Category Archives: house

Nailbase Insulation Panels for Deep Energy Retrofits

Ooooh. Didn’t know “they” made these. I assumed I could have a SIPs manufacturer make them though. Just didn’t know they had a name.

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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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Filed under about the house, erik-green, green, house

VS: home heating — heat pumps vs wood (or solar)

There are many in green circles — superinsulated/zero energy home/passivhaus circles — who think that heating with electricity (ideally with an air-source heat pump) is the ideal way to heat a house with solar electric (PV) panels on the roof (well, or yard). Example link

As someone with a house that is exactly that, let me chime in.

Heat pumps: PROS
1. No hole needed in house for exhaust or air intake
2. No air-quality or safety concerns since no burning of wood or fossil fuels in the house
3. Math is easy if you are trying to be net-zero. If everything is electricity, then there is no complicated math to do converting gallons of propane or cords of wood burned into KWh. (not much of a reason)
4. Now you have AC too. OK, so you saved a few bucks. Window ACs are only $80 though. And you house probably doesn’t need much more than one of those. Really.
5. No baseboards taking up space. But there are other approaches (forced hot air and such) to deal with that.
6. Quiet inside. Wow, very very very quiet. No furnace, furnace fan, or boiler making a racket. (Aside: And no humidifiers in winter… thanks to the tight superinsulated house part…)
7. Electricity tends to be price-stable vs the price of propane and heating oil which seems to whip-around a lot.
8. Usually a bit cheaper to install vs a “central” system esp in a very small house. But add in the price of the HRV or ERV stuff if you have that too.
9. Point source: I list “point source” below as a con too. Some like point source heat since it allows zoning, getting cozy by the “fire” and such. Flip side to everything.
10. Future safe. Electricity can come from many primary sources.

Heat pumps: CONS:
1. Can be a bit loud outside (well not LOUD, but there is a fan running, like for central air-conditioning, all winter) So if you are noise sensitive maybe there is a quieter heating approach? Not sure what qualifies as the quietest. Radiant floor heat?
2. PVs should not be thought of as anything more than an offset in my opinion. Don’t think of that electricity your panels made as yours. Who cares WHO uses it. The point is to reduce CO2/greenhouse gases overall. In other words, if you make electricity, dump it into the grid for your neighbor to use, and burn some wood to keep warm instead, then you are ahead (in my eyes) of someone using that electricity directly to heat their house with a heat pump.
3. In very cold areas, you will need either a HYPERHEAT model that keeps up with sub-0F temps, or some back up (maybe electric space heaters). Most other air-source heat pumps drop their output by a lot when it is VERY cold.
4. Power outages. You will have no heat. Now, that might not matter as much, because your superinsulated house has a certain amount of “passive survivability” built into it with all that insulation, but if we are talking comfort here, then grab a wood stove or a propane heater needing no electricity to run. There are a few!
5. “Non-traditional” Looks: Some might think they are ugly. I don’t mind them. Just different. And controls. Our Mr Slim one has a “remote” vs a traditional thermostat. And the model we got doesn’t control all 4 internal heads. So like a house with zoning, you have to walk around and set each individually.
6. Point source: We have 4 of these inside “heads”. One on a wall on each floor (basement, 1st, 2nd, 3rd (attic)) But there is not heat/coolth pumping into every last room. Doesn’t matter much, but bedrooms are a little cooler — 5F? Coldham/Rocky Hill study seems to say. Ask google.

Wood: PROS
1. Local
2. Carbon neutral
3. Ambience
4. Simple technology (especially if not pellets and not catalytic)
5. No electricity needed (heat when power outages)

Wood Stoves: CONS
1. Lugging stuff
2. Might be difficult to vent properly in a very tight house. Indoor Air Quality risk. Especially with a pellet stove which loses electricity.
3. Even the smallest pellet stoves will overheat some houses that are superinsulated. But big whoop. Run it on thermostat-mode. And open the window if you must!
4. Particulate pollution. You might live pretty near other people or in a town or city that prohibits wood burning.
5. Related… Gotta know what you are doing. (slow-burning, smoldering wood stove fires pollute like crazy and smell up the neighborhood.)

Solar Thermal Heating: MIGHT BEAT WOOD IF…
1. You have sun
2. You have a spot to put the solar thermal panels and a HUGE 1000 gallon tank in your basement
3. You have already done energy efficiency fixes — insulation, CFLs, etc. (see
4. CON: Up front cost is going to be higher than the wood (at least a pellet stove vented out the side of a house) unless you are a DIY person (see

Prius: PROS (W/holistically speaking, maybe this is a better place to start…)
1. Do the calculations in KWh. If you cut the number of gallons of gas you use in half by driving a hybrid or electric car, how much is that in KWh?
2. Energy Independence: coal and nukes (for making electricity) are “local” to the US, vs gasoline comes mostly from other countries. Propane is 90% from US. Natural Gas is ???
3. Use as a backup generator for house

So what would I do?
Well right now we use an air-source heat pump to heat our almost passivhaus ZEH. But I hope to do more solar-thermal heating in the future. 5 days of storage would get you to 97% solar “if cloudy days are like coin flips”. And the no-electricity propane heater is intriguing, especially for a little backup. Check back in a year!

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Filed under contrarian, erik-green, erik-VS, futuresafe, heating with wood, homesteading, house, HVAC, passive house, simple, solar, superinsulation, zero energy home

Under the microscope

We agreed to let Fraunhofer add little sensors to EVERY plug in our house. It’s a pilot program that Lawrence Berkeley National Laboratory is running Miscellaneous and Electronic Loads Research. It will report usage every 10 seconds from every plug back to the interweb via UDP

I am trying to imagine what useful information could come out of this for the greater good, and I can’t quite come up with anything. Perhaps they will be able to use the detailed data to disambiguate data coming from a single smart-meter on a house. (like Google Powermeter) In other words, being able to tell “oh, that’s the fridge coming on” vs “oh, someone turned on a light” or “that’s the dishwasher”. Who knows.

On a personal level, I probably won’t learn anything… but that’s totally fine, I am happy to help! I have pretty much figured out anything I wanted to know via a Kill-a-watt and the eMonitor/TED 5000 approach of “circuit” level monitoring.

I suspect it would be better to “follow the money”. I bet people (in New England at least) spend a lot more heating and cooling their house than they do on phantom loads from electronics and leaving lights on.

Both are worth doing I guess. Like Gary did with his “half” plan.

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Build Tight. Ventilate Right.

When we built our house we decided to have an Energy Star rater calculate the HERS score for the house (11 was it? 12? Not that I verified that they used the right numbers for our insulation, etc, but OK, not bad.) And part of the Energy Star Homes process is that a blower-door test is done to determine how leaky the house is. Since that’s the other way one can lose heat/coolth from the house. Not just thru walls and windows and doors, but from actual airflow thru all the cracks.

Well anyway, our house is quite tight. It was 200 CFM50 which works out to

200 CFM50 * 60 min/hr / (2310 sqft * 8.2 ft/floor) = 0.63 ACH50 (air changes per hour at 50 pascals)

I don’t know if I’m using quite the right volume for the house (that’s 2310 including basement) but if so, that is JUST shy of the 0.60 ACH50 needed for Passive House certification. Nice. We’re probably a bit worse than this, but really, I can’t complain given we are using mostly double hung windows and double hungs don’t seal up as nicely as casements.

It was the tightest house the Energy Star person had tested in 10 years or so of blower-door testing. I believe our house is apparently what is called a “Tier 3” / “Tier III” certified home for Energy Star Homes.

In New England, I reckon we are one of about a few dozen or so such energy efficient homes. Something like that.
Here’s a list I am compiling. More at the Green Buildings Tour website I am sure.

Ventilate Right

The idea of Building Tight is that it is actually better for
– durability
– indoor air quality
– saving money

Durability: fewer mositure/mildew/rot problems because there is little concern with
1) moist summer air driven from outside to in
2) most winter air (since outside is very dry) being driven from inside to out.

Indoor Air Quality: Instead of relying on leaks in a closed up house (in winter or summer) to provide fresh air, one can bring in exactly the right amount! And filter it to your heart’s content! And put it right where you want it!

Saving Money: The idea is this… in the winter for example: instead of 68F air exiting the house and 25F air coming in…. thru leaks… one can instead use an HRV (heat recovery ventilator) which is essentially a fancy air-to-air heat exchanger. The incoming and exhausting air cross paths in a fancy cross-woven area and 60 or 70% of the heat that would be normally lost is recovered and plunked into the incoming air. Clever! One has to factor in the cost of installation and running the fan, but the fan costs almost nothing, and the control over the IAQ and durability is worth it.

Some others recommend slightly different approaches:
– not building QUITE as tight (but still 10x tighter than a typical house)
– using Panasonic Whispergreen bathroom fans on timers or humidistats or CO2 monitors to do “exhaust only” ventilation.

Lots more on this topic over at — free blogs and Q&A sections. I sound like an advertisement I know. Sorry, it’s a very helpful site!

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Filed under erik-green, house, passive house, superinsulation, zero energy home

our electricity bill skyrockets!

After recent monthly electricity bills of $0.68 and $3.61 (or whatever the exact numbers) this month the electricity bill went WAY up. $26.21!!! We still had quite good numbers on the PV production side, and didn’t use much, but since there is no net-metering (our electricity supplier is a municipal and so is exempt from the MA law requiring that electricity companies allow net-metering for grid-tied PV and wind systems. I’m not really complaining, just explaining.

So anyway, our billing is “time of use” so any time the sun isn’t shining and we use electricity, we pay for it full price whereas when we have extra on sunny days that we put back into the grid, we are paid back for this on $0.44550/KWh (roughly 3 or 4 times less than what we pay).

So that’s basically how we end up with a $26.21 electricity bill even though we put 571 KWh back into the grid and only used 381 from the grid.

If there was net metering I suppose our bill would be something like:

571-381=190KWh extra made, so…

Min charge from the electric company is: $21.63
– 0.15 x 190 (the rough amount paid per KWh is 15 cents)
= 21.63 – 28.50 = -$6.87 (credit)

I guess one could calculate the amount this will likely add up to over one year. Rough assumptions:
1. Exactly net-zero for the year
Our PVs make exactly the amount expected from the “avg year” from the “PV Watts v1” calculator on the web (I believe it is ~9000KWh for our 6.9KW PV system)
2. Worst case scenario: we use exactly 0 KWh of our electricity we make during the day — everyone is away and somehow the house magically uses nothing in phantom loads (impossible since the smoke detectors have to run at the very least!) — and therefore we have to buy 100% of our electricity (at night).

If net-metering, our bill for the year would be exactly $0.00. Simple.

With our current arrangement it will be (worst case) per month: $21.63 + 0.15 * (9000/12 – 200) (Note: -200 since 200KWh are included in the $21.63 monthly base charge and we will likely always use at least this much in eves)
= $134.13

That’s per year = 12 * 134.13 = $1609.56

In reality it will be much less than this because we DO use a lot of our electricity during the day. So let’s say 1/2 that… $800.
$66 per month.

And that’s for everything, heating/cooling (heat pump), all appliances, cooking, hot water (also heat pump), mowing, well pump, etc, etc.

Anyway, I’ll report back in a year with the actual numbers.

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Filed under erik-green, house, solar, zero energy home

Michael Marquis Finish Carpentry

Review: Mike Marquis is the finish carpenter who did the finish work on our three flights of stairs in our house in Stow, MA. He also installed our kitchen cabinets. He is a meticulous craftsman! I could imagine it might be difficult to find good people who do good work so here is my advice: Highly recommended! Mike works in Massachusetts, the Boston area, and in Southern New Hampshire on a variety of projects and I would highly recommend you consider him for any type of finish carpentry work including custom projects. More at his website: michael marquis finish carpentry His phone: 603-759-1198

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