel bad about putting in nice windows there! That’s me. (I would aim for R40 walls including basement, R80 roof, R5 windows, R20 slab)
  4. On the other hand, I would also ENCOURAGE everyone to VERY EARLY in the project to seek out a Certified Passivhaus Consultant (such as ours in the Boston, Massachusetts area: DEAP GROUP) and have them model your house plans in PHPP. Even if you don’t follow all the Passive House advice, you will be very well informed!
  5. On Solar PV panels: I really like the Enphase microinverter approach we took, but I can’t help but think that the grass-is-greener — IOW, a central inverter. I like that a central inverter approach would have 1) been a little cheaper, and 2) allowed for a “hybrid” grid-tie AND small battery approach, and 3) w/ battery, allowed for some degree of “off-grid” use in case the grid goes down during storms and such. Ah well, I probably would be wishing we had microinverters had we gone with a central inverter approach! I am remembering that I think part of my decision for microinverters had to do with worrying about shade. I should have trusted the solar survey more! We are pretty much totally shade free except at the beginning and end of the day. Which microinverters don’t help much with I don’t believe.
  6. I would probably try to use as little foam as possible. Cellulose all the way! And generally, vapor-open envelope assemblies seem like a Good Idea. I now like this thinking better than the Lstiburek “perfect wall” approach which is closer to what we have. Ah well, grass is greener…
  7. I would use bigger windows in some spots and remove them in others. I guess trying to be a bit more site-aware. Where are neighboring houses… where are views, etc. We did this to some extent, but there are a few misses where I wish there was a double bank of windows. That sort of thing.
  8. I would have looked into unusual choices IN PERSON a bit more. I think it would have helped, for instance, to visit a house with had the Thermotech windows we were considered upgrading too. We were feeling stuck on using double hung (which we love) vs casement (which we do not). But maybe we would have been swayed seeing them in person?
  9. Sorta related to that… I would have in some cases gone with the experience of the subcontractors (on paint brand choice) but in other cases, considered using a different contractor who had specific experience using an uncommon but greener product (OSMO Poly-X floor finish). So there are 2 alternate sides to the same issue of trying too hard to use a product that is maybe greener, but if it also gets installed wrong might mean expensive undoing or redoing. And “wasting” green ($) is not green! 🙂
  10. I said not to worry about custom house plans, but on the other hand, I will admit that it is a Very Good Idea to have it worked out ahead of time exactly where the HVAC ductwork will go. I think it is wrong to leave it to the contractors. Better to have it worked out ahead of time.
  11. I might have considered more seriously a “backwards saltbox” approach (we face south, so the long roof would be in front) since it would give more room for panels.
  12. I think everyone who builds a house feels this way, but there are definitely a few spots where I wish a light-switch or outlet was in a different spot. Our electrician did a great job helping us with this, but maybe there is a way to get this even MORE right. Not sure how without living in it first.
  13. OK, that’s a pretty short list actually. More as I think of it…

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Got Monitoring?

Our house has a few types of monitors at the moment:

  1. electricity use at the whole house and circuit level via a eMonitor**
  2. outside weather conditions (via a Onset U30 weather station) **
  3. inside temp/RH at 4 locations using Onset Hobo U12-013’s **
  4. inside CO2 at 2 locations **
  5. temps inside the HRV at 4 locations in the actual HRV **
  6. Fraunhofer used a very expensive I think infrared camera to measure the temp diffs on our walls/windows/etc on a cold day. I keep meaning to get a cheapo $30 one which will do the job well enough for my curiosity on windows **
  7. electricity use at all plugs via custom plug-in meters at every plug in the house ++
  8. hot water usage via a DLJ water meter (manually, not yet connect to anything logging it)
  9. overall electricity IN and OUT (manually at the iTron brand electricity meter outside our front door) — I think there may be a way to automate this with the eMonitor and ZigBee
  10. Solar PV output (via the Enphase website)

    During construction:

  11. the HVAC people used a digital manometer to help balance the HRV. I might get a pitot tube setup to look at this more closely.
  12. the Energy Star folks used a blower door test to figure out how leaky or tight the house is. (0.7 ACH50. Almost passivhaus)
  13. I have also used a Radio Shack sound level meter to measure dBA’s in figuring out what is wrong with our heat pump compressor outside.


  14. I have just added a very inexpensive Lacrosse WeatherDirect TX60U-IT setup that connects via ethernet to my router and will allow wireless temperature monitoring in the house and logging to the website. The u10 and u12 HOBOs are WAY too expensive. And I also want: 1) wireless and 2) realtime, not just logging and 3) totally handsoff — I want to just be able to click a link and see graphs! And to do that with Onset (or anything else I could figure out) would cost even MORE money. We are talking probably 10x what I think the La Crosse Weather Direct setup is going to cost. It maybe would be more accurate. But I’m not convinced that would even be necessary. Anyway, we’ll see how this works out. I’ll report back. BTW, if I didn’t need/want the wireless part, I would probably look into something like THIS but it’s still pretty expensive and I think more work to setup?

** by Fraunhofer CSE
++ by LBNL/Fraunhofer CSE

To what end?

Good question! I hope we can provide some information that helps people in choosing how to build or retrofit their houses in the future. At the very least I think we can provide some evidence that one doesn’t need to use a lot of energy to heat a house, even in New England, if you build a superinsulated home. And that it’s more comfortable than a typical house. (No drafts or big temperature gradients between rooms or between times that the heat turns on and off.)

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