What Is The Answer to the Ultimate Question ?

R42 *

That is If your question was how much insulation is enough?

If that wasn't your insulating question, how about:


How long will it take to pay back?  Click Here

Should I look into insulating if I did so already?  Click Here

How Green is it?  Click Here
Is Superinsulation for me?  Click Here

What is it's carbon content?  Click Here

How much insulation is too much?  Click Here

What are the carbon savings from insulating?
Is foam better than fiberglass or rock wool?  Click Here and Click Here

What about renewable and recycled insulations?  Click Here


Quick answer:

It depends….

… on so much it costs as much to figure it out as do it. 

Yet, knowing some typical situations, extrapolating from those and then shooting from the hip you can get a reasonable idea, especially for that big question, how much insulation do I need?  However, you, the "client" do know that shooting from the hip can we wildly inaccurate too – check out the Myth Busters Episodes for more on that.


Here’s the quick and dirty of what’s likely to work


You want your answer and you want it NOW!:  Click Here for a one size fits all retro fit insulation system 


Living on the edge: Easy answers to how much insulation you need:
  1. COLD CLIMATE: If you are in a climate that is really cold (or hot), 8,000 DD and up, a foot plus works.  Look into superinsulation and deep energy retrofits.  In hot climates, look into reflective "insulation" also.

  2. NEW BUILDING: If you are building new,  superinsulation, R40 walls and R60 roof.   4 inches of high density glass wool OUTSIDE your structural sheathing.  Dense pack cellulose between 4 inch studs.  Vapor barrier.  2 inch furring with all electrical and piping run in this space, packed with high density glass wool.  Code compliant insulating might run 6% of total costs $10,000 out of $250,000.  Super insulation $20,000 bumping the cost to $260,000, the mortgage payments by $700 a year, and save $1,400 a year over typ. min. code insulation.

  3. NO INSULATION: If you don’t have it, INSULATE.  In this order: attic (also cuts air infiltration), then air sealing, then walls, then foundation. No money?  Start with ANYTHING and add more from yearly savings.  Attic:  Start with 6 inches of batt insulation in two 3 inch layers laid with seams staggered to cut air leaking out of the house.  Might cost $1,000, and probably saves $2,000 a year.   Walls:  Blown in high density cellulose, about $4,000 by a GOOD professional, and save $1,000 a year.  Too much money, get just one inch of high density glass wool board, furr out the inside walls and cover with new gypsum board or even wrap in heavy fabric and velcro to the walls.  Either of these can run up to $6,000 BUT you can do one floor at a time, or one elevation (start with NORTH).  Even doing one room at a time will help save money, and make that one room ALOT warmer.  Foundation, see the frost proof shallow foundation system under the Catskills tab.   Another job that can be done over the years to save money. 

Note:  All calculations inc. DIY labor, double costs to high a GC.  See DIY notes below.

Anything else, the answers become fuzzy fast:


  1. Minimal existing insulation.  The bad news is the payback is probably 5 – 15 years.  The good news, fiberglass batt, the most common of insulating material is also the mostly poorly installed, so you aren’t as insulated as you think – making payback faster!  If you have “old” blown in wall or attic insulations, it may well have settled.  Attic:  Anything up to 20 inches of glass fiber, fiberglass or cellulose (Hire a pro) is justifiable.  20 inches ontop of 6 inches will payback in 3 - 4 years, costing up to $2,000 (pro blown cellulose maybe $3,000) and saving up to $1,000 a year.  Then move on to your foundation, see the frost proof shallow foundation system under the Catskills tab.  Between foundation and attic you are likely to cut your air infiltration over half, saving $200 and probably more a year.  Walls are the problem.  If you have settled blown in insulation, blow more in for $3,000 and savings of $500 maybe for a 6 yr. payback.  Otherwise, you are looking at a 15 - 60 yr. payback.  If your inside walls cracking old plaster that you hate, and you have the money, then 1 inch of high density glass wool covered with gypsum board INSIDE will run $7,000 and save $400 a year for a 8 yr pay back AND you get the walls you've always wanted - Priceless, eh?  You can do it one room a year, you’ll get there.  Otherwise, skip to air sealing, and add more attic insulation!

  2. Air sealing:  The low hanging fruit to save energy, yet not easy to find leaks, and may not be easy to seal.  Insulating your attic and foundation should cut much air infiltration by nearly eliminating stack effect. However, take a trip into the basement and see if you can find cracks between the foundation and wood sitting on it, spray foam it.   Don’t spray foam the whole rim joist (moisture and insect damage potential).  You can get a cheap smoke pencil and walk around on a windy day, see if you can find any big holes to spray foam into - not too much, don't want the wall to pop out from the pressure of the expanding foam.  You can caulk too, but if you have a breeze, you probably have a void, not just a crack, caulking will still mean cold air in the wall.

  3. Windows: Leaky windows, look into replacing failed weather stripping, take a piece to local home improvement stores, see if they have it.  There are also surface stick on "sweep" types.  Open cell foam - useless, decays in a year or two.  If building new, double glazing and maximizing south windows is all that is economically justifiable.  Double glazed windows with ½ a day of sun or more are net energy producers!  Don't spend $600 on a high tech window (as much as a wide screen TV!).  Save the money and buy a Heat Recovery Ventilator (will cost less than all the high tech high R windows) and save more energy.
  4. Siding?  Should I rip it off to insulate? Nooooo!  unless the siding is rotted and needs replacement.  Are you going to reside just so you can stop painting, then leave the old siding on, have insulation blown inbetween the studs, you'll get a discount because the installer can put on rough patches, after all, you are residing, then put 4 inches of high density glass wool over the old siding, a rain barrier, furing, and your new siding.  With that and 20 inches in the attic you’ve got superinsulation.  Siding job alone costs $10,000 and up.  Insul. adds $4,000 ($7,000 with blown insulation too)  but saves $2,000 a yr if you are un-insulated and $500 plus a yr if minimally insulated, 2 – 8 yr pay back times.  DO NOT reside JUST to insulate, payback 28 yrs.  DO NOT rip the sheathing off your walls so you can insulate between the studs – 15 yr payback AND you'll get a weaker wall with modern sheathings - really.     

  5. Deep Energy Retrofit – Minimal goal is reducing energy use 50%, which, isn't really all that hard, and can be cost effective with a 7 - 15 yr payback, even if you are already minimally insulated.  However, DER's are now code for ego energy trips.  What you generally read about are retrofits MINIMIZING energy use.  Superinsulation is always the first step, along with residing, re-roofing, new windows, heating system, PV system.... - which means, at least a 20 plus year payback time.

  6. DER – WHY DO IT?  Because the property WILL stay in your family.  Because you care so much about the environment.  Because you can easily live without the money it will cost – in which case you SHOULD do a deep energy retrofit.

  7. DER – PROBLEMS?  Yes.  Most deep energy retrofits rely on encasing the building in foam basement to roof peak.  Best method?  Nope!  Slightly cheaper for GC’s to build and professionals to detail, and both are familiar with it.  A DER is like an addict, addicted to foam even though it’s bad, and there are alternatives.  Click here for more on foam.

  8. How do you save energy, save money, and reduce carbon use if it’s not economical to add insulation? Collect solar energy!  This can be as simple and inexpensive as plexi-glass around your porch, using it as a huge solar hot air collector. The simple low cost solutions often provide the highest efficiencies and fastest paybacks too!

  9. Money = Carbon. Energy is a great proxy for carbon. Money is a great proxy for energy. Meaning, the more you spend every year on energy, the more carbon you produce. Spend half as much, you are probably producing half as much carbon.

  10. What’s the greenest insulation?  The only shortcut I know is if it’s made from oil, how on earth can it be green?  Sounds simplistic, but it’s true.  Rock Wool is massively energy intensive to make, you have to MELT ROCK, yet is still far greener than foam insulation.  If you’ve ever been on the Jersey Turnpike, you’d know what it takes to turn crude oil into anything over 60 miles of stinking desolation.

  11. Blow your own insulation at your own risk.  Density and wetting is vital to performance, and all too many pros get it wrong. Ditto foaming in blind cavities. You need to know the rules, be savvy to the tricks of the trade, and have the equipment, starting with a thermal imager, which are upwards of $1,500 for the most basically useful.

  12. If having insulation blown or foamed into blind cavities, withhold 10% until thermal imagery of the entire house is performed and missed voids filled, and imaged proving they are filled. No one is that good that they can get 100% of the blind cavities filled the first time. This will mean having work done in cool weather, so you get good thermal imagery. Or waiting 6 mo.

  13. DIY labor.  Double payback times if you hire a GC.  Luckily, insulation is the easiest of DIY jobs, and You Tube is full of how to videos.  Also, you’ll be the one emptying your attic and basement for the GC, and that is at least half the work involved, and I think the hard half.

  14. You should consider first getting an energy audit, for seniors and the economically disadvantaged look into government programs to provide these.

  15. All calculations inc. DIY labor, double costs to high a GC.  See DIY notes below.


In Progress:

Few can afford professionals, why?


It's possible to predict heat loss and gain accurately and easily, for new construction.  However, air infiltration, combustion and ventilating equipment, window orientation, and more materially effect heating and cooling.  For retrofits, much harder, on site testing is needed, and ideally, during cold weather.  Not just a blower door test and a 5 min walk around with an infra red camera.  A day, or two, if your basement and attic are chock full of stuff.   You are still shooting from the hip though.  To know with some accuracy you need a  building energy model.  It's really impossible to predict energy use, but to even make a good try takes several iterations / runs of the software and will cost the A/E about 50 cents per square foot, , to pay for an in house specialist or to hire a seperate engineer Why a seperate engineer.  GIGO, garbage in, garbage out.  For a house hundreds of data entries need to be made, for commercial building, thousands.(Add QA and O&P ontop of that).  

Instead we rely on contractors to provide “unbiased” advice.

Most do as well as they can. 

Which isn’t to say most do well. 


Corporate and political hype doesn’t help.  Both have been with every word so long that their word for it, “spinning” the truth, is now something every business person is expected to embrace to succeed.  So sad.  If you don’t have time to research the truth, you’re best off assuming EVERYTHING a corporation, politician, or government agency says is a lie.  You’ll be wrong some of the time, but right most of the time.


Finally, there are also the dishonest, which is why you CHECK references and use businesses that have been around 10 yrs, or you know someone who’s used them.


There are problems with the favored retrofit air barrier, foam, which is fast and thorough.  Foaming the rim joists can create moisture problems rotting the wood.  In the basement it will make it impossible to inspect the wood for termite damage and if it drips over the termite shield, provide a hidden path for them into your framing.


I’d try to leave the existing siding in place, to save money, and landfill space.  If you aren’t replacing your siding, then DON’T RIP OFF YOUR SIDING JUST TO INSULATE – again, 20 yr payback.


It might significantly add to the resale price of the property, certainly won’t hurt it.


Finding data, evaluating competing manufacturer’s claims and spin, is time consuming and difficult.  If you aren’t a pro who knows, go by instinct.  Imagine what it takes to make it. Such as, you grow it, mine it, harvest it or drill for it.  Transport it to a refinery, smelter or factory, then another, then to the construction site. At the site once it’s sliced, diced and incorporated into the building it’ll need tape, glue, screws and nails.  The wrappers and scraps tossed in a dumpster to go to the landfill, segregated on or off site for recycling, and transported to the dump or off for recycling. Also consider what will happen to the materials when the building is demolished.  Now, imagine you’re the worker at each step, which work environment would you prefer?  That’ll probably tell you which product is greener.  If you think, oil rig, oil refinery, Iccccccccck smelly filthy polluting places I don’t want to work there, yep, you guessed right, any insulation made from oil is always going to be among the least green products.


Yet foam has two big issues that could destroy your home, moisture retention and a home for termites.  Foam also has one way to kill you, fire and smoke.  Foam however is GREAT at trapping moisture to rot your house, and it’s GREAT at providing a hidden expressway for ants, termites and vermin into your house.  Relying on mechanical ventilation to solve moisture problems means a single point of failure.  Even if the GC puts in a termite shield through ALL layers of insulation and into the concrete foundation, that won’t stop the buggies from turning your foundation insul into useless swiss cheese unless complicated and expensive methods are used to wrap and encapsulate the foam. 
* (Google Hitch Hikers Guide To the Galaxy),
Foam Insulation 
Super - Insulation
 Nothing is that easy.

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For a ton of information on wrapping your building in foam.

Sustainability Pays 
Upfront where it hurts
the most, your energy bills.

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To see my savings from
my work to date
50% energy reduction
To find out why
Energy Conservation
can be a hard sell.

Insulation - 
Super Insulation
    What Is IT?
Quick answer -

Retrofitting Insulation
Everything you never wanted to hear about retrofitting insulation
Click Here   


Experiences w/

Old House Rehab


It is saving me the $40,000 or so it would cost to underpin the house, install a foundation and insulate it.  Nor would this have addressed the rim joist, a major source of heat loss.


For those concerned with vermin and bugs, termites, etc. in the skirt.  I've had one element in 3 yrs, in a vermin and bug heavy area, with only a few spiders taking up residence.  I suspect in addtion to being pretty well sealed, it's dry and foodless.


We have noticed that we no longer have ants invading the kitchen every spring, and flies infesting the area outside the kitchen in the summer.  There might even be fewer mice.


In addition, the boxout is a great ledge for planters at a real easy height to maintain, with the plants and flowers visible from inside.


I'm going to try some parsely and carrots that we can't grow in the garden, the moles keep eating them.


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