Can you build a "green" house in the Adirondacks?

[mooregm]

Overall that's about what I'd build myself structure-wise, though I'd make minor tweaks like 2x6@24" construction with cavity & exterior continuous 4" foam from ground up to roof and down the other side. Using attic trusses gives extra "free" loft space that goes unused with normal ceiling insulation. Or vaulted ceilings if that is preferred. Here is a video of a guy doing it in Texas if you have not seen that method before. It creates continuous thermal breaks for the whole house except windows and doors. The double stud is similar, but obviously misses the roof, floor joists, and possibly foundation walls. Cost should be roughly the same.

https://www.youtube.com/watch?v=yTbMVdmnNlw

One major factor is the on-grid or off. I do not want a primary or secondary house that I need to babysit daily. It's crazy, but I think it actually costs me more to run my fireplace than use the heat pump when you factor in chainsaw, tractor, blower fan, leaked makeup air. That's with a better old-school non-gasification fireplace with dedicated makeup air from 40 years ago. On the flip side, there is a 6" hole and metal front conducting heat away 24/7. That said, we still do burn most Saturdays out of preference and an abundance of wood on-site. Doing the window coverings makes sense to the engineer in me, but that breaks my babysitting goal and also creates condensation issues if done from the inside. They had those in the Alaska videos I referenced above.

So if on-grid, I'd try to build a reasonably well insulate house geared towards a 5-day power outage -- namely pipes do not freeze for several days allowing time to get a fire/generator going if there is an extended outage. It makes no real sense design for 30-day stretches of winter and a true zero house in this case. Keep it simple with smaller tanks, less thermal mass, smaller solar array, smaller battery backup, perhaps a small propane furnace for backup when not in town when heat pump is out -- or with the new air source pumps when it's less than 5* outside.

If off-grid -- first I'd decide if this is a house or camp. If camp, then probably best to do as has been done for decades. Wood + Propane -- defeats your goal, but really makes no sense to spend $100k+ on off-grid panels/batteries/heat pumps/etc when it's only going to be used for ~20 days in the non-summer. No geothermal or water-radiant heating as it's too much of a liability. But if it's a camp today and home in 10-years, then that's even harder call to make. Personally I'd do whatever can only be done now (unused radiant tubes in floor, insulation, and wait to upgrade solar/batteries/heat pump later if it were to become my primary house.

If primary house, then I'd personally shoot for 7-days autonomy. Meaning no fire, no generator, no anything and the house will run for 7-days if starting from "full" batteries and thermal tank. Then on day 5 or so of clouds you can see both if batteries and tanks are low/cold and act if the forecast shows no real solar for next few days. Then start a fire to raise the buffer tank temp, thus shutting off the heat pump so batteries recover to get ahead of things again. Similarly you can take a vacation without worrying too much, particularly if you lower the thermostat buying extra days. I'd probably still do some extra things like insulate basement ceiling to create a second layer against freezing, and make upstairs pipes easy to drain when leaving in winter. Simple to do during building and pays dividends in 25 years when life changes.

So to answer your question on a post-construction "green" house. If grid connected, I think it's possible to get good enough without too much effort -- much better than the current practice of "net zero". At a certain point it makes more sense to not shoot for true zero and spend the extra money in far more impactful ways.

If off-grid, assuming you allow some burning of wood as "green", I think it can be done to a modern standard that my wife would not notice the difference -- my personal standard of success on our all upgrades. If you are trying to be "green", then wood should be a secondary source of heat via a gasification fireplace/boiler -- say with a design goal of less than a cord per year. That may not work in other regions, but locally we can easily find a cord of wood with just dead/dying/down trees if you own or have access to a few acres of property. That wood is turning to CO2 in a matter of a few years anyways while being fully offset by new growth. No fuel generator. But probably ~$100K in batteries and solar panels and the need for space to put them all.

Now if only I had bought the place on 7th Lake when the marked tanked 12 years ago...

[montcalm]

But if it's a camp today and home in 10-years, then that's even harder call to make. Personally I'd do whatever can only be done now (unused radiant tubes in floor, insulation, and wait to upgrade solar/batteries/heat pump later if it were to become my primary house.

This is the likely situation I'd be in. I'd though maybe it would be best to shoot for a camp now, home build later... but I don't know if I have two in me.

Thanks again for all the great information, lots more to learn.

I was kind of figuring if I'm going to invest the big money in a foundation, and I'd assume that's going to be a good portion of the budget, I'd spend the little extra and make sure I can upgrade how I like, even if maybe it's more than I need at the moment. Like I said earlier, seems like if you're gonna pour a slab, adding the radiant tubes isn't all that much more and way more of a PITA to try to add later.

Obviously the biggest factor is going to be availability of grid. I've seen many great lots over the years that were off-grid. A generator might be OK for emergency or the weekend in the winter, but no way do I want that going during the summer - I live in a noisy area, that's the last thing I want up there. Propane has always been on the list, and it may be for a reliable way to keep the pipes from freezing in winter while I'm away, and for a stove. I don't know that I'd invest in a propane fridge though, I had always been thinking go straight DC and solar for that. And other things such as pumps, etc...

I'm also firmly against the babysitting of the house. I figure if I have to purchase a cord of wood from a local, it's not the worst thing in the world. Even the most "green" of all the technologies has some impact to it i.e. batteries, pvs, concrete, blah, blah. If I start fresh I'd like to have a path to energy independence. But the reality of the matter is my minor decisions here probably don't amount to squat in the grand scheme of things, so it's really a matter of cost/efficiency/headache...

[John H Swanson]

A few points about recent comments to the thread:

If I was building a cabin in the woods I would do 2x6 construction on 24" centers. If I was building a house I would favor a wall construction with 2x4 vs. 2x6. 40 years ago my college professor said if you hire a framing contractor to build a house with 2x4s they will build that frame in no time. Ask them to do 2x6 on 24" centers and the whole project slows to a crawl and the price increases. I'm not a framing carpenter but it makes sense to me.

Concerning insulation: Rigid insulation is much more costly than other forms. Loose fill tends to compact resulting in very bad voids. Fiberglass stays in place better. And the best for staying in place would be sprayfoam. I still have some stuck to my fingers. /s I would probably still consider a 1-2" layer of rigid insulation over the outside of the house.

So this led me to the double wall 2x4 with fiberglass

As I believe I previously mentioned air inflitration (leakage) accounts for about 1/2 of the heat loss in a normal design house. A typical house has about 1 air change an hour, but this can be reduced to 1/2. That's a 25% energy savings.
As you go lower, you need to control the introduction of fresh make up air eventually with an air to air heat exchanger. In order to lower the infiltration losses, it was common to have a full plastic liner to the house with taped seams just under the sheetrock. Penetrations (like electrical outlets) need to be managed. Spray foam insulation applied after the electrical work is done might be a good solution here, but I dont know about the cost, and one should also consider the off gassing to be sure there are no health issues. I remember they had an issue with huricane relief trailers that were sprayfoam insulated. Alternately, I remember seeing an episode of "This old house" where they reported on a NH company, Bensonwood, that manufactured modular and kit homes that use a composite wall with insulation with a very high R value. Might be worthwhile looking into their practices.

The amount of energy used is directly dependent upon the delta T (difference between T outside and inside) If you lower the inside temperature you use less energy. This really only works when the thermal mass of the house is smaller and the temperature can be manipulated reasonably quickly or for a long period of time. Hence I favor low thermal mass in the heated area of the house. Then set up dedicated zones and heat them when you are in them. For this electric heat is easiest. Electric allows for the most easiest adaption of a green approach as you can implement solar, hydro, wind... and when/if we take climate change seriously the grid will convert away from carbon fuels.

[montcalm]

I'm not 100% educated on the subject yet, but I like the double 2x4 because your thermal break for the studs is on the interior rather than exterior. That seems a better solution for vermin who'll want to gnaw at it and burrow into it. Not sure about the builders - 2x6's are used in a lot of other parts of the construction, but people tend to do what they want. I may frame myself, so that's less of a worry.

Yeah - looking at the physics of the situation I'm totally sold on "isolating" and controlling the thermal mass. That's why the basement slab radiant is genius, IMO. It's just down there doing nothing - it has a lower delta T between the "outside" because the outside is the relatively regulated earth, and insulating will let it hold its energy even longer. It would gently warm the rest of the house through convection, but not enough I don't think that I'd cry about it - the upstairs (living area) is generally isolated - allowing it to be quickly adjusted in temps, although I'd shoot for tight regulation of 69* all year if I was there.

I don't like spray foam for a number of reasons. Number one is recyclability of materials in the future - not that anyone seems to do this but we could easily salvage entire frames of houses and rebuild them - coating it with foam that needs to be chiseled or scraped away is a guaranteed recipe for it going in the garbage. There's so many wood building products out in existence already it is almost getting to the point where we don't need a huge volume of new boards. It just so happens it's cheaper now to buy new, but maybe that won't always be the case. Anyway - I think we should think more about the ENTIRE product life cycle rather than just its short "service" period. That meaning, how do we recover and reuse as much of the material possible when we need to upgrade? Obviously for a home, I'm thinking out of my lifetime, but I believe these are the questions we need to think about when engineering something.

[John H Swanson]

I don't like spray foam for a number of reasons. .

I corrected my previous post. I thought Bensonwood used sprayfoam, but it uses celulose fiber. There's a youtube video about it.

here is an interesting site for ideas.

https://bensonwood.com/passive-house/

[montcalm]

Thanks John!

[Wldrns]

I built a new 'seasonal camp" on the western edge of the Adirondacks in 2019 (https://ncsbarns.com/homes-garages/custom-homes/). When I changed the design from a simple two story design camp to a different style with a vaulted kitchen/great room ceiling and a second story bedroom/loft, the price jumped by 10s of thousands, because of the NY insulation requirement for that style, I was told. it has 6" studs spaced at 24" with spray foam insulation on ceiling and walls, plus fiberglass insulation in addition over the foam. the interior is all pine wood board walls. The outside is half cedar log-look siding over Tyvek and real plywood sheathing. The basement is bare concrete floor and walls with spray foam on walls from the ceiling down to just below the ground level. I debated a long time over what kind of heat to install, propane (like most others in the area) or wood pellet, or wood with electric backup when I am not there. I decided on the latter, since I have heated my home with wood very successfully and economically ever since I lived at home as a kid with wood, and then for the past 40 years in my own central NY homes with wood (plus oil heat backup at home). I am surrounded by tall trees, although the front porch faces south and could support a number of solar panels.

The new high efficiency wood stove I researched and bought for the camp does a good job when I am there to stoke the fire. it takes a couple of hours to raise the cold soaked interior from 40 to a stable comfortable mid-60s where like to easily keep it. Camp is only 30 minutes from my home so I go there whenever the temperature is due to go to near zero or below several times during the average winter because I would rather cut wood in the summer than to pay NG in the winter for heat, even when set to 40 degrees. That works fine for now, but I know that philosophy will not last forever as I get older, so I know I will have to consider some kind of alternative heating method in the future. Maybe ground water or propane like the neighbors, if it is still still available by then.

[montcalm]

I think our state is going to make a big push toward geothermal heat pumps on new homes. I wouldn't be surprised if there's major subsidies into the future.

The solar ones are pretty damn good for this state. I calculated, best case scenario, I'd pay mine off in around 12 years. Worst case maybe like 15. Warranty on pvs I saw was 15 manufacturer and 25 year voltage output (for Panasonic). So I'd expect real life expectancy to be somewhere in the middle.

But this is all with current subsidies, which are making it economical ATM.

It's tough to say, I don't spend all that much on utilities currently, but less would always be better. I have a feeling if this catches and demand follows the sun, it'll be worth less if you're producing surplus, but I think it'll be a long, long while before we even saturate summer demand. Especially with moving to EVs - that's a huge electric load to add.

[Zach]

For me wood seems like the obvious choice for a few reasons. It's plentiful and local and cleanish, and especially cleanish with a new stove which meets EPA 2020 regulations. I've been burning wood since I was large enough to put it in the stove as a kid, whenever that was, and for the last 20 years with a gasification boiler, so I'm used to it. When I move I don't intend to go away overnight during the heating season, so I'll be there enough to keep the fire going. I plan to save my camping and any traveling for the warmer months when it's more comfortable, and to stay at home and work in the workshop during the colder half of the year.

[montcalm]

I'm kinda with mooregm on this - I think wood is great, for a secondary source. Or if it's just a seasonal, weekend kind of thing.

I'd burn a good deal in the summer just for "entertainment". Although I do enjoy cooking on wood when I feel like dedicating the time to it.

I'd also like to sugar, if I had enough land with some decent maples. Hard to imagine a place that doesn't have that in ADKs, but I suppose it's possible. Not for money - just for something to do in the spring. So I'd definitely use wood for that.

Other than for enjoyment factor, I have no real interest in the never-ending work of using wood as a primary heat source, especially in an older home. I grew up that way, and I don't miss it.

[fosterap]

Great informative dialog!

Hi, this is a great informative dialog! The collective technical know-how is way above my pay-grade. Regardless, for what it may be worth, below is some info and a few comments/questions about our ongoing climate change/energy upgrade project to a year-round, grid-connected ADK residence. We are firmly in mooregm's "good enough" over "pure net zero" camp. Goals: switch from fossil fuel use to efficient all-electric living, minimizing current use of grid power w/rooftop solar, followed by further greening over time as the overall grid greens.

Bought circa 1990 waterfront camp in the general Tupper Lake area, so we are at ~ 1,750 ft. elevation. A-frame vaulted main room w/south facing windows to lake and bulky fireplace w/chimney filling middle of room (1/2 story loft behind), wing w/small BRs and BAs to the west, fortuitously giving adequate south and sw facing roofs for solar, trees far enough from house to not be an issue, nearing end-of-life asphalt shingles. 1,500 or so sf living space on 1 floor, unfinished basement (concrete slab) and attached 2-car garage (ditto). Existing utils: 750 gal. UST feeding old oil burner, baseboard water heat in 1st floor living areas; unfinished basement and attached garage each have 1 old ceiling-mounted blower (over water pipes) for heat. No AC. Ancient (2!) connected domestic H2O heaters supplied from open-hole well of unknown depth. NatGrid electric. Septic w/separate grey H2O system discharging to a drywell. 1st fl. wall insulation is standard fiberglass covered by Celotex panels, A-frame ceiling is fiberglass; in wing, fiberglass sits on top of plywood ceilings in attic space. Camp empty for several years+ before purchase, so no relevant historical NatGrid usage info. Big ugly issue with "pet" smells, plus borderline hoarder situation. Inspection report identified ~25 fully "defective" conditions (and pretty much everything else "marginal" at best). Hoping for at least a little inspiration, my wife asked the inspector to tell us the "good news" about the house. "Well," he said, "the view is really nice." Funny guy. Yes, we like taking on projects.

1. Earlier this fall gutted down to studs plus some areas of pet-smell plywood flooring yanked/replaced, lots of work by us, contractor took over for hard stuff. Thank goodness the smell is finally gone.

2. Spray foam by subcontractor on A-frame and attic roofs. Used SES Nexseal closed cell spray foam to about 4-5". Should yield R factor to around 35-40, at ~97% effectiveness on curve. Local code enforcement will approve. Agreed w/contractor that spraying to 6-8" would only provide "marginal" additional benefit for much too high additional cost. I understand concern voiced above in thread re: overall foam life-cycle & recycling issues. Figure 30+ structure (and with luck, human?) life years after renovation, meanwhile immediate positive climate change/energy impact; new tech in 30 years will be different in ways none of us can accurately predict. Foam also adds structural strength for rooftop solar installation (see below). W/research, not concerned about off-gassing, just stayed out for 48-72 hours after application. Not formaldehyde like FEMA trailer issues. Be interested if others (after research) disagree. Regardless, too late now for us ...

3. Replaced the two old H2O water heaters with high COP Rheem hybrid unit. So far, only concern is hum/noise from heat pump (only when heating, otherwise silent), something we were aware of pre-purchase. Ultimately plan acoustic/insulated utility room in basement to hopefully mitigate. Meanwhile, before bed we just turn down H2O temp and turn off integrated heat pump, start up again in am.

4. Currently planning interior renovation (1st floor, plus much of unfinished basement and attached 2-car garage into living space), hopefully work done in upcoming spring/summer, presumably spilling a bit into the fall. Will include:

A. More, new, bigger windows! Especially on south and west, but even some on north and, even more insane, likely some through otherwise concrete block basement walls (south and sw sides only; north side basement is fully underground). On trade-off between light/solar gain and glass heat loss, for us there is clear winner. Newer windows are thermally much better, light/views are glorious, and that's why we chose to live here.

B. After new windows installed, will have walls including basement concrete block covered with the same spray foam insulation, thickness to be determined. Opinions welcome.

C. Empty and abandon in place 750 gal UST and replace with electric heat pump serving air ducts. Contractor pushed/pushing for radiant heat system below basement ceiling, but for us the added plus of AC tips the scales to air (ADK warming is happening with alacrity; already several stretches in high summer where having AC is really nice; who amongst you think that trend is NOT going to continue?!). Ducts to 1st fl. will be through floor. Still studying air-source vs. water-source heat pump, and getting quotes, but current thinking is go geothermal (would have to be closed loop vertical in new borehole; existing well is not adequate for both geo and domestic supply, and pond-source is off-the-table for many reasons). All contractors hereabouts have strongly pushed for propane (non-starter for us b/c fossil fuel), or cold climate air-source units as second choice. But, taking geo operating efficiencies plus various federal/state tax and credit programs into account, and everything else, the geothermal route is looking best for us.

D. Rooftop solar on south and sw sloping roofs will be added in 2022. Size not decided; have quotes between low of about 5 kw/15 panels to 15 kw/45 panels (would be a very tight fit). Installation in 2022 is important to meet current NYS 12/31/22 deadline for locking in net metering before VDER tariff hits. Leaning strongly toward largerish installation, especially because we plan to switch to EVs later this year or in 2023 at latest, and will provide local support/source for greater electric need for vehicle charging.

E. Speaking of EVs, we likely will not purchase/install battery backup for the planned rooftop solar system at this time. With NatGrid connection and net metering, we effectively will use the grid as the mother of all back-up batteries. The alternative would be an expensive battery that rarely gets used, given no time-of-use tariff/arbitrage availability (at least that's my understanding; someone in thread above described different night and day elec. rates; I'd be very interested to learn if that currently (ha!) is available here, didn't think so). Hopefully bi-directional use of EV car batteries will be implemented before too long, rendering many home back-up batteries obsolete). Meanwhile, we have a portable generator to run H2O well, heater, minimal essential circuits during very infrequent blackouts).

F. Yanked the old great room fireplace during demo. However, we will be installing a new, smaller, EPA qualifying wood-burning stove, primarily for enjoyment. We know/accept that it is a guilty pleasure, a terrible trespass of the fundamentally wise "don't burn anything" ethos. Downed/dead wood from the property will supply effectively 100% of our needed fuel.

Comments, questions, constructive criticisms, advice welcome!

[Wldrns]

As an aside regarding roof insulation...

My 30 year old home has a very thick layer of original blown in insulation above the second floor ceiling and good soffit ventilation above. I live in very heavy lake effect snow country. I have a noticeable difference in my heating needs, be it woodstove (as primary) or oil furnace (as backup and as adjunct when extremely cold) when the roof has a thick layer of fluffy lake effect snow compared to a bare roof in November-December before heavy snow comes. i do not have any melt or icing issues on the roof whatsoever. In some past winters I have gone on the garage and porch roofs with a shovel as a preventative measure to reduce the load weight of more than 4 feet of accumulated snow on those roofs.

[mooregm]

[QUOTE=fosterap;288421]

3. ... So far, only concern is hum/noise from heat pump (only when heating, otherwise silent).../QUOTE]

This was my #1 issue when we bought this house in 2017. So much so that I'm now crazy about motor hum/noise. I've worked from home for years, and it's beyond annoying to hear the hum of the geothermal heat pump + water heater heat pump + heat ventilation recovery system + fridge all day in an otherwise perfectly quiet house.

Our HVR was ~40 years old and the geothermal heat pump was ~20 years old. Fortunately and unfortunately the heat pump died in September and the new one is in-audible outside the utility room (and has an actually measured COP of 5! vs 3 from the old one). The HRV was so bad I stopped running it except on a 30-minute timer per day. Tore the old one out and bought a new one last month but have yet to install it. In 2017 I installed an air-sourced heat pump water heater similar to yours, and it was very loud too. I eventually had it run only at night and then this past summer I was not at all disappointed when it died. The new goethermal unit preheats our water in a 30gallon tank to about 95*-105* and then it's brought up to ~115* in the final 85 gallon tank, so I just use resistance element for that.

If noise is an issue, one massive change we made solved this unintentionally for us. We moved to time of use EV charing rates when we installed solar -- basically ~4c/kwh at night, but slightly higher than normal ~14c/kwh during day. We moved all loads -- heat/AC (thermostat setbacks/forwards), domestic hot water (timer), dishwasher (manual delay button), laundry (manual delay button), etc so they run between 11pm and 7am to take advantage of the cheap night rates. The unintended side effect of this was all the noise is while we sleep upstairs. You may be able to do something similar, but set it to be say from 5am > 9pm -- missing the critical first half of your night when you are trying to fall asleep or back a sleep.


Regarding geo vs air vs others. Geo is definitely better and Tupper regularly sees nights below zero. If easily installed, geo is always a great idea, but if you have to do vertical and such it may not be worth the hassle/cost. One thing to keep in mind is for close loop systems, the water in the loop come February is no longer around 50* -- it can be around 25-35* (glycol). That's why you will see two number in the stats -- one for open loop (our is always 53* year-round) and closed loop. Open loop have a the higher COP. To offset this and allow for one loop to fail, I would install extra tubing to offset this if doing closed loop, but with vertical that gets expensive fast. Personally it sounds like you may be a candidate for air source + propane backup (my choice b/c of grid failures -- parents have this) or air source + electric resistance (your choice) backup for when the temps plummet. With the air source water heaters remember you have to provide enough BTUs to heat the space and water. I think the key thing for you will be insulation. If possible think about insulating INWARD of the studs. Our vaulted ceilings all have foam board insulation between the drywall and studs. That makes a huge difference in providing a thermal break and given where you are at, should be trivial to install. Just offset the outlet boxes or add outlet extensions. As the snow melts, you can see exactly where there is not foam board -- namely a support post and interior wall -- otherwise we have no noticeable snow melting from interior loss.

Something you may want to watch below from John Siegenthaler. He is a local engineer, nationally a leader, who specializes in HVAC, specifically hydronics/radiant. He designed a ground-up system for his Daughter's house and goes through it here. It's technical, but really gets your mind turning on how to design an efficient system from end-to-end and why contractors are pushing for radiant heat. Given you have things down to studs, you certainly are in your now or never position.

https://www.youtube.com/watch?v=CVXGMuB8wlU&t=4552s

[mooregm]

D. Rooftop solar on south and sw sloping roofs will be added in 2022. Size not decided; have quotes between low of about 5 kw/15 panels to 15 kw/45 panels (would be a very tight fit). Installation in 2022 is important to meet current NYS 12/31/22 deadline for locking in net metering before VDER tariff hits. Leaning strongly toward largerish installation, especially because we plan to switch to EVs later this year or in 2023 at latest, and will provide local support/source for greater electric need for vehicle charging.

Here is what I did, and I think you have similar thoughts.

1.) Use the grid as a battery as you suggest -- I have a small battery/inverter so I can run the well pump without a generator -- but it is not economically rational to do large-scale batteries yet on-grid here. Changing the net metering laws is necessary to stop the free-loading, but when in Rome...

2.) National Grid has two components -- delivery and supply. I expect supply to be stable for the next decade as solar and wind grow creating continued downward pressure, but delivery rates keep climbing with no end in site and is the majority of the bill. EVs with both help and hurt this, so I'm expecting a wash. The more you can self-generate, the better as it's untaxed locked in rates.

3.) If going EV and heat pump, definitely get on the EV rate. One thing not well published is that net metering works within each block -- so with three zones -- off-peak (night), peak (day) & super peak (summer weekdays 2-6pm). For example, any solar credits created during say super peak can only be used in future super peak periods. This creates weird things -- such as we run A/C heavily during this time period while still back feeding excess to the grid. We get paid a few cents per kWh in the spring for the overage sent back (~$20 per year). Fair tradeoff for using the grid as a battery. We are nearly even with day-time peak annually. We generated with 27 325w panels/enphase 250w inverters 6,400 kwh and used a bit over that during the day time last year. This is with most of our loads shifted to night and excluding EV. NatGrid has two time of use rates available -- only the EV one makes sense.

4.) 75-100 solar panels would probably be what is needed for a single 12k miles per year car to net zero. We were quoted 54 panels to net zero without a car based on actual usage. A car@12k miles / year will add about 4000 kwh load or about 20 panels. Perhaps a bit more driving in the mountains and cold. So 54 + 20 gets to 75. We are 2600sq ft and not light on electrical use. The 54 turned out to be an undercount -- in reality it's probably closer to 65+25 due to inefficiencies.

5.) If you have any shading, particularly in low angle months, take any numbers provided with a grain of salt. Make sure any production quotes are based on actual location including shading. We are hitting around 80% of proposed output. We have shading and an 18-degree roof (4-12 pitch). Both were taken into account during quotes, but perhaps national calculators do not include that regular lake effect snow does not slide off. Similarly shading cuts in more than expected. You will have your own challenges I'm sure.

6.) Incentives -- NYS 25% caps at $5,000. So anything more than $20,000 does not provide any additional rebates. But that's your cost, so with NYSERDA rebates that go directly to the installer (if they still exist) allow you build a ~$22k system, which drops to ~$20k with rebate, and then 25% (state) and 26% (federal) for a system in the $9,500 range. That's where we ended up and if I were to do it again, I'd do the same.

7.) Run wiring now. No need to have ugly external conduit wiring. If going with Enphase -- it's just a few runs of normal 10/2 is needed. If going with DC systems, you need to run *metal* conduit. Install any DC inverters/boxes/etc inside the utility room. Outdoor temperature fluxuations is one reason these things die.

8.) Size -- this one is hard. But I'd suggest either "fill the roof" or hit the NY $20k limit. You will not be disappointed with either.

9.) Not sure locally there as schools/municipalities can opt in/out, but your taxes may go up. Our assessor adds 1/3 of total install cost. Fortunately taxes are generally cheaper per $100k in the ADKs, so this should not matter much.

Hope that helps. I'd just suggest that you do it right once, with a quality local installer where you can call the owner directly. Do not create a phase I / II approach with the roof -- that will cost far more in the long run.

Aside on Windows: "windows are thermally much better" >> This is actually not true unless you go with 3-pane windows or are comparing to windows prior to say 1980. My 1982 windows have the same ratings and my new 2020 windows. Frankly, they are all are equally terrible. 3-pane windows are great, but be prepared to pay 5x for them. I quoted both and I could not justify as there is a highly negative ROI. Also, to allow solar gain, you have to omit some of the UV films they put between the panes. We ended up with 27' x 5' of southern glass over 3 windows and one patio door, double pane, with a mid-range UV film. We were concerned about UV rays damaging internal couches/etc like we had happen in a boat a few years back -- no UV protection with presumably non-UV-rated pillows. Normal is I think 90% blocking locally, I think ours are 65% UV blocking. The best thing you can do for cost and efficiency is have fixed windows -- no opening at all. You have to ask for these specifically as they are far cheaper and most people do not want them. Can not be used in a bedroom as you need at least 1 window escape. They prevents air leakage, is very cost effective, and allows for significantly more glass and unobstructed views. We have normal sized east and west windows that open for the 10 days a year we do a cross-breeze.

[montcalm]

As an aside regarding roof insulation...

My 30 year old home has a very thick layer of original blown in insulation above the second floor ceiling and good soffit ventilation above. I live in very heavy lake effect snow country. I have a noticeable difference in my heating needs, be it woodstove (as primary) or oil furnace (as backup and as adjunct when extremely cold) when the roof has a thick layer of fluffy lake effect snow compared to a bare roof in November-December before heavy snow comes. i do not have any melt or icing issues on the roof whatsoever. In some past winters I have gone on the garage and porch roofs with a shovel as a preventative measure to reduce the load weight of more than 4 feet of accumulated snow on those roofs.

That's interesting. I mean I kind of would have thought that would be the case, but thinking critically about this, if the soffit is well vented, then technically there's very little heat exchange between the void and the outside via the snow. Any heat loss should escape via the fresh air exchanged in the vents and be consistent based on outside air temp.

My personal situation, at my current home, is we have a partial vaulted ceiling upstairs. There's probably a technical name for it, but as I see it, just a way to save money on building materials and still get a full ceiling height. Anyway, our vaulted section (about 2.5' in from the outside walls) was not insulated well, or ventilated well to the soffit. I had air channels installed, a new soffit vent and foam insulation installed in this area and it improved it, and probably noticeably improved the heating efficiency of the house. I also have a few more inches of blown insulation.

I can still watch the snow melt, but it's much, much slower (as one would expect, adding insulation to vaults doesn't stop the melting, it just slows it). There's still not enough air flow in the vents under the vault to keep an ice dam from forming, but as I said, significantly reduced.

Long story short, I would not recommend this design. Maybe if the rafters were taller. Whatever they are (2x6's?) are not enough space for adequate insulation and ventilation over a vault.

High, open ceilings to me see to be a trouble areas. If you can pack enough insulation and have a nice, cold air channel over that, then if could probably perform the same as well insulated, well ventilated attic space, but to me, that seems a bit of a challenge. Admittedly I have no looked to see what the current building specs are for something like this. Many of us are dealing with 60's technology (or worse) today.