We bought our home a little over 2 months ago and are now working on improving what is a very poorly insulated house.

Towards the end is where I'm asking for specific advice, but anything that someone can add from the additional information would be helpful.

To start, the bad news...We are located the northern sections of the NY Metro area, so it gets pretty cold up here in the winter.  The house is a 2,500 sft ranch so there is lots of attic space into which to leak heat.  It still has only the original insulation of R-13 and in some small areas the insulation is missing and the ceiling drywall is bare.  Most of the master bedroom hangs out over open air and has only R-13 insulation sitting at the bottom of 9" joists.  It has a vaulted ceiling in the center of the house starting at a 16' square and narrowing to a about an 8' square at the top where there is a domed, single-layer, plastic skylight.  The drywall on this section stops just above the ceiling joists for the rest of the house with only insulation to block air infiltration to the attic.  While in the attic I could stick my hand into the house through the openings.

The basement is finished, but only half of it is insulated.  The insulated part was finished later and has what seems to be R-13 fiberglass in the space between the finished wall and the foundation.  The uninsulated part is older and has wood paneling on studs located about 6-7" from the foundation leaving a large area in between, but not large enough to get behind to do any work.  There is no insulation in the ceiling above the basement or in or near the sills or band joists.  (One section is large enough to get behind.)

There is no insulation in the space between the garage and the floor above.

The good...It has baseboard heat with 4 zones.  The previous owners replaced their boiler with a high-efficiency condensing unit: a Dunkirk 95M 150K BTU unit that is also used for hot water heating.

My plan is to seal and insulate the attic and gradually put radiant heat panels under the floor in various parts of the house and then insulating.

So far I have use 2x6s to close off the gaps between the vaulted ceiling and the ceiling drywall and then sealed the cracks with foam and DAP sealant.  I've replace all but 4 recessed light fixtures with ICAT cans and I'll do 3 of the rest in the next few days.  (5 of the units I replaced were basic remodel cans with huge holes in them.)  I don't think I can get to one as it is sitting under the A/C airhandler.  I'm in the process of sealing off other holes such as those around sewer-drain vents and a dropped soffit.  Once this is done I've located an insulation contractor to blow an additional R-40 of cellulose into the attic and wrap R-19 around the outside of the vaulted ceiling.

There are a few questions I had regarding what I will do after this.

1.  I can easily put R-19 insulation in the one section of basement where I can get behind the wall.  But can I have cellulose simply blown in behind the other sections and not worry about mold?  I had heard that the ideal method is to spray foam on the foundation wall and then insulate the walls with cellulose or fiberglass, but that would entail removing the wood paneling.  Not an impossibility, but enough of a chore that I wanted to know if the benefit was worth the effort.

2.  I want to remove the panels and insulation under the master bedroom and put in heat transfer plates with PEX tubing myself.  The floor opens directly into the boiler room so no problems there.  But I had a few questions regarding this.  a) Can I do this during the winter, or is PEX not something I want to mess with in the cold.  b) I was thinking of using extruded plates from a guy on ebay who seems to have it at a price about half of other retailers I've seen.  

I haven't done the heat-load calculations yet, but I'm not sure that even with the additional insulation above and below that I'd get enough heat in the room given that roughly 70% of the walls and 75% of the floor is against the outside and there is a glass sliding door in the room to the outside.  If it can't, can I (and should I) use the radiant panels as the primary heat source and the baseboard panels as a secondary for when the delta is really large?

3.  Can the boiler handle controlling the water temperature by itself or do I need to use a control panel help mix the water temp down?

I'm sure there are some things that I missed, but I figure this is more than enough to start.

Thanks in advance.

Hi Boazbez
I'm not clear on the ceiling/attic configuration, but increasing the insulation level there is a good idea. Will you be installing air channels next to the roof sheathing? Ideally they shoudl be sealed to the plate & roof with spray foam. Hopefully the insulatuion conctractor willl know about this. You shoudl also have ridge vents or gable vents to allow the moisture which will end up in the attic a way out.

The one area where you are definitely on the wrong track is the basement exterior/foundation walls. Putting fiberglass or cellulose againt concrete is a recipie for disaster - condensation, mold & rot. Best would be to glue 2" XPS (like Styrofoam) or Polyiso with the aluminum foil on both sides to the concrete. It should be sealed around the edges. You could then build a stud wall & put batts in that. The otehr thing you should do is spray foam the rim joist & sill where it meets the foundation & carry the spray foam onto the sheet foam. You can have this done or buy boxes of two part spray foam & do it yourself.

I'm not clear why you are going to radiant heat but be aware it may give you fewer BTUS in the room than the baseboard. You should be able to have your supplier do a heat loss calcs & help you with the layout. I'm not a plumber but I'm pretty sure the boilder won't be able to regulate the temps in your radiant heat floors.

Best way to insulate wood floors is with spray foam; 2nd best is fiberglass with 2" of EPS or XPS underneath, taped & sealed. Remember that the insulation will have to breath so don't install anything that will act as a vapor barrier.
Bob Irving

Before you insulate anything, KEEP AIR SEALING it to the best you can get then blower door verify it and fix all the rest or you'll be redoing it. For the basement you may want to spring for one of the 600bd-ft 2lb foam kits to seal & insulate the sill & band joist or have a contractor do it. But it sounds like you're on the right track.

If you don't put something against the wall that is mold-proof and at least semi vapor-permeable you're asking for mold problems. DON'T use foam board with foil or poly facers- it has to pass ground moisture vapor through the insulation into the basement to keep the sills from saturating & rotting out from below, or the causing exterior of the above-grade portion of the foundation to degrade efflorescence & spalling issues. You need to keep anything cellulosic (like wood studs or cellulose insulation) on the interior side of the foam layer warm enough to not condense moisture from room air in winter too. Cellulose insulation without the foam layer will eventually saturate with ground moisture, and studs without thermal break between the stud & foundation will form mold or rot. A combination of an inch or two of un-faced rigid foam against the foundation in combination with a batt-insulated studwall works. (Or go all foam, held in place with furring through-screwed into the foundation to hang the code-required gypsum thermal barrier on it. I used recycled R20 fiber-faced iso board on mine works great, takes about the same total depth as a 2x4 studwall would have, and delivers nearly 2x the performance.) Use UNfaced batts or blown fiberglass if you go with a foam + studwall approach, and at least 1" of XPS or fiber-faced iso, or 1.5" of un-faced EPS behind the studwall to keep the studs warm enough while still allowing the foundation to dry toward the interior.

After you're done insulating the place the Dunkirk will be about 3-5x oversized for your design day load. (My house in Worcester MA is about that size and not nearly as well insulated in the attic, has a MEASURED design day heat load of a bit under 30K. Yours might be lower than mine when you're done!) Your baseboard water temps on design day are also likely to be close enough to the radiant that you can use the same water temp & outdoor reset curve on all zones but it may short cycle a bit if any of those zones are small.

You can probably find days warm enough to do the radiant installation in winter, but I'm not an expert PEX-bender by any means. You can always tent it off and use a portable propane air heater to keep temps up in the work area. After it's up and pressure tested I'd dense-pack cellulose in there to affordably max out the R-value since you're looking at a significant delta-T on design day between the 0-5F outdoors and the likely 130F-140F PEX. (You might do it with 120F on design day, but I doubt it'll be as low as 110.)

Zone the radiant seperately, even if it's the same water temp as the baseboards it's response time will be different. Use an appropriate thermostat for it too, something that anticipates & self corrects the circulator or zone-valve's duty cycle. (PID algorithm or similar.)

Dana1:
If you are saying that moisture has to penatrate from the concrete wall through the foam layer, that is incorrect; but it is correct at the band joist. Thermax brand aluminum faced polyiso is the only foam OKd (in the currect IRC code book for use on foundation interiors without covering it with sheetrock or something else non flamable.

If the radiant heat is anywhere near the temp of baseboard heat, you'll cook the flooring & probably ruin any hardwood or tile above.
Bob I

There's a whole lot of science that disagrees with you on the ground moisture issue in foundation walls Bob. The ground moisture that creeps into the concrete has to leave it in the least destructive path possible.  For a synopsis, see:

http://www.buildingscience.com/documents/information-sheets/5-thermal-control/basement-insulation/

Do NOT use Thermax on a foundation interior as it will raise the moisture level of the concrete, and without a very impermeable sill gasket, it'll rot the sill.  In cool moist areas like Westchester County NY it'll cause efflorescence on the exterior of the foundation where above grade, as well as spalling from freeze/thaw cycles.

The boiler is a mod-con and can be run in outdoor reset mode to a programmed curve. The temp requirements of the baseboard on design day AFTER the insulation upgrades will be well below what it took to heat the place when it was a drafty barely insulated wreck. Assuming it was as high as 180F on design day before, it probably won't need to be even 150F now, and the average will very likely be below 130F.  Since the boiler will be raising/lowering the output temp, even if it had to go to 180F for an hour or so 5 times/year that will NOT destroy hardwood floors, contrary to popular myth (in MN they have to run 'em that hot fairly often, but we're talking much warmer NYC type weather.)  I've run my radiant constant-temp 140F for a decade (before I swapped boilers and insulated the place better) with no discernable issues with the wood.

There's no reason to run baseboards at constant-temp 180F with a mod con, even in an uninsulated wreck of a  house, even if 180 is necessary to meet the design-day heat load.  The average heat load on the coldest is generally less than half the design load, and that can be met with much lower temperatures, even with fin-tube baseboard.  When tweaking in a system after a bunch of envelope upgrades like we're talking here, start low, and raise the reset curve 5-10F at a time if it's not keeping up with the coldest zone until it does.  I'll bet the baseboard never needs to be over 150F after all of that, and unless the master bedroom has some HUGE heat loss factor like 100 square feet of single-pane glazing it'll make it survive just fine cycling 150F water on/off in heavy plates under the sub-floor. It's not the temperature of the water, but the temperature of the finish floor that will affect the finish floor, and it'll never have to be all that hot to deliver the heat once it's insulated. Again, this is metro NY, not Whitehorse Yukon.

I've included a JPG of a brief 3D sketch I made of the roofline.

The contractor will be building something to keep the existing air channels in the soffits clear and an air channel into the rest of the attic.  The roof is already well ventilated with new vents installed about 8 years ago with a new roof.  (The old one was destroyed by moisture that got in through by ice dams.)

<The one area where you are definitely on the wrong track is the basement exterior/foundation walls. Putting fiberglass or cellulose againt concrete is a recipie for disaster - condensation, mold & rot.>

On half of the basement I may have to live with it for a bit.  It's probably what's in there when I bought the house (2 months ago) and I can't afford a full renovation of the basement right now.  I'll keep it in mind for the future.

<Before you insulate anything, KEEP AIR SEALING it to the best you can get then blower door verify it and fix all the rest or you'll be redoing it.>

My problem is that a blower door test will still show tons of leaks as most of the air will simply run down to the basement and out those uninsulated wall spaces to the garage.  I don't have the resources to do everything at once and I'd like to get the attic done ASAP as it's probably the biggest loss right now.

<For the basement you may want to spring for one of the 600bd-ft 2lb foam kits to seal & insulate the sill & band joist or have a contractor do it. But it sounds like you're on the right track.>

Either way I'm going to have to pull down the walls in that section of the basement and then put them back up when I'm done. 

I'll wait to see what you guys have to say on insulating that section before I move forward.

<After you're done insulating the place the Dunkirk will be about 3-5x oversized for your design day load. (My house in Worcester MA is about that size and not nearly as well insulated in the attic, has a MEASURED design day heat load of a bit under 30K. Yours might be lower than mine when you're done!) Your baseboard water temps on design day are also likely to be close enough to the radiant that you can use the same water temp & outdoor reset curve on all zones but it may short cycle a bit if any of those zones are small.>

So there's still a risk of short-cycling on a condensing boiler?

I was thinking that the radiant wouldn't be enough for the master bedroom on its own.  I was thinking of putting a 2-stage thermostat on it with the radiant heat set as the primary and the baseboard set as the secondary for days when the radiant heat can't cut it on its own.  I want to keep the radiant temperatures low enough to make sure I don't damage the hardwood floors.  I wasn't planning on eliminating any of the baseboard units anyway.

Thanks for the advice so far.  Keep it coming.

What's the lowest modulation on the mod-con, and what's the thermal mass in the SMALLEST zone? You BET you can short-cycle a mod-con, and the more zones you set up, the more likely that becomes. This bit of analysis was looking at a larger facility picture, but the math works for boilers in micro-zoned houses too:

http://www.patkelco.com/uploads/files/4bf77cff8bc8411bb00c67e962d0ef7d.pdf

Mind you, whereas your design-day heat load may have been 60-80K when they installed the Dunkirk, there's a good chance it'll be under 35, or approximately the min output of the boiler, so it's not DISASTEROUSLY oversized, and with some tweaks can probably inhibit it from ever firing at max except for maybe when HW heater is callling for heat (it has some mass to it.) But your smallest zone is likely to have a design day heat load of under 5K, and less than 5 gallons of water in it. The boiler has less than a gallon of water in it, so yeah, unbuffered it's likely to short cycle. There's about a gallon of water in every 40' of 3/4" piped baseboard- count the linear feet. 8.34lbs/gallon x say 20F delta-T, how many BTUs is that? What's the flow on that zone? It may already be plumbed with a buffer tank, but if not maybe a single central buffer in series with the boiler return can build-in a guaranteed minimum burn independent of which zone is calling for heat. A competent heating system designer should be able to look over the system topology and figure out where/how to place the buffer and tweak the system for maximum efficiency once the real heat load (& micro-zone loads) are known (measured using system behavior, not estimated manual-J style.)

To do dual-stage reasonably on the radiant zone you may need the Tekmar 545 thermostat to keep the second stage from kicking on too soon. It's not cheap
(~$250 via internet sales.) With heavy plates you should be able to deliver over 30btu/ft^2 with reasonable water temps, more if you let it rise to 150F at the extreme on design day- just how lossy do you think that room is going to be? (If it's say 250ft^2, @ 30BTU per, that's 7500BTU/hr out of the radiant which is more than 1/4 of my whole home's design day heat load.) If you live in a glass bedroom, maybe...