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where2 10-21-15 10:37 PM

Where2's Whole House Retrofit?
Project: Single level ~1200sqft Ranch home (over 100% unfinished 7' basement) at 45.8N (Northeastern Maine),
Elevation: 580' located on a ridge open to the prevailing west winter winds.
Year built: early 1970's.
Walls: 2x4 16"O.C. with R7 foil faced fiberglass. Holes drilled for wiring are unsealed through the bottom and top plates of walls.
Exterior: Masonite lap siding over tar paper. I think there's 3/4"x6" or 3/4"x4" horizontal planks as sheathing.
Windows: Combination of single and double pane, several 4'x8' expanses are original wood frame units with after-thought double pane exterior panes installed (unsealed). Most bedrooms have been upgraded to modern vinyl double pane double hung units (possibly 10 years old).
Ceiling: 9"x9" ceiling tiles are hung on 3/4" wood framing with visible gaps between the wood.
Attic: Framed on site rafter system with (at most) 3.5"-5.5" of insulation above the 9" square ceiling tiles. I can see every ceiling truss peeking up between the existing batts of insulation in the attic.
Floors: zero insulation between habitat and unfinished basement.
Basement walls: Poured concrete; No existing insulation. Earth bermed against 70% with 1' above grade showing on 3 walls, 4th wall (25x7) open walk-out with very poor fitting site built door. The basement vent openings have been poorly sealed with wood. (improper and inefficient venting in summer, not a wet basement, but certainly damp in summers with no ventilation).
Basement Floor: 90% dirt, 10% concrete (where the previous owner played pool on a pool table)
Roof: Metal (PBU Profile, appears to be standing on purlins)

Climate info:
Plant Hardiness Zone: 4a (Average Annual Minimum Temperature -25F to -30F)
Average annual snow fall: 94"
Average annual rainfall: 45"

Heating System: NY boiler (oil fired, installed 2012), baseboard radiators in every room along exterior walls, except forced air radiator (toe kick) in kitchen under sink.
Cooling system: Open windows, use ceiling fans.
Domestic hot water: provided by boiler system, (serves: laundry, one bathroom + kitchen, no dishwasher).
Available energy sources: Grid electric & tanker delivered petroleum products. No plumbed gas available.

Solar resources: single solar obstruction in late afternoon (after 3PM) from twin trunked pine tree. Roof ridge runs ~25 north of west. Roof is 5/12 pitch. Additional winter (Nov-Jan) solar obstruction from nearby 24x40 gambrel barn southeast of house. Once barn is rehabilitated, might consider using it as additional solar mount, presently unsuitable to mount solar array. Considering the latitude of this property, I don't consider the shading from the barn as a serious loss of energy. Winter is a tough time to collect PV. I neglected to perform a solar sky view plot.

General rennovation comments: Most flooring materials have been removed (down to particle board sub-floor). Many of the rooms may have the wall materials (paneling/drywall) and ceiling materials removed during the renovation process in an attempt to rid the house of smoke odors from previous owners. Opening the walls also affords the opportunity to seal and add insulation where needed. Absolute comfort in the dead of winter is NOT an absolute requirement. Plenty of basement space available for solar thermal storage system. 50'x200' shallow pond (less than 6' deep) approximately 450' from house. Upgrades will include a 4.6kW solar array.

Things I'm considering: multiple high-efficiency ASHP units to provide 3-season heat and minor cooling in summer (there were nights in September when we needed heat, and others where we wished we had A/C!). ASHP water heater definitely on my list to dehumidify basement and create hot water, because running the oil boiler in the summer seems silly. Mooney Wall upgrades to exterior walls. Removing the baseboard plumbing and running PEX under the floors for radiant heating.

Other thoughts: Trenching >400' across the farm field to get to the pond to utilize it for GSHP seems rather extreme. However, I note that the pond is there because many many ecorenovators would LOVE to have a pond as a potential GSHP resource. Pond elevation and basement floor elevation are within 20 feet of each other.

Soils: Loamy with shale type gravel; an occasional large granite chunk and occasional shale or granite ledge. Haven't probed it to see how deep the ledge is between the house and pond, but suffice it to say that ledge is common in this area. The pond maintains constant water level year-round. Tap water pumped up through the well serving the property was providing 52F ground water in early September.

Random Comments: Neighbors with ASHP's (Fujitsu Halcyon systems) LOVE their ASHP's. The East side of the house where the basement wall is exposed would afford the most "height" above snow in winter. However, I question whether a 1200 sqft house could be efficiently heated (or cooled) with a single ASHP.

Goals: well sealed, energy efficient "three season" house with functionality to be liveable in "dead of winter" if we ever decide to visit during winter.

After reading through ecorenovator build threads for years, I have come to the conclusion that rather than embark alone on my own idea train and ask for help fixing problems I encounter later, I should probably just toss the raw project out for ideas before I really get going. I'm really thinking Mooney walls while I have the drywall down. Years of drafts blowing through the house have pushed soot into every nook and cranny of the house walls. In a location that sees -25F winters, R-7 fiberglass doesn't seem nearly enough! Several inches of spray foam over a mooney wall to avoid thermal bridging seems like a good start, then more insulation in the attic over the trusses.

What would you do?

Daox 10-26-15 12:05 PM

I would suggest working on sealing as much as possible with the open walls. After that the mooney wall is a great idea IMO. With that you should be sitting pretty good, probably worlds better than most of the other houses around you.

JRMichler 10-27-15 08:17 PM

If I wanted to insulate an existing house once and for all, here's what I would do:

Dig down to the footings. Redo drain tile if needed. Add 4" Styrofoam to the outside of the basement walls, 6" if I was really ambitious. Seal all openings to the outside. Backfill. Your basement will now be warm, so will not condense and turn into a swamp in summer.

Dig out the basement floor. Add 4" foam, then concrete on top. This step can be done any time.

Strip off the siding. Add 4" or 6" polyiso (foil face) to the outside. Caulk/foam and tape all joints. Stagger the joints. Add vertical strapping, and new siding.

Frame in the window openings, and install new efficient windows centered in the foam.

Go into the attic. Seal all openings to heated space. Then strip out the insulation, and have a foam contractor foam everything with at least 1" of closed cell foam. Then blow in two to three feet of blow in insulation.

That should get the heat loss down to less than 15,000 BTUH at -20 deg F outside AND make it completely comfortable inside. Even at below zero temperature with a howling wind.

Your problem will then be how to find a heating system small enough to properly heat it.

AC_Hacker 10-28-15 02:19 PM


Originally Posted by where2 (Post 47579)
Removing the baseboard plumbing and running PEX under the floors for radiant heating.

If there is any way that you could put your radiant system on top of the floor rather than underneath, you will have much better efficiency.

There are lengthy discussions here on EcoRenovator about this.

A 1.5" Gypcrete floor with PEX works well.

Also, a built-up layered floor with aluminum spreaders is great.

If you must put your PEX under the floor, it should be directly in contact with the floor, and you should use aluminum spreader plates.

Do not use 'suspended PEX'. It's easy, it's cheap, is really, really inefficient.



where2 10-29-15 08:27 PM


Originally Posted by Daox (Post 47638)
With that you should be sitting pretty good, probably worlds better than most of the other houses around you.

That is precisely where I'd like to end up sitting with this property. This structure is not particularly "bad" construction, it's just obvious it was knocked together in a limited amount of time on a limited budget to serve a purpose. Efficiency does not appear to have been considered.


Originally Posted by AC_Hacker (Post 47680)
If there is any way that you could put your radiant system on top of the floor rather than underneath, you will have much better efficiency... Do not use 'suspended PEX'. It's easy, it's cheap, is really, really inefficient.

To clarify, when I said "Under the floors" I really meant installing PEX with spreaders on top of the existing particle board subfloor, then installing hardwood flooring on top of that. (Similar to Daox's office retrofit) A PEX staple up install using spreaders in the basement would be quick, but since I have the flooring removed in the main living room, and all three bedrooms, it seems better to put the PEX closer to where I want the heat.

Regarding that "suspended PEX" inefficiency, I noticed walking through the house in socks that I could tell where the copper pipes to the baseboards were suspended in the basement below. You guessed it, NONE of the baseboard heating pipes are actually insulated.

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